Larry T. Brooke

Integrated assessment of contaminated sediments in the lower Fox River and Green Bay, Wisconsin.

Samples of sediment and biota were collected from sites in the lower Fox River and southern Green Bay to determine existing or potential impacts of sediment-associated contaminants on different ecosystem components of this Great Lakes area of concern. Evaluation of benthos revealed a relatively depauperate community, particularly at the lower Fox River sites. Sediment pore water and bulk sediments from several lower Fox River sites were toxic to a number of test species including Pimephales promelas, Ceriodaphnia dubia, Hexagenia limbata, Selenastrum capricornutum, and Photobacterium phosphorum. An important component of the observed toxicity appeared to be due to ammonia. Evaluation of three bullhead (Ictalurus) species from the lower Fox River revealed an absence of preneoplastic or neoplastic liver lesions, and the Salmonella typhimurium bioassay indicated relatively little mutagenicity in sediment extracts. Apparent adverse reproductive effects were noted in two species of birds nesting along the lower Fox River and on a confined disposal facility for sediments near the mouth of the river, and there were measurable concentrations of potentially toxic 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), and planar polychlorinated biphenyls (PCBs) both in the birds and in sediments from several of the study sites. Based on toxic equivalency factors and the results of an in vitro bioassay with H4IIE rat hepatoma cells, it appeared that the majority of potential toxicity of the PCB/PCDF/PCDD mixture in biota from the lower Fox River/Green Bay system was due to the planar PCBs. The results of these studies are discussed in terms of an integrated assessment focused on providing data for remedial action planning.

An assessment of the toxicity of phthalate esters to freshwater benthos. 2. Sediment exposures

Tests were performed with the freshwater invertebrates Hyalella azteca, Chironomus tentans, and Lumbriculus variegatus to determine the acute toxicity of six phthalate esters, including dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), butylbenzyl phthalate (BBP), di-n-hexyl phthalate (DHP), and di-2-ethylhexyl phthalate (DEHP). It was possible to derive 10-d LC50 (lethal concentration for 50% of the population) values only for the four lower molecular weight esters (DMP, DEP, DBP, and BBP), for which toxicity increased with increasing octanol-water partition coefficient (Kow) and decreasing water solubility. The LC50 values for DMP, DEP, DBP, and BBP were 28.1, 4.21, 0.63, and 0.46 mg/L for H. azteca; 68.2, 31.0, 2.64, and > 1.76 mg/L for C. tentans; and 246, 102, 2.48, and 1.23 mg/L for L. variegatus, respectively. No significant survival reductions were observed when the three species were exposed to either DHP or DEHP at concentrations approximating their water solubilities.

Bromacil and diuron herbicides: toxicity, uptake, and elimination in freshwater fish.

Fathead minnows, 30 days old, were exposed to technical grade bromacil and diuron in flow-through tests to determine acute toxicity. LC50 values for bromacil were 185, 183, 182 and 167 mg/L at 24, 48, 96, and 168 hr, respectively; and for diuron, 23.3, 19.9, 14.2, and 7.7 mg/L at 24, 48, 96, and 192 hr, respectively. Eggs, newly hatched fry, and juvenile fish were continuously exposed to lower concentrations of the herbicides for 64 days. Growth was significantly reduced (p ⩽ 0.01) at the lowest bromacil exposure of 1.0 mg/L. Therefore, it was not possible to determine a “no effect” concentration. The “no effect” concentration for diuron was 33.4 μg/L, while the lowest concentration which resulted in adverse effects was 78.0 μg/L. Adverse effects at 78.0 μg/L were an increased incidence of abnormal or dead fry immediately after hatch (p ⩽ 0.01) and decreased survival throughout the exposure period (p ⩽ 0.05). Neither herbicide accumulated significantly in fish tissue, as bioconcentration factors were <3.2 and 2.0 for bromacil and diuron, respectively. Rainbow trout (Salmo gairdneri) injected with radiolabeled bromacil or diuron eliminated over 90% of the radioactivity within 24 hr. Parent compound and metabolites were detected in the aquarium water in both cases. Metabolites of diuron recovered from the water included 3,4-dichloroaniline and several demethylated products.

