STUDY (APIOS) A4 p 5 ISSN 0824-880X ISSN 0835-4456 ACIDIC PRECIPITATION IN ONTARIO STUDY (APIOS) ANNUAL PROGRAM REPORT 1989/1990 Report prepared by: The Acidic Precipitation Office Ontario Ministry of the Environment APRIL 1991 oe LU IMPRIMÉ SUR DU PAPIER RECYCLE Cette publication technique n'est disponible qu'en anglais Copyright: Queen's Printer for Ontario, 1991 This publication may be reproduced for non-commercial purposes with appropriate attribution PIBS 1534 hy Table of Contents LIST OF FIGURES LIST OF TABLES INTRODUCTION ATMOSPHERIC PROCESSES STUDIES A. Emissions Inventory B. Modelling C. Deposition Monitoring Network D. Oxidants Strategy Development E. Meteorological Studies AQUATIC EFFECTS STUDIES A. Chemical Studies Calibrated Watersheds Calibrated Watersheds Metal Contaminants Extensive Lake Monitoring B. Biological Studies Algae Zooplankton Invertebrates Toxicity Studies Biological Survey Biological Monitoring Metal and Organic Residue Monitoring MNR Fisheries Acidification Program MNR Wildlife Studies C. Remedial Methodologies Development The Acidic Lake: Bowland Lake The Endangered Lake: Trout Lake Summary and Conclusions Table of Contents TERRESTRIAL EFFECTS STUDIES A. Vegetation Studies B. Soil Studies C. Forest Productivity and Decline Studies D. Terrestrial Wildlife Studies BIOGEOCHEMICAL STUDIES Mineral Weathering Studies Soil Studies Bioaccumulation Studies Hydrological Studies Wetland Studies Watershed Manipulation Experiments HIHI Oe ENVIRONMENTAL MANAGEMENT AND ECONOMICS STUDIES A. Damages and Benefits B. Costs of Abatement and Mitigation LABORATORY SUPPORT AND METHODOLOGY STUDIES A. Interlaboratory Comparison Analysis B. Analytical Methodologies ABATEMENT LEGAL INITIATIVES COMMUNICATIONS INITIATIVES Ontario United States APPENDIX I International LRTAP Projects - MOE Co-funding International LRTAP Projects - MOE Participation APPENDIX II APIOS Related Technical Reports, Data Reports and Submissions APIOS Related Publications/Papers List of Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18a Figure 18b Figure 19a Figure 19b 1988 Ontario Base Year Emissions for SO,, NO,, VOCs 1971-89 Ontario Total SO, Emissions CO, Emissions by Sectors Modelled vs Observed Concentration of Total Nitrate in Air Modelled vs Observed Concentration of Total Nitrate in Precipitation Regionally Averaged Daily SO, Concentrations Regionally Averaged Daily Sulfate Concentrations Comparison of Sulfate Concentrations in Rain Sulphate in Air at Dorset Sulphate in Precipitation at Dorset Nitrate in Air at Dorset Nitrate in Precipitation at Dorset Average Annual Wet Depositions of SO, (kg/ha) 1981-86 Percentage of Lakes Sampled in Each Part of the Province Total Sulphur Deposition Zones (1983 data) Lake pH in Relation to Sulphur Deposition Change in Fish Communities Due to Acidification Trend in pH in Bowland Lake Trend in Alkalinity in Bowland Lake Trend in pH in Trout Lake Trend in Alkalinity in Trout Lake ili List of Figures Figure 20 Figure 21 Figure 22 Growth Rates of Lake Trout in Trout Lake Compared with Other Nearby Lakes Sugar Maple Growth Across a Pollution Gradient in Ontario Laboratory Workload Summary 55 List of Tables Table 1 Table 2 Table 3 Table 4 Table 5 Table 6 pH Above Which 95% and 90% of Ontario’s Sensitive Lakes Will Remain For Specific Sulphate Deposition Rates Estimated Number of Sport Fish Lakes in Ontario Affected by Acidification Summary of Classification of Terrestrial Sensitivity to Acidic Deposition in Ontario Legal SO, Limits for the Four Countdown Companies Ontario Hydro’s Acid Gas Limits Estimated 1989 Emissions 22 32 43 sl 58 58 Last ( ‘ques ; goldal te agp" ; HQE à oman à 25 oR? bar RTE SOA ss ech i eendel amis os? wl pine AN Wen dal : as «jan à Pollution Cet ain Loos (1 esi ai nogd to om oF | Sn ir | Sri vd ive? laitizeroT Io pole 16 ne ae - : onminO dl polis] aha. VF. slanted néon: ort alt wo? LL Oe ingat: di ui à am) hisA s'edivH pif a? woleclnil Se Semel Introduction In the mid-seventies, results from the Ministry of the Environment Sudbury Environmental Study and _ Lakeshore Capacity Study demonstrated the importance of long range transport of acid rain precursors and the negative impacts of acidic deposition on the environment. In 1979, the Acidic Precipitation in Ontario Study (APIOS) was launched to further study and document the effects of acid deposition, and to implement an effective abatement strategy. APIOS operates on a 5-year planning cycle and the second five year plan (1986-1990) has been completed. A third five year plan (1991-1996) has been developed and includes global warming and air toxics programs. The APIOS program has four major components; scientific research, abatement, communications, and litigation. The APIOS Office is responsible for the co-ordination of these components within Ontario, at the federal level and internationally. The Office also provides administrative support to the APIOS program and has been involved in coordinating the review of a green paper on global warming and providing input into the Environmental Assessment review of Ontario Hydro’s Demand/Supply Plan. The scientific research component is divided into six tasks and its programs are developed and implemented through six interbranch or interministerial working groups. Task 1: Atmospheric Processes Studies Task 2: Aquatic Effects Studies Task 3: Terrestrial Effects Studies Task 4: Biogeochemistry Studies Task 5: Environmental Management and Economics Studies Task 6: Laboratory Support Services and Methodology Studies The credibility of the scientific research is assured by a documented and operational quality assurance program. Ontario’s research and emission control efforts are coordinated with other parts of Canada and the United States since the solution to the long range transport of air pollutants (LRTAP) requires action by all jurisdictions. The APIOS program does not have a health effects or materials damage component as these are addressed by small federal specialist groups on a Canada-wide basis. The APIOS Office endeavours to keep abreast of developments in these two areas and ensures that APIOS technical support is provided when needed (e.g. deposition data). This report will describe the programs and provide accomplishments and major findings in the six scientific work groups and provide background on APIOS abatement, communications and litigation initiatives for the period April, 1989 to March, 1990. Appendix I provides a summary of international LRTAP projects with MOE involvement. 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BOUT 0 aoa In aviary) Qosmio aol Aan Wal feed 0, Hi orme "nt LT emi & Esdivorg. | Mo À HOM tiftw oston “té PCT (ui leg ap Tehivety i stood itty al otrnigey Lith ay to pad Lan OI hn: xi moti elite asic udigé secret a $a" rodssdns fa veer fl manage ut) bintenaertly i nim. ioe WW Boat - à bios Mars conl Nan er ott OT!) 9 mens en von? oh Al Di os vhs rlrast ut buse ail Lite niiiles yt Ui do et rm fit 2193404 1007 @ 10 Siege nly weal? bates get bad! A teva age aed asi! “ai 14. fUGE bus gahoww induite Wen oi ef tarantir divtacist CHAR aT roy til Gym 1 equtgiibe-o, so) ARR ati dù jars! iw 40 onl | enero. ‘a Of Eutyqué SU uf al eviews neod add pes ho Tope tty à te WT aly ef dia fsa ia get arta Nyvralurt a > SN natty Ta Ca = traine immo ge Loqolaval #2 ati a À na danetdneart 1: duré de AU Quid wr lunre eso ia Phils Moot vi eis +00 NE Atmospheric Processes Studies (Task 1) Contact: D. Yap There are five subtasks in the Atmospheric Processes Studies program: Emissions Inventory, Modelling, Deposition Monitoring, Oxidants Strategy and Meteorological Studies. A. EMISSIONS INVENTORY The compilation of statistics on the production of sulphur dioxide (SO,), nitrogen oxides (NO,) and other pollutants serves several purposes: a. trends in emissions of acid producing gases are determined and matched with changes in deposition patterns; b. detailed information on SO, and NO, and volatile organic compounds (VOC) emissions by geographic location is provided and required by all of the atmospheric models; c. knowledge of the location and magnitude of emission sources is obtained which is essential in planning cutbacks of acid gas emissions. The Ontario Acid Rain Emission Inventory has achieved its goals to include other pollutants such as ammonia, alkaline dust, cadmium, arsenic, manganese, and iron during the period 1986 to 1990. In order to maintain a consistent emission methodology, the standard EPA Source Classification Code (SCC) coding system was adopted to facilitate the breakdown of VOC species and analysis of Ontario, Canada and U.S. emissions during FY 89/90. The 1985 base year, previously updated with Mobile 3C (Canadian version of U.S. EPA transportation model for vehicles) factors for the transportation sectors, was revised in cooperation with Environment Canada using the latest factors of Mobile 4C. Improved information on solvent usage was also included. Figure 1 provides the most current information on the 1988 Ontario base year emissions for SO,, NO, and VOCs. An industrial survey, expanded from the 1985 data base to cover more potential sources, was carried out to collect data for 1986 and 1987. The results are being finalized and integrated into the emission inventory system. Surveys for 1988 and 1989 are currently being undertaken. A Fast Reference Emission Document (FRED) was compiled from several sources to provide timely emission information covering Ontario and North America. A regular schedule to update and revise this document with the latest emissions information available is planned. The preliminary SO, estimates for 1989 show a slight decrease of about 7% compared with 1985, mainly due to the reduction of Inco emissions. The 1971-1989 Ontario total SO, emission trend is shown in Figure 2. The general decreasing SO, trend is projected to continue until 1994 when the Countdown limit is expected to be achieved. NO, emission levels in the 1980’s appear to be relatively constant. NO, emissions from vehicles account for about half of the SO2 (1,000 metric tons) 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 Year Major Sectors Figure 2 provincial total. With the introduction of more stringent emission standards for light duty vehicles, NO, emissions are expected to decline in the period to 2000 in spite of the expected increase in vehicle population. Emission trends of SO, and NO, in North America for the period 1980-1985 were also prepared for the Federal-Provincial Research Monitoring Coordination Committee (RMCC) 1990 Assessment Report during FY 1989/90. With reference to the global warming issue, a preliminary CO, emissions by sectors inventory for Ontario was derived for 1987 (see Figure 3). “us Utilities BE Non-Fe Smelters 1971-89 Ontario Total SO, Emissions B. MODELLING Numerical models have been used to quantify the source-receptor relationships that exist between acidic precursors emissions and final acid loadings. Linear and comprehensive models have been developed with different applications in mind. Linear models have undergone extensive evaluations (e.g., the Memorandum of Intent between Canada and the U.S. in 1980 and the International Sulphur Deposition Model Evaluation in 1986). Comprehensive models like ADOM (Acidic Deposition and Oxidant Model) have also been evaluated for periods representing ONTARIO ANTHROPOGENIC CO2 EMISSIONS 1987 — BY SECTOR(*) INDUSTRY (33.7%) COMMERCIAL (8.1%) (*) Tentative total CO2; about 150 million tonnes. MOE/ARB/AQM -— February 6th, 1990 Figure 3 CO, Emissions by Sectors different seasons of the year (e.g., OSCAR Oxidant and Scavenging Characteristics of April Rain) and a summer oxidant study. These studies, reported in earlier annual reports, have largely been limited to comparison of SO,” concentrations in precipitation. They show that total deposition of sulphur (wet and dry) is nearly linearly related to SO, emissions, and that about 50% of acidic deposition in south- central Ontario comes from U.S. sources. Other modelling studies indicate that nitrogen oxide emission control will result in a decrease in acidic deposition and oxidant levels in southern Ontario. The Eulerian Model Evaluation Field Study (EMEFS), which is a cooperative venture between the TRANSPORTATION (28.3%) UTILITIES - ONT HYDRO (19.2%) RESIDENTIAL (10.8%) Ontario Ministry of the Environment, Environment Canada, the U.S. E.P.A., the Electric Power Research Institute, and the Florida Acidic Deposition Monitoring Program, was designed to evaluate the performance of modern models of long range transport, chemical transformation and deposition. The field study ended on May 31, 1990. An initial model evaluation has already taken place; a more detailed evaluation will be carried out when all of the monitoring data are available. The first phase of the EMEFS’s intensive data collection was conducted between July and September, 1988 and provided both surface and aircraft measurements of air and precipitation concentrations of a number of key acidic species and oxidants. ADOM