Bioassays of 2,4-D with earthworms in different soil classes

Abstract

2,4-D is a highly toxic herbicide, neurotoxic, teratogenic, possibly carcinogenic  and well-known by its capacity of causing damages on human health and biota. This work proposes the assessment of 2,4-D toxicity levels in four Brazilian soil classes, using bioassays with earthworms (Eisenia andrei). Acute toxicity tests were performed with one sedimentary, two colluvial and one residual soils previously infected with solutions of agronomical concentration. No significant levels of mortality were observed, suggesting low acute toxicity to soil earthworms. However, the results revealed that lower levels of toxicity were linked to the textural appearance and high microporosity. The largest toxic potential was attributed to the quartz sandy soil. Such results may support the future establishment of toxic reference values able to reflect Brazilian pedological occurrences, subsiding future ecological risk assessments and decision-making in actions of environmental health.