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Certified Reference Material: Modern Polar Pesticides in Water

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Assisting regulation on water quality

The European Commission has set standards concerning allowable levels of certain pesticides in drinking water. In order to effectively enforce these standards it is necessary to make Certified Reference Materials (CRMs) available to national regulatory agencies.

Climate Change and Environment

The world's growing population has increased demands upon modern agriculture and pesticides have become a necessary evil in helping to increase crop yields. Pesticides eliminate unwanted pests as well as competing plant life. Some pesticides are designed to dissipate quickly following application, but others linger and seep into the soil and then into the groundwater. Rain can also remove the pesticides from the crops and transport them to nearby rivers, lakes and other bodies of water that feed into drinking water supplies. Once the drinking water supply has been contaminated it is very difficult and very expensive to remove the pesticides. It is also very difficult for regulatory agencies to measure exactly how much pesticide is contained in a particular water sample. For that reason, the European Commission has funded efforts (e.g. the Measurements and Testing Programme) to develop Certified Reference Materials (CRMs). CRMs are water samples containing specified amounts of a given pesticide that have been freeze-dried. A Spanish university was funded to develop CRMs for polar pesticides. Polar compounds have an asymmetrical distribution of electronic charge, a chemical property, which makes them dissolve easily in water. The university successfully developed several CRMs, and, perhaps more importantly, also managed to mass-produce these CRMs for distribution across Europe. Mass production was successful when the samples were lyophilised. Several quality checks were performed, including homogeneity between similar samples, intercomparison with other samples, the effect of long shelf life and so on. A useful result was the discovery that the characteristics of some pesticides were altered during the freeze-drying process and thus were not the same when reconstituted with water. While the exercise was successful for many polar pesticides, it was not possible to produce a CRM for pesticides containing glycine. The university seeks additional research support to resolve the issues concerning glycine and to proceed with certification.

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