ORGANOCLORATED AND ORGANOPHOSPHORUS PESTICIDES IN THE PELOTAS RIVER SEDIMENT

ABSTRACT Aquatic sediments are widely used for the evaluation of anthropogenic contamination due to their ability to adsorb particles and contaminants, making them historical environmental archives. Therefore, the objective was to evaluate the contamination of the Pelotas River sediments, at the border between the states of Santa Catarina and Rio Grande do Sul, by organochlorine and organophosphorus compounds, determining the ecological risk. The evaluation was carried out with quarterly sediment collections in 8 points, totalizing four campaigns within one year, with the aid of the Peterson dredger. Among organochlorines, p'p'DDT stands out regarding environmental persistence, representing 53.23% of the contaminated samples, with values varying up to 0.158 ppb. As for the organophosphates, Methyl Parathion obtained larger representation with 48.4% of the contaminated samples, with concentrations ranging up to 2.42 ppb. The ecological risk of selected organochlorines demonstrated no problems associated with the biota. Regarding the organophosphates studied, Disulfoton presented a risk factor with significant potential for adverse effects on organisms. Therefore, the need for monitoring and sustainability in the use and application of pesticides is well known, aiming at environmental quality and the preservation of natural resources.

摘要 水生沉积物因可吸附颗粒物与污染物，可作为历史性环境档案，被广泛应用于人为污染评估。本研究旨在评估圣卡塔琳娜州与南里奥格兰德州交界地带佩洛塔斯河（Pelotas River）沉积物中有机氯（organochlorine）与有机磷（organophosphorus）化合物的污染状况，并开展生态风险测定。本研究采用彼得森采泥器（Peterson dredger），于一年内在8个采样点开展季度沉积物采集，累计完成4次采样作业。在有机氯类污染物中，p,p'-滴滴涕（p'p'DDT）因具备较强的环境持久性而尤为突出，占受污染样品总量的53.23%，浓度最高可达0.158 ppb。就有机磷类污染物而言，甲基对硫磷（Methyl Parathion）占比最高，在受污染样品中占比达48.4%，浓度最高可达2.42 ppb。针对所选有机氯污染物的生态风险评估结果表明，其未对生物群落造成相关不良影响。而在所研究的有机磷污染物中，乙拌磷（Disulfoton）呈现出显著的风险因子，对生物体具备较强的潜在不良影响。由此可见，为保障环境质量与自然资源保护，开展农药使用与施用的监测工作并维持其可持续性，已是学界共识。