The determination of toxic effects of pollutants with the marine polychaete worm Ophryotrocha diadema

As part of an integrated program on biological test methods for aquatic toxicology the acute and chronic toxicity of pentachlorophenol (PCP), dieldrin, and 3,4-dichloroaniline (DCA) have been determined for the marine, hermaphrodite, laboratory-cultured, polychaete worm Ophryotrocha diadema. LC 50·96-hr values have been calculated for larvae and adults. Two types of chronic tests have been performed, one starting with 2- to 3-day-old larvae until the first 2 weeks of reproduction; the other starting with 4-week-old adults, of which reproduction has been observed during 30 days. Tests, both acute and chronic, starting with larvae appear a little more sensitive than those starting with adults. Mortality provides only a very limited picture of the toxic action of the test substances. For none of the test agents was a significant growth suppression observed, whereas reproduction inhibition in all tests appeared a very sensitive toxicity parameter. No “toxic effect levels” for reproduction inhibition were reached at 0.003 mg PCP liter −1, 0.0001 mg dieldrin liter −1, and 0.003 mg DCA liter −1.