The importance of adult Hediste (Nereis) diversicolor in managing heavy metal pollution in shores and estuaries.

The main aim of the toxicity test is to be able to measure toxicity in organisms, and therefore to assess whether a nationally or internationally preset standard is met. LC50 values (median lethal concentration that kills 50% of the population at a given time) or LT50 values (median lethal time in which 50% of the test species died) provide useful information for risk assessment. However, extrapolating laboratory data to actual field conditions is difficult because of changing environmental factors like temperature and salinity. LC50 copper data for Hediste diversicolor treated multifactorially show the plasticity of the worm to environmental variables. Increasing temperature, 12 to 22°C, and increasing salinity, 7.6 to 30.5‰ reduced toxicity of copper to the worms without sediment. In the presence of sediment increasing temperature and increasing salinity increased toxicity of copper to the worms.