Avaliação toxicológica de solo contaminado com efluente sanitário

Abstract

The disposal of sanitary effluents without adequate treatment in the soil, entails numerous environmental consequences and risks to human health. The present study aimed to investigate the toxicological effects of soil contaminated by sanitary effluent on the behavior and breeding of earthworms of the Eisenia andrei species by means of ecotoxicological tests. In addition, the effects of exposure through enzymatic biomarker catalase (CAT) and superoxide dismutase (SOD), cell membrane lipid peroxidation (TBARS) and neurotransmission by acetylcholinesterase (AChE). The results of soil sample collection indicated accumulations of the heavy metals Cu and Zn at relevant points in the area, due to the effluent discharge. Ecotoxicological results indicated that the soil was toxic to reproduction and organism behavior. Contaminated soils caused significant changes in biomarkers. Increased activity of the enzymes superoxide dismutase and catalase as antioxidant defense mechanisms was observed. The significant increase in malondialdehyde levels and the inhibition of acetylcholinesterase activity indicate the occurrence of lipid peroxidation of the cell membrane and changes in neurotransmission due to the contaminants present in the soil of the contaminated area. Soil attributes, such as pH and organic matter were key elements in the responses of organisms, and should be considered in a toxicological approach. Thus, the use of E. andrei earthworms to analyze the toxicity potential of soil contaminated by sanitary effluents was efficient, indicating the need for remediation of the area, aiming to remedy the risk to the environment and human health.