Pesticide Leaching Leads to Groundwater Contaminationvr, 08/28/2009 - 19:00 — Henk Tennekes The European Plant Protection Products Registration Directive (91/414/EEC) requires that there is not an unacceptable impact on non-target organisms in the aquatic and terrestrial environment and that the annual average concentration of an active substance or relevant metabolite does not exceed 0.1 microgram per liter in any ground water. Leaching is a major process for the transport of pesticides to ground and surface water. Four factors govern the potential for groundwater contamination by pesticides passing through the soil: properties of the soil and of the pesticide, hydraulic loading (total amount of water applied to the soil) on the soil, and crop management practices. The most sensitive soil is an irrigated sandy soil with very low organic matter content. The least sensitive soil is a well-drained clayey soil with high organic matter content. Recommended methods to reduce pesticide entry into water from leaching are restricted application areas, to restrict application to products with appropriate properties to minimise leaching, to manage soil structure e.g. create fine tilth to increase sorption and retention, and to incorporate additives to soil surface e.g. organic material or stabilisers. The European Plant Protection Products Registration Directive (91/414/EEC) requires that there is not an unacceptable impact on non-target organisms in the aquatic and terrestrial environment and that the annual average concentration of an active substance or relevant metabolite does not exceed 0.1 microgram per liter in any ground water. Concerns over pesticide entry into water are divided into two areas: protection of aquatic ecosystems and promotion of the sustainable use of water resources. The European Drinking Water Directives (80/778/EEC AND 98/83/EEC) require that no individual pesticide in supplied drinking water exceeds a concentration of 0.1 microgram per liter and total pesticides do not exceed a concentration of 0.5 microgram per liter. It is not a toxicologically based standard: 0.1 microgram per liter was the analytical limit of detection for most active substances analysed at the time of the first Directive (1980). The European Plant Protection Products Registration Directive (91/414/EEC) requires that there is not an unacceptable impact on non-target organisms in the aquatic and terrestrial environment and that the annual average concentration of an active substance or relevant metabolite does not exceed 0.1 microgram per liter in any ground water. Research over the last few years has identified a number of potential entry routes which vary according to the nature and properties of the active substance and the prevailing agroclimatic conditions. For plant protection products applied as sprays, a key potential route to surface water is from spray drift. Leaching is a major process for the transport of soluble to ground and surface water. Some of the most serious cases of water contamination have arisen from misuse, accidental spilling or inadequate handling or storage conditions. Four factors govern the potential for groundwater contamination by pesticides passing through the soil: properties of the soil and of the pesticide, hydraulic loading (total amount of water applied to the soil) on the soil, and crop management practices. The most sensitive soil is an irrigated sandy soil with very low organic matter content. The least sensitive soil is a well-drained clayey soil with high organic matter content. Recommended methods to reduce pesticide entry into water from leaching are restricted application areas, to restrict application to products with appropriate properties to minimise leaching, to manage soil structure e.g. create fine tilth to increase sorption and retention, and to incorporate additives to soil surface e.g. organic material or stabilisers. Bronnen: Pesticide Outlook, August 2000 http://www.rsc.org/delivery/_ArticleLinking/DisplayArticleForFree.cfm?do... Oregon State University Extension Service: http://www.pw.ucr.edu/textfiles/Soil%20Properties%20and%20Groundwater%20... University of Florida Cooperative Extension Service: http://citrusbmp.ifas.ufl.edu/References_Publications/Appendix%201%20-%2... | 
