AAARCH 1981 CI UILU-WRC-8T-157 RESEARCH REPORT 157 f/^C UNIVERSITY OF ILLINOIS ATURBANA-CHAMPAIGN WATER RESOURCES CENTER Identification of the Water Quality Factors Which Prevent Fingernail Clams from Recolonizing the Illinois River, Phase II By Richard E. Sparks and Michael J. Sandusky, Illinois Natural History Survey, River Research Laboratory, Havana, Illinois and Anthony A. Paparo, School of Medicine and Department of Zoology, Southern Illinois University, Carbondale, Illinois *fS€A«C* Digitized by the Internet Arciiive in 2010 with funding from CARL!: Consortium of Academic and Research Libraries in Illinois http://www.archive.org/details/identificationofOOinspar IDENTIFICATION OF THE WATER QUALITY FACTORS WHICH PREVENT FINGERNAIL CLAMS FROM RECOLONIZING THE ILLINOIS RIVER PHASE II by Richard E. Sparks and Michael J. Sandusky ILLINOIS NATURAL HISTORY SURVEY RIVER RESEARCH LABORABORY Havana, Illinois 62644 and Anthony A. Paparo SCHOOL OF MEDICINE AND DEPARTMENT OF ZOOLOGY SOUTHERN ILLINOIS UNIVERSITY Carbondale, Illinois 62901 TECHNICAL COMPLETION REPORT Project No. B- 119- ILL Agreement No. 14-34-0001-9069 The work on which this report is based was supported in part by funds provided by the United States Department of the Interior as authorized under the Water Research and Development Act of 1978. Contents of this publication do not necessarily reflect the views and policies of the Office of Water Research and Technology, U.S. Department of the Interior, nor does mention of trade names or commercial products constitute their endorsement or recommendation for use by the U.S. Government. March, 1981 TABLE OF CONTENTS Page LIST OF FIGURES v LIST OF TABLES vii ACKNOWLEDGEMENTS viii ABSTRACT i^ INTRODUCTION AND BACKGROUND 1- METHODS 8 Collection of Fingernail Clams 8 Culture Techniques ° Addition Bioassays, Using Clam Gills H Sediment •'■ ^ River Water 12 Deletion Bioassays, Using Intact Clams 12 RESULTS AND DISCUSSION 17 Results of Different Culture Techniques 17 Clam Mortality 17 Clam Growth 20 Addition Bioassays, Using Clam Gills 22 Sediment 22 River Water 24 Deletion Bioassays, Using Intact Clams 25 Deletion Bioassay Number 1 25 Clam Mortality 27 Clam Growth 29 Deletion Bioassay Number 2 32 Clam Mortality 33 Clam Growth 33 SUMMARY '^3 RECOMMENDATIONS '^5 RELATION OF THIS RESEARCH TO WATER RESOURCES PROBLEMS 46 LITERATURE CITED ^^ PUBLICATIONS RESULTING FROM THIS RESEARCH 50 REQUESTS FOR PROJECT INFORMATION FROM 1 OCTOBER 1978 TO 31 MARCH 1980 52 LIST OF FIGURES Page Figure 1, Map of the Illinois and Mississippi Rivers 2 Figure 2. Utilization of the Illinois River by lesser scaup ducks ^ Figure 3. Bioassay laboratory 9 Figure 4. Schematic diagram of deletion bioassay 13 Figure 5. Deletion bioassay apparatus 14 Figure 6. Stock clam mortality at two weeks 17 Figure 7. Stock clam mortality at four weeks 19 Figure 8. Response of clam gills to four layers of sediment from Quiver Lake, Illinois River 23 Figure 9. Response of clam gills to Illinois River water .... 24 Figure 10. Water levels in the Illinois River during dele- tion bioassays 1 and 2 25 Figure 11. Mortality of clams exposed to well water, raw Illinois River water and treated river water for two weeks in deletion bioassay number 1 27 Figure 12. Mortality of clams exposed to test conditions for four weeks in deletion bioassay number 1 28 Figure 13. Shell length of clams exposed to well water, raw Illinois River water and treated river water for two weeks in deletion bioassay number 1 29 Figure 14. Shell length of clams exposed to test conditions for four weeks in deletion bioassay number 1 30 Figure 15. Mortality of clams exposed to well water, raw Illinois River water and treated river water for two weeks in deletion bioassay number 2 36 Figure 16. Mortality of clams exposed to test conditions for four weeks in deletion bioassay number 2 37 Figure 17. Mortality of clams exposed to test conditions for six weeks in deletion bioassay number 2 38 vl LIST OF FIGURES (continued) Page Figure 18. Growth of clams exposed to test conditions for two weeks in deletion bioassay number 2 39 Figure 19. Growth of clams exposed to test conditions for four weeks in deletion bioassay number 2 40 Figure 20. Growth of clams exposed to test conditions for six weeks in deletion bioassay number 2 41 LIST OF TABLES