Uptake, elimination, and metabolism of three phenols by fathead minnows

Uptake rates of total14C in fathead minnows (Pimephales promelas) exposed to sublethal concentrations of radiolabeled test compounds followed the order: phenol > 2,4,5-trichlorophenol >p-nitrophenol. Mean whole body14C concentration factors were 15,800, 1,850, and 180 for phenol, 2,4,5-trichlorophenol, andp-nitrophenol exposures, respectively. Only minor amounts of tissue14C was parent compound after 28 days of exposure in fish exposed to phenol andp-nitrophenol, while 78.6% of the14C was parent compound in 2,4,5-trichlorophenol exposed fish. Tissue14C in fish exposed to 2,4,5-trichlorophenol was eliminated at a faster rate than in fish exposed to phenol orp-nitrophenol. Observed mean14C depuration half-lives for lower and higher exposures combined were 387, 150, and 12 hours for phenol,p-nitrophenol, and 2,4,5-trichlorophenol, respectively. Parent compound comprised 1.5, 2.7, and 0.7% of total14C for phenol, 2,4,5-trichlorophenol, andp-nitrophenol, respectively, after 28 days of depuration.The percentage of acetone-unextractable14C increased from the end of uptake to the end of depuration for phenol and 2,4,5-trichlorophenol, and decreased slightly forp-nitrophenol.14C contribution from polar metabolites increased relative to total14C during the depuration phase for 2,4,5-trichlorophenol andp-nitrophenol.

Toxicity, bioconcentration, and metabolism of the herbicide propanil (3′,4′-dichloropropionanilide) in freshwater fish

Fathead minnows (Pimephales promelas) were exposed to technical grade propanil (3′,4′-dichloropropionanilide) in a flow-through diluter system to determine acute lethality. LC50 values were 11.5, 10.2, 8.6, and 3.4 mg·L−1 at 24, 48, 96, and 192 hr, respectively. Eggs, newly hatched fry, and juvenile fish of this species were similarly exposed but at lower concentrations and for a period of 58 days. The 58-day “no effect” concentration was between 0.4 and 0.6Μg·L−1, based upon the physiological parameters of length and dry weight of juvenile fish.14C-Propanil did not bioconcentrate significantly in fathead minnows (1.6× for parent propanil in whole body). Rainbow trout (Salmo gairdneri) readily metabolized propanil, forming at least ten products. One metabolite recovered from trout bile was identified as either 3′,4′-dichloro-2-hydroxypropionanilide or 3′,4′-dichloro-3-hydroxy-propionanilide. The technical grade propanil also contained 0.67 mg·g−1 of 3,3′,4,4′-tetrachloroazobenzene as a contaminant.

Acute and chronic toxicities of arsenic(III) to fathead minnows, flagfish, daphnids, and an amphipod

Acute and chronic toxicities of arsenic (III) (As) to four species of freshwater organisms were determined. All tests were flow-through exposures except the daphnid (Daphnia magna) tests which were static concentration renewal exposures. Acute exposures of fathead minnows (Pimephales promelas), flagfish (Jordanella floridae), and an amphipod (Gammarus pseudolimnaeus) to As resulted in 96-hr LC50 or EC50 estimates of 14,100, 14,400, and 874 μg/L, respectively. Daphnids were exposed to As with and without food resulting in 96-hr EC50 estimates of 4,340 and 1,500 μg/L, respectively. Chronic exposures of 28 to 31 days duration were made for fathead minnows, flagfish, and daphnids. The chronic limit ranges (highest tested exposure concentration having no adverse effect and the lowest tested exposure concentration having an adverse effect) based upon the most sensitive measured parameters of body length and wet weight were 2,130 to 4,300 μg/L for fathead minnows and 2,130 to 4,120 μg/L for flagfish. Daphnids had chronic limits of 633 to 1,320 μg/L based upon survival and the measured parameters of reproduction and body length. Calculation of an acute test/chronic test ratio for fathead minnows, flagfish, and daphnids (fed and unfed) resulted in a range of values from 1.64 to 4.80.

