b'32Assessing direct cattle access contribution to streambedsediment nutrient and faecal pollution in Irish agriculturalcatchmentsAntunes P1,hUallachin D2, Dunne N2, Kelly-Quinn M3, OSullivan M3 and Jennings E11Centre for Freshwater and Environmental Studies, Dundalk Institute of Technology, Dublin Road,Dundalk, Republic of Ireland2Crops, Environment and Land Use Programme, Teagasc, Johnstown Castle Environment Research Centre, Wexford, Co. Wexford, Ireland3School of Biology and Environmental Science, Freshwater Ecology Research Group, University College Dublin, Dublin, Republic of IrelandAgriculture is one of the major causes of water pollution and water quality impairment globally. Although livestock agriculture, particularly the use of farmland watercourses bylivestock for drinking water or as crossing points, has been shown to have a negative impact on stream biogeochemical parameters such as bank stability, sedimentation or faecalcontamination, the information available in literature regarding its impacts on water quality in a European context is scarce. In this study, bed sediment was collected at sites actively used by cattle in five agricultural catchments across a range of water quality status in Ireland at two times of the annual cattle management cycle. At each study site, the sediment was sampled at the cattle access site and at reaches of the stream not used by cattle. Sediment samples were analysed for organic carbon (OC), total nitrogen (TN), carbon:nitrogen (C:N) ratios, totalphosphorus (TP) and Escherichia coli (E. coli) concentrations. Cattle access to watercourses significantly increased sediment TP and E. coli concentrations, whereas OC, TN and C:N ratiosdid show any significant change as a result of cattle access. These results show thatunrestricted cattle access to watercourses can lead to 1) high levels of faecal contaminantsin stream sediments, with implications for both human and animal health, and 2) a localisedaccumulation of TP in sediments at access sites, potentially contributing to a legacy effect in streams that can hinder the effects of mitigation measures, with subsequent implications for water quality and the achievement of WFD objectives.76'