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 negative effect of the application of the residue at a dose of 234 t ha-1 on Oligochaeta activity. However, the application of BaSO4 alone did not show damage to the earthworms, unlike what was observed for NaCl application. These results indicate that sodium was the element that most restricted the activity of these organisms.

摘要 钻井与勘探作业产生的残渣中，含量最丰富且最为关键的元素为钡与钠。生态毒理学测试常被用于评估土壤中有毒物质所引发的毒性效应。本研究旨在探究油井钻井残渣施入土壤后对寡毛类（Oligochaeta）生物活性的影响。将土壤与不同剂量的钻井残渣——硫酸钡（BaSO4）与氯化钠（NaCl）——共同温育后，本研究开展了三项生态毒理学测试，以赤子爱胜蚓（Eisenia andrei）作为生物指示物。回避行为测试结果显示，当钻井残渣施用量达234吨每公顷（t ha⁻¹）时，会对寡毛类生物活性产生负面影响。然而，单独施用硫酸钡并未对蚯蚓造成损伤，这与氯化钠施用后的观测结果截然不同。上述结果表明，钠是对这类生物活性抑制作用最强的元素。