John W. Arthur

Seasonal toxicity of ammonia to five fish and nine invertebrate species

Ammonia is a widely distributed chemical found in surface waters. Its toxicity to aquatic life is principally due to the un-ionized (NH3) form. An extensive review on ammonia toxicity to aquatic life has been recently compiled by the US EPA with most information consisting of fish test values and limited data available for aquatic plants and invertebrates. Invertebrates were found to be generally more tolerant to ammonia than were fishes. This laboratory study is part of a larger evaluation in assessing the impact of ammonia nitrogen in outdoor experimental streams at and above derived water quality criteria concentrations. Primary objective for this laboratory study was to determine the relative sensitivity of un-ionized ammonia to fish and invertebrates in river water at ambient seasonal temperatures.

Acidification effects on macroinvertebrates and fathead minnows (Pimephales promelas) in outdoor experimental channels

Abstract Three outdoor experimental channels at the U.S. EPA Monticello (Minnesota) Ecological Research Station were employed to assess in the field acidification effects on macroinvertebrate communities and populations of fathead minnows (Pimephales promelas). One channel served as ambient (pH 8), the second was acidified with sulfuric acid to pH 6 and the third to pH 5 for 17 weeks. Acidification did not markedly increase toxic metal concentrations in the channels; however, there was some evidence of possible mercury mobilization. Benthic macroinvertebrate densities were lower in the acidified channels during most of the study and final diversity indices were 2.1, 1.7 and 1.2 in the ambient, pH 6 and pH 5 channels, respectively. Drift of amphipods and leeches was stimulated in the pH 5 channel early in the study. The number of insect taxa and percentages emerging from the ambient, pH 6 and pH 5 channels, respectively, were 30 and 56%, 28 and 31%, and 18 and 13%. Macroinvertebrate tolerance to the acidification was classified as follows: damselflies, isopods and leeches most tolerant; chironomids, some amphipods (Crangonyx) and flatworms of intermediate tolerance; and other amphipods (Hyalella azteca) and snails (Physa gyrina) most sensitive. Fathead minnow spawning and embryo production were similar in the ambient and pH 6 channels with little spawning and no eyed-embryos found in the pH 5 channel. Newly-hatched larval fish did not survive to the juvenile stage in the pH 6 channel. Continued acidification would likely have further decreased the diversity of the macroinvertebrate community, increased relative abundance of more tolerant species, and caused extinction of the minnow population.

Effects of diazinon on macroinvertebrates and insect emergence in outdoor experimental channels

Abstract Effects of diazinon on macroinvertebrates were assessed in three outdoor experimental channels from mid-May to mid-September, 1980. One channel served as a control and two channels as low and high treatments. Three dosing regimes were employed. The low and high treatment channels were continuously dosed for 12 wk to nominal concentrations of 0.3 and 3 μg/l, then increased to 6 and 12 μg/l for 4 wk, then the high treatment was increased to 30 μg/l with the low treatment channel returned to ambient. Diazinon concentrations did not reach the intended levels during the latter two dosing regimes. No consistent interchannel differences were observed in total macroinvertebrate abundance or in species diversity induces. Effects were noted at the lowest concentration for amphipods and insects. As diazinon concentrations were increased interchannel community structure changes became more pronounced. Elevated drift, especially amphipods and snails, occurred in the treated channels 4 wk after dosing began and following the increases in concentrations. Total numbers and species of insects emerging from the three channels were not greatly different but lower numbers of mayflies and damselflies emerged from the treated channels. Tolerance of macroinvertebrates to diazinon were as follows: flatworms, physid snails, isopods and chironomids most tolerant; leeches and the amphipod Crangonyx less tolerant; the amphipod Hyalella, mayflies, caddisflies and damselflies sensitive.

