TOWARDS A HOLISTIC CLASSIFICATION OF DIFFUSE AGRICULTURAL WATER POLLUTION FROM INTENSIVELY MANAGED GRASSLANDS ON HEAVY SOILS

With the increasing demand for food security comes an increasing pressure on the environment. Contamination of surface water by diffuse agricultural pollutants is widely recognized as an area of concern; however, this has still led to a fragmented approach to scientific research. Pollutants tend to be treated in isolation and only infrequently in the context of an environment where other pollutants may be an issue. This is an important concept, as to achieve cost-effective mitigation the effect of any method implemented must take into account the positive as well as the negative effects on other pollutants which exist in the environment in which a method has been implemented. In this chapter, we synthesize the current state of understanding relating to a suite of typical aquatic diffuse pollutants associated with agricultural systems, more specifically those that may originate from intensively managed grassland systems on heavy, clay-rich soil types. This chapter is necessarily wide ranging but tries to draw together the information on each pollutant and present it within a single framework. This is only possible by characterizing the pollutants using shared characteristics along a source-mobilization-delivery (SMD)-continuum. Through this process, we highlight five possible SMD scenarios which can lead to contamination of water bodies. Further information on the nature of these SMD-scenarios can be gained by assessing the relationship between pollutant concentration and discharge of multiple pollutants. In this regard, we highlight the lack of literature available detailing multiple pollutant dynamics and also draw attention to areas of research that we feet need to be addressed if a more holistic approach to diffuse pollution mitigation is to be achieved.