Acute lethal toxicity of environmental pollutants to aquatic organisms

The acute lethal toxicity of environment pollutants including chlorophenol, haloalkane, quinone, and substituted nitrobenzene (i.e., nitrophenol, nitrobenzene, nitrotoluene, and aniline) compounds to aquatic organisms was determined. Determination of toxicity of chemicals was performed with chlorella, daphnia, carp, and tilapia. The toxicity of chlorophenols had no relation to the number of chlorine atoms on the benzene ring, but monochlorophenol had lower activity than more chlorine-substituted compounds. The tolerance levels of daphnia and carp to haloalkanes was found to be higher than that of chlorella; toxicity to chlorella was several hundred times higher than to daphnia. The toxicity of naphthoquinone compounds to chlorella and carp was higher than that of anthraquinone. A compound with a monochloride substitution on anthraquinone ring was less toxic to carp than those substituted with amine, hydroxyl, and dichlorine groups. Nitrobenzene compounds with an additional substitution group on the p position were extremely toxic to daphnia and carp.     

Uptake and toxicity of toxaphene in several estuarine organisms

The organochlorine insecticide, toxaphene, was tested in flow-through bioassays to evaluate its toxicity to estuarine organisms. The organisms tested and their respective 96-hr LC5Os (based on measured concentrations) are: pink shrimp (Penaeus duorarum), 1.4g/L; grass shrimp (Palaemonetes pugio), 4.4g/L; sheepshead minnow (Cyprinodon variegatus), 1.1g/L; and pinfish (Lagodon rhomboides), 0.5g/L. Toxaphene concentration estimated to reduce shell deposition in American oysters (Crassostrea virginica) by 50% (EC50) was 16g/L. Concentration factors (concentration of toxaphene in tissues divided by concentration measured in water) for fishes and oysters in 96 hr ranged from 3,100 to 20,600 and for shrimp, from 400 to 1,200.Individuals from various ontogenetic stages of longnose killifish (Fundulus similis) were exposed to toxaphene for 28 days in flow-through bioassays. Toxaphene was toxic to embryos, fry, juveniles, and adult fish, but fertilization of ova in static tests was not affected by the concentrations tested (0.32 to 10g/L). The 28-day measured LC50s for all stages ranged from 0.9 to 1.4g/L. Toxaphene was accumulated in ova and other body tissues of the longnose killifish; concentration factors in ova were 1,000 to 5,500, and in whole-body tissues, 4,200 to 60,000.Contribution No. 269, Gulf Breeze Environmental Research Laboratory.Portions relating toFundulus similis based on a thesis submitted by S.C.S. in partial fulfillment of the degree of Master of Science from the University of West Florida, 1975.     

Acute and chronic aquatic toxicity of ammonium perfluorooctanoate (APFO) to freshwater organisms

Recent concerns have been raised concerning the widespread distribution of perfluorinated compounds in environmental matrices and biota. The compounds of interest include ammonium perfluorooctanoate (APFO, the ammonium salt of perfluorooctanoic acid, PFOA). APFO is used primarily as a processing aid in the production of fluoropolymers and fluoroelastomers. The environmental presence of perfluorooctanoate (PFO⁻, the anion of APFO) and its entry into the environment as APFO make quality aquatic toxicity data necessary to assess the aquatic hazard and risk of APFO. We conducted acute and chronic freshwater aquatic toxicity studies with algae, Pseudokirchneriella subcapitata, the water flea, Daphnia magna, and embryo-larval rainbow trout, Oncorhynchus mykiss, using OECD test guidelines and a single, well-characterized sample of APFO. Acute 48–96 h LC/EC₅₀ values were greater than 400 mg/l APFO and the lowest chronic NOEC was 12.5 mg/l for inhibition of the growth rate and biomass of the freshwater alga. Un-ionized ammonia was calculated to be a potential significant contributor to the observed toxicity of APFO. Based on environmental concentrations of PFO⁻ from various aquatic ecosystems, the PNEC value from this study, and unionized ammonia contributions to observed toxicity, APFO demonstrates little or no risk for acute or chronic toxicity to freshwater and marine aquatic organisms at relevant environmental concentrations.     

Acute toxicity of a zinc-polluted stream to four species of salmonids

Four species of salmonids were exposed to different dilutions of water from a stream polluted by zinc. Test duration was 14 days for all species. The TL₅₀ for rainbow trout (Salmo gairdneri) was 0.41 mg zinc/ liter. TL₅₀ values for zinc to brown trout (Salmo trutta), cutthroat trout (Salmo clarki), and brook trout (Salvelinus fontinalis) were 0.64, 0.67, and O.96 mg/liter, respectively. Rainbow trout were least tolerant of zinc and brook trout were the most tolerant. Cutthroat trout were considered more susceptible to zinc than brown trout.     

Effects of particle composition and species on toxicity of metallic nanomaterials in aquatic organisms

Metallic nanoparticles are among the most widely used types of engineered nanomaterials; however, little is known about their environmental fate and effects. To assess potential environmental effects of engineered nanometals, it is important to determine which species are sensitive to adverse effects of various nanomaterials. In the present study, zebrafish, daphnids, and an algal species were used as models of various trophic levels and feeding strategies. To understand whether observed effects are caused by dissolution, particles were characterized before testing, and particle concentration and dissolution were determined during exposures. Organisms were exposed to silver, copper, aluminum, nickel, and cobalt as both nanoparticles and soluble salts as well as to titanium dioxide nanoparticles. Our results indicate that nanosilver and nanocopper cause toxicity in all organisms tested, with 48-h median lethal concentrations as low as 40 and 60 mug/L, respectively, in Daphnia pulex adults, whereas titanium dioxide did not cause toxicity in any of the tests. Susceptibility to nanometal toxicity differed among species, with filter-feeding invertebrates being markedly more susceptible to nanometal exposure compared with larger organisms (i.e., zebrafish). The role of dissolution in observed toxicity also varied, being minor for silver and copper but, apparently, accounting for most of the toxicity with nickel. Nanoparticulate forms of metals were less toxic than soluble forms based on mass added, but other dose metrics should be developed to accurately assess concentration-response relationships for nanoparticle exposures.     

Comparative acute toxicity of potassium permanganate to nontarget aquatic organisms

Potassium permanganate (KMnO4) is used worldwide in freshwater pond aquaculture for treatment and prevention of waterborne external parasitic, bacterial, and fungal diseases. Nevertheless, KMnO4 has not been approved by the U.S. Food and Drug Administration, and insufficient information exists to allow evaluation of the environmental risk of KMnO4 exposures. Limited data exist concerning KMnO4 toxicity to nontarget species in systems receiving aquaculture effluent from treated ponds. The goal of this research is to generate effects data for use in developing an ecological risk assessment of KMnO4. Toxicity tests were used to compare the relative sensitivities of five standard aquatic test species to KMnO4. Acute toxicity test results using synthetic moderately hard water show static 96-h mean median lethal concentration (LC50) values +/- standard deviation (SD) of 0.058 +/- 0.006 mg/L for Ceriodaphnia dubia, 0.053 +/- 0.009 mg/L for Daphnia magna, 2.13 +/- 0.07 mg/L for Pimephales promelas, 4.74 +/- 1.05 mg/L for Hyalella azteca, and 4.43 +/- 0.79 mg/L for Chironomus tentans. Most of these values are below the recommended KMnO4 treatment rate of at least 2.0 mg/L or 2.5 times the water's potassium permanganate demand (PPD; an estimation of the available reducing agents in the exposure water), suggesting significant environmental risk. However, repeating these laboratory tests using pond water resulted in significantly reduced toxicity, with static 96-h mean LC50 values (+/-SD) of 2.39 +/- 0.36 mg/L for C. dubia, 1.98 +/- 0.12 mg/L for D. magna, 11.22 +/- 1.07 mg/L for P. promelas, 13.55 +/- 2.24 mg/L for H. azteca, and 12.30 +/- 2.83 mg/L for C. tentans. The PPD of synthetic moderately hard water was 0.329 +/- 0.114 mg/L; however, pond water PPD was 5.357 +/- 0.967 mg/L. The effective disease-treating dose based on 2.5 times the PPD would thus be 0.823 and 13.392 mg KMnO4/L, respectively, exceeding the LC50 for most of these nontarget organisms, even in pond water, immediately after treatment.     

Acute cadmium toxicity studies upon nine species of aquatic insects.

Continuous-flow bioassays were employed to determine 96-hour median tolerance limits (TLm), for the stonefly, Pteronarcella badia (Hagen) (TLm was 18.0 mg Cd/l) and the mayfly, Ephemerella grandis grandis Eaton (TLm was 28.0 mg Cd/l). Ninety-six hours TLm values for other species of aquatic insects tested were not determined, since these species were relatively insensitive to cadmium.Insects exposed for four days in cadmium-containing water, then placed in tap water, show a linear rate of cadmium loss. This loss may lower or prevent mortality under ideal conditions.     

Acute toxicity of selected herbicides and surfactants to larvae of the midgeChironomus riparius

The acute toxicities of eight commercial herbicides and two surfactants to early fourth instar larvae of the midgeChironomus riparius were determined under static conditions. The formulated herbicides tested were Eradicane^® (EPTC), Fargo^® (triallate), Lasso^® (alachlor), ME4 Brominal^® (bromoxynil), Ramrod^® (propachlor), Rodeo^® (glyphosate), Sencor^® (metribuzin), and Sutan (+)^® (butylate); the two surfactants were Activator N.F.^® and Ortho X-77^®. In addition, technical grade alachlor, metribuzin, propachlor, and triallate were tested for comparison with the formulated herbicides. The relative toxicity of the commercial formulations, based on percent active ingredient, varied considerably. The EC50 values ranged from 1.23 mg/L for Fargo^® to 5,600 mg/L for Rodeo^®. Fargo^®, ME4 Brominal^®, and Ramrod^® were moderately toxic to midge larvae; Lasso^®, Sutan (+)^®, and Eradicane^® were slightly toxic; and Sencor^® and Rodeo^® were practically non-toxic. The 48-hr EC50 values of the two surfactants were nearly identical and were considered moderately toxic to midges. For two of the herbicides in which the technical grade material was tested, the inert ingredients in the formulations had a significant effect on the toxicity of the active ingredients. Fargo^® was twice as toxic as technical grade triallate, whereas Sencor^® was considerably less toxic than technical grade metribuzin. A comparison of the slope function values indicated that the toxic action of all the compounds occurred within a relatively narrow range. Published acute toxicity data on these compounds for other freshwater biota were tabulated and compared with our results. In general, the relative order of toxicity toC. riparius was similar to those for other freshwater invertebrates and fish. Maximum concentrations of each herbicide in bulk runoff during a projected critical runoff event were calculated as a percentage of the application rate lost in a given volume of runoff. A comparison between estimated maximum herbicide concentrations in runoff and results of acute tests indicated that Ramrod^®, ME4 Brominal^®, and Lasso^® pose the greatest direct risk to midge larvae during a storm event.Send reprint requests to Edna Head at U.S. Fish and Wildlife Service, National Fisheries Contaminant Research Center, Route 1, Columbia, Missouri 65201, USA.     

Acute and embryo-larval toxicity of phenolic compounds to aquatic biota

Because of the prevalence of phenolic compounds in various types of effluents, both acute and embryo-larval bioassays were performed on eight phenolic compounds with rainbow trout, fathead minnows andDaphnia pulicaria. In flow-through bioassays, the 96-hr LC₅₀ values for rainbow trout and fathead minnows ranged from <0.1 mg/L for hydroquinone to >100 mg/L for resorcinol.Daphnia pulicaria was consistently the least sensitive species tested as measured in 48-hr bioassays, while fathead minnows and rainbow trout varied in their relative sensitivity to phenolics as measured in 96-hr tests. Fathead minnows were more sensitive to phenol at 25°C than at 14°C.In embryo-larval bioassays with phenol, fathead minnow growth was significantly reduced by 2.5 mg/L phenol, while rainbow trout growth was significantly reduced by 0.20 mg/L phenol. For both species the embryolarval effects concentration was 1.1% of the 96-hr LC₅₀. Another embryolarval bioassay was attempted withp-benzoquinone, a highly toxic phenolic compound found in fossil fuel processing wastewaters, which was discontinued because the compound was rapidly degraded chemically or biologically in the headtank and aquaria.Work funded under an Interagency Agreement between the U.S. Department of Energy and the U.S. Environmental Protection Agency under Contract No. DE-AS20-79 LC 01761 to the Rocky Mountain Institute of Energy and Environment, University of Wyoming.     

Assessment of the toxicity of triasulfuron and its photoproducts using aquatic organisms

The toxicological effects of the sulfonylurea herbicide triasulfuron and its photoproducts were assessed on four aquatic organisms. Toxicity varied with tested organism and with triasulfuron irradiation time. Triasulfuron and its photoproducts had no significant effects on the crustacean (Cladocera) Daphnia magna (causing 50% effective concentration [EC50] [48 h] = 49 +/- 1 mg/L) and the marine bacteria Vibrio fischeri (EC50 [30 min] > 100 mg/L). In contrast, primary producers (the duckweed Lemna minor, the microalgae Pseudokirchneriella subcapitata, and Chlorella vulgaris) were very sensitive to triasulfuron (EC50s < 11 microg/L). For these organisms, triasulfuron photoproducts were less toxic than the parent compound but the residual toxicity observed still represented a potential environmental hazard.