Morphological and physico-chemical properties of British aquatic habitats potentially exposed to pesticides

Abstract

Approaches to describe the exposure of non-target aquatic organisms to agricultural pesticides can be limited by insufficient knowledge of the environmental conditions where the compounds are used. This study analysed information from national and regional datasets gathered in the UK describing the morphological and physico-chemical properties of rivers, streams, ponds and ditches. An aggregation approach was adopted whereby the landscape was divided into 12 hydrogeological classes for agricultural areas and a 13 th class that comprised non-agricultural land. The data describe major differences in the abundance, dimensions and chemistry of water bodies in the different landscapes. There is almost an order of magnitude difference in the total input of pesticide per unit area between the different landscapes. Ditches are shown to be most proximate to arable land, streams and rivers intermediate and ponds the least proximate. Results of the study have implications for the development of standard scenarios for use in protective screening steps within the risk assessment. Data can be used to produce more realistic estimates of the exposure to pesticides and to examine how that exposure varies across the landscape.

A comparison of the catchment sizes of rivers, streams, ponds, ditches and lakes: implications for protecting aquatic biodiversity in an agricultural landscape

“…The study area contained three Department for Environment, Food and Rural Affairs (Defra) agricultural landscape classes (Table 1) (Biggs et al, 2003) and was considered typical of lowland agricultural landscapes (Brown et al, 2006). Arable cultivation dominated the landcover (75%), with 9% under woodland, 7% improved grassland, 2% urban and the remaining 7% made up of water, semi-natural grassland and bare rock (Fig.…”

How does crop type influence risk from pesticides to the aquatic environment?

“…Beyond any practical considerations, the resolution of the cropping and usage data is insufficient to link a particular crop or pesticide to a particular stream segment and its related physical characteristics. Thus, the median dimensions of streams in different landscapes [17] were used to calculate concentrations of pesticide in water from a given input via spray drift or drainflow. This approach ignored any ameliorating impact on risk if smaller water bodies tend to have faster flow and, thus, shorter exposure times.…”

“…Description and total area of the hydrogeologic landscapes and characteristics of streams used for risk calculations[17] …”

Nature based measures increase freshwater biodiversity in agricultural catchments

“…Measures to protect the aquatic environment within farming landscapes currently cost many millions of pounds annually, with expenditure exceeding £470 m per annum in the UK alone (Rayment, 2017). This spend reflects a widespread recognition that agriculture, which makes up about 40% of land cover worldwide and 70% in Britain (Foley et al 2005;Brown et al 2006), plays a major role in modifying, and commonly degrading, freshwater ecosystems and the services that they provide (Moss, 2008;Gordon, et al 2008). In Europe, for example, member states report that nutrient pollution significantly degrades 28% of all surface water bodies classified in the Water Framework Directive (Carvalho et al, 2018).…”