Contaminants of emerging concern in agricultural systems: a risk to soil and plant health?

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In order to sustainably secure global food for a growing population, it is critical that crop dependence on chemical-based fertilisers (e.g. nitrogen, phosphorus, potassium) is reduced and alternative water supplies identified which address water scarcity issues. Agriculture is the largest consumer of available freshwater (70%) with demand expected to increase by a further 19% by 2050. The depletion of global phosphorus and potassium reserves within 100 years also pose major threats to future fertiliser supply and our ability to grow enough food.One of the most promising options to secure future agricultural productivity is the use of wastewater treatment by-products, including sludges and Treated Wastewater (TWW). However, chemicals used in our everyday lives, including pharmaceuticals (e.g. prescription and non-prescription), personal care products (e.g. soaps, disinfectants) and fibres (e.g. plastics) can pass through wastewater treatment plants and contaminate the TWW and sludges. These pollutants are referred to collectively as "contaminants of Emerging Concern" (ECs). Our ability to boost yields and nutritional content of food to meet future demand may be impacted by the presence of ECs in soil-plant systems.Pharmaceuticals, in particular, are biologically active chemicals and their presence in agricultural systems could result in undesired toxic effects for plant, soil and human health. Pharmaceuticals are now ubiquitous global contaminants; however, our scientific understanding of potential ecosystem risks posed by these pollutants is scarce, especially in agricultural systems. Research has established that plants can accumulate pharmaceuticals that persist in soils, but we know very little about impacts of >1,500 pharmaceuticals estimated to be in current use on plant and soil health and ultimately crop productivity. The proposed programme of research for the first phase of the Fellowship aims to fill these knowledge gaps by uniting scientific expertise to explore the:1. Impact of pharmaceuticals associated with sludges and TWW on soil functioning in relation to maintaining sustainable agricultural production2. Accumulation and effects of pharmaceuticals on plant health and implications for crop productivity3. Assessment of the risks in the future (20-100 years) accounting for changes in land use, climate and associated changes in application rates of sludges and TWWThe second phase of the Fellowship will use the science platform created during the first phase to investigate the impact of a wider range of ECs that have the potential limit agricultural productivity such as nanomaterials and plastics as well as exploring solutions to mitigate against observed effects. Application of wastewater by-products to land is an accepted practice in a number of countries where populations have a relatively high use of pharmaceuticals (e.g Israel, Southern Europe, Southwest US). Pharmaceuticals have been identified in soils receiving sludges and TWW, and coupled with a recent drive to increase the use of TWW for agricultural irrigation in countries experiencing water shortages, there is an urgent need to establish the global risks of these chemicals in our agricultural systems. Whilst the UK does not currently use TWW for agricultural irrigation, the Environment Agency has suggested there will be significant water supply deficits in the UK by the 2050s. TWW may therefore offer a means of supplementing our demand for freshwater irrigation; however, this solution must be evaluated to ensure environmentally safe protocols are established which promote agricultural sustainability. Outputs of this research will also provide effective evidence for use by non-academic end users (e.g. environmental regulators, water industry, agricultural sector), guiding post-Brexit TWW reuse policies to ensure the UK maintains a world-leading position on mitigating risks of ECs in the environment whilst maximising sustainable reuse.