Cloud to coast: integrated assessment of environmental exposure, health impacts and risk perceptions of faecal organisms in coastal waters

ABSTRACT

The proper recognition and calculation of polluted sources and the fate and transport of faecal organisms in catchments, river networks and coastal waters are very important to the assessment of environmental exposure, health impacts and risk perceptions of faecal indicator organisms (FIO) in coastal waters. The paper reviews the integrated modelling techniques for faecal processes from cloud to coast, including sediment and faecal bacteria interactions, and then presents a theoretical and case study in the numerical modelling for FIO levels in the river Ribble and Fylde Coast using the two-dimensional or three-dimensional environmental fluid dynamics code and the 1D Flow And Solute Transport in Estuaries and Rivers models, respectively. The related key parameters in the linked model are illustrated and analysed, together with validation of the hydrodynamic processes and the faecal bacteria concentration levels being undertaken using measured related data acquired in 1999. Using the model results, a quantitative microbial risk assessment is undertaken, where a moderate dose for swimming in faecal coliform-laden flows is accepted, as given by the European (EU) water quality standard requirements. The results show that some local regions of relatively high concentration exist near the outfalls and these values are not compliant with the mandatory and tighter microbial standards in the UK, as governed by the new EU Water Framework Directive. Finally, some new research and key challenges for the future are discussed in the paper.

Keywords:

• Cloud to coast (C2C)
• faecal indicator organisms
• river Ribble
• environmental exposure and health impacts
• numerical modelling
• quantitative microbial risk assessment (QMRA)

Acknowledgements

The authors are grateful to the Environment Agency North West for their provision of data and to all colleagues from the universities of Aberystwyth and Sheffield working on the NERC C2C project.

Additional information

Funding

The research reported herein is funded by the Natural Environment Research Council, the Medical Research Council, the Department for Environment, Food and Rural Affairs and the Economic and Social Research Council [GR NE/I008306/1] UK. The third author is funded through a Case Studentship, funded jointly by CH2M HILL and the Natural Environment Research Council.