was run for parts of the EMEFS period and evaluated during FY 89/90. During the evaluation process, the model was used in the capacity of a diagnostic tool to identify problems in the NO, emissions which were common to both ADOM and the U.S. EPA comprehensive Regional Acidic Deposition Model (RADM). This was later confirmed by further investigations. The results of the evaluations for two periods (July 28 - August 8, 1988 (Period 1) and August 25 - September 5, 1988 (Period 2)) are summarized below. Eight species from the ADOM model have been evaluated. They are the ground level concentrations of SO,, SO,”, total sulphur (SO, and particulate SO,”), NO,, nitrate and O,, and concentrations of SO, ? and nitrate in precipitation. The performance of the model in predicting these species was as follows: Ground level SO,: Mean overprediction by 10 to 30 percent with higher overprediction at the low end. The model explains about 55 per cent of the variance. Ground level SO,”: Mean underprediction of 40 to 60 per cent. The model explains between 65 and 85 per cent of the variance. Ground level Sulphur: Mean modelled concentration is within 8 per cent of the observed mean. SO,” Concentration in Precipitation: Mean precipitation-weighted model concentration agrees with observations to within 10 per cent. The model explains less than 16 per cent of the observed variance. Ground Level NO,: Mean underprediction of 5 to 20 per cent. The model explains between 5 to 47 per cent of the observed variance. Ground Level Nitrate: Mean underprediction of less than 10 per cent. The model explains about 50 per cent of the variance (Figure 4). Nitrate Concentration in Precipitation: Mean underprediction of 20 to 25 per cent. The model explains less than 10 per cent of the observed variance (Figure 5). Ground level O;: Underpredicts the peaks in heavy emissions areas with a slight overprediction of the magnitude of peaks in remote areas. Preliminary results indicate that the inclusion of non-precipitating stratus clouds in the model improves the results significantly (see Figure 6 for ground level SO,, Figure 7 for ground level sulphate and Figure 8 for SO,” concentrations in precipitation). The large scatter in the concentrations in precipitation is caused by the mismatch in the spatial scale of representation: the observation is a point measurement which is subject to sporadic precipitation whereas modelled output is a grid average for 127 x 127 km’. This variability can be reduced by taking longer time averages. The overprediction of SO, in air and the underprediction of SO,” in air is common to both ADOM and RADM and it is the focus of current investigations. A winter simulation was also performed from January 28 to February 7, 1985. The predicted nitrate/sulphate ratio in precipitation was 1.6 which was higher than the predicted spring ratio (during OSCAR) of 0.8. This agrees with the trend in ADOM VS OBSERVED AIR NITRATE UG/M**3 9 8 7 6 5 4 3 2 Figure 4 Modelled vs Observed Concentration of Total Nitrate in Air ADOM VS OBSERVED WET NITRATE, mg/L waa aan B © OBSERVED 4 PERIOO 1 x PERIOD 2 Figure 5 Modelled vs Observed Concentration of Total Nitrate in Precipitation 7 Figure 6 Regionally Averaged Daily SO, Concentrations Fa tel ala A RCE BIE Pele 1k BEA >: he à "3 FA a [au (a © e = rd [.W~ 3 4 3 An (Sa 0 Yo « oe %e Go ‘ 1S 20 25 Observed SO4 (ug/m3) Figure 7 Regionally Averaged Daily Sulfate Concentrations 8 Observed Concentration (mg/l) Comparison of Sulfate Concentrations in Rain Figure 8 observed ratios at the same sites (2.4 in winter and 0.9 in spring). This study investigated the various pathways involved in the production of nitrate that result in the higher winter nitrate/sulphate ratios. The above modelling works are also contained in the document prepared for the RMCC 1990 Assessment Report during FY 89/90. A modelling project recently initiated is to adapt ADOM to study the transport, transformation and deposition of mercury. The mercury system (Hg, HgCl and particulate mercury) has been incorporated into this framework. The sources of mercury in the modelling domain are anthropogenic emissions, natural emissions and elemental mercury (Hg’) residing in the free troposphere which is transported into the domain at the boundaries. The scavenging of the mercury species within clouds involves nucleation scavenging of particulates and continuous exchange of gases at the air - water droplet interface. Observations indicate that more than 95 per cent of the airborne mercury is Hg* which is very insoluble. For this system the determining step in the net scavenging of mercury in clouds is the rate of aqueous phase oxidation of elemental mercury and the original partitioning of the emissions between Hg”, HgCl and particulate mercury. This model can be used to address a number of questions about the poorly understood mercury system: + the importance of natural emissions; + the background air concentrations of Hg’; ° the factors which control the wet deposition of mercury (i.e. possibly O, air concentrations and the pH of cloud water droplets). Preliminary runs have been made to show that the model results are in the range of observed values. Based on new information on emissions and the deposition and scavenging processes occurring, the model will be modified and run for scenarios such as those discussed above. Another project initiated during FY 1989/90 was to obtain a subgrid scale version of ADOM for use in urban modelling of oxidants and for investigating the spatial variability of acid species. C. DEPOSITION MONITORING NETWORK Operation of both the daily and cumulative (28-day) networks continued through FY 1989/90. Data from selected sites in the daily network are included in the Eulerian Model Evaluation Field Study (EMEFS). Two periods of intensive measurement were embedded within EMEFS. The first took place in the summer of 1988, and was reported previously. The second was carried out during March and April of 1990. The concentrations of a number of chemical species, such as formaldehyde, hydrogen peroxide, ozone, peroxyacetyl nitrate (PAN), etc., were monitored on an hourly time scale at three Ontario locations, including the APIOS Dorset site. Similar measurements were also made on board an aircraft flying between these sites. Measurements made during this intensive study will supplement the network data in model evaluation. In particular they will provide a detailed testing 10 of the model’s chemical simulation under early spring conditions. The cumulative network is the Province’s instrument for determining the long term trends in acidic deposition. A recent analysis of data from the Dorset site indicated that sulphate in air and precipitation has decreased since the start of the network in 1980 (Figures 9 and 10), but that nitrate in air and precipitation has not changed appreciably (Figures 11 and 12). These findings, which are in accord with emissions inventory data, have been included in the recent RMCC Assessment Report "Source-Receptor Relationships: Current Understanding and Implications Regarding Emission Controls". In general, annual wet sulphate deposition exceeds 20 kg/ha/yr over most of southern/central Ontario. There has been, however, a decline in the spatial extent over which the 20 kg target loading is exceeded. Other key findings remain valid i.e., that nitrogen oxides contribute almost as much to acidic deposition as sulphur oxides (wet and dry), that sulphates dominate in summer precipitation and nitrates in winter precipitation and that the measurable decreases in atmospheric sulphur deposition occurred in response to SO, emission changes. Monitoring of acidic deposition in Ontario will continue for the foreseeable future, so that the effectiveness of controls introduced under Countdown Acid Rain, and elsewhere, can be monitored. However, it is also clear that airborne toxic materials (e.g. pesticides, PCBs, trace metals) are also a significant concern. Rationalization of acidic deposition monitoring has made it possible to monitor these toxic materials without requiring additional resources. To this end, both the daily and cumulative networks have been Seasonal Air Concentrations Total Sulphur AFRAARAX/ AR) OO OO LOGO SO GEST See Ta*. 42%. %e% a a¥a% an’ ets ee 4 0 00 0 ./ @ LAA aa. te 4 A DOGO SRE RSR RSSeSE GES sss a AA 7 (A HICK ee RCE AARAARARAAA LOS 06260207 LAR AAAAAS tete tata e a 4 LA AAAA/ PLS CX KAN À AAA PQQ TRA AAAS POO RER EX Manet CRT 0.0.0.0, 0.0.0.9, 0.0.9 LXAXAXXX HOCX TOO ORNE 2 Q CXAXAXX XXXXKAXAXAXAAXXA AAPA SSA VS BOCK CK CH A88 W88 S88 2 y t- œ ¢ ht 2 wo og < 2 n œ < n 2 n + 2 < FA n SS = Lae) 2 uw) a 2 < nN mn n rm 2 < S83 W84 S84 W85 S835 W86 S86 W87 S87 W82 S82 W83 Season ir at Dorset A In Sulphate 9 Figure 2 LPP PAPAS 000000000060 aa ee OF KOON ARR ST EOCX DRE OOO pe 0e 0 6201010707 KK PO ae er ed OO RER RRQ KKK or KL 7 CAZ 2 a PRK KN FPO va LTD ee. Sulphate n & 9 ü 5 Sc O O es O O Cc © is + ipi EO ER ERK BOO rd RS RSR DRE Op RKO Oa ora 7, 046466 BIO KAPITI A T9908, 8,0, 0, 0,0 0 X À Pe LOI PROD VIA : 1660" Seasonal Prec Season Dorset in Precipitation at ate $81 A81 S82 A82 S83 A83 S84 A84 S85 A85 S86 A86 S87 A87 S88 A88 Sulph W81 S81 W82 S82 W83 S83 W84 S84 W8S S85 W86 S86 W87 S87 W88 S88 10 Figure 11 ions ir Concentrat Tore) Nitrate SeasonalA CXARAA/ eee VaTatatalartat aa, 62000000 Se Se SOS OPP VV EHR eee KXXX2 2004060. RETRO RTS RE eo Oo Net DORE Q 100.00 0.0 OOOO) OOK Lx Kr ASAAA/ Y, Late ete oo ete CAAN/ CA) 1606060 OS 2S 06 LAAAS 7, ose" 260d 604.0 COSCOCEO XX A 1 KAPPA NAN LG2S2626260 0000 ree: RAA/ 200 KAP STA sateratare’ 0.0%, 9.9, 9.0.0.9, 260000000050 60S CKKKAINOICAOOTONCT UK XX ee O OO OOOO 52509 O CAC OX NE CAR XX X X SSP PSS OOD Cx xO SII I ey ree OKO IY) OOOO N 3 (CoeN dn) une") RRRSERRERRERERNNRO IONS OOK OO MO) PASTY OOOO C7 , XXXXXXMA A87 S88 ABS CRAN AS / LA 2000000500 et 0 00100010 eee RER RI 0 oe RIRES Re ER a ion Concentrat 5 S85 W86 S86 W87 S87 WEB S88 Nitrate S85 ABS S86 A86 S87 RARAZA)J XX XX KK CHAXAKAAXA] RRNRSSTEN 8 J— © — DO XX Ip A7 AO AAA KR atete tee LOC ROSE SE AAPA SA / R262625062S. RCACACICACACRCACA ACAS CROATIA A oe DOC XX OOO G07 CRA AAAS/ LAA 0 DCR AA KA A A POP rr? Oo? Dorset RAR ir at A CAXRRKAKERARAA CKXXK}X XX A i OOK a Tata ete a ee POV 25 IIIS Tore OO IG? 2026060 CXAXKARAA/ Ser ltrate in SRSCONX S82 A82 S83 A83 S84 AS84 N 2000.00. PARA vw wy Br PSS Seasonal Prec W82 S82 W83 S83 W84 S84 Figure 11 Season W8S S85 W86 S86 W87 S87 W88 S88 82 S83 A83 S84 A&84 S85 ASS SR6 A86 S87 A87 S8B AB8 Dorset W83 S83 W84 S84 itrate in Precipitation at $81 W82 S82 A81 S82 A N Figure 12 i2 Figure 13 reduced by the removal of approximately 30% of the sites. Site selection for removal was based on an objective analysis, so that data quality will not be compromised. As an example, Figure 13 illustrates the sulphate deposition pattern calculated for the province with all sites included, and with the selected sites removed. D. OXIDANTS STRATEGY DEVELOPMENT An oxidant control strategy document was completed during FY 89/90. The report Average Annual Wet Depositions of SO, (kg/ha) 1981-86 13 supports the Ontario initiatives already being considered to reduce oxidant precursor emissions (NO, and VOCs). These initiatives are the Clean Air Program (CAP) and the Vehicle-related Emissions Strategy. CAP is aimed at the control of all Stationary source emissions, including both NO, and VOCs, as well as air toxics, and will address emission reduction through the application of control technology for the protection of the air environment. The vehicle-related emissions strategy wibl” reduce evaporative emissions through lowering of summer gasoline volatility and through the control of emissions during the distribution of vehicle fuels. Reductions will also be achieved through an active inspection and maintenance program. As an integral part of the program, Ontario supports the Federal initiative to adopt the 1993 California emission standards. Other initiatives, under development cooperatively with other Ministries, include: alternate fuels, changing transportation demand and improved efficiency. In addition to the above, Environment Ontario has been an active participant in all phases of the NO,/VOCs Management Plan developed by the Long-Range Transport of Air Pollutants (LRTAP) Steering Committee for the Canadian Council of Ministers of the Environment (CCME). The purpose of the plan is to address serious health and environmental concerns related to ground- level ozone, NO, and VOCs on a regional basis through reduction initiatives such as source control, energy conservation, product control, consumer choice and lifestyle and other mechanisms. The final report is expected by November 1990. In support of this and other related actions, regional and urban oxidant modelling studies will be carried out during the next fiscal year. E. METEOROLOGICAL STUDIES An operational Meteorological Data Acquisition System (MDAS) has provided on-going support for special studies, episode analyses and modelling activities over the 5- year period 1986 to 1990. MDAS is a computerized system which collects and stores meteorological data supplied by Environment Canada from the North American network of weather stations. Air parcel trajectories are generated by the system for interpreting event precipitation and other air quality data. During FY 1989/90, a satellite dish was acquired and installed as part of the Anikom 100 service to receive meteorological data from Environment Canada. The data acquisition via satellite transmission was successfully implemented and became operational in 1989. With increased data and data transmission rate, an improved MDAS computer system is required. Accordingly, feasibility studies are currently underway to enhance the MDAS system and to replace the aging Eclipse S/130. 