Private water supplies in Wales: information to support public health priorities

点击翻译按钮获取中文摘要

Private water supplies (PWS) are used by a significant proportion of households in some British regions. Chemical and physical factors both have the potential to impact upon the well-being of PWS users.The chemical quality of PWS can vary greatly, dependent on the composition of the surface or groundwater from which they are drawn, and the infrastructure and treatment of the water supply. Recent Public Health England/NERC-BGS research has shown that PWS users often do not treat to improve chemical quality, or do not maintain their treatment systems. PWS tap water quality cannot be assumed to be improved from its natural state, and may be significantly worse than drinking water standards. It is important stakeholders across all scales (household, local and national) better understand the distribution of factors which influence water quality.We have established that current efforts to assess national and regional water quality priorities in Wales are hindered by a two-way knowledge barrier. Stakeholders are unaware of the large NERC data resource which could be used in their assessments, whilst NERC data holders do not have sufficient understanding of stakeholders' needs, and how the data can be most usefully presented and disseminated. Barriers to direct uptake of this NERC data include: the current format (hard-copy or digital documents); chemical element mapping formats (which may divide the concentration range into arbitrary intervals and not show thresholds of relevance to users); bespoke indices using more than one variable are needed (e.g. plumbosolvency); and, resource pressures on public body officers (e.g. time, expertise, computing, GIS).A further problem exists which NERC data can contribute to resolving. Assembling the evidence base to determine what, if any, action should be undertaken at national or regional scales is compromised by the lack of systematic registration, in any database, of the most prevalent type of PWS, i.e. "Single Domestic Dwellings" (SDDW). SDDW users are not compelled to register their supply with the Local Authority, and in Wales, 85% of registered PWS are SDDWs. There is widespread awareness, at all levels of governance, that there are considