Metaldehyde Transport Processes in a Water Abstraction Catchment in Essex, Southeast England

Abstract This paper addresses the issue of pesticide loss from agriculture and its impact on aquatic environment. Specifically, this study assesses transport relatively water-soluble polar molluscicide compound metaldehyde in a small (14 km 2 ) water abstraction catchment Essex, southeast England during 14-month period (January 2019–February 2020). A rise concentrations was observed at all monitoring points, to varying extents, months seasonal applications. The highest increases (up 0.05 µg L –1 across were autumn December. These findings reinforce mobile nature pesticide, with surface field drain runoff likely be predominant mode transfer waters. scale individual sources influx Ardleigh storage reservoir showed that contribution total flux transferred adjacent River Colne catchment. Atmospheric deposition followed similar pattern levels runoff, certain accounted for higher input than (May, August–October 2019). Monthly values mass ranged 27.7 47.4 g. An increase associated elevated sources. Relatively stable are probably due aqueous solubility decreased degradation rates