14 As part of the RMCC 1990 Assessment Report, a study on ozone in southern Ontario for the period 1979 to 1988 was prepared. Data analysis indicates no apparent long- term trend in ground level ozone concentrations. Meteorological analysis of the ozone data clearly shows the importance of emission sources in the United States to ozone air quality standard violation in southern Ontario. Other related meteorological data analyses during FY 89/90 include ozone episodes and the air pollution index. The sector analyses study of the relative contribution of emissions in the U.S. and Canada to acidic wet deposition in Ontario for the period 1981 to 1985 was completed. The results show the U.S. sector as the dominant contributor to the total annual wet deposition of H*, NO; and SO,’ in the border regions of Ontario, typically 80% for southwestern Ontario and 60% for southeastern Ontario. 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BAC A l'ENS sf ARS EU Amos | 7 Reg cum duré in oe ae ang Da or Aquatic Effects Studies (Task 2) Contact: W. Keller The Aquatic Effects Studies are divided into three major subtasks; Chemical Studies, Biological Studies and Remedial Methodologies Development. A. CHEMICAL STUDIES Calibrated Watersheds a. Trends in Deposition and Lake/Stream Chemistry In response to a decrease in SO, emissions in eastern North America in the last decade, the atmospheric deposition rates of SOS and H* have decreased by 35% to 40% in central Ontario. Averaged over the period 1976-85, the mean change in the annual average SO concentration in precipitation was about 4 yeq L" yr’. The decline in H* concentration was 3.3 peq L' yr' while nitrogen species and base cation concentrations remained unchanged. During this time, however, Plastic Lake, in the Muskoka-Haliburton region of Ontario, which has been monitored since 1979, acidified. Its alkalinity dropped an average of 2 peq L'yr’ between 1979 and 1985. For the same period, total base cations decreased in the lake while SO? did not change significantly. Since 1986, however, sulphur (and acid) deposition at Dorset has not declined further. The lake’s alkalinity and pH, correspondingly, have not continued to decrease. 15 The chemistry of the streams draining the Plastic Lake catchment has also been monitored. Water quality of the runoff in an upland site improved rapidly in response to decreased SO? and H* deposition; pH and alkalinity increased, while SO; and Al decreased. These improvements, however, were negated by a small wetland area downstream and the extremely dry summers of 1983, 1987 and 1988. The wetland reversed most of the changes in water quality (also see Biogeochemistry Studies Section) and the dry periods resulted in very high concentrations of SO; in the streamwater, probably due to re-oxidation of substantial amounts of reduced sulphur in the catchment. Sulphur emissions from Sudbury also declined between 1978 and 1985 by an estimated average of 0.73 X 10° tonne yr". As a result, SO? concentrations of lakes in the Sudbury area have decreased and the pH of each of the acidic lakes studied has increased. Aluminum, Cu, Ni, and Zn concentrations have also decreased, likely as a result of decreased emissions from the smelters. These results, together with those from the upland site at Plastic Lake, clearly demonstrate that chemical acidification of aquatic ecosystems is reversible, and that beneficial effects from the reduction of sulphur deposition can be expected within a few years to a decade of the deposition decreases. b. Modelling Lake Chemistry A better understanding of the acidification mechanisms can be obtained by a combination of field studies and mathematical modelling. A complete model would require very extensive information about the catchment (e.g., precipitation, water chemistry, soil chemistry, vegetation). Few data sets satisfy this requirement, however, a modelling effort is still worthwhile and may provide the insight required to plan further field work. The Birkenes model, previously used for modelling stream chemistry in Norwegian catchments was modified to predict discharge and sulphur concentration in a stream draining the Harp Lake catchment in Ontario. The predicted hydrology is generally in close agreement with the measured hydrology. Good agreement between calculated and observed sulphur concentrations was obtained when a reduction (or adsorption) process for SOf in the deeper soil horizons was introduced. During dry periods, however, SO{ is produced by oxidation in the upper soil layer. Sulphate concentrations in the stream water during snowmelt are remarkably constant and, according to the model, could be explained by the existence of an easily soluble sulphur reservoir in the soil, which is considerably larger than the annual sulphur flux. Even with the modifications for Harp Lake, the basic structure of the models applied in Norway and Ontario was the same, and it seemed likely that the model would be applicable to other catchments with only minor modifications. Application of the model to two other subcatchments in the Harp Lake watershed proved successful. The model was then extended to include a 16 hydrological submodel with a snow reservoir and two soil reservoirs, a sulphate submodel and an ion submodel which included H’, Ca* + Mg”, Al, Na*, HCO, and organic anions. Major processes incorporated included different hydrologic flow patterns during highflow and lowflow, SO; adsorption and desorption, ion exchange, weathering, gibbsite (amorphous alumino- silicate) solubility and CO, equilibria in soil and stream water. The model reproduced important daily and seasonal trends in the observed streamwater chemistry of a tributary to Harp Lake. Finally, this extended model was run to simulate a doubling and a 50% reduction in the 1983 sulphur deposition. The simulations showed little change in lowflow stream pH with changing deposition. At snowmelt highflow, however, a 50% reduction in deposition caused a pH increase of 0.2 to 0.5 unit. Doubling the deposition resulted in pH depressions of 0.5 to 0.9 unit. Within the last two years the MAGIC model has also been used. The MAGIC model began as a groundwater model but can now be used to model streams and lakes. The model consists of a soil solution equilibrium component and a mass balance component. The MAGIC model takes a series of equilibrium and mass balance equations and a collection of parameter definitions and fits modern water and soil chemistry. The model results are strongly driven by historic deposition chemistry. For Plastic Lake, which has experienced a four-fold decrease in alkalinity and a 0.25 unit drop in pH over the past nine years, the model was successful in predicting historic water chemistry (ANC, SOF and pH). The model, however, did not predict the observed trends in alkalinity and pH. According to the model, decreased sulphur deposition should have led to rapid reversal in the acidification of Plastic Lake. Poor prediction is probably due to sulphur storage in the wetlands which is released over a long period of time, lending a lag time to the recovery of the lake. c. Effects of Nitrogen The relative contribution of HNO, to precipitation acidity in eastern Canada has increased in recent years. This caused concern that the relative importance of NO; deposition in the acidification of terrestrial and aquatic ecosystems may increase. Alkalinity and pH depressions in streams and lakes, as a result of snowmelt, are seen in the Muskoka - Haliburton area, and have been well documented in the literature over a broad geographical scale and a wide range of alkalinity. It was thought that in areas of high acid deposition SO} and NO; may dominate these alkalinity depressions when anions, accumulated in the winter snowpack, are released over a brief melt period. The relative contribution of base cations and acid anions to alkalinity decreases was measured on 15 headwater streams and lake outflows in three central Ontario catchments. It was found that neither nitrate nor organic acids were significant contributors to the observed alkalinity depressions. Base cation dilution by snow meltwater was found to be the major contributor to alkalinity depressions. Cations are very low in the snowpack and very little is picked up from the soil. Further studies on the importance of nitrogen included the calculation of annual mass balances for NO; and NH for several forested catchments and lakes. Ammonium retention by forested catchments was consistently high compared to NO; retention. Inorganic N retention was influenced by catchment grade and areal water discharge, where areal water discharge 17 equals the ratio of lake mean depth to water residence time. In the lakes, NO, and NH export were linearly related to areal water discharge. Nitrate retention did not seem to be a function of the degree of acidification of the lakes. Nitrogen consumption-related acidification was most likely to occur when the areal discharge was less than 1.5 m yr’. d. Mass Balances Alkalinity It recently has become apparent that internal (in-lake) processes are significant sources of alkalinity, and in some cases more important than external sources such as silicate and carbonate dissolution, ion exchange reactions and redox processes. Alkalinity and ion budgets were measured for eight lakes and 24 subcatchments in southern Ontario for periods ranging from 6 to 10 years. The contributions from the lakes’ catchments and from the atmosphere were quantified. For Harp and Plastic Lakes, which have the highest and lowest alkalinities, respectively, the loss of alkalinity from each lake via the outflow greatly exceeded the total input. In Plastic Lake there was an output of alkalinity even though the input was negative. If the catchment were the only source of alkalinity in each case (external source) the alkalinity concentration in Plastic Lake should be -75 peq L’ and in Harp Lake should be 13 peq L’. In fact, the measured alkalinities are 8 and 64 peq L' respectively, indicating a significant contribution from in- lake processes. Mass balance calculations indicated that the major in-lake contributors were the removal of organic anions followed by SOf and NO; reduction. Cations Cation flux from the lakes’ catchments was found to be controlled by the atmospheric input of strong acids of anthropogenic origin. Organic acids and H,CO, were less important factors. Sulphate Over the past 10 to 15 years there has been a decrease in the atmospheric deposition of SO and strong acid as a result of decreased SO, emissions. The SO budgets for the Plastic and Harp Lake catchments indicate that the export of SO? from both catchments exceeds the input on an annual basis over several years. A new steady state will eventually be reached. On a short-term basis the SO? fluxes are not in equilibrium. In the summer, SO is stored in the catchment. In the winter and spring, there is a net release of SOŸ The storage and release are almost certainly controlled by redox processes. In very dry summers, streams dry up and oxidation of the stored sulphur occurs. On return of stream flow, flushing of H,SO, from the catchment results in extreme conditions that are as detrimental as, or worse than, the spring snowmelt. Carbon To better understand the cycling of dissolved organic carbon (DOC) in the watershed, carbon isotope analysis (‘°C and “C) was done on the DOC and dissolved inorganic carbon (DIC) in Harp Lake. At the study site soil gas, lysimeter leachate, piezometer and bedrock well water, stream, precipitation and sediment samples were collected. DOC concentrations were 18 compared for the period of August 1988 (low flow) and April 1988 (high flow). The major findings of this work can be summarized as follows: a) the lake is a sink for DOC and therefore organic acids; b) in the summer there is an in-stream source of DOC; c) 50% to 74% of the DOC is hydrophobic (humic and fulvic acids, and neutrals); d) the wetlands and beaver ponds have older carbon; e) a rapidly cycling component exists apart from the fulvic and humic acids; f) the groundwater contains older carbon which suggests a fractionation or cycling of DOC in the upper soil zone; g) all the alkalinity in Harp Lake is from silicates, and h) the lake is exporting