Metabolism of a burrowing polychaete: Precaution needed when measuring toxic effects

The technique of direct calorimetry has been used to monitor the metabolic activity of the polychaete, Neanthes virens, an organism commonly used for testing the toxic effects of chemicals in the marine environment. In these tests Neanthes showed unpredictable alternating periods of hyperactivity and rest when deprived of sediment. If used in this abnormal state for toxicity tests, the results would represent the effects of the chemicals on abnormal organisms and may not, therefore, be realistic information for judging the chemical's harmful effects on it and other species in nature. In toxicity tests with heavy metals that have been reported in the scientific literature, the shorter survival time of test organisms without sediment, as compared to those in sediment, was probably the result of the abnormally high metabolic rates of the former group.