Page Table 1. Water Chemistry and Temperature in Stock Tanks ^8 Table 2. Growth and Survival of Stocks of Finger- nail Clams ^^ Table 3. Water Chemistry and Temperature During Deletion Bioassay No. 1 26 Table 4. Results of Deletion Bioassay No. 1 31 Table 5. Water Chemistry and Temperature During Deletion Bioassay No. 2 34 Table 6. Results of Deletion Bioassay No. 2 35 ACKNOWLEDGEMENTS We are grateful to: the Illinois Department of Conservation for providing laboratory space in the Fisheries Field Headquarters, located next to the Illinois River at Havana, and especially to the two supervisors during the project period, Hubert Bell and Rudi Stinauer and to Rod Horner, fish pathologist, who allowed us free use of his laboratory and analytical instruments; Dr. George Sprugel, Chief of the Natural History Survey (now retired), for his encouragement of this research; Robert 0. Ellis, Larry D. Gross and James W. Seets of the Natural History Survey for laying the pipe and installing the manhole between the Illinois River and the laboratory; Kevin B. Anderson, the graduate research assistant during Phase I of this project, who returned from his job as a plumbing/ heating contractor in Alpha, Illinois to install the submersible sewage pump in the river on a cold winter day that turned into a long, cold winter night; Dan Fusing, Mr. Anderson's co-worker; Dennis W. Leonard, Manager of Industrial Minerals Marketing, Anaconda Copper Company, 555 17th Street, Denver, Colorado 80217, who supplied the clinoptilolite (Zeolite lOlOA) free of charge; Victoria Atchley who typed the report and never lost her patience with numerous additions and changes. ABSTRACT Water samples taken from the Illinois River on 5 October and 22 April 1977 inhibited the beating of the cilia on isolated clam gills, within two hours of exposure. The April sample was significantly more toxic than the Octo- ber sample. Sediment taken on 14 December 1970 from Quiver Lake, a bottom- land lake which receives sediment from the Illinois River and where finger- nail clams were abundant prior to a die-off in 1955-58, was toxic to isolated clam gills. A sediment layer from the 2.6-5.1 cm depth showed the greatest toxicity, the 0-2.5 cm depth the next greatest toxicity, and deeper layers showed significantly less toxicity. From 3 April to 8 May 1980, intact fingernail clams were exposed to raw Illinois River water (containing sus- pended sediment) , clean well water, and raw river water subjected to three treatments: (a) sand filtration (b) sand filtration + carbon filtration (c) sand filtration + clinoptilolite filtration. After two weeks of exposure, clams in raw river water suffered significantly greater mortality (42.5%) than other clams. After six weeks of exposure, 62.5% of the clams in raw river water had died, the next highest mortality (47.5%) occurred in sand- filtered water, and mortality in the other two treatments did not differ significantly from the well-water controls (24% mortality). The clams probably survived better in the treated water for two reasons: (1) clinop- tilolite and carbon each removed ammonia, which is found in Illinois River water and which is toxic to fingernail clams (2) the additional physical filtration provided by the charcoal and clinoptilolite removed additional sediment, which contains unidentified toxic factors. Surviving clams grew better in river water and treated river water than in clean well water, probably because they fed upon fine organic matter which passed through the filters. The latter results indicate that the unidentified toxic factor acts directly on the clams, rather than indirectly by affecting their food supply. The rapid assay, using fingernail clam gills, and the deletion bioassay, where toxic components are selectively removed from raw water samples and the corresponding reduction in toxicity measured, are promising means of identifying effective treatments for complex wastes and polluted streams. Sparks, Richard E., Michael J. Sandusky and Anthony A. Paparo IDENTIFICATION OF THE WATER QUALITY FACTORS WHICH PREVENT FINGERNAIL CLAMS FROM RECOLONIZING THE ILLINOIS RIVER Technical Completion Report to Office of Water Research and Technology, Department of the Interior, March 1981 KEYWORDS — water pollution effects/ bioassay/ bioindicators/ animal