CO, at all times of the year. e. Acidification and Phosphorus Export Acidified lakes are often exceptionally clear, and it has been hypothesized that this phenomenon is the result of a decline in productivity driven by a fall in phosphorus output from acidified watersheds. The chemical theory underlying the hypothesis was tested on streams in the Muskoka- Haliburton region of Ontario. Watersheds with clear, circumneutral streams will export more phosphorus when further acidified. Coloured, acidic streams already export elevated amounts of phosphorus. Phosphorus loadings to a lake will, therefore, depend on the relative inputs of clear water and brown water streams. Metal Contaminants a. Aluminum The acidified lakes and streams in the Muskoka - Haliburton region have been found to contain high levels of aluminum, In order to determine the sources, sinks and forms of aqueous aluminum, 26 different streams in the Plastic and Harp lake catchments, and 60 lysimeters at different locations in the catchment and soil profile were monitored. Inorganic monomeric aluminum was found to originate primarily from the Bf horizon in the soils and was found in all downstream locations. The mineralogical source and sink for inorganic monomeric aluminum appeared to be an aluminum trihydroxide solid phase. Organic monomeric aluminum and dissolved organic carbon were obtained from two widely separated sources: the soil LFH horizon and the wetland. b. Mercury Environment Ontario and the Ministry of Natural resources have _ surveyed contaminants in the sport fish from Ontario lakes since the 1970’s. Survey data have revealed that mercury contamination in Ontario fish is common and widespread in lakes on the Precambrian Shield, even though most lakes are remote from industrial or municipal contamination sources. Mercury levels in the large size classes of fish often exceed the concentrations considered safe for eating. As a result, size specific consumption restrictions have been placed on fish from most of these lakes. Initially, the mercury in these lakes was thought to be primarily from natural sources (probably geological) since the affected lakes were mainly on the mineralogically rich Precambrian Shield. It was also hypothesized that the mercury distribution in these lakes might be, in part, due to atmospheric deposition. Until recently, however, the analytical capabilities for measuring mercury in water were inadequate to correctly assess the relative importance of these sources. 19 Within the last five years, the necessary analytical capabilities were developed for the measurement of mercury at low levels in water samples. Runoff from a group of calibrated watersheds and precipitation in the Muskoka/Haliburton area of south-central Ontario were examined. The annual volume weighted concentration of mercury in precipitation was four to eight times higher than in streams. In a typical headwater lake, more than half of the annual mercury load to the lake entered directly through precipitation. Most of the watershed-derived mercury entered the lake during spring runoff. It is likely that much of the mercury in the runoff was derived from precipitation. Most of the mercury in the watershed was removed from the atmosphere. Mercury export from each watershed was only 10% to 20% of the atmospheric load to the watershed. Current data, therefore, clearly indicate that contrary to previous thought, the mercury in fish from Precambrian Shield lakes is derived directly from atmospheric deposition and not bedrock weathering. The retention of mercury deposited on watersheds from the atmosphere varies considerably. The amount exported increases linearly with the amount of wetland in the watershed. Wetlands appear to retain only about 20% of the mercury deposited on them, whereas upland areas retain more than 90%. The variation in retention may explain some of the variation in the mercury content of fish in lakes on the Precambrian Shield. The relative importance of anthropogenic and natural sources of mercury in the atmosphere is under debate. Mercury concentrations in sediment profiles suggest that, as found in other North American locations, mercury input to lakes in Ontario has increased two to three fold since pre- industrial times. Scattered measurements across the northern and southern hemispheres indicate a gradient in atmospheric concentration with the most southerly stations exhibiting the lowest concentration. Although emission inventories prepared in the mid-1970’s suggest that natural sources of mercury play a larger role than anthropogenic sources, mass balance calculations using the most recent data suggest an overestimation of soil emissions by a factor of 10. Present data indicate that the current mercury load to the atmosphere (and eventually to the lakes) is largely of anthropogenic origin. c. Other Metals The trace metals Cu, Pb, Cd and Zn and their patterns of transport within the Plastic Lake catchment in the Muskoka - Haliburton region were also examined. The aqueous metal concentrations were followed from the precipitation through the catchment to a DOC, acidified soil water seep, a high DOC wetland outflow and finally to the Plastic Lake outflow. Lead and Cu patterns are identical to DOC and Al. Levels are relatively high in precipitation, with their lowest median concentrations occurring in the soil water seep, elevated concentrations in the wetland ouflow and lower concentrations at the lake outflow. In contrast, Cd and Zn have their highest median concentrations in the acidified soil water seep and reduced values further downstream. Lead and Cu transport patterns can be explained by the metals’ affinity for DOC and transport patterns for Cd and Zn can be explained by the metals’ solubility in dilute acid and mineral soils. 20 Extensive Lake Monitoring For the past six years, Environment Ontario in co-operation with the Ministry of Natural Resources, conducted lakes surveys to determine the sensitivity of Ontario lakes to acidic precipitation. Results have been summarized each year in a report entitled "Acid Sensitivity of Lakes in Ontario" issued by Environment Ontario. During the last 4 years the emphasis has been on the collection of data on lakes underrepresented in the existing data base. These lakes were smaller lakes (< 10 ha) in all of Ontario, and lakes of any size in northwestern Ontario. The percentage of all lakes sampled in each part of the province, is illustrated in Figure 14. By examining only low conductivity lakes, quantitative relationships between sulphur deposition and the sulphate content of lake water were established. Similar relationships were developed for lake pH and alkalinity. A detailed descriptive analysis of the 6,000 lakes in the Acid Sensitivity Database was also completed. Lakes were grouped by quaternary watershed according to zones of sulphur deposition. For several lake size groupings, the available data were extrapolated to the total number of lakes in the sulphur deposition zone. This process yielded the most accurate estimates to date of the number of lakes with alkalinity <0 and lakes with a pH < 6 in the province (i.e., pH < about 5.0). Over 7,000 lakes were estimated to be acidic, and over 19,000 were estimated to be acidified to less than pH 6, the point at which some biological damage occurs. The most acidified area of the province is the Sudbury deposition zone, where impacts from the sulphur emissions from the % of Lakes Sampled | >15% | 10-157 5-10% 1-57 <1% No Data IH Figure 14: Percentage of Lakes Sampled in Each Part of the Province Sudbury smelters were greatest. Large numbers of acidified lakes, however, occur throughout central Ontario (Haliburton, Muskoka, Parry Sound, Nipissing, and parts of Algoma and Timiskaming). Within each of the sulphur deposition zones, the degree of lake acidification was a function of lake size. Smaller lakes are generally more acidic than larger lakes, with lakes in the 1-10 ha range accounting for most of the acidified lakes. An analysis of the chemical data collected for a total of 1,180 soft-water lakes surveyed between 1981 and 1987 showed a strong relationship between both the mean lake pH and mean lake alkalinity and the sulphur deposition of the zones (Figure 15 and Figure 16). Assuming that the chemical characteristics in the lowest deposition zone indicate "background conditions", substantial alkalinity has been lost in all of the other regions. The large sample size of the survey data also allowed it to be used to assess the so-called "critical" load of SO for Ontario lakes. The statistical relationship between sulphur deposition and lake pH or alkalinity was used, in combination with the defined lake pH or alkalinity below which biological effects occur, to estimate the critical or threshold sulphur deposition below which effects are not observed. There was a significant relationship between sulphur deposition and lake chemistry only for sensitive lakes (i.e., softwater lakes defined as those with a conductivity of < 50 us cm). This implies that, in lakes with higher conductivity, either SO} deposition does not control lake chemistry or that there are other sources of SO in these lakes. The critical lake pH of 6.0, corresponding to an 22 alkalinity of about 50 peq L'\, is generally agreed to be the level below which biological damage occurs. This figure was used to calculate the portion of lakes in Ontario which will not drop below these chemical criteria when exposed to differing levels of SO? deposition.The results, summarized in Table 1, indicate that in order to protect 95% of the sensitive lakes in Ontario, the SO deposition must not be greater than 9 kg ha! yr', while less than or equal to 15 kg ha” yr’ will protect 90% of the lakes. Table 1. pH Above Which 95% and 90% of Ontario’s Sensitive Lakes Will Remain for Specific Sulphate Deposition Rates. Total SO kg ha! yr’ 95% 90% 3 6.14 6.31 6 6.06 6.24 9 5.98 6.16 12 5.90 6.08 15 5.82 6.00 18 5.74 5.92 21 5.67 5.85 Since approximately half of all lakes in the province can be classified as sensitive according to the criteria used here, 9 and 15 kg ha! yr! will protect 97.5% and 95% of all the lakes, respectively. On the other hand, 20 kg ha’ yr’, the critical load originally estimated as acceptable in Ontario, will protect only 80%-85% of the sensitive lakes in the province. Figure 15: Total Sulphur Deposition Zones (1983 data) 23 sl (See) O> Ga ab QO. 0 x 0 2. Where mi SD Ge Je 0.000,25) 0.50 0.75% «LOD lame Total Sulphur Deposition (g m7 yr”) Figure 16: Lake pH in Relation to Sulphur Deposition. B. BIOLOGICAL STUDIES Algae a. Paleolimnology and Lake Acidification History In the absence of direct measurements of alkalinity loss in several Muskoka- Haliburton area lakes over several decades, indirect methods of inferring lake acidification were examined. Three algal components (chrysophyte scales, chrysophyte cysts and diatoms) all of which leave identifiable remains in lake sediments, were used to develop calibrations of algal species vs lake acid sensitivity (alkalinity, pH). In a set of 50 calibration lakes in the Muskoka- Haliburton-Parry Sound area, relationships between algal species composition in surface sediments and present day water chemistry were developed for the three groups of indicators. These were then applied to an independent set of five test lakes with present day alkalinities ranging from -0.4 mg L" yr’ to 66 mg L' yr' and corresponding pH values of 49 and 7.9 respectively. Predictive relationships for the validation lake set were highly significant (R? values for predicted vs measured pH and alkalinity between 0.75 and 0.96). The best predictors were the chrysophyte cysts. Reports were prepared in 1988 for all three calibrations (cysts, scales and diatoms). Publication of the findings is now in progress. Reports on the pH/alkalinity history of several Parry Sound and Muskoka area lakes are now in preparation. These involve application of the calibration equations to lake sediment cores. Analyses of algal indicators and 7'°Pb dating were done at regular intervals in the core from the sediment surface to a 30 cm depth. 