A Field Screening Method Using Earthworms (Eisenia Foetida Andrei) to Evaluate Contaminated Soils

Abstract

An on-site biological assessment for soil toxicity was performed using a lumbricid earthworm, Eisenia foetida andrei(Bouche), at the Milltown Reservoir Superfund Site on the Clark Fork River near Missoula, MT. The assessment provided an opportunity to evaluate test containers and methodologies. Sixty-four field test stations, each consisting of three test containers of site soil, a control container of artificial soil, and a container to house soil moisture and temperature recording devices, were used. Laboratory tests were conducted on soil samples from selected field stations. The test containers were constructed from sections of polyvinyl chloride pipe and were found to be suitable in preventing escape of test organisms and damage by animals. The site soils had levels of arsenic, lead, cadmium, copper, and zinc higher than those in surrounding watersheds. Combined mortality for exposure to the site soil was similar in both the laboratory and field tests (1 to 3%). Combined sublethal responses to the site soil were also similar in both laboratory and field tests (3 to 4%). Artificial soil controls in both field and laboratory tests resulted in combined mortality rates of 1% or less. The methodologies employed proved successful in maintaining an adequate soil moisture level and allowed for measurement of soil temperature.