physiology/ fingernail clams/ Sphaerium transversum/ Musculium transversum/ Sphaeriidae/ silt/ ammonia/ suspended solids/ suspended sediment/ Keokuk Pool/ Mississippi River/ Illinois River/ pollutant identification/ toxicity/ clams/ mussels/ mollusks/ bivalves/ water pollution treatment/ water quality/ zeolites/ clinoptilolite/ activated carbon/ filtration/ pollution abatement/ sediment/ water pollution sources/ food webs/ limiting factors/ secondary productivity/ aquatic productivity/ assay INTRODUCTION AND BACKGROUND Richardson (1921, 1928) conducted surveys of the bottom fauna in the Illinois River and found that fingernail clams and snails were abundant or common in a 180-mile section of the river between the mouth and the upper end of Peoria Lake (Figure 1) during the years 1913-1915. The clam population declined after 1915 from river miles 80.1 to 180.5 (river miles are measured upstream from the confluence with the Mississippi River) as a result of the increased sewage pollution from the Chicago Sanitary and Ship Canal which opened January 1, 1900, and diverted Chicago sewage from Lake Michigan to the Illinois River. Degradation of the bottom progressed downstream at a rate of 8 to 16 miles per year (Richardson 1921). The bottom fauna exhibited a recovery pattern from 1920 to 1925 (Richardson 1921, 1928), probably in response to the installation of sewage and industrial waste treatment facilities in the Illinois Valley. After 1925 there is a gap in bottom fauna data until a 1964 survey by Starrett and Paloumpis (1964). Starrett and Paloumpis found no finger- nail clams in the Illinois River above Beardstown (river mile 86.9), so the clams had died out in a 100-mile section of the river sometime between 1925 and 1964. Anderson (1977) surveyed the bottom fauna in the Illinois River in 1975. Distribution of fingernail clams in the Illinois River in 1975 was essentially the same as it was in 1964. However, there appeared to have been a drastic decrease or loss of snails in the lower Illinois River. Although Starrett and Paloumpis (1964) found no snails above 2 Beardstown, they reported an average of 34/m from Beardstown to Grafton; no snails were collected in the 1975 study. There are three lines of evidence indicating that the die-off of fingernail clams occurred in the 1950 's. Paloumpis and Starrett (1960) observed a die-off of fingernail clams in three Illinois River bottomland lakes in the 1950' s. To use Quiver Lake as an example: in 1952, sphaeriid 2 clams, mainly Musoulium transversum , occurred in numbers exceeding 20,000/m . During the next four years, 1953-1956, populations of fingernail clams and certain snails declined to zero. A slight recovery occurred in the following WISCONSIN |*B"^T^^»B^ DRE-SDEN LOCK & DAM, MILE 271.5 MARSEILLES ^-^^ ,, , STARVED LOCK & DAM '^''^^ HENRY 20% mortality), the entire stock was discarded and not used for bioassays. An exception was made for stock 8, where heavy mortality between the 2-week and 4-week check was attributable to a power failure which interrupted water flow and aeration to the stock aquaria. These clams were used in deletion bioassay number 1 because no other clams were available. A small amount of the sieved sediment was added to each petri dish, and the remainder stored at room temperature in unchlorinated well water in a 3.8-liter glass jar. Silt was added to the petri dishes because we found that only 7 out of 20 clams survived a 4-week test in bare petri dishes, whereas 18 out of 20 survived in silt from the Mississippi River. The beneficial effect of the sediment seemed to last only 2 weeks, so the old sediment was discarded and stored sediment added to the dishes every 2 weeks when the clams were examined and counted. Fingernail clams are very active and climb the sides of glass containers, so the petri dishes were covered with a plastic snap-on lid in which a 50-mm hole was cut to allow circulation of water. The hole was covered with 30-mesh nylon screen. Because the clams were small, active, fragile-shelled, and nearly transparent, some were unavoidably lost when the contents of the petri dishes were being sieved at 2-week intervals. If any clams were missing at each 2-week check, the numbers missing were recorded and are reported in the tables of results. Of course, missing clams