Instituto Superior de Agronomia, University of Lisbon, Centro de Engenharia dos Biossistemas (CEER), Tapada da Ajuda, 1349-017 Lisboa, Portugal.
IMAR-CMA, Department of Life Sciences, University of Coimbra, Apartado 3046, 3001-401 Coimbra, Portugal.
Ecotoxicol Environ Saf. 2014 May;103:36-44. doi: 10.1016/j.ecoenv.2014.01.029. Epub 2014 Feb 21.
The present study aimed to assess the environmental fate of the insecticide and nematicide ethoprophos in the soil-water interface following the pesticide application in simulated maize and potato crops under Mediterranean agricultural conditions, particularly of irrigation. Focus was given to the soil-water transfer pathways (leaching and runoff), to the pesticide transport in soil between pesticide application (crop row) and non-application areas (between crop rows), as well as to toxic effects of the various matrices on terrestrial and aquatic biota. A semi-field methodology mimicking a "worst-case" ethoprophos application (twice the recommended dosage for maize and potato crops: 100% concentration v/v) in agricultural field situations was used, in order to mimic a possible misuse by the farmer under realistic conditions. A rainfall was simulated under a slope of 20° for both crop-based scenarios. Soil and water samples were collected for the analysis of pesticide residues. Ecotoxicity of soil and aquatic samples was assessed by performing lethal and sublethal bioassays with organisms from different trophic levels: the collembolan Folsomia candida, the earthworm Eisenia andrei and the cladoceran Daphnia magna. Although the majority of ethoprophos sorbed to the soil application area, pesticide concentrations were detected in all water matrices illustrating pesticide transfer pathways of water contamination between environmental compartments. Leaching to groundwater proved to be an important transfer pathway of ethoprophos under both crop-based scenarios, as it resulted in high pesticide concentration in leachates from Maize (130µgL(-1)) and Potato (630µgL(-1)) crop scenarios, respectively. Ethoprophos application at the Potato crop scenario caused more toxic effects on terrestrial and aquatic biota than at the Maize scenario at the recommended dosage and lower concentrations. In both crop-based scenarios, ethoprophos moved with the irrigation water flow to the soil between the crop rows where no pesticide was applied, causing toxic effects on terrestrial organisms. The two simulated agricultural crop-based scenarios had the merit to illustrate the importance of transfer pathways of pesticides from soil to groundwater through leaching and from crop rows to the surrounding soil areas in a soil-water interface environment, which is representative for irrigated agricultural crops under Mediterranean conditions.
本研究旨在评估杀虫剂和杀线虫剂乙草膦在模拟的地中海农业条件下（特别是灌溉条件下）玉米和马铃薯作物施药后在水土界面中的环境归宿。研究重点关注土壤-水的迁移途径（淋溶和径流）、施药后（作物行）和非施药区（行间）之间农药在土壤中的迁移、以及各种基质对陆地和水生生物区系的毒性影响。采用半野外方法模拟“最坏情况”乙草膦施药（玉米和马铃薯作物推荐剂量的两倍：100%浓度 v/v）在农业田间情况下，以模拟农民在实际条件下可能的误用。在两种作物情景下，都在 20°的坡度下模拟了降雨。采集土壤和水样进行农药残留分析。通过使用来自不同营养级的生物进行致死和亚致死生物测定来评估土壤和水样本的生态毒性：等节跳虫（Folsomia candida）、赤子爱胜蚓（Eisenia andrei）和大型水蚤（Daphnia magna）。尽管大部分乙草膦被吸附到土壤施药区，但所有水样都检测到农药浓度，说明在环境介质之间存在水污染物的迁移途径。在两种作物情景下，乙草膦淋溶到地下水都被证明是一个重要的迁移途径，导致玉米和马铃薯作物情景下淋出液中的农药浓度很高（分别为 130µgL(-1)和 630µgL(-1)）。在推荐剂量和较低浓度下，乙草膦在马铃薯作物情景下的应用对陆地和水生生物的毒性影响大于在玉米作物情景下。在这两种作物情景下，乙草膦随灌溉水流迁移到行间未施药的土壤中，对陆地生物造成毒性影响。这两个模拟的农业作物情景具有重要意义，说明了在土壤-水界面环境中，农药从土壤向地下水通过淋溶和从作物行向周围土壤区系的迁移途径的重要性，这代表了地中海条件下灌溉农业作物的特点。
