AN EVALUATION OF A NAIDID OLIGOCHAETE AS A TOXICITY TEST ORGANISM

Concern over sediment toxicity has increased the need for toxicity test information with organisms that inhabit sediments. Oligochaetes are exposed to toxicants through feeding and body contact with sediments and interstitial water. Chronic testing with oligochaetes has historically focused Ron tubificids with test lengths of 1 year or more to encompass several generations. Most naidid oligochaetes have generation times of 3 to 7 d. The cosmopolitan-distributed naidid Pristina leidyi Smith 1896 has potential for sediment toxicity testing. Cultures of Pristina leidyi were maintained in the laboratory for over 2 years. A rabbit chow suspension provided both substrate and food source. A reproducing viable culture with little variation in growth was maintained at 24 +/- 4-degrees-C and a 16:8-h light:dark photoperiod. Population growth in a characterized reference sediment peaked at 24 d with an increase in variation. It is recommended that test lengths should not exceed 18 d. The 48-h LC50s for cadmium and vanadium using Pristina leidyi were 215-mu-g/L and 30,830-mu-g/L, respectively, at a water hardness of 95 mg/L as CaCO3.