Assessing the ground-water contamination potential of agricultural chemicals: a flexible approach to mobility and degradation studies†
✍ Scribed by Mills, Margaret S.; Simmons, Nick D.
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 415 KB
- Volume
- 54
- Category
- Article
- ISSN
- 1526-498X
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✦ Synopsis
Understanding the fate of agrochemicals in surface and sub-surface environments is of vital importance for the protection of water quality and for responsible environmental stewardship of crop-protection products. This paper demonstrates the need for a versatile approach to study experimental designs, aimed at a fuller understanding of the mobility and degradation of particular compounds in surface and sub-surface environments. Where appropriate, the environmental proÐle of a crop-protection product is built up using a combination of the following four study types : (a) radiolabelled laboratory studies to establish the routes of degradation and key degradates, supported by nonradiolabelled small-scale Ðeld studies to quantify key degradates under Ðeld conditions ; (b) small-plot radiolabelled Ðeld studies for tracking the fate of products with low usage rates or those exhibiting rapid and extensive metabolism ; (c) small-scale prospective ground-water studies (PGWs) to assess the potential for a compoundÏs sub-surface mobility in vulnerable ground-water settings, and (d) large-scale ground-water monitoring studies to measure actual environmental concentrations of an in-use product. The determination of which studies are required is product-speciÐc. Examples include radiolabelled laboratory and Ðeld studies conducted to investigate the rapid dissipation of the post-emergence herbicide tralkoxydim and its subsequent metabolites in surface soil. A PGW approach is illustrated, used to assess the degradation and mobility of the contact herbicide fomesafen under vulnerable ground-water conditions. Finally, large-scale monitoring studies are described which are used to assess the impact of the selective post-emergence herbicide Ñuazifop-P-butyl and fomesafen in vulnerable ground-water regions of northern Italy and Germany. These examples illustrate how Ñexibility and diversity of study design are essential to the development of a meaningful database of environmental fate information for cropprotection products. Such a database provides critical data for risk assessments and predictive modelling, and enhances our fundamental understanding of environmental science.