Estimating the population exposed to arsenic from groundwater-sourced private drinking water supplies in Cornwall, UK

Abstract

Introduction: Many properties in the UK are served by private water supplies (PWS) where mains connection is not possible. Chronic exposure to chemicals in PWS may have an adverse effect on health causing cancers and skin lesions, although no evidence observed in the UK. The SW of England is an area with elevated arsenic concentrations in groundwaters supplying a number of domestic property PWS. A Prescribed Concentration Value (PCV) of 10 µg/L is set by Regulations enforced by local authorities. However, there remains uncertainty as to the precise extent of the local population exposed to arsenic. We undertook to calculate exposure to arsenic in PWS in Cornwall to help estimate the health burden. Methods: We invited known PWS users on a register to take part in a water sampling programme from 2011-13. We asked for information on the number of residents drinking PWS water and if properties shared the supply. The number of PWS in Cornwall and mean household population was estimated using GIS. We calculated population exposure to the range of concentrations found in samples. Results: 497 PWS were sampled, serving 868 properties supplying 1,979 (95% CI 1,901-2,057) residents. An estimated 4,044 properties are served by PWS in Cornwall supplying 9,625 (95% CI 9,504-9,746) people. The proportion of the population exposed to arsenic levels ranged from 71%: <1µg/L, 24%: 1-10µg/L and 5%: >10µg/L. Conclusions: Extrapolation estimates that 600 people are drinking water over the PCV in Cornwall. Households were given public health advice and recommendations to regularly test water for arsenic.