were not counted as survivors or dead clams. Dead clams were easily Identified under the microscope, because the shells gaped and were usually empty. When a clam dies, the elastic hinge ligament forces the shell open and the soft body parts decay and disappear within a few hours. Stock clams were fed a concentrated suspension of the algae Saenedesmus quadrioauda (Chlorophyta) , delivered to the stock aquaria with a 50-ml pipette twice a day. The following changes were made in our culture techniques during the course of this research: (1) Starting with stock 9 (collected 23 October 1979) an automatic feeding system was added to the stock tanks, which delivered 3.2 ml of concentrated algal suspension to each stock tank every 5 minutes. (2) Starting with stock 11 (collected 20 March 1980) petri 11 dishes containing clams and sieved sediment were placed in bare aquaria conmining no other clams or sediment, following a suggestion by Gale (1972:22) that the decomposing remains of dead clams may induce a resting state (no growth) in live clams kept in the same container. Water temperatures and dissolved oxygen concentrations in the stock aquaria were measured 5 times a week, pH 2 or 3 times per week, and alkalinity once a week. Results are reported in Table 1. ADDITION BIOASSAYS, USING CLAM GILLS During Phase I of this project, water samples from the Illinois River and sediment samples from an adjacent backwater lake connected to the river were collected and tested on fingernail clam gills. Not all the results had been analyzed and graphed at the time the Phase I Report was prepared (Anderson et al. 1978), so the methods and results are presented in this report. Since sediment or river water were added to clean water, these tests are called addition hioassays. Sediment On 14 December 1976 a sediment core was taken from Quiver Lake, which opens into the Illinois River at Havana. Quiver Lake was the location where Paloumpis and Starrett (1960) documented a die-off of fingernail clams in 1955-58, and where Sparks failed to find any live clams in 1973. The core was extruded from the 10-cm diameter steel corer onto a plastic tray, and divided into the following segments: (1) surface to 2.5 cm depth (2) 2.6-5.1 cm depth (3) 5.2-7.6 cm depth (4) 7.7-10.2 cm depth. Each segment of the core was placed in a separate jar and shipped to Southern Illinois University for testing. At Southern Illinois University, the core segments were stored overnight in a refrigerator, warmed to room temper- ature the next day, and used immediately. Equal volumes of wet mud from each core segment were placed in 1 liter of invertebrate physiological solution, making four test solutions in all. After the effects on the clam gills were determined, a measured volume of test solution was passed through a membrane filter, air dried, and weighed. The sediment concentration (in mg per liter) was then calculated. The average particle size was measured under 12 a microscope with an ocular micrometer and particle counts made with a hemocy tometer . The clams had been acclimated at least one week in invertebrate physiological solution in Instant Ocean aquaria at a temperature of 17C and a pH ranging from 7.8 to 8.2, Gills were excised from the clams and placed in petri dishes, where a continuous flow of standard physiological solution or solution to which the sediments had been added was maintained by means of metering pumps. Temperatures and dissolved oxygen concentrations in the petri dishes were monitored by thermistor meters and membrane elec- trodes. The clam gills were observed under a microscope, and the movement of particles across a known distance in the microscope field was timed so that the particle transport rate (in ym per second) could be calculated. The average rate in a microscope field showing approximately 50 gill fila- ments was determined. Gills from 5-7 clams were observed, and the means and standard deviations for the transport rates are reported in the results. River Water Water samples were dipped from one foot below the surface of the Illinois River at Havana on 5 October 1977 and 22 April 1978. The samples of river water and a sample of well water from the laboratory at Havana were shipped to the laboratory at Southern Illinois University for testing on clam gills. At Southern