In addition, sublethal effect parameters should be included in toxicity testing with aquatic oligochaetes.ĪPHA (American Public Health Association) (1995) Standard methods for the examination of water and wastewater. Study findings support the need for using indigenous tropical species in risk assessments in the tropics. sowerbyi was more sensitive to both metals tested than the coldwater species T. Sublethal effects were generally noted at concentrations lower than those leading to mortality. Results and discussionīoth test species were more sensitive to Zn than As in water-only tests, which is in agreement with previous studies evaluating the toxicity of these metals to aquatic oligochaetes. The lethal (LC 10 and LC 50) and effect (EC 10 and EC 50) concentrations were also determined to assess metal sensitivity for both species. Both lethal and sublethal endpoints (autotomy of the posterior body parts, abnormal behavior and appearance) were determined in the tests. The tests were conducted considering the environmental conditions in the natural habitat of T.

Water-only (96 h) and sediment (14 days) toxicity tests were conducted with both species evaluating a concentration series of arsenic and zinc. sowerbyi in the risk assessment of sediments in the tropics are discussed. Relative sensitivity with the coldwater species Tubifex tubifex was compared.

This study aimed at evaluating the acute effects of arsenic and zinc to the warmwater aquatic oligochaete Branchiura sowerbyi.

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