Studies On The Toxicity Effects Of 1,8-dihydroxyanthraquinone And 1-aminoanthraquinone On Daphnia Magna

Acute, sublethal and chronic toxicity of two representative intermediates of anthraquinone dyestuffs, 1,8-dihydroxyanthraquinone (1,8-dihAQ) and 1-aminoanthraquinone (1-aAQ), to Daphnia magna were assessed. The acute toxicity of 1,8-dihAQ and 1-aAQ, as expressed by 48 h ZC50, were 0.37 and 0.23 mg/L, respectively. Filtration and ingestion rate were adopted to characterize sublethal toxicity. The indices for chronic toxicity include: days to the first brood time, total number of neonates per female, total number of broods per female, brood size and intrinsic rate of natural increase for population. Boost effects of 1-aAQ at 0.02 mg/L were observed, with respect to the feeding, reproduction and population indices. Feeding behavior of Daphnia magna was severely affected by the two compounds. When Daphnia magna were exposed to 0.2 mg/L of 1,8-dihAQ and 0.1 mg/L of 1-aAQ for 5 h, their filtration and ingestion rate were inhibited by about 97 % and 76 %, respectively. Survival in chronic tests only descended significantly at 0.15 mg/L of 1,8-dihAQ. Reproduction ability decreased dramatically after exposing to sublethal concentration of 1,8-dihAQ (0.025 - 0.15 mg /L) and 1-aAQ (0.04 - 0.08 mg/L). The intrinsic rate of natural increase declined with increasing concentration, especially in those animals exposed to 0.15 and 0.1 mg/L of 1,8-dihAQ and 1-aAQ. The feeding and reproductive parameters are sensitive indices in charactering toxicity of the compounds to Daphnia magna, among which the most remarkable are the total number of neonates per female and brood size. The intrinsic rate of natural increase of a population is a comprehensive parameter which could be widely adopted in ecotoxicological risk assessment. In addition, the NOEC and LOEC values for longevity and several reproduction parameters were also provided.