Short‐term fish and amphibian embryo‐larval tests for determining the effects of toxicant stress on early life stages and estimating chronic values for single compounds and complex effluents: Complex mixtures

Abstract

-A short-term embryo-larval test is described for use with single compounds or complex effluents. Exposure was initiated soon after fertilization and maintained for 4 d after hatching, which gave an exposure period of 6 to 8 d for a number of fish and amphibian species. Test responses included mortality and teratogenesis. Probit analysis was used to calculate median lethal (LC50) and threshold (LCl) concentrations. Standard statistical tests also were performed to determine no observed effect concentrations. Multiple tests were performed with cadmium as the reference toxicant, using continuous-flow and static-renewal procedures; results substantiated high precision and good repeatability. Cadmium LCI values agreed closely with cadmium chronic values determined in life-cycle studies. The review of published data also supported close correlations between LCls and chronic values for metals. The procedure also worked satisfactorily for a multiple-species test in which eggs of three species were maintained in mixed populations using the same exposure chambers. The test also was conducted in the laboratory to screen seven major industrial effluents. The test for effluent biomonitoring was further evaluated in two major field studies.As compared with 96-h flow-through acute tests with the fathead minnow, the short-term embryolarval test was decidedly more sensitive and reliable for characterizing the toxicity of complex effluents.

Latent effects of early life stage exposure to triclosan on survival in fathead minnows,Pimephales promelas

“…24 h embryos were exposed through 4 days post 50% hatch for a total of 10 days. [41,46] Preliminary experiments determined that at 25 C hatching began at 4 days post fertilization (dpf) and continued through 7 dpf, with a 50% mean at 6 dpf. TCS stock solutions (5 g L ¡1 ) were prepared by diluting pure TCS (Irgasan, Sigma-Aldrich, St. Louis, MO, USA) in 100% ethanol (EtOH, Fisher Scientific, Pittsburgh, PA, USA).…”

Chronic effects of fire suppressors on the reproduction of the copepod Nitocra sp.

“…Other four decreasing concentrations, in logarithmic scale, were defined. The selected concentrations were 1%, 0.1%, 0.01%, 0.001% and 0.0001%, and they prepared by diluting the stock solutions in filtered autoclaved sea water (Birge et al, 1985). Four replicates were used for each concentration of test-solution and the respective controls (clean sea water).…”

EFFECTS OF TEMPERATURE AND METALS (ZINC AND CADMIUM) IN EMBRYONIC STAGE OF Anabas testudineus: AN ALTERNATIVE FRESHWATER FISH EMBRYO TEST IN THE SOUTHEAST ASIA REGION

“…Table 2 shows the median lethal concentration (LC 50 ), lowest observed effect concentration (LOEC), and no observed effect concentration (NOEC) values of each zinc and cadmium test in several types of embryos. In terms of sensitivity, A. testudineus embryos were not as sensitive as rainbow trout (Salmo gairdneri) (Van Leeuwen et al, 1990) towards zinc and fathead minnows (Pimephales promelas) (Birge et al, 1985) to cadmium. However, the LC 50 , LOEC, and NOEC values of both zinc and cadmium in A. testudineus embryos in the present study are comparable to the African catfish (Clarias gariepinus in Nguyen & Janssen, 2001) (see Table 2).…”