25 Considerable developmental work was necessary in order to apply these techniques. It resulted, however, in significant advancements in the taxonomy of scaled chrysophytes. This work has been recently published. The information gained has led to improved paleolimnological applications not only in this APIOS project, but also in similar studies in Europe, Scandinavia and the U.S.A. b. Filamentous Algae Synoptic and long term field studies of filamentous algae in acid sensitive lakes have demonstrated the propensity for certain zygnematalean species (notably Zygogonium tunetanum - Lievre and Temnogametum tirupatiense Iyengar) to proliferate as metaphytonic "clouds". A survey of 4,400 cottagers on 214 lakes in central Ontario indicated that filamentous algae are present in 48% of the lakes in the area A Statistically significant positive relationship was observed between algal presence and lake sensitivity to acidification. A high proportion (92%) of all cottagers reporting filamentous algae on their lake were concerned about reduced enjoyment of the lake. Whole lake experiments including either neutralization (Bowland Lake) done by the Ontario Ministry of the Environment or acidification (Lake 223, Experimental Lakes Area, Kenora) done by the Federal Department of Fisheries and Oceans have demonstrated striking responses in filamentous algae. Some additional work was done through the University of Toronto to examine the relative impacts of cyprinid, larval amphibian and crayfish grazing in lakes of different acid sensitivity. The final results of this work will be available in the near future. Evidence from other lakes (e.g. Swan Lake, Sudbury), where acid deposition has declined in recent years as a result of decreased SO, emissions, suggests that filamentous algal densities have also declined. c. Odour Causing Algae Chrysochromulina breviturrita Nicholls was described in 1978 as a new species of planktonic prymnesiophyte occurring in Ontario softwater lakes. In 1979 and during the 1980’s this species caused lake-wide "rotten-cabbage" like odours in several lakes in Ontario and four New England states. Laboratory studies of C. breviturrita in unialgal culture demonstrated its optimal growth requirements in low pH (5.5-6.0), low alkalinity growth media. It will not grow above pH 7. This species also has a selenium requirement and is apparently only able to utilize nitrogen in the form of NH}. C. breviturrita has been found in about 100 Ontario lakes. Statistical analyses of a 610 lake-year data set (with and without C. breviturrita) showed a significant negative relationship between relative abundance of C. breviturrita and lake pH and a positive relationship with DOC. More than one-half of all occurrences of C. breviturrita were in samples from lakes with alkalinities of less than 5.8 mg CaCO, L" yr'. With only one exception, all lakes experiencing blooms and odour problems had summer pH values of 5.6 to 6.2. It is highly significant that one of these odour episodes developed in the south basin of Lake 302 near Kenora which was being acidified with sulphuric acid by the federal Department of Fisheries and Oceans. Importantly, large populations have not developed in the north basin of Lake 302 which was acidified with nitric acid (D. Findley, pers. comm.). d. Phytoplankton Monitoring Between 1985 and 1989 inclusive, 4,836 26 phytoplankton samples were analyzed from acid sensitive (and a few moderately well buffered) lakes in central, northeastern and northwestern Ontario. Most of these originated from collections by Dorset Research Centre staff in the Muskoka- Haliburton-Sudbury area. About 20% of the total sample input, however, was submitted by regional offices of Environment Ontario, the Ministry of Natural Resources’ Fisheries Assessment units and the federal Department of Fisheries and Oceans. Zooplankton The zooplankton community of Plastic Lake was compared with that of three non-acidic reference lakes over the last decade. Inter- annual variations in community structure were larger in Plastic Lake than in the three reference lakes. The average species richness in Plastic Lake declined over the decade in comparison with the reference lakes. This indicates that the zooplankton community structure was degrading at sulphur deposition rates characteristic of the 1980’s. Daphnia galeata mendotae is one of the dominant species of crustacean zooplankton in Ontario. Abundance patterns obtained from a survey of 450 Ontario lakes were compared with thresholds of acidity determined in laboratory bioassays. This comparison demonstrated that the acidification of Ontario lakes to pH levels less than 6 has had widespread negative impacts on this important species. There are at least 20,000 such lakes in Ontario. Other species of Daphnia are also sensitive to acidification. A comparison of survey and intensive lake data demonstrated that two other common species of Daphnia (D. dubia and D. retrocurva) are less abundant in acidified than in non-acidified lakes. Acidification impacts at pH’s less than 6 can also be seen in the ice-free season averages of species richness (the entire Crustacean zooplankton community) of 54 south-central Ontario lakes. It has long been hypothesized that many of the effects of acidification on zooplankton have indirect causes related to altered predation pressure. Detailed examination of data from an acidic lake near Sudbury showed that intense predation from larval phantom midges can cause very unusual zooplankton community structures (i.e., almost total dominance of the community by rotifers). Scandinavian and Ontario researchers have reported apparent differences in the impacts of acidification on larval phantom midges. A large survey of carefully selected lakes demonstrated that this apparent difference is largely attributable to the size and depth of the lakes selected. Larval phantom midges are important members of the zooplankton in small, fishless, acidic lakes in Ontario, as in Scandinavia. Indeed, phantom midges are often more important contributors to total zooplankton biomass in these lakes than microcrustacea. It has been well established that the water quality of acidic lakes improves in response to sulphur emission reductions, but the response of zooplankton, and indeed most other aquatic biota, is unknown. A comparison of changes in zooplankton communities from 8 lakes in the Sudbury area from the mid-1970’s to the mid-1980’s indicated that substantial biological recovery had occurred in half of the lakes. Community structure, however, had not yet returned to the characteristics of non- acidified lakes. No recovery was recorded in some lakes that were particularly heavily contaminated with acid and metals in the mid-1970’s. 27 The acidification of lakes influences the accumulation of cadmium by zooplankton. In clear water lakes of pH circa 5.5, that are remote from Sudbury, cadmium levels in zooplankton are elevated. This is likely due to elevated Cd levels in atmospheric deposition compared to historical levels, and because Cd export from watersheds is elevated by acidification of stream waters. Cadmium levels in zooplankton are not elevated in lakes of pH less than 5.0 despite elevated aqueous Cd levels due to competition between protons and Cd in acidic systems. Invertebrates Stream invertebrates (insects) have been shown to be important monitors of anthropogenic stresses such as acidification. These previous experimental studies also have indicated that short-term changes in acidity and associated aluminum concentrations could significantly alter invertebrate assemblages. During the last five years, three experimental approaches have been used to determine the influence of acidification on changes in species composition and biomass of stream invertebrates. First, different aquatic life stages of mayflies and blackflies indigenous to the Muskoka- Haliburton districts were transplanted, prior to and during snowmelt, from streams with a range of hydrogen ion concentrations to streams with lower pH and high aluminum concentrations. Some species of mayflies were sensitive to short-term exposures to elevated acidity. Immature _ blackflies survived low pH (~ 4.0) and high aluminum concentrations (700 pg L" yr") during all of the transplant experiments. In the second experiment, additions of acid (H,SO, and HCl) were added to stream reaches to simulate’ short-term pH depressions in streams that have been naturally subjected to high and low deposition of acids (high=Dorset, mean H* deposition, 70-100 meq yr'. Low=Kenora, mean H* deposition of 8-10 meq yr’). Many of these invertebrates had lower survival in pH depressed streams, indicating that damage to stream invertebrates, as a result of acidification, has already occurred near Dorset, Ontario. The final approach was to conduct surveys of insects in acid and circumneutral streams. This approach has helped corroborate the previous experimental findings. Quantitative studies of stream insect populations were made from 1937 to 1947 in Algonquin Park. Resurveys of the same locations have revealed that acid-sensitive species (mayflies and stoneflies) have decreased, and acid- tolerant species (caddisflies and blackflies) have increased in acid streams. No significant differences were found between the 1937/47 survey and the 1985 survey for non-acidic streams. The increase in blackflies, as a result of acidification has been supported by additional toxicity studies. Toxicity Studies The absence of a species from a lake with low pH or a population failure in an acidifying lake does not constitute proof that a species is adversely affected by acid. Initially, toxicity testing focussed on sport fish. The lethality of H* and Al** to the early life stages of the following eight softwater fish species was investigated: common shiner, white sucker, smallmouth bass, lake whitefish, walleye, largemouth bass, lake trout and brook trout. Laboratory toxicity studies (as measured by reproductive success) were conducted along with the collection of population data in the field. For all species except largemouth bass, lake 28 trout and brook trout, the population data confirmed the laboratory studies. Common shiner were the most sensitive to acidification both in the field and laboratory, followed by white sucker and smallmouth bass. Largemouth bass, lake trout and brook trout all showed higher tolerance to acidic conditions in the laboratory than in the field. Aluminum additions in the laboratory did not significantly change the reproductive success. Acute lethality studies of metal mixtures (Al, Cu, Zn, Fe, Mn, Ni and Pb) at ratios typical of acidified water were performed with rainbow trout and fathead minnow larvae in soft, acid water. Aluminum was more toxic to trout at pH 4.9 than any other component of the mixture, while copper was more toxic at pH 5.8. For fathead minnows, copper was responsible for toxicity at pH 5.8. Recent data suggest that many of the small forage fish, in particular the cyprinids, are the most acid sensitive group of fish. For this reason, the sensitivity of the early life stages of cyprinids to acid in soft water was investigated. Seven species of minnow from the Dorset area were captured and brought to the laboratory. Where possible, eggs were stripped from females of golden shiner (Notemigonus chrysoleucas), creek chub (Semotilus atromaculatus), pearl dace (Semotilus margarita), blacknose dace (Rhinichthys atratulus), and northern redbelly dace (Chrosomus eos.) Fathead minnow (Pimephales promelas) and bluntnose minnow (P. notatus) were cultured in the laboratory. Eggs and larvae were exposed continually, for up to 40 days to water with a pH between 4.3 to 7.0 depending on species. With the exception of fathead minnow, mortality increased significantly and whole body ions decreased significantly, at the lower pH’s. Individual LC,, varied widely across species, from about 5.9 for bluntnose minnow to less than 4.6 for pearl dace. The median LC,, found in the laboratory showed excellent agreement with the pH for extirpation in the field. This indicates that early life stage lethality is a good predictor of species success. Although there are clearly other determinants of cyprinid distribution in the field, these laboratory findings provide evidence of an acid effect on cyprinid distribution, and indicate that the role of other metals such as Al and Cu is probably restricted to that of a modifier. Fathead minnow larvae were then exposed to a range of pH in static bioassays to determine the potential ameliorating effects of NaCl and CaCl,. The working hypothesis was that increased Na should enhance Na influx and that increased Ca should increase gill membrane stability thereby reducing Na efflux. To overcome the difficulty of measuring unidirectional Na fluxes in organisms this small, and to determine the effect on the entire organism, survival time was used instead. In general, NaCl or CaCl, were beneficial in decreasing toxicity based on LC,, values. A preliminary study was done on the effects of parasitism on the acid sensitivity in adult bluntnose minnow and northern redbelly dace. Adult fish with heavy parasite infestations showed only slight increases in acute acid sensitivity. The ETSO survival times were used since there were not enough fish for a full ‘bioassay. Early life stages were much more sensitive to acid than adults and unless the adults show some increased sensitivity to metals, parasitism appears to play little role in determining fitness in adult cyprinids. 