Effects of pentachlorophenol on invertebrates and fish in outdoor experimental channels

Abstract Pentachlorophenol (PCP) was selected to assess the applicability of a toxicant criterion concentration for protecting aquatic communities in outdoor experimental channels. The criterion concentration was derived from on site laboratory bioassays. In 1982 three channels were continuously dosed with PCP for 12 wk at nominal concentrations of 48 μg/l (low, criterion level), 144 μg/l (medium, 3 × criterion) and 432 μg/l (high, 9 × criterion). In 1983 the low and medium treatments were repeated for 12 wk. Each year an untreated channel served as control. Invertebrate responses measured were changes in density, community composition and drift; fish responses were changes in survival, growth, reproduction and larval drift. Some ecosystem effects were detected at all treatment levels with fish being the most sensitive animals. Microinvertebrate densities were lower in the medium PCP channel than the control. Survival of the snail Physa gyrina was substantially reduced in the high treatment channel; no other macroinvertebrates were adversely affected by the toxicant. All fathead minnows and bluegill sunfish stocked in the high treatment channel died within the first 8 days of dosing. Fish survival was similar in all remaining channels. Fish growth and larval drift were lower in the treated channels than in the control channels and spawning was reduced in the medium dose channels. The numbers of fathead minnows collected both years from the medium dose channels were lower than the criterion and control channels. Highest numbers of bluegills were recovered from the control channels. The study indicated that the criterion concentration derived from laboratory tests did not fully protect the animals in the experimental channels.

Chronic effects of linear alkylate sulfonate detergent on Gammarus pseudolimnaeus, Campeloma decisum and Physa integra

Abstract Three invertebrate species were submitted to acute (96 hr) followed by chronic (6 week) detergent exposures. The average 96 hr TL m values for Campeloma decisum, Physa integra , and Gammarus pseudolimnaeus were 27, 9 and 7 mg/l linear alkylate sulfonate (LAS) respectively. Newly hatched amphipods that were recovered after termination of the second 6 week study were further exposed to the detergent for 15 additional weeks, thus enabling more than one generation cycle to be tested under toxicant stress. Survival, growth, reproduction, feeding, and mobility were the responses used for determining the chronic toxicant effects. Under the test conditions described, the maximum acceptable LAS concentrations for Gammarus pseudolimnaeus and Campeloma decisum were between 0.2–0.4 and 0.4–1.0 mg/l respectively. Responses by Physa integra were not significantly altered under the chronic test concentrations.

Effects of elevated ammonia levels on the fingernail clam,Musculium transversum, in outdoor experimental streams

The effects of ammonia on survival, growth, and reproduction of the fingernail clamMusculium transversum were tested in outdoor experimental streams. In the summers of 1983 and 1984 caged clams were exposed in the streams. During the 1983 studies, the weekly mean NH3 ranges in the low, medium and high concentration streams were, respectively, 0.02–0.08, 0.04–0.25 and 0.14–0.56 mg/L; in 1984 the ranges in the same streams were 0.04–0.20, 0.07–0.38 and 0.48–1.17 mg/L. In the first year studies, survival was highest (50–85%) in the control and low NH3 streams, lower (30–55%) in the medium NH3 stream and no clams survived the high NH3 treatment. Growth was also greater in the control and low NH3 streams. In the second year studies, total yields of clams in the control, low, medium, and high NH3 streams, respectively, were 12.8 x, 4.7 x, 1.1 x and 0.03 x the original stock. During 30-day tests, the second year mean growth was 2 mm less and reproduction 90% lower in the low NH3 than in the control stream. Un-ionized ammonia concentrations affecting survival and growth were lower than in previous reports. The site-specific criterion concentration was low enough to protect the clams in the streams.

