Fathead minnows

AH of the propylene glycols are considered to be practically nontoxic to fish on an acute basis (LC q < 100 mg/L) and practically nontoxic to aquatic invertebrates, also on an acute basis. Acute marine toxicology testing (38) on propylene glycol showed that the 96-h LC q for fathead minnows was 54,900 mg/L and the 48-h LC q for Daphnia magna was 34,400 mg/L. A 24-h NOEL of 50,000 mg/L was also observed for fingerling trout. Similar results were observed for guppies and rainbow trout (39). 

Environmental Concerns. Few data on the environmental effects of the nitroparaffins are available. However, they are known to be of low toxicity to the fathead minnow (109). Based on their uv spectra, the nitroparaffins would be expected to undergo photolysis in the atmosphere. The estimated half-life of 2-nitropropane in the atmosphere is 3.36 h (110). Various values have been determined for the half-life of nitromethane, but it is similar to 2-nitropropane in persistence (111). Reviews of the available data on the environmental effects of nitromethane and 2-nitropropane have been pubhshed by the U.S. Environmental Protection Agency (112,113). 

The impact that a silver compound has in water is a function of the free or weaMy complexed silver ion concentration generated by that compound, not the total silver concentration (3—5,27,40—42). In a standardized, acute aquatic bioassay, fathead minnows were exposed to various concentrations of silver compounds for a 96-h period and the concentration of total silver lethal to half of the exposed population (96-h LC q) deterrnined. For silver nitrate, the value obtained was 16 )-lg/L. For silver sulfide and silver thiosulfate complexes, the values were >240 and >280 mg/L, respectively, the highest concentrations tested (27). 

The chronic aquatic effects which relate silver speciation to adverse environmental effects were studied on rainbow trout eggs and fry. The maximum acceptable toxicant concentration (MATC) for silver nitrate, as total silver, was reported to be 90—170 ng/L (43). Using fathead minnow eggs and fry, the MATC, as total silver, for silver thiosulfate complexes was reported as 21—44 mg/L, and for silver sulfide as 11 mg/L, the maximum concentration tested (27). 

Aquatic toxicity is reported in mg/L for Pimepha/espromealas (fathead minnow), 69-h LC q 7650 (17) for Daphnia magna (water flea), 48-h EC q 3310 (18) for Mjriophjllum spicatum (water milfoil), phytotoxicity (EC q for growth) 5962 (19) and for Pana breviceps (frog), no observed effect concentration (NOEC) 400 (20). LC q and EC q are lethal and effect concentrations, respectively, for 50% of the subjects tested. 

Both acute and chronic toxicity testing of the treated effluent on daphnia shrimp and fathead minnows have indicated that the effluent is completely suitable for discharge into receiving waters with no adverse impact (42). 

Fathead minnow Pimephaies promeias) MMTC 96-h LC50 320 320 Ward etai. (1996a)... 

Fathead minnow Pimephaies promeias) DMT(EHMA) 96-h LC50 >1000 >1000 Wardetal. (1995c)... 

Ward TJ, Kowalski PL, Boeri RL (1995c) Acute toxicity of the water accommodated fraction (WAF) of aikyitin MA to the fathead minnow, Pimephales promelas. Marblehead, MA, T.R. Wilbury Laboratories, Inc. (Study No. 861-MO). 

Harries, J.E., Runnalls, T, and Hill, E. et al. (2000). Development of a reproductive performance test for endocrine disrupting chemicals using pair-breeding fathead minnows Pimephales promelas). Environmental Science and Technology 34, 3003-3011. 

Jensen, K.M., Makynen, E.A., and Kahl, M.D. et al. (2006). Effects of the feedlot contaminant 17 alpha-trenholone on reproductive endocrinology of the fathead minnow. Environmental Science and Technology 40, 3112-3117. 

Nebeker, A.V., Puglisi, E.A., and Defoe, D.L. (1974). Effect of polychlorinated biphenyl compounds on survival and reproduction of fathead minnow and llagfish. Transactions of the American Fisheries Society 103, 562-568. 

Panter, G.H., Hutchinson, T.H., and Hurd, K.S. et al. (2006). Development of chronic tests for endocrine active chemicals—Part 1. An extended fish early-life stage test for oestrogenic active chemicals in the fathead minnow (Pimephales promelas). Aquatic Toxicology 77, 279-290. 

Drevnick PE, Sandheinrich MB. 2003. Effects of dietary methyhnercury on reproductive endocrinology of fathead minnows. Environ Sci Technol 37 4390 396. 

Organophosphate Ester Hydraulic Fluids. Very little information on the food chain bioaccumulation of organophosphate ester hydraulic fluids is available. It is known that some organisms bioconcentrate components of organophosphate ester hydraulic fluids (values are 133-2,807 for rainbow trout and 596-928 for fathead minnows) (Lombardo and Egry 1979 Mayer et al. 1981 Muir et al. 1983a Veith et al. 1979). Given the concerns over the toxicity of this class of hydraulic fluids, further research on this topic would be useful. 

Broderius SJ, Smith LL Jr, Lind DT. 1977. Relative toxicity of free cyanide and dissolved sulfide forms to the fathead minnow (Pimephales promelas). Journal of the Fisheries Research Board of Canada 34 2323-2332. 

TEST allows for estimates of the value for several toxicity endpoints [29] 96 h Fathead minnow LC50, 48 h Daphnia magna LC50, 48 h Tetrahymena pyriformis IGC50, Oral rat LD50, bioaccumulation factor, developmental toxicity, and Ames mutagenicity. TEST also estimates several physical properties... 

For the ecological assessment, risk analysis was based on the traditional PEC/ PNEC ratio (Hazard Quotient) where PEC is the predicted environmental concentration (resulting from chemical analysis) and PNEC the predicted no-effect concentration. Ecological assessment for aquatic species was based on rainbow trout or fathead minnow while terrestrial assessment was based on small rodents like mice rats and rabbits. Exposures associated with HQ<1 were considered negligible. 

Lazar (http //lazar.in silico.de/predict) is a k-nearest-neighbor approach to predict chemical endpoints from a training set based on structural fragments [43]. It derives predictions for query structures from a database with experimentally determined toxicity data [43]. Model provides prediction for four endpoints Acute toxicity to fish (lethality) Fathead Minnow Acute Toxicity (LC50), Carcinogenicity, Mutagenicity, and Repeated dose toxicity. 

Aquatic toxicity Daphnia magna 48 h LC50 and fathead minnow (fish) 96 h LC50... 

Lazar [59] derives predictions for four endpoints Fathead Minnow Acute Toxicity (LC50), Carcinogenicity, Mutagenicity, and Repeated dose toxicity. 

Finally, the Aquatic Toxicity module predicts fish and daphnia toxicity providing LC50 values (mg/L) for Pimephales promeals (Fathead minnow) and Daphnia magna (Water flea). Experimental values (if present) and similarity to test compound are shown for the five most similar structures from the training set [65]. 

Table 13 Results from QSARs 96 h LC50 fathead minnow...

Carlson, A.R., Kosian, P.A. (1987) Toxicity of chlorobenzenes to fathead minnows (pimephales promelas). Arch. Environ. Contam. Toxicol. 16, 129-135. 

Pickering, Q.H. and M. Gast. 1972. Acute and chronic toxicity of cadmium to the fathead minnow (Pimephales promelas). Jour. Fish. Res. Board Canada 29 1099-1106. 

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