29 Biological Survey In addition to the adverse effects of acidification on sport fish, research has also concentrated on more sensitive organisms such as benthic invertebrates. Biological surveys of softwater Shield lakes were designed to identify aquatic invertebrates that may be sensitive to low pH and to quantify their response. The invertebrate community along the littoral zone (shoreline) was sampled on approximately 60 lakes during the fall of 1987. Water samples were also collected for chemical analysis. Additional samples were collected in the fall of 1988 to augment the data on low alkalinity lakes. Species were identified to the lowest practical taxon. The data are currently being analyzed and when completed will reveal any significant relationships between water chemistry and invertebrate distribution. Biological Monitoring Initial biological monitoring of lakes in the Muskoka-Haliburton region resulted in several documented cases of. local, abrupt species extinctions: snails (Amnicola) in Heney Lake and amphipods (Hyallela) in Plastic Lake. In addition to H° sensitivity, certain life history characteristics lead to extinction over short periods of time. Extinctions may, therefore, occur when lake water chemistry degradation is slight. Lake chemistry fluctuates on a time scale on the order of months in response to changing seasons and on the order of years in response to climatic fluctuations and atmospheric deposition. The lake biota respond differently to these changes depending on their life spans relative to the time scale of the fluctuations. Small organisms such as algae and zooplankton, having short life spans, tend to respond mostly to seasonal changes in lake chemistry. Large organisms such as fish, with life spans of several years, may reflect changes in lake chemistry, due to acidic deposition, over a period of a number of years, perhaps decades. Benthic invertebrates, however, which have life spans of about one year respond to changes in water chemistry on an annual scale. Because these fluctuations may be large relative to the long-term changes, catastrophic collapse of such populations can occur. As a result, these organisms yield a relatively high signal:noise ratio in their response to acidic deposition. Benthic invertebrates are easily sampled as a group with simple techniques which yield a large number of species. They are, therefore, ideal subjects for monitoring the effects of changing acidic deposition from both a practical and theoretical standpoint. Initial work emphasized evaluation of sampling times and methods. Results of this work indicated that the fall is the best time to sample, yielding 10 times the number of organisms as the spring, using the "kick and sweep" method Preliminary sampling of 12 lakes showed four of them to contain Orconectes virilis, a species of crayfish which is known to be sensitive to acid conditions. The lakes spanned a pH range from slightly acid to circumneutral and all animals caught in the most acidic lake were large adults. No young animals were caught and it appears that the crayfish in this lake are the remnants of a population on the verge of local extinction. A federal-provincial biomonitoring program was established emphasizing _ benthic invertebrates in Eastern Canada. 30 Environment Ontario contributes by monitoring 14 lakes in the Muskoka- Haliburton region of south central Ontario. The program is too new to detect population changes, but has been successful from other standpoints. Over 500 taxa from 12 lakes were collected during the first year of sampling, and despite the use of very simple sampling techniques, the precision of relative abundance estimates is well within expected limits. Metal and Organic Residue Monitoring Investigations over the 1986-1990 period focused on 2 principal concerns: a. Monitoring mercury (Hg) levels in yearling yellow perch; and b. Investigating relationships between Hg in sportfish and environmental variables. Some work also began in 1989 on the investigation of links between organic residues in sportfish and long range transport of organics. a. Monitoring Mercury in Yearling Yellow Perch Yearling yellow perch (Perca flavescens) were collected from sixteen Muskoka- Haliburton lakes to determine interrelationships between water quality, Hg residues in fish and fish condition. The lakes studied had a pH range of 5.6 to 7.3 and total inflection point alkalinities of 0.4 to 16.0 mg L’. Mercury residues in yellow perch ranged from 31 to 233 ng g' and were inversely correlated (p <0.001; r = 0.84) with lakewater pH. Stepwise linear regression analyses selected lakewater pH as the only significant parameter associated with Hg accumulation. Alkalinity, sulphate, calcium and dissolved organic carbon (DOC) were not significant. Likewise, lakewater pH and Hg residues in yellow perch were inversely (p <0.001) correlated with fish condition. Lakewater pH accounted for 74% and Hg in fish a further 11% of the variance in fish condition. Terrestrial drainage size/lake volume ratios, were also correlated (p <0.05; r = 0.78) with Hg accumulations in perch from a subset of nine headwater lakes. No temporal trends in Hg residues were evident in yellow perch from 1978 to the present. Fewer years of data on Hg in yearling yellow perch from lakes in the Sudbury, Chapleau and Thunder Bay areas were also collected. No temporal trends were evident in these data either. b. Mercury in Sport Fish in Relation to Environmental Variables Data from the Contaminants in Sport Fish Program and the Acid Sensitivity Program were used to assess the relationship between Hg residues in sport fish and environmental (primarily water quality) variables. To date, analysis has focused on lake trout, smallmouth bass, walleye and pike collected over the period 1978-1984. Concentrations of mercury in dorsal muscle tissue of lake trout (Salvelinus namaycush) were positively correlated with variables indicating lake dystrophy (DOC, colour, iron, transparency) and were also correlated with watershed area and lake area. Stepwise multiple regression selected DOC as the only variable which explained a significant amount of variance (37%) in Hg concentrations in lake trout. The relationship between dissolved organic carbon and Hg appeared to be strongest in the group of lakes with values of DOC less than 4.0 mg L'. In contrast, Hg concentrations in smallmouth bass 31 (Micropterus dolomieui) were correlated with variables reflecting both water hardness (magnesium, calcium, conductivity) and acidity (pH, alkalinity). The relationship was inverse for the water hardness variables and positive for acidity. Stepwise regression identified three variables significant in explaining variation in Hg in smallmouth bass: calcium, DOC and latitude. The relationship between mercury levels in walleye (Stizostedion vitreum) and northern pike (Esox lucius) in Ontario lakes was examined. Walleye and pike occurred together in 79 of the 346 study lakes. The standard Hg concentrations in walleye and pike in these 79 overlapping lakes were highly (p <0.05) correlated. The mean Hg concentration in standard length walleye and northern pike from these lakes was 0.65 pg g' and 0.52 pg g’, respectively. Lake chemical and physical parameters related to Hg concentrations in both species were examined to determine if the same environmental factors affected mercury accumulation in walleye and northern pike. Descriptors associated with lake dystrophy (DOC and iron) were positively correlated (p <0.05) with Hg levels in both walleye and pike. Alkalinity, pH and hardness variables (calcium, conductivity, and magnesium) were negatively correlated (p <0.05) with Hg concentrations in pike but not walleye. Latitude was positively correlated (p <0.05) with Hg levels in walleye only. Finally, the relationship between Hg in 3 species of sport fish (lake trout, smallmouth bass and walleye) and background levels of Hg in lake sediment was examined. Using background sediment Hg as a reflection of geological Hg levels, the analyses suggested that lake to lake differences in Hg levels in fish cannot be accounted for by differences in geological Hg. Taken together, the data support the premise characteristics act together to influence Hg levels in fish. Common elements do emerge. Lakes with higher DOC levels tend to have sport fish with higher Hg levels. Lakes with lower pH and alkalinity tend to have sport fish with higher Hg levels. Lakes of lower hardness (lower Ca, Mg, Conductivity) tend to have sport fish with higher Hg levels. c. Organic Residues in Fish: Relationships to Long Range Transport Work began in FY 1989/90 on the subject of the long range transport of organics and the significance of this pathway to organic residue accumulations in sport fish. In a preliminary assessment, PCB and total DDT concentrations in sport fish were found to be highly correlated for most lakes, suggesting a common source for these contaminants. A lack of correlation was useful in identifying lakes where local point source PCB contamination had occurred. The presence of planktivorous fish was associated with elevated PCB and DDT concentrations in lake trout. MNR Fisheries Acidification Program a. Extensive Surveys This program has used extensive survey data to examine relationships between fish species presence/absence and lake physical/chemical parameters. Fish survey data were gathered on 9000 lakes and 3200 of these lakes had recent chemical data. The total number of species was found to increase with lake area, whereas the number of cyprinids (minnow species) was generally unrelated to lake size. When the effects of lake size were taken into account, a decline in number of fish species occurred below pH 6.0. Cyprinids appear to be very sensitive to low pH as their occurrence declined below pH 6.0. The distribution of each species was 32 examined to evaluate the potential of the 13 most common small (S 10 cm total length) fish species to be used as early indicators of change in the fish community due to acidification. The most promising species were common shiner (Notropis cornutus), fathead minnow (Pimephales promelas), bluntnose minnow (Pimephales notatus), blacknose shiner (Notropis heterolepis) and slimy sculpin (Cottus cognatus) (Figure 17). Losses of sport fish populations in Ontario were calculated using, 1) observed pH thresholds for mortality based on survey data (pH <5.5 for lake trout, walleye and smallmouth bass; pH <5.0 for brook trout, Salvelinus fontinalis), 2) atlases describing species’ distributions, and 3) the extensive Ontario chemical data set. The estimated number of lakes that have either lost their former populations or have had residual non- reproducing populations in Ontario were 119 lake trout, 39 brook trout, 52 smallmouth bass, and 14 walleye lakes (Table 2). Table 2 Estimated Number of Sport Fish Lakes in Ontario Affected by Acidification SPECIES Number of Lakes LT BT SMB W Total # in Ontario 2,318 2,100 2,421 4,038 # Sampled for pH 1,296 639 901 989 # Sampled with pH < species thresholds 78 8 27 7 Estimated # with pH < species thresholds 119 39 52 14 # Affected lakes in Sudbury Area 94 14 18 8 LT = Lake Trout BT = Brook Trout SMB = Smallmouth Bass W = Walleye SPECIES Slimy sculpin Blacknose shiner Fathead minnow Common shiner Bluntnose minnow lowa darter Finescale dace Lake chub Brook sticklebock Creek chub Pearl dace N. redbelly dace Golden shiner Figure 17 b. Comparative Lakes Netting surveys and field bioassays were conducted in many Northeastern Region lakes to generate the pH thresholds for survival and reproduction of lake trout, brook trout, smallmouth bass, and walleye. These thresholds were used to derive the provincial estimates of sport fish resources affected by acid rain. Recently, many of these lakes have been resurveyed to examine the recovery rates of affected fish populations. Many of these lakes are affected by sulphur dioxide emissions from the Sudbury smelters. Emission reductions have led to improvements in water quality in many Northeastern Region lakes. In Whitepine Lake, where a residual population of non- reproducing adult lake trout occurred, recruitment resumed when lake pH rose above pH 5.5. Increased competition and 33 Change in Fish Communities Due to Acidification predation by lake trout then resulted in the collapse of a large population of yellow perch. In Joe Lake, a reproducing brook trout population was re-established through stocking after water quality improved. Lake pH has improved in 25 former lake trout lakes in the Sudbury area, allowing fishery managers to stock hatchery reared lake trout and begin rehabilitation of sport fisheries in this area. c. Trend-Through-Time-Studies Field studies located in the Muskoka/Haliburton area have assessed the status of fish populations in eighteen (18) low alkalinity lakes. A subset of these lakes will be used to assess the impact of future acid deposition levels on fish populations in this acid sensitive area of Ontario. These studies have found that acid sensitive species such as common shiner, fathead minnow, bluntnose minnow and blacknose shiner, are present in lakes with pH >5.5. Acid tolerant species such as yellow perch, northern redbelly dace (Chrosomus eos), golden shiner (Notemigonus chrysoleucas), and pearl dace (Semotilus margarita), are present in low pH lakes (lakes with pH <5.5 and >5.3). MNR Wildlife Studies The objectives of this