Illinois University, the water samples were refrigerated overnight, warmed to room temperature the next day, and used immediately. Apparatus and methods specially developed for this research (Anderson et al. 1978) were used to determine the ciliary beating rate of lateral cilia (in beats per second) on isolated clam gills from 5-7 clams as they were exposed to the 3 samples of water, and to samples of river water diluted in various proportions with well water. DELETION BIOASSAYS, USING INTACT CLAMS A submersible sewage pump delivered raw Illinois River water and sediment to a 208-liter polyethylene drum containing a float switch. When- ever water in the reservoir fell below a set point, the submersible pump switched on. When the reservoir was full, the pump switched off, and the back flow of water in the pipe purged debris from the impeller and intake 13 screen of the pump. The pump was capable of grinding up and passing 3.8- cm solids, but the protective intake screen was approximately 1-cm mesh. A small pump circulated the water in the reservoir, to keep the sediments from settling out, and supplied a head box which delivered water by gravity flow to the test chambers and treatment systems described below. All parts of the delivery water system were made out of nontoxic materials, including glass, polyethylene, teflon, nylon and silicone rubber. The only exception was the metal impeller of the pump, but analyses by atomic absorption and flame emission spectroscopy showed no differences in metal concentrations between water samples taken simultaneously at the intake and in the reservoir. Figure 4 shows how the raw river water was treated to Temove certain components, hence these tests are called deletion bioassays. EXPERIMENTAL DESIGN: DELETION BIOASSAYS Charcoal Filter Raw Illinois' River -^Sand Filter Water & Sediment V Clinoptilolite resin CLEAN WELL WATER Clam Test Chamber No. 1 Clam Test Chamber No. 2 Clam Test Chamber No. 3 Clam Test Chamber No. ^ Clam Test Chamber No. 5 Figure 4. Schematic Diagram of Deletion Bioassay. 14 Treatment consisted of filtration through various media. Sand was used to remove suspended material, charcoal to remove a broad class of organic chemicals, and clinoptilolite to remove ammonia. Sand-filtered water was delivered to the charcoal filter and the clino filter to prevent rapid clogging of these expensive media with sediment. Raw Illinois River water and unchlorinated well water were also delivered to individual test chambers, so that the following 5 types of water were tested: (1) unchlorinated well water, (2) Illinois River water filtered through sand and clinoptilolite, (3) Illinois River water filtered through sand and charcoal, (4) Illinois River water filtered through sand, and (5) raw Illinois River water contain- ing suspended sediment. The filters were made from plastic garbage cans (see Figure 5.) Figure 5. Deletion Bioassay Apparatus. The automatic algae feeder is mounted on the white pegboard. The black 55-gallon drum is the reservoir for river water. The household garbage cans contain the filtration media. Test chambers are in a water bath in the fore- ground. 15 The outlet at the bottom of each garbage can was covered with plastic screen and a pad of fiberglass in the bottom of the can kept the media from plugging the outlet. Sand, charcoal, or clino was added next, and covered with another pad of fiberglass which could be removed easily and washed. Water flowed by gravity from the constant head box to the sand filter, then to the other filters or test chambers. The test chambers were 37.8-liter glass aquaria with outlets to maintain the volume at 23 liters. The test chambers were immersed in a water bath to control water temperature. Water flow from the deletion apparatus into the test chambers was approximately 100 ml per minute and was checked 3 times a day. Sediment occasionally clogged the delivery tubes overnight, but because of the large volume of the test chambers in relation to the small size and oxygen requirements of the clams, oxygen levels in the test chambers did not decline. The maximum length of time the flows could have stopped was 12 hours, and we do not feel that these infrequent stoppages had any effects on the results of our deletion bio- assays, which lasted 3-6 weeks. During deletion