Aspectos do comportamento da atrazina no solo e potenciais efeitos ambientais

Abstract

Atrazine is one of the most used herbicide to control broadleaf weeds, especially in maize, sugarcane and sorghum crops, of which present high relevance in Brazilian economic scenario. The herbicide mechanism of action is based on inhibiting the photosystem II on susceptible plants. This study presented as literature review aimed to address atrazine behavior aspects in the soil and its potential environmental effects. Atrazine presents complex dynamics on the ground, controlled by retention, transport and transformation phenomena. The main sorbent of this herbicide is the soil organic matter, suggesting close and positive relationship with organic matter quantity, hydrophobicity and aromaticity. The runoff and leaching are the most important transport process; the leaching process is inversely related to the sorption and linked to the presence of the herbicide in groundwater. The transformation in soil occurs primarily by microbial action, and the degradation can reduce both water contamination potential as the effect on weed control. This herbicide does not seem to affect significantly the soil biota, but its presence in aquatic environments has provoked concern on ecossistemic potential effects due its high mobility. The effects of atrazine in humans are not convincingly described yet, but the carcinogenic potential of atrazine is apparently out of possibility. The atrazine widespread use and investigations with contradictory results reinforce the need for continuous research into the dynamics and potential environmental effects, since from those investigations depend the conscious use and even the continued use of this herbicide in agricultural practice.