Risk Assessment of 1,2,4-Triazole-Typed Fungicides for Groundwater Pollution Using Leaching Potential Indices
2021
Aliste, Marina | Pérez-Lucas, Gabriel | Garrido, Isabel | Fenoll, José | Navarro, Simón
The main objective of this study was to learn the leachability of three widely used triazole fungicides (flutriafol, myclobutanil and triadimenol) in clay-loam soil to assess the risk of groundwater pollution by means of leaching potential indices (LPIs). For this, sorption, degradation and leaching experiments were conducted in a lab to evaluate the behaviour of the fungicides in a typical semiarid Mediterranean soil (calcareous Regosol). The sorption study was carried out following the batch equilibrium method. The degradation test was performed in aerobic and dark conditions (21 °C) for 60 days. Finally, the leaching potential was assessed using disturbed soil columns. Samples of soil and water were analysed by HPLC-MS². Low adsorption in the soil (log KOC ≤ 2.5) was observed for the three fungicides. The half-lives ranged from 79 to 136 days for triadimenol and flutriafol, respectively, showing moderate to high persistence in soil. All fungicides were detected in leachates with percentages ranging from 12% (triadimenol) to 26% (myclobutanil) of the initial mass added. Concentrations found in total leachates (13, 17 and 23 µg L⁻¹ for triadimenol, flutriafol and myclobutanil, respectively) were in all cases higher than the maximum admissible concentration (0.1 µg L⁻¹) established by the EU for groundwater. In accordance with the screening indices used (GUS, RLPI, LIX and ELI), all fungicides behave as mobile or very mobile compounds. The findings suggest that the studied fungicides are candidates to pollute groundwater resources, mainly in areas with intensive yearly rainfall regimes.
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