Pathogen Risks in Agricultural Catchments: Towards International Collaboration And Learning in Modelling (PRACTICAL Modelling)

Around the world the prediction of microbial water pollution is important for informing policy decisions in order to safeguard human health. However, modelling the fate and transfer of microbial pollutants, such as E. coli (& other pathogens) at different spatial scales poses a considerable challenge to the research and policy community. In the UK much research has focused on trying to understand the movement & survival of pathogens in environmental systems with a view that better knowledge and data on the behavioural characteristics of these micro-organisms will improve our ability to model and predict their interactions with, and responses to, the world around us. The NERC-funded project ReMOFIO (NE/J004456/1) provides an example of research undertaken in the UK to improve our understanding of the magnitude and spatial distribution of microbial risks in the landscape. In turn, this new knowledge has enabled the refinement of a simple modelling framework to allow for improved prediction of microbial risk on agricultural land, based on livestock numbers, farming practices and E. coli survival patterns under environmental conditions (e.g. rainfall and temperature fluctuations). However, our model is built using data common to the UK; this International Opportunity Fund (IOF) will allow us to test the NERC funded ReMOFIO model in landscapes typical of different catchment systems around the world and to determine how transferable the approach is beyond the UK in order to evaluate its global relevance.

To do this we will use the 'PRACTICAL Modelling' IOF to establish a new international partnership, with the UK acting as a 'junction-box' connecting data and modelling skills from across Ireland, New Zealand and the USA. We have enlisted the expertise (and associated catchment data and modelling approaches) of three leading international scientists, in addition to other UK experts, in order to evaluate the wider application of data emerging from the ReMOFIO project. We will also investigate the potential for other models and tools to be linked to the ReMOFIO model to see if, conceptually, we can develop a more holistic model that becomes bigger than the sum of its internationally disparate parts. Part of our assessment will focus on the strengths and weaknesses of different modelling approaches that are currently being applied to assess pathogen risks in agricultural catchments. We will consider the transferability of these different approaches across contrasting agricultural systems typical of the UK, US, Ireland and New Zealand with a focus on the inherent differences in catchment characteristics (natural, managed, engineered and socio-economic), uncertainties of the underpinning data provided by international colleagues, and how these factors might impact on our ability to adopt or combine international modelling platforms.

Ultimately, our international partnership will explore key questions that challenge scientists working in the field of microbial pollution from agriculture: how do the different pathways in the soil, that connect pathogen sources to water bodies, vary in space & time across different catchment types & how does this impact on microbial travel times through the environment; to what extent does the probability of pathogen die-off vary for different environmental conditions around the world; how do we integrate pathogen behavioural characteristics (e.g. their ability to persist or move in the environment) into risk-based models that are useful for policy-makers; and how will the export of microbial pollutants from the landscape alter under projected climate change? The PRACTICAL Modelling project will begin to tackle these important questions using an international forum and, collectively, we will develop a global 'roadmap' of research priorities and needs required for a co-ordinated response to improve the prediction of microbial risks in agricultural landscapes.

As with all models, their transferability to different geographical areas is essential for wider international uptake. Maximising the impact from the wider application of data emerging from the current funded ReMOFIO project is at the heart of 'PRACTICAL Modelling'. Significant leveraging of 'in-kind' funds from international partners demonstrates that the aims & objectives of our project transcend international boundaries and align strongly with the interests of the United States Department for Agriculture and AgResearch Ltd in New Zealand. The original modest sum of funding secured from NERC (£80k) to deliver the ReMOFIO project and enable associated data collection & model development has therefore attracted access to international data not freely available in the public domain & with a combined worth in excess of £90k.

In the UK & Republic of Ireland this pump-priming activity will benefit several central government departments and agencies, most specifically the Scottish Environment Protection Agency, Environment Agencies of England, Wales, Northern Ireland & the Irish Environment Protection Agency, Defra, The Irish Department for Agriculture & Food, and will be of use to water utilities too. Faecal bacteria are key parameters monitored within the revised Bathing Waters Directive & Shellfish Waters Directive to regulate EU compliance of microbial water quality. Thus, any improvement in our ability to model the potential source loadings of faecal bacteria from livestock, & the risk of their onward transfer is important to those who work in areas of research and business linked to these Directives. Thus, policy makers and regulators will benefit from a range of direct (e.g. scheduled meetings with the international collaborators, our project outputs) & indirect (e.g increased cross-fertilisation of international expertise across the UK academic community) impacts likely to emerge from this IOF (see support from SEPA).

This research has clear relevance to international policy beyond Europe too. For example, in the US for improving predictions and modelling of Total Maximum Daily Loads (TMDLs) within the Clean Water Act given that pathogen indicators (predominantly E. coli and faecal coliforms) are the leading cause of watercourse impairment is the US. In New Zealand, the National Policy Statement for Freshwater Management plays a pivotal role in driving forward an agenda for delivering better national water quality. Remediation of microbial pollution of surface waters is a high priority in NZ, so much so that Fonterra, a multinational dairy co-operative that dominates NZ milk production, signed the 'Clean Streams Accord' in 2003 to commit to their integrated involvement in delivering clean water quality & reducing impacts from dairy farming. This has since been succeeded by "Sustainable Dairying: Water Accord" that seeks a further step change in the management of risks to waterways posed by dairying, & is based on the common desire to identify, protect & enhance the benefits and experiences New Zealand enjoys in freshwater. Therefore, our pump-priming will benefit stakeholders that extend far wider than our immediate project partners in the US and NZ, including, for example, the US Environmental Protection Agency, the New Zealand Government (Ministry for the Environment) & NZ Environmental Protection Authority & their regulation of the Resource Management Act, & of course wider society and their enjoyment of clean and safe water.

Modelling & catchment-based risk-assessment tools are recognised as an essential component of integrated catchment management in Europe, the US and New Zealand, & by all of those agencies and industry bodies listed above. Thus, the recommendations that will emerge from our programme of international integration, & the strengthening of collaborative understanding for co-ordinated responses to future research challenges, will deliver significant international societal and economic impact.