Understanding pesticide dynamics at the catchment scale for the management of drinking water reservoirs

了解流域规模的农药动态以进行饮用水水库管理

• 批准号: NE/G012415/1
• 金额: $ 9.08万
• 依托单位: University of Bristol
• 依托单位国家: 英国
• 项目类别: Training Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FG012415%2F1
• 关键词: Understanding; pesticide; dynamics; catchment; scale

Pesticides applied on farmland are a source of pollution for the surrounding areas and in particular for local watercourses. During rainfall events pesticides are transported away from the area of application towards the rivers via surface runoff and attached to eroded sediment. Where such local watercourses supply water to drinking-water reservoirs, a variety of different pesticides ultimately end up in the reservoirs. However, the timing of pesticide arrival and their concentrations in the reservoir, vary throughout the year as a function of both rainfall variability and the timing and type of pesticide application on fields. Because at present there is no legislative requirement to record pesticide application on fields, companies such as Wessex Water have no information on the seasonal dynamics within the catchment that will affect the pesticide levels within their reservoirs. Hence, monitoring and managing pesticide levels within the reservoirs are a serious problem with important implications for public health. The project will adopt a field-based methodology in which the catchment hydrological and erosion responses will be characterised within a hierarchical approach. The study site will be the Durleigh catchment which is one of Wessex's lowland agricultural catchments and one which is most prone to pollution from pesticides. The first part of the work will involve a pilot study in which classes of persistent pesticides will be identified from water and sediment samples from the rivers in relation to classes found in the reservoir. Any existing available data on pesticides, land use and hydrology will also be collated and synthesised for a broader historical understanding of the pesticide dynamics within the catchment. The second part of the study will be carried out over 12 months and will involve spatial sampling of river water and riverbed sediment every two weeks. Wessex already carries out routine sampling of the reservoir water every two weeks. Both water and sediment samples will be analysed for the classes of pesticides identified in the pilot study and related to the reservoir pesticide levels. The third part of the project will build on the data collected in the previous year to identify catchment 'hotspots' of pesticide response and, over a 6-month period, carry out within those a more detailed characterisation of pesticide transport, particularly within individual rainfall events and at the individual farm system scale. A particularly innovative aspect of the project is the comparison between the dissolved and sediment-bound pesticide transport mechanisms in relation to catchment processes. Currently, Wessex Water has no information on the role of sediment-bound pesticides within their catchments but there are serious implications of the potential for this component, through desorption mechanisms, to act as a sustained source of pesticide pollution in the reservoir long after their initial mobilisation from the fields. The synthesis of these data will provide a much needed detailed understanding of catchment dynamics in relation to pesticide transport mechanisms and how these affect the pesticide dynamics within the Durleigh drinking-water reservoir. This understanding will lead to better management practices of the reservoir and ultimately to the design of mitigation measures at the farm level. The project combines different strands of investigation into an innovative and achievable course of doctoral training with great practical application to a pressing pollution and water-quality problem. The student will benefit from the different expertise offered by the supervisors both at the University of Bristol and Wessex Water. The student will benefit from establishing contacts with Wessex Water as well from the training opportunities offered at Wessex. The pesticide analyses of the water samples will be carried out in the Wessex labs and the student will have training in analytical techniques.

在农田中使用的杀虫剂是周围地区，特别是当地水道的污染源。在降雨期间，农药通过地表径流从施用区流向河流，并附着在侵蚀的沉积物上。在这些地方水道向饮用水水库供水的地方，各种不同的农药最终会进入水库。然而，农药到达的时间及其在水库中的浓度，全年都因降雨量的变化和农药在田间施用的时间和类型而异。由于目前没有立法要求记录农田中的农药施用情况，Wessex Water等公司没有关于集水区内季节动态的信息，这些信息将影响其水库中的农药水平。因此，监测和管理水库内的农药含量是一个严重的问题，对公众健康有重要影响。该项目将采用一种基于实地的方法，在这种方法中，将在一种分级方法中描述集水区水文和侵蚀反应的特点。研究地点将是德利集水区，这是威塞克斯低地农业集水区之一，也是最容易受到农药污染的地区之一。这项工作的第一部分将涉及一项试点研究，根据水库中发现的持久性农药类别，从河流的水和沉积物样本中确定持久性农药的类别。还将整理和综合关于农药、土地使用和水文学的任何现有数据，以便更广泛地了解流域内农药动态的历史。研究的第二部分将在12个月内进行，每两周对河水和河床沉积物进行一次空间取样。威塞克斯已经每两周对水库水进行一次例行采样。将分析水和沉积物样本，以确定试验研究中确定的农药类别，并与水库农药水平相关。该项目的第三部分将以前一年收集的数据为基础，确定农药反应的流域“热点”，并在6个月的时间内，在这些区域内，特别是在个别降雨事件和个别农场系统规模内，对农药运输进行更详细的描述。该项目的一个特别创新的方面是比较与集水过程有关的溶解和沉积物结合的农药迁移机制。目前，Wessex Water没有关于沉积物结合农药在其集水区中的作用的信息，但这一成分通过解吸机制可能会产生严重影响，在最初从田地中动员后很长时间内，该成分可能会成为水库中农药污染的持续来源。这些数据的合成将提供一个非常需要的详细了解流域动态农药运输机制，以及如何影响农药动态内的德利饮用水水库。这种理解将导致更好的水库管理做法，并最终在农场一级的缓解措施的设计。该项目将不同的调查链结合到一个创新的和可实现的博士培训课程中，并将其实际应用于紧迫的污染和水质问题。学生将受益于布里斯托大学和威塞克斯水务大学的主管提供的不同专业知识。学生将受益于建立与威塞克斯水接触，以及从威塞克斯提供的培训机会。水样的农药分析将在威塞克斯实验室进行，学生将接受分析技术培训。