A combined approach for the estimation of groundwater leaching potential and environmental impacts of pesticides for agricultural lands.

Pesticide pollution can degrade the quality of land, water, and air, and imposes risks on people, flora and fauna. Pesticides are frequently chosen based on their agricultural effectiveness and cost, rather than their potential environmental impacts. The aim of this study is to present a combined approach to estimate the leaching potential and environmental impacts of pesticides for agricultural lands. The pilot study area (PSA) is the agricultural plain of the Lower Aksu Stream Basin in Antalya - Turkey. The groundwater of the agricultural plain contributes to around half of the flow rate of the stream. The first phase of the combined approach involved pesticide monitoring to screen the target pesticides, the second phase involved evaluating the physicochemical properties of the target pesticides and estimating their leaching potential using several indices, and the third phase involved environmental impact analysis of the target pesticides using the Environmental Impact Quotient (EIQ) risk indicator. Additionally, Principal Component Analysis was conducted to examine the correlations between physicochemical parameters of pesticides and the leaching potential index results. By the application of the combined approach, 45 target pesticides were identified for the PSA and the indices were consistent to estimate similar leaching potentials for the same pesticides. Moreover, the computed EIQ-Field Use Rates provided valuable information to rank target pesticides according to their environmental impacts on consumer, farmworker and ecology. The applied methodology provided a practical approach to select pesticides with the least leaching potential and environmental impacts to protect water quality and ecosystem health.