A cross-sectional study of the association between arsenic consumption from private drinking water supplies and measured biological levels in the population of Cornwall, UK – Project Update July 2014

Background to the study

Sampling private water supplies in Cornwall, England

Between 2011 and 2013, Public Health England (PHE), the British Geological Survey (BGS), with later involvement from the University of Manchester (UoM), worked together on a two-phase sampling programme of private water supplies (PWS) in Cornwall. Results were collected for around 500 households and showed that, in the case of arsenic (As) alone, nearly 6% of drinking-water samples exceeded the 10 μg/L Prescribed Concentration or Value (PCV) as prescribed by the Private Drinking Water Supply Regulations, 2009. These findings, in addition to the well documented high environmental arsenic concentrations in the region, warranted further investigation into the potential uptake of this element by the local population. This is an issue that has long been recognised and investigated previously, however no study has targeted PWS users, a possible vulnerable sub-group. This project will be the largest arsenic biomonitoring study conducted in the UK, and serves as a pilot for similar studies in other areas of the UK where exposure from PWS is a potential concern.

Results of the water samples taken during the biomonitoring study

The results of the water samples are ready to be sent back to householders. The water samples collected during the biomonitoring study in 2013 showed similar levels of arsenic and other naturally occurring substances as those found in the previous sampling campaigns (2011-2013). Analysis of the water samples suggests that 41 households (32%) had elements in their private water supplies at levels which exceed current UK drinking water standards. Exceedences of eight chemicals were found, including arsenic, aluminium, copper, iron, lead, nickel, manganese and antimony. Drinking water from 15 households (12%) exceeded the arsenic PCV. Since households with high arsenic levels were targeted for recruitment, there is a higher proportion of households with arsenic exceedences than the previous studies.

Communicating the results to householders and stakeholders

Participants will shortly receive the results of their drinking water samples. In the same approach as the previous studies, households will be sent the results of their water samples by means of a letter, giving the results for the elements where exceedences of the PCVs exist in the study population. A public health advice sheet will be included if any of the chemicals in the water sample exceed a PCV. Around 15 householders with very high chemical levels will be contacted personally with tailored advice. Advice on mitigation measures is provided by Cornwall Council. Results of the analysis of biological samples will be sent separately, later on in the year. For high urine levels, information from the exposure questionnaire will be used if possible, to highlight possible routes of exposure. Any participants with high urinary arsenic levels will be encouraged to visit their GP for a further examination and re-testing.

Results of the environmental samples will help to explain any relevant exposure from the local environment. The results from household dust wipe samples and rice samples will complement research conducted by the British Geological Survey and University of Manchester investigating possible exposure routes of arsenic from the environment.