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

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-1-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 EC50 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.