Comparative toxicity and bioconcentration of nonylphenol in freshwater organisms

Degradation of alkylphenol ethoxylates to more persistent alkylphenols such as nonylphenol occurs in wastewater treatment plants where nonylphenol is released to aquatic systems. In this study, acute and chronic tests were conducted to determine the toxicity and bioconcentration of nonylphenol to freshwater organisms for use in deriving national water quality criteria. Acute median effect concentrations (EC50s) based on loss of equilibrium, immobility, and lethality for species representing several taxonomic groups ranged from 21 to 596 microg/L. The EC50s were up to a factor of 2 less than median lethal concentrations (LC50s) and decreased with time over the test periods of 24 to 96 h. In chronic tests, early life stages of rainbow trout were 14 times more sensitive to nonylphenol than in acute tests and approximately 20 times more sensitive than Daphnia magna exposed over their complete life cycle. Comparisons of chronic test endpoints showed that 20% effect concentrations (EC20s), determined by regression testing, and chronic values, determined by hypothesis testing, were similar for both the rainbow trout and Daphnia magna. The lowest mean tissue-effect concentrations of nonylphenol appeared to be greater for the fathead minnow than bluegill, and ranged from approximately 130 to 160 microg/g after 96-h exposure and from approximately 20 to 90 microg/g after 28-d exposure. Mean lipid normalized bioconcentration factors (BCFs) associated with no-effect concentrations were approximately 180 and 50 for the fathead minnow and bluegill, respectively. The present test results suggest that long-term exposures to nonylphenol at concentrations found in some surface waters could adversely impact sensitive components of freshwater communities.

Comparative toxicity of methanol and N,N-dimethylformamide to freshwater fish and invertebrates.

The organic solvents methanol and N,N-dimethylformamide (DMF) are used widely as industrial solvents. Although some toxicity data appear in the literature for methanol and DMF, there have been few studies which have been flow-through tests for a standard 48- or 96-h exposure period with measured toxicant concentrations. In this study, 96-h flow-through acute toxicity tests with methanol and DMF were conducted with three species of freshwater fish - rainbow trout (Salmo gairdneri), bluegill (Lepomis macrochirus) and fathead minnow (Pimephales promelas). Static acute toxicity tests (48 h) were conducted with DMF and two species of freshwater invertebrates - a midge (Paratanytarsus parthenogeneticus) and a daphnid (Daphnia magna). Median lethal (LC50) and median effect (EC50) concentrations for 96-h exposures were determined for fish and 48-h EC50s were determined for invertebrates.

Observations on the 10-Day Chironomus tentans Survival and Growth Bioassay in Evaluating Great Lakes Sediments

Absstract A 10-day bioassay with larval chironomids ( Chironomus tentans ) was used to evaluate sediment samples from harbors at Michigan City, IN, St. Joseph, MI, Grand Haven, MI, and Toledo, OH for toxicity, based upon the endpoints of survival, dry weight, and growth. Larval responses in sediment samples from each harbor were compared to responses of larvae in reference sediments collected from or near each harbor. An inverse relationship between the number of survivors and mean organism dry weight or growth indicated that food was limiting in the bioassay for some samples. The confounding nature of this interaction was minimized by evaluating effects on the basis of total biomass per replicate. A site from Toledo Harbor was the most toxic. Reduced larval growth at this site indicated the likelihood for a negative populational impact. The importance of reference sediment selection was noted, as the assessment of sediment quality varied considerably for Toledo Harbor depending upon the particular reference sediment that was used for statistical comparisons.