bioassay number 1, a 50-ml pipette was used to deliver the concentrated algal suspension to each test chamber twice a day. However, high concentrations of algae could not be maintained in the test chambers with pipette feeding. An automatic feeding system (separate from the one used on the stock aquaria) delivered 100 ml of algal suspension to each test chamber every 5 minutes during deletion bioassay number 2. Algal concentrations were measured by procedures described in Standard Methods (American Public Health Association 1976:1024-26). Clams from stocks number 8 (collected 21 June 1979) and 11 (collected 20 March 1980) were used in deletion bioassays 1 and 2, respectively. The procedures were the same as in the culture tests: (1) each test chamber held 2 petri dishes containing 20 clams each (for a total of 40 clams exposed to each test solution), (2) the clams were 2.4 to 3.0 mm in shell length, (3) clam survival and growth were checked at 2-week intervals, and (4) sieved sediment collected from the Mississippi River on the same date the clams were collected was added to the petri dishes at the beginning of the bioassay and at 2-week intervals thereafter. Water temperatures and dissolved oxygen concentrations in the test chambers were measured 5 times a week, pH 2 or 3 times per week, and alkalinity 16 once a week. Results are reported in Tables 3 and 5. Water levels on a gage at Havana were recorded during deletion bioassays 1 and 2 and are plotted in Figure 10. Variance tests (Snedecor and Cochran 1967) were used to determine whether there were significant differences in clam mortality between treat- ments. Mortalities in duplicate petri dishes within each test chamber were pooled. An analysis of variance, ANOVA (Steel and Torrie 1960), was used to determine whether there were significant differences in shell lengths of clams exposed to the different test solutions and the clean well water. If the mortality in a test solution was significantly different from mortality in the well water control, the length data were not analyzed, because of the possiblity that mortality was size-dependent. If, for example, the rate of uptake and effect of a toxic substance in the river water depended on the body volume or gill surface area of a clam, mortality would be size- dependent, and size differences between clams exposed to the various treat- ments and the well water would reflect differential mortality rather than differential growth. All differences were considered significant at a probability, P = .05. 17 RESULTS AND DISCUSSION RESULTS OF DIFFERENT CULTURE TECHNIQUES Water chemistry and temperature in the stock aquaria are given in Table 1. Clam Mortality Clam stocks 7-11 maintained during this phase of the research had lower mortalities after 2 and 4 weeks in the laboratory than stocks 1-6 maintained during Phase I (Figures 6 and 7). The confidence limits +110- +100- § +50H +ilO +20H OH -10 " 5 10 11 I I I I I I I I ■ M I M I j' I S I N I J I I'l I M I J I S I N I J I M AJAODFAJAODF 1978 — 1979 - COLLECTION DATE 1980 Figure 6. Stock Clam Mortality at Two Weeks. Brackets indicate 95% confidence limits. ^Mississippi River silt added. ^Algae added automatically every five minutes. '^Algae added by pipette twice a day. 18 4-1 m 0) •H O or c U C •H tn n) .H o OS (fl ^ 05 ^D CN 00 ■— 1 C -■^, m 611 tu X s: \£) vD t-O lT) lO 00 0^ ^ ^ ON 00 00 00 00 00 00 o^ CTv 00 s] O 1 —1 00 ON C -J- o c CM in CNi 00 CNi o 00 m lo n vD J ro ^ Csl IN (N CVJ I I I CO -a- tfl ^ ^ CO •H •H 0) 0) ;ii rH OJ 0) o OJ ■H 3 3 o T3 22 remainder of that particular stock collection. These clams were, therefore, exposed to the decomposing remains of clams in that stock which had perished. Clams from stock 11, placed in an aquarium not containing other clams, responded with the fastest growth seen for any stock group for the first 2 weeks (Table 2). These clams, however, failed to grow after the 2-week check when the original silt was replaced. Storage of the silt at room temperatures may result in prolonged bacterial activity which depletes the silt of nutrients the clams may use, or the microbial flora may shift from species the clams can utilize to less nutritious or less assimilable species (personal communication, 22 May 1980, Dr. Robert Gorden, Aquatic Microbiologist, Illinois Natural History Survey, Champaign, Illinois). Silt used in future testing will be collected fresh from the Mississippi River every two weeks or stored in a refrigerator. ADDITION 3I0ASSAYS, USING CLAM GILLS Sediment The deeper layers of sediment from Quiver Lake were less toxic to fingernail clam gills (depressed the particle transport rate less) than the two shallower layers (Figure 8) . Although we did not attempt to date the sediment layers, these findings are consistent with the fact that fingernail clams thrived in Quiver Lake until the die-off in 1955-58 (Paloumpis and Starrett 1960). If a toxic material were introduced to the river, starting in 1955, it might be bound to the sediments deposited at that time (perhaps represented by the second layer) . The deeper and older sediments (third and fourth layers) would not contain the toxicant. The decline in toxicity from the second layer to the surflcial layer might reflect a reduction in toxicant input to the river or dilution by a greater volume of sediment eroded from farmlands and banks of tributary streams. 23 The size (ym) , weight (mg/1) and particle concentration (particles/1 x 10^) for each sediment layer, following dilution to make up a test solution, are given below (mean + standard deviation) : Layer Size Weight Particle Concentration 0 2 5 7 0-2.5 cm 6-5.1 cm 2-7.6 cm 7-10.2 cm 5 2 4 3 3 ± 1 8 ± 0 5 ± 1 8 ± 0 2 9 1 9 53 44 61 78 8 ± 8.2 1 ± 6.7 2 ± 11.2 1 ± 9.8 2.8 ± 0.9 5.1 ± 1.9 3.8 ± 1.2 4.5 ± n.6 cr: O Q_ CO 0.7- 0.6- 0.5 0.4- 0.3- 0.2- 0.1- 0 SEDIMENT CORE FROM QUIVER LAKE 14 DECEMBER 1976 TEST CONDITIONS pH = 7.5 Oz =8.0 ppm temp = 20OC 2.6-5.1 I 7.7-10.2 0-2.5 5.2-7.6 SEDIMENT DEPTH (cm) Figure 8. Response of Clam Gills to Four Layers of Sediment from Quiver Lake, Illinois River. 24 River Water Anderson et al. (1978) demonstrated that the cilia on isolated clam gills beat normally for at least 6 hours in well water from our laboratory at Havana, but the ciliary beating rate dropped to practically zero when the gills were exposed to Illinois River water for 2 hours. The present results confirm the earlier ones: samples of water taken from the Illinois River on two dates severely inhibited the cilia on clam gills, and reduction in inhibition was proportional to the dilution of the river water with well water (Figure 9). It is not surprising THE EFFECT OF RIVER/WELL WATER ON THE AVERAGE RATE OF BEATING OF LATERAL CILIA ON THE GILL OF MUSCUUUM TRANSVERSUM ILLINOIS RIVER WATER SAMPLE NO. 1 (10/5/77) ILLINOIS RIVER WATER SAMPLE NO. 2 (4/22/78) pH=7.5 02 = 80 ppm 0/100 10/90 20/80 30/70 40/60 50/50 60/40 70/30 80/20 90/10 100/0 RIVER/WELL RATIO Figure 9. Response of Clam Gills to Illinois River Water. 25 that the degree of inhibition differed significantly between water samples taken on different dates (Figure 9), because the input of toxi- cant to the river could vary; the volume of flow in the river (hence the dilution) varies; and physical/chemical factors, such as toxicant absorption or desorption from sediment, may vary. DELETION BIOASSAYS, USING INTACT CLAMS Deletion Bioassay Number 1 Deletion bioassay number 1 started on 29 June 1979. Water levels in the Illinois River during the bioassay are shown in Figure 10 and the water chemistry and temperature in Table 3. The test terminated CD •— ■ CO •\ ^ — ^ ^ I o: Lu > > :i: I I —I ct o Od 03 LU I— Od LU LU Ui Li- o ^40—1 438— 436- 434- 432— 430- -^ \ DELETION BIOASSAY NO. 2 \ 3 APRIL-15 MAY, 1980 DELETION BIOASSAY NO. 1 26 JUNE-7 AUGUST, 1979 ^ 5 I 15 I 25 I 35 I 45 10 20 30 40 DAYS OF EXPOSURE Figure 10. Water Levels in the Illinois River During Deletion Bioassays 1 and 2. 26 >, ^^ 4J cr (1) •H O w C u c •H (0 tfl iH c; Pi CO 1-1 <; rH fH c tfl cn 01) dJ 4-1 S s 0 r^ 00 r^ r~ r-. 0 as O O ^ 1—1 >-. C o 01 cn OJ Cfi S 00 00 00 00 00 00 r-- 00 vD o in .^ 0) w: d) £2 S-4 ni 3 e^l 1 vO vO ^ o 00 si CN Cs) CN CM CM 0 r-~ r^ r^ C3^ 00 r-l CNI u -a o Ta iH u CO pu M fti cn Pi 27 prematurely on 7 August 1979 when a pump delivering well water to the control chamber failed and could not be repaired or replaced immediately. Clam Mortality. There were no significant differences in mortality between clams maintained in well water and in raw river water or treated river water (Figures 11 and 12, Table 4). +100- +90- £ +70 I 4J (U in O a .H W1 R cfl CIJ c R 0) X CIJ S <}■ ^ CM CO CSl CO -4- o o o o o r~. CN O CM CJ CN CO CO - •H •H •rH •H 4-1 14-1 IH Pi „ „ , m V< t-l H •H CI) CIJ CU O u 4-1 4J rt cfl Cfl cfl •H s & IS 1-1 H u l-l OJ OJ (\) > > > & ;3 Vj j_i Vj i-i — I Csl OO J- LO 32 Clams maintained in well water did not grow at all (Table 4)1 Laughlin et al. (1981) report a phenomenon called hormesis, where animals exposed to sublethal stress grow more than unstressed animals. The stress evidently triggers hormonal and neuronal responses which activate defensive mechanisms against the stress. The increased hormonal/neuronal activity increases growth as a side effect. A more likely explanation for the lack of growth in clams in well water during our experiments, in contrast to the rapid growth in raw river water, is a lack of food. The clams were kept in Mississippi River silt which had been stored at room temperature and which had probably lost its nutritive value for clams, as explained above. In addition, there were probably not enough algae added to the test chambers (50 ml of algal suspension added by pipette twice each day) for the clams to feed upon. The clams in raw river water received a constant influx of silt, organic detritus, and microorganisms, which they undoubtedly fed upon. Toxic materials were either not present in the river water and sediment from 26 June to 7 August 1979, or toxic effects could not be detected because the clams in the clean well water and treated well water were starving, while clams in river water were receiving food. Another indication that lack of food limited the growth of the clams during bioassay number 1 is the fact that clam growth was inversely proportional to the amount of filtration of the river water. We observed that some fine sediment passed through the sand filter into the test chambers. Less sediment entered test chambers which received water passed through two filters (sand + clino or sand + charcoal). The more filtration, the less food the clams received from the river water. Deletion Bioassay Number 2 The automatic feeding system was installed prior to the start of deletion bioassay number 2 on 3 April 1980. The mean numbers of algal colonies (a colony was defined as two or more algal cells) per ml of 33 suspension delivered to the test chambers during bioassay number 2 were: 4 April 3032 16 April 3666 18 April 9197 24 April 324 7 May 2294 14 May 2909 One hundred ml of algal suspension was delivered to each test chamber every 5 minutes. The concentrations of algae delivered to the test aquaria during deletion bioassay number 2 are of the same order of magnitude as the total green algae (Chloroplyta) numbers found in Keokuk Pool, Mississippi River, by Gale and Lowe (1971:508). Water chemistry and temperature in the test chambers during bioassay 2 are reported in Table 5. Clam Mortality. Clams exposed to raw Illinois River water during deletion bioassay number 2 suffered significantly greater mortality than all other groups after 2 weeks and 4 weeks of exposure (Table 6, Figures 15 and 16). After 6 weeks, clams exposed to Illinois River water had significantly greater mortality than all groups except those clams exposed to sand-filtered Illinois River water (Figure 17). The control group of clams, exposed to unchlorinated well water, had the lowest mortality after 4 weeks and 6 weeks (Figures 16 and 17). Clam Growth. Although mortality of fingernail clams exposed to raw river water was high, growth of the survivors after 2 weeks and 4 weeks of exposure was only slightly worse than clams in treated water (Table 6, Figures 18 and 19) and after six weeks, comparable to the clams in treated water (Table 6 and Figure 20) . Clams in clean well water showed the poorest growth of all, so lack of food may still have been affecting the control clams despite automatic feeding of algae. Sedi- ments continuously accumulated in test chambers receiving raw river water as well as in chambers receiving filtered river water, but no additional sediment accumulated in the well water control. As mentioned above, the 34 n (ij n 01) u c CD m u Cd ^ c 6C TO 00 00 Co' 00 00 00 ;^ o LA O -' r; ^ art p a 0) r p (I) ,r: cu S CAl ^ — I O O -H u-i o -H -H ^ d CJ^ 0^ O 0^ (^ -3- ^ r^ eg CN CM CN CNI o o o o o CN LT) CT\ C3^ ^-H in LO I — r-^ o o o o o o o o o o CO O O ^ r- csi