Effect of elevated water temperature on insect emergence in outdoor experimental channels

Abstract Emergence of adult aquatic insects was determined weekly with plexiglass traps positioned in two outdoor experimental channels from April through August 1977. One channel was seasonal Mississippi River water temperature and the other maintained at 10°C higher. Maximum water temperatures reached 31·0°C in the ambient and 40·8°C in the heated channel. Chironomids comprised 84% of the insects collected in both channels. Percentage composition differed between the ambient and heated channels for the chironomid taxa while the mayfly, damselfly and caddisfly taxa were more similar. The temperature in the heated channel (10°C above ambient) advanced the emergence of two Chironominae, one Orthocladiinae, one Ceratopogonidae and one Zygopteran species by one to four weeks. Few insects emerged from the heated channel during the period of maximum temperature. Insect emergence was spatially distributed throughout each channel even though dissolved oxygen concentrations were near zero at sunrise and supersaturated at mid-afternoon hours at downstream stations.

Ammonia effects on microinvertebrates and fish in outdoor experimental streams

Laboratory data on ammonia effects, the US EPA national water quality criteria for ammonia, and ammonia site-specific criteria were evaluated in four outdoor experimental streams (one control and three treatment streams) over a 76-week period. Calculated un-ionised ammonia concentrations varied daily and seasonally according to pH and temperature changes. Populations of four major microinvertebrate taxonomic groups (cladocerans, copepods, rotifers and protozoans) were monitored during a 4-week period early in the study, and six fish species (fathead minnows, bluegills, channel catfish, white suckers, walleyes, and rainbow trout) were tested for various time intervals, from 4 to 26 weeks, throughout the 76-week study period. Copepods and rotifers were unaffected in all three treatment streams, based on comparisons with the control stream. Cladoceran and protozoan populations were reduced in at least two treatment streams, but because of large variability, effects were considered to be inconclusive. However, complete mortality of cladocerans did occur in the high and medium treatments when placed in in situ biomonitor chambers. All six fish species were affected in one or more treatments. Generally, the fish effect values agreed with most laboratory effect values. Of 12 fish groups tested, one channel catfish group and one white sucker group were affected below the recommended protection levels of the national and site-specific criteria. The lowest effect concentrations tested for the other ten groups occurred above the criteria levels.

Effect of elevated water temperature on macroinvertebrate communities in outdoor experimental channels

Abstract Macroinvertebrates were sampled monthly from December 1976 to September 1977 in two 520m long outdoor experimental channels. One channel was maintained at ambient seasonal Mississippi River water temperatures and the other 10°C higher. Maximum water temperature reached 31.0°C in the ambient and 40.8°C in the heated channel. Elevated temperature seasonally altered macroinvertebrate abundance and life history in the channels. Few animals were found in the heated channel during the period of maximum water temperature. Most macroinvertebrate density and composition differences were confined to the channel riffles rather than the pools. Peak total density in the heated channel riffles occurred 3 or 4 weeks before the ambient channel. Total macroinvertebrate density was appreciably higher in the heated channel riffles during the winter and spring months and in the ambient channel riffles during the summer months. This seasonal alteration was due to composition differences of several identified taxa. Reproductive periods for one snail and one isopod species began approx. 2 and 3 months earlier in the heated channel than in the ambient channel. No marked change occurred in the reproductive activities of an amphipod in the two channels.

Toxicity of sodium nitrilotriacetate (NTA) to the fathead minnow and an amphipod in soft water

Abstract Amphipods, Gammarus pseudolimnaeus Bousfield and fathead minnows, Pimephales promelas Rafinesque, were submitted to acute (96-h) and chronic (generation-cycle) bioassays with sodium nitrilotriacetic acid (NTA). All measurements are reported as Na3NTA. The average 96-h TL50 values under flow-through conditions were 98 mg 1−1NTA for the amphipod and 114 mg 1−1 for the fathead minnow. The acute toxicity of NTA was caused in part by the high pH resulting from the addition of large amounts of NTA (> 100 mg 1−1) to soft water. Controlling pH reduced the lethality of NTA by at least one-half to fathead minnow larvae. The chronic no-effect level of NTA to the amphipods was 19 mg 1−1; in fathead minnows, it exceeded the highest exposure level (> 54 mg 1−1).