Toxicity of Drilling Waste from Oil Wells on Oligochaeta

ABSTRACT The most abundant and critical elements in residues from well drilling and prospecting are barium and sodium. Ecotoxicological tests have been used to evaluate the toxicity caused by toxic substances present in the soil. The objective of the present study was to verify the effect of the application of drilling residue from oil wells on Oligochaeta activity. After incubation of the soil with residue doses – BaSO4 and NaCl – three ecotoxicological tests were performed in which the species Eisenia andrei was used as a bioindicator. The avoidance behavior test showed that there was a...