study were to: a. Determine the association of wetland acidity with reproductive parameters and insect prey of the Eastern Kingbird near Sudbury, Ontario. b. Determine the contribution of inorganic and organic acids to the acidity of wetlands in the Killarney area. c. Determine the toxicity of aluminum to amphibians in waters containing natural organic acids. d. Determine the levels of cadmium in the common goldeneye. e. Assess the influence of lake acidification on the reproductive success of the common loon in Ontario. a. Wetland Acidity and the Eastern Kingbird A three year study investigated the relationship between water quality variables associated with acidification and the reproduction of the Eastern Kingbird near Sudbury. The major percentage of variation in Kingbird reproductive factors measured (including egg weight loss and bone growth), was explained by genetic differences between siblings or by environmental differences between nests. However, an additional amount of variation was explained 34 by lake acidification. Metal enrichment of aquatic prey insects was related to acidity in the study area. However, no food limitation for the Kingbird could be attributed to lake acidity. b. Sources of Acidity in Killarney Wetlands The role of natural or organic acidity in Killarney area wetlands was addressed in another study which was published in 1986. Data indicate that acidity comes predominately from sulphates and that organic acidity plays a minor role in the Killarney study sites. c. Aluminum Toxicity to Amphibians Further surveys of amphibian habitat in the Sudbury area were carried out in 1986 and 1987 to determine if organic compounds in acidic pond water ameliorate the toxic effects of aluminum and other metals on amphibians. Laboratory and field survey information suggests that aluminum and copper are not toxic to amphibians in ponds containing even low levels of dissolved organic compounds while organic compounds are probably toxic to amphibians in low pH, dark water ponds. d. Cadmium Levels in Goldeneye the Common A program to determine the levels of cadmium present in the common goldeneye (Bucephala clangula) and to test the feasibility of using feathers as a reliable, non-fatal field sampling technique to monitor cadmium burden was carried out with Trent University from 1986-1988. Results indicated that feather cadmium levels of Ontario goldeneye were higher than those reported elsewhere. Cadmium levels were greater in females than males, but no difference was measured between juveniles and adults. e. Lake Acidification and the Common Loon A joint program with the Long Point Bird Observatory from 1989 to 1992 is to examine the mechanisms responsible for the effects of acidity on the reproductive success of the Common Loon (Gavia immer). The use of observations of feeding behaviour and reproductive performance of this species as an indicator of water quality in lakes will also be assessed. Preliminary results show evidence of lower loon chick production (fewer lakes producing six week old chicks) in more acid sensitive lakes. There may be an optimum alkalinity (about 5 or 6 mg L”) at which adult loons spend the least effort feeding their chicks. More efforts were spent feeding chicks in lakes with higher aluminum concentrations. C. REMEDIAL METHODOLOGIES DEVELOPMENT Two lakes in central Ontario, Bowland and Trout Lakes, were limed to examine the feasibility of using liming as a mitigative measure for lakes acidified by anthropogenic acidification. Bowland Lake, 70 km north of Sudbury, was a clear, oligotrophic lake with a flushing rate of ~ 2 years, which had once supported a native lake trout population. In 1982 it had pH <5.0, total Al of 130-150 pg L'! and a population of yellow perch but no lake trout was found in index netting. A trial introduction of lake trout before liming had failed. Bowland Lake was limed in August 1983 using 84 tonnes of calcite dropped as a dry powder from a Canso aircraft. 35 Trout Lake, 50 km north of Parry Sound, was clear, marginally acidic (pH 5.8-6.2) with low total Al (25-40 pg L"). In 1982 it supported a complex community of 16 species of fishes including lake trout and smallmouth bass; however, the pH had reached 5.8 to 6.0 and severe spring melt episodes of very acidic melt water (pH <4.5) were occurring. Trout Lake was also limed in May 1984 with 135 tonnes of slurried calcite dropped from a Canso. The Acidic Lake: Bowland Lake After the calcite addition, the pH in Bowland Lake increased from <5.0 to 6.7, alkalinity increased from -0.3 to 4.5 mg L'! and Al declined gradually to 30 mg L" (Figure 18a, 18b). By 1989, six years after liming, lake flushing had reduced the pH to 5.7 and alkalinity to 1.5 mg L", Al had risen to 60 mg L', DOC remained higher than pre- liming and Secchi depth continued to be less than pre-liming. The biological community of Bowland Lake changed after liming. Lake trout were successfully introduced as adults and fingerlings the fall after liming. Bioassays of caged lake trout fry and fingerlings which had shown <10% survival before liming resulted in 100% survival after liming. Lake trout eggs had also shown <10% survival in the acidic lake in overwinter bioassays. Survival of eggs increased to >75% in the winter and spring after liming and stayed over 50% for the next six years of sampling - comparable to the results on a circumneutral reference lake. Successful recruitment by the stocked lake trout was documented when three and four year old fish were sampled which could only have been from natural recruitment. Growth of stocked lake trout fingerlings in limed Bowland Lake was comparable to other lakes in the region, however, adult 6 5 3 = Figure 18a Trend in pH in Bowland Lake Whole lake alkalinity (mg CaCO3 / L) Figure 18b Trend in Alkalinity in Bowland Lake 36 trout, which had been transferred from circumneutral lakes, lost condition and died over a six year period perhaps indicating their inability to adapt to the Bowland Lake forage base. The yellow perch population appeared to be driven primarily by lake summer temperatures and lake trout predation. A strong 1983 year class resulting from high summer temperatures, drove the population of >1+ perch to a high of 353,000 in 1985. Gradually, natural mortality and predation reduced the population to 76,000 by 1989. Preliminary results from application of a fish bioenergetics model suggest that year class strength of yellow perch is a driving force in the lake’s ecology. Small yellow perch feed on zooplankton and zoobenthos as well as being a source of food for larger perch and lake trout. Annual variation in this population will effect the direction and efficiency of energy flow through the system. Phytoplankton biovolume in the photic zone did not change with liming. Analysis using multivariate ordination techniques is under way to identify possible compositional changes that may have occurred in the plankton. Zooplankton composition was affected by liming. Certain acidophilic species decreased in abundance and certain species preferring less acidic conditions either became more abundant or appeared. The abundance of rotifers and ciliates generally increased after liming whereas the abundance of crustaceans declined slightly. Extensive sampling of the zoobenthos occurred in the four years after liming. Five sampling strategies were applied in late summer to sample a range of habitats to determine the species richness and abundance of benthic invertebrates. The species richness of benthic invertebrates was consistently higher in the post liming years. There was a notable failure of certain 37 important types of acid sensitive invertebrates including gastropods and amphipods, to recolonize Bowland Lake up to 5 years after liming. The abundance and biomass of invertebrates declined in hypolimnetic sediments. The size specific decline in chironomids in hypolimnetic sediments, responsible for the overall decline in community biomass, is thought to be a consequence of lake trout feeding which began concurrent with lake neutralization. The Endangered Lake: Trout Lake The pH and alkalinity in Trout Lake increased to 6.6 and 2.6 mg L', respectively, immediately after liming then were reduced by lake flushing to 6.0 and 2.0 after six years (Figure 19a, 19b). Total Al levels were reduced by 40% to -25 mg L'. Ca concentrations rose from 2.2 mg L' to 3.8 mg L" directly after liming then dropped to 2.6 mg L" by 1989. DOC, Secchi depth and manganese remained unchanged by liming. The biological community did not show as great a change as in the acidic lake however some important changes did occur. In the phytoplankton community, while the peak summer biovolume did not change, ordination analysis clearly segregated three groups of samples: a preliming group (1983/4), an intermediate early postliming group (1985/6) and a late postliming group (1987-89). While phytoplankton biovolume was predominantly diatoms throughout the study, the biovolume of chrysophytes declined after liming and the cryptophytes increased. Zooplankton abundance and biomass declined in the first three summers after liming then returned to preliming levels. Rotifers became more abundant in the plankton starting three years after liming. Average ice free abundances of crustaceans were reduced the first three summers and then abundances returned to preliming levels. Figure 19a Trend in pH in Trout Lake 24 > © oO oO D = 2 = S t 50 ja ATOME : laut tu pS WEY 4 [EN Mak mathe +7 t i bu 6 * 7 ) ZAC } \ Town ai it cbt Or wy) oe ay: Fr CT = 7 Heaoe 1! f ( | i ; a : FM LC) LL hf be OI er Me re SUE 1 ; Ti Sil) fll 0 Wim oven à th yi Habit Nr eat + put | MINE VO 4 aies Lonel Tye? demie Vis to \NOUASo an!) 1 ita + [04448 Ph, ER I “7 MNT 430 avin aver ae bris tailed) a ‘ 1 Ff oD 0) -ANCIACPG Orn 1 ye ah -OniNSD O1 boUUpe oS sis ; 1 : D + + ? . ‘ à } ’ ALI ut fret >} gate, vere be , sue ) ‘yg CAPES : Le. tte vw sw OUT ve ak Rés Cr | où | id Dit A! | ite Van ROUR 99 5 tbe y old i : Fr at J ame ln CURE Bisind vs ren a ale * Li # + ‘ ii DAD tthe | d + gla oie 4 = P ‘ A * ‘ JMIOVE ‘i : WW } i! i "ai § . 4 - ‘ i. ) “4 ‘ ‘A 1: ys . | ates mé apt P Au 1 > & " © ,! 4 ele] 4579} ‘ Y hm ' (414 NU CRM Lab REET d. 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Lutte à à > Dave mat rt iA siya se no ps ~ arr ’ Tee P salé anal. ie, “la t Wi AN : j Tynes ; SUS 018 Li 9 Evil, se CAN TA | om RA TT TT MT HOnih Baldy BR? rae? ni? : 4 Bettas Ne WE UE Hee mesh nm | Hu Org! ban ive fui a 1 OR Nae | At at Wy hottes | 4 PIS i din a vd sit ee ee ok rien Lewitt to yoelni 0.4 init Of vere} U we si he > cdi" “A aff St dei) A con dre, Cee old 49) ee ~~ ae it = 5 V 7 5 ae a Biogeochemical Studies (Task 4) Contact: P. Dillon The purpose of the biogeochemical studies is to determine how catchments interact with acid deposition and how streams and lakes are affected as a result of these interactions. There are six subtasks being investigated which include Mineral Weathering, Soil, Bioaccumulation, Hydrological and Wetland Studies, and Watershed Manipulation Experiments. A. MINERAL WEATHERING STUDIES Primary mineral weathering is a source of secondary minerals, a source of essential nutrients for vegetation and is one of the major sources of acid neutralization in soils. The following is a summary of the results of mineral weathering studies conducted in the Muskoka-Haliburton region over the last five years. Weathering has created an aluminum-rich layer on the surface of feldspar grains in the B horizon of Plastic Lake soils. This layer may be responsible for some of the Al leached from these soils by acidic deposition. The major minerals weathering in the Plastic Lake catchment are feldspars. Long-term weathering rates determined from depletion profiles of soil minerals are less than current denudation rates suggesting that current rates may be elevated by acidic deposition. A study of the secondary mineralogy of 49 Plastic Lake has been completed. Vermiculite dominates in the Ae horizon and the clay mineral suite in the B horizons is comprised primarily of hydroxy-interlayered vermiculite and kaolinite. Amorphous Al in the B horizon and aluminum present in the vermiculite interlayer, is likely the result of eluviation from upper horizons (Ae). These results agree well with and complement the soil/soil solution studies (see below). Laboratory leaching studies on feldspar minerals using aqueous solutions, similar in composition to those found in the soil water of Plastic Lake, have demonstrated minimal leaching profiles on mineral grains similar to those found in the Ae horizons of Plastic Lake. This suggests that under field conditions, the feldspars are dissolving congruently. Carbon isotopes (°C and “C) were used as natural tracers to evaluate the sources and sinks of inorganic carbon in the Harp Lake catchment. Analysis of the C isotopes in dissolved inorganic C (DIC) showed that all of the alkalinity produced in the catchment and transported to the streams and/or lake (including the groundwater) resulted from silicate mineral weathering, not from any carbonate sources. B. SOIL STUDIES Soil/Soil Water Interactions The chemistry of the leachate from 12 sets of lysimeter pits along with streams and deep groundwater in the Plastic and Harp lake catchments was monitored over the last 5 years. The major difference in the stream chemistry between Plastic and Harp catchments can be accounted for by the long residence time of the groundwater at Harp Lake. The Plastic lake soils are very thin and there is comparatively little groundwater. Differences in the unsaturated zone soil chemistry also occur and are important to vegetation and soil modelling of long-term changes in acidic deposition. Harp soil solutions from the LFH (upper organic) horizons have greater alkalinity, pH and base cation concentrations than similar horizons at Plastic Lake. Leachate draining the soil from the B and/or C horizons have similar base cation concentrations. Furthermore, the concentration of inorganic SO? is much higher in the B horizons than the LFH/Ah horizons at both sites, but levels are higher in the Plastic Lake soils. These findings confirm that the differences in alkalinity and pH of water leaving the soils at the two sites are not due to differences in base cation release, but to differences in the release of aluminum and, more importantly, sulphate. It is thought that the strong uptake of base cations in the B horizon at both sites is due to the large amounts of hydroxy-interlayered vermiculite present in these horizons. Higher levels of adsorbed SO? at the Plastic Lake site result in greater SO release from the soils (see below). Aluminum release is also greater at Plastic Lake and is probably due to greater dissolution of vermiculite containing Al in the interlayer position, as well as allophane and other amorphous Al complexes. Selective soil extraction studies at Dorset have shown that the major amorphous Al-Si compound in Plastic and Harp Lake mineral 50 soils is 2:1 allophane. The Al component is in equilibrium with hydroxy- interlayered vermiculite. Soil solution concentrations of Al and Si agree well with this hypothesis. Future work will attempt to verify this hypothesis. Sulphur Studies Sulphur adsorption and release are the major geochemical reactions in soils that buffer acidic deposition. Greater levels of adsorbed SO? are found in Plastic Lake soils than in Harp Lake soils, and correspond well to the soil solution results reported above. Almost all the inorganic sulphur in the soil solution is SO; which has the same isotopic composition as organic sulphur. This Suggests that it has passed at least once through the organic sulphur pool. A new method for organic sulphur analysis has been developed by the Laboratory Services Branch, and will permit the accurate measurement of organic sulphur in small amounts of soil water from the lysimeters. This will allow quantitative estimates to be made of the relative importance of organic sulphur flux from the LFH to the B horizons. Its role in providing SO? through decomposition to the adsorbed SO? pool can then be identified. Laboratory SO{ adsorption and desorption studies have demonstrated the pH dependence of SO} adsorption/desorption processes. In the upper mineral horizons there is more adsorbed SO} and greater desorption under ambient pH conditions. This agrees well with the field results described above and will provide a quantitative basis for modelling this process. C. BIOACCUMULATION STUDIES The accumulation of base cations in vegetation can be a significant factor in a catchment’s overall budget. This accumulation can also generate acidity in the soil. To evaluate these effects, trees over 10 cm in both the Harp 4-21 subcatchment and Plastic Lake PC-08 subcatchment have been cored for temporal dating and chemical analysis. The dating and chemical analyses have recently been completed and collected into a database awaiting interpretation. D. HYDROLOGICAL STUDIES Hydrology plays an important role in routing acidic deposition to various components of the landscape. These components have markedly different impacts on water chemistry. As previously mentioned, hydrological studies have demonstrated the importance of deep, long-residence time groundwater as a contributor to stream chemistry differences between the two basins. The relative importance of saturated overland flow (runoff) in different parts of the Plastic Lake catchment has also been documented. Water that has had little contact with the upland mineral soils or wetlands has a substantially lower pH and lower Al and Si concentrations. With the exception of the wetland areas during spring melt, most precipitation passes through the soil. E. WETLAND STUDIES Wetlands in a watershed have been reported to have a significant effect on nutrient 51 budgets for the watershed by acting as nutrient sources and sinks and as the site of nutrient transformations. To investigate this, monthly and annual input-output budgets for total N, total organic N, total inorganic N, NH; nitrogen, nitrate, total P and DOC were measured on a total of five wetlands, located in Harp Lake, Plastic Lake and Paint Lake catchments. The wetlands transformed N by retaining inorganic N and exporting an equivalent amount of organic N. Beaver pond wetlands retained NO; and allowed NH to pass through while conifer swamps retained both NO; and NHj. DOC fluxes into and out of the beaver ponds were equal but output from the conifer swamps exceeded input by greater than 90%. Phosphorus retention was less than 20% of the P input, and budget uncertainties were greater than or equal to retention rates. Marked seasonal trends in nutrient retention were observed. Nutrient retention coincided with stream flow, increased evapotranspiration and biotic uptake during the summer. Net nutrient export occurred during the winter and spring when stream flows were highest and biotic uptake was low. Future work on the wetlands will concentrate on sulphur budgets and methane (CH,) production. F. WATERSHED MANIPULATION EXPERIMENTS Catchment Manipulations Environment Ontario has contributed to the funding of two catchment-scale manipulation experiments. The first and largest of these is the RAIN (Reversing Acidification in Norway) project. This experiment’s purpose is to examine the effects of changes in precipitation chemistry on soil and surface water acidification. At a pristine area in western Norway, two catchments are being acidified by the addition of H,SO, and H,SO, + HNO; respectively. At an acidified catchment in southern Norway, ambient acid deposition is excluded by means of a roof and clean precipitation added underneath. At the pristine sites, results over 5 years indicate that the acid-sensitive catchments responded rapidly to increases in acid deposition. Single severe episodes may be sufficient to acidify runoff to the extent that pH and Al levels are toxic to some fish. Chronic or long-term acidification of runoff resulted in only 3 or 4 years. Soil acidification also took place. At the acidified sites, data from the acid- exclusion experiment showed that reductions in acid deposition result in decreased concentrations of strong acid anions in runoff. Soil acidification also began to reverse. The changes in runoff and soil chemistry at the two study areas can be explained quantitatively in terms of the key soil- chemical processes including sulphate adsorption, cation exchange, weathering and organic acid buffering. The MAGIC model (discussed in the section "Aquatic Studies") successfully predicted the observed changes in runoff chemistry at both the pristine and acidified sites. The RAIN project shows that sensitive catchments respond to changes in acid deposition (increases or decreases) within a few years. The reversibility of the acidification process observed here agrees well with the studies of the Sudbury lakes and Plastic Lake (see Aquatic Studies). 52 Parts of the terrestrial uplands of Lake 302 in the Experimental Lakes Area near Kenora were also acidified. Nitrogen and sulphur deposition, within six small catchments and one larger catchment (8 ha in size), were manipulated to simulate southern Ontario deposition by spiking the snowpack with ammonium nitrate and sulphuric acid. During the study, the hydrologic pathways and outflow generation pathways were monitored to explain the observed stream chemistry at different locations within the catchment. Two distinct landscape areas were monitored, bedrock areas with no infiltration of precipitation and forested areas with substrate infiltration in a soil depth averaging seven centimeters. The bedrock sub-basin showed peak flows at snowmelt and during rain events. Aluminum levels peaked during these periods, and increased over time possibly as a result of different contributing areas during the runoff even. The forested sub-basin also peaks at these times but a lag effect was seen. After acidification of one of the catchments, pH decreased by 0.2 units. Cations and sulphate also decreased initially before returning to control levels. In the control watershed, the inorganic Al fraction was one third to one half of the monomeric organic fraction. However, for the acidified watershed, until three weeks into the melt period, inorganic Al dominated. Environmental Management and Economics Studies (Task 5) Contact: J. Donnan A. DAMAGES AND BENEFITS Acid Deposition Effects models that were developed in the early 1980’s were reviewed and, where possible, updated. These models are programmed in the Interactive Financial Planning System language which is supported on the Government mainframe computer network. Five submodels were originally developed for the following receptor categories: Forests, inland lakes with commercial fisheries, agricultural crops, commercially harvested fur-bearing wildlife and materials and structures. Based on effects research to date, only three of the receptor categories are at some risk to acid deposition: forests, materials and structures and agricultural crops. The 100 or so inland lakes with commercial fisheries in Ontario are generally very large with high alkalinity and buffering capacity and little risk of acidification. Research has revealed no verified dose-response relationships between acid deposition and fur-bearing mammals. 53 B. COSTS OF ABATEMENT AND MITIGATION Sulphur dioxide and NO, abatement technology and cost information for Stationary sources in Ontario that was developed by consultants during fiscal 1988- 1989 was applied to estimate the costs of achieving further emission reductions after the Countdown Acid Rain program is completed in 1994. Costs were estimated to achieve reductions in total emissions of SO, and NO, from Stationary sources (including the four major corporate sources under regulation and the remaining industrial establishments which are not subject to specific regulations) by 10%, 30% and 50%. Based on the type of technologies used for cost estimation at stationary sources only, further SO, reductions would be less costly per tonne removed than NO, reductions. Analyses of abatement cost functions indicate that the major regulated sources of SO, would be the most cost-effective sources for further emission reduction after the Countdown program has been completed. NO, reductions at Ontario Hydro thermal power plants would also be the most cost effective for NO, reductions at stationary sources. Further reductions of NO, by mobile and area sources (ie. the automobile and other internal combustion engines) were not considered in this study because reliable cost estimates of additional controls by automobiles were not available. Another study had been proposed to investigate various approaches to reduce mobile source emissions beyond levels achievable with "on-board" emissions control devices. It was subsequently agreed to join with the Ministries of Energy and Transportation to Carry out a more comprehensive effort. A new terms of reference was completed and a competition initiated under the administration of the Ministry of Energy. The objective of the expanded study is to “identify and evaluate measures and approaches to reduce energy use, improve energy efficiency and reduce emissions in Ontario’s transportation sector.” A draft report is expected in February 1991. 54 Laboratory Support and Methodology Studies (Task 6) Contact: F. Tomassini Through the coordinated efforts of the 1. Precipitation - The LSB received 10 Central and Dorset Laboratories, the submissions (100 samples) for Laboratory Services Branch (LSB) continued major ions, nutrients, physical to support the various APIOS programs. A parameters analyses in addition to a summary of the total test load for the single submission for low level program is shown in Figure 22. The anions (chloride, nitrate 1989/90 fiscal year was a productive year and sulphate analyses). (Workload and the highlights are: 2251 tests). 2. Air Filters - In January 1990, a new A. INTERLABORATORY study was initiated on air sampling COMPARISON ANALYSIS filters of nylon, Teflon and