From Catchment to Tap
: Source and Fate of Polar Pesticides and their Associated Risks

  • Adam Christopher Taylor

Student thesis: Doctoral Thesis

Abstract

Polar pesticide pollution impacts environmental waters globally, leading to reductions in water quality and potential risks to human and environmental health. This is widely acknowledged to be a growing problem however, relatively little is known about polar pesticide fate. Polar pesticides regularly occur at trace concentrations however, these can change dynamically due to the stochastic nature of pesticide pollution. Traditional methods for sampling and analysis are widely acknowledged to be ill suited for use in pesticide monitoring programmes. Discrete sampling methods lack temporal resolution, only providing a “snapshot” of pollution at the time of sampling. Routine instrumental methods for pesticide analysis are limited to pesticides in the predetermined analytical suite. A novel strategy combining temporally representative sampling and a comprehensive analytical suite is needed. Water utilities require a method that characterises pesticide fate during transport from the catchment origins of pollution through the treatment stream of drinking water treatment plants.
i) We develop a novel method using passive sampling coupled to suspect screening and multivariate analysis of qualitative screening data. Chemcatcher® passive sampling devices were deployed (14 days) over a 12-month period at three sites in South East England to validate the method. A data interpretation and handling strategy was developed to characterise pesticide fate and prioritise pesticide risk.
ii) We used this novel monitoring strategy to perform long-term monitoring at eight representative sites in a catchment used as a source of raw water for a drinking water treatment plant. Pesticide fate was described for 128 pesticides in the catchment. Our analysis prioritised 61 pesticides. We designed a seasonal monitoring programme and a workflow for incorporating our method into existing regulatory monitoring.
iii) We used this novel monitoring strategy to describe pesticide fate at six sites throughout the treatment stream of an operational drinking water treatment plant. We developed a management plan containing controls, triggers, and responses for six pesticides prioritised based on their current and future risk to treated water quality.
This work has furthered the understanding of pesticide fate at the catchment scale and throughout the treatment stream for numerous polar pesticides, most of which were not included in previous monitoring programmes.
Date of Award10 Feb 2022
Original languageEnglish
Awarding Institution
  • University of Portsmouth
SupervisorGary Fones (Supervisor) & Graham Mills (Supervisor)

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