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Keywords:

  • Pollution;
  • risk assessment;
  • sheep dip;
  • sheep dipper;
  • watercourse

Abstract

Following an initial exploratory survey in 1989, a detailed survey was carried out in 1990–91, the results of which indicated that a significant number of sheep dippers in the River Tweed catchment were at risk of polluting adjacent watercourses. Those dippers identified as medium to high risk of causing pollution were re-inspected in 1992 as a follow-up to the previous survey and, although in many cases dipping practices had greatly improved, a number were still at risk – emphasizing the importance of continued monitoring.

To complement the survey, environmental samples were taken and, in most of the catchments, the dip-active ingredients diazinon and propetamphos were found, confirming that the leaching of dip into a watercourse was occurring over a wide area throughout the Tweed catchment. The analysis of the environmental samples taken during the main dipping period each year of the survey showed that, in general, there was a significant decrease in diazinon and propetamphos in 1991 and 1992, compared to previous years.