Ref ID : 6118
Benjamin L. Preston and Terry W. Snell; Full life-cycle toxicity assessment using rotifer resting egg production: implications for ecological risk assessment. Environmental Pollution 114:399-406, 2001
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The majority of standardized toxicity tests incorporate only a fraction of the test organism's life-cycle. However, in natural ecosystem, organisms may be exposed at various times during their life-cycle or throughout their life-cycle. Thus, ecotoxicological data from standardized toxicity tests is of limited ecological relevance. Existing standardized toxicity tests using the freshwater rotifer Brachionus calyciflorus utilize 24-hr survival or 48-hr asexual reproduction as endpoints, despite evidence that sexual reproduction is more sensitive. A 96-hr B. calyciflorus resting egg toxicity test was developed and used to estimate the toxicity of pentachlorophenol (PCP) and copper. Results were compared to a variety of acute and sublethal endpoints for both toxicants. The B. calyciflorus 96-hr resting egg production NOEC for PCP of 10 µg/l was 20 times lower than the 48-hr asexual reproduction no observed effect concentration (NOEC) and 120 times lower than the 24-hr acute lethal concentration 50%. The 96-hr resting egg production NOEC for copper of 2.8 µg/l was 7 times lower than the 48-hr asexual reproduction NOEC and nine times lower than the 24-hr acute LC50. Resting egg production was a more sensitive indicator of toxicity than several other sublethal endpoints as well. These results indicate that partial life-cycle toxicity tests are not sufficiently sensitive to detect ecologically relevant adverse effects.