Relative sensitivity of three daphnid species to selected organic and inorganic chemicals

Abstract

Static acute and renewal chronic tests were conducted with Daphnia magna, Daphnia pulex and Ceriodaphnia reticulata to determine their relative sensitivities to selected organic and inorganic chemicals: 2-chloroethanol, 2,4-pentanedione, pentachlorophenol, hexachloroethane, 2,2,2-trichloroethanol, 2-methyl-l-propanol, 2-methyl-2,4-pentadiol, Endrin@, silver, lead, chromium, cadmium, copper, arsenic and mercury. The three species tested yielded comparable acute EC50 values for most chemicals tested. The acute EC50 values for D. magna, D . pulex and C. reticulata varied twofold for hexachloroethane, Endrin, cadmium, arsenic and mercury. Chronic EC5O values for the three species were within one order of magnitude for 2-chloroethanol, 2,4-pentanedione, cadmium, chromium and silver. Differences in the sensitivities of these three popular cladoceran test species were within one order of magnitude. Reproductive impairment in all three test species appeared to be a more sensitive indicator of chronic toxicity than survival. This study suggests that the 7-d Ceriodaphnia chronic test may be used as an alternative short-term method for the screening of chemical toxicities.

Evaluation of the toxic effects of selected municipal wastewater effluents on aquatic invertebrates

“…The LC50 values, 3.2% and 13.4%, probably do not differ significantly. These findings are in contrast to that of Elnabarawy, et al (14), who found Daphnia magna, Daphnia pulex and Ceriodaphnia reticulata equally sensitive to various organic, inorganic and pesticide chemicals in both acute and chronic tests. While cladocera may be equally sensitive to pure chemicals, they may not respond in the same way to the possible additive, synergistic or antagonistic toxicity dynamics present in municipal effluents.…”

Evaluation of the sensitivity of three cladoceran species widely distributed in Mexico to three reference toxicants

“…[15] Our results in C. dubia with Cr(VI) are similar to those reported by Elnabarawy et al (0.195 mg L −1 ), [36] and although Cowgill and Milazzo [30] report a 5-times higher value (1.2 mg L −1 ), the difference could be due to the higher hardness of the dilution water used by them.…”

Chromium in the Canadian environment

“…Much lower lethality threshold for both Cr(V1) and Cr(II1) have been reported, however. Elnabarawy et al (1986) found a 20% death rate for adult Daphnia pulex exposed to 1.5 kg Cr(VI)/L. The lowest reported median lethal concentration (LC50) for Daphnia magna was 6 kg/L for Cr(II1) (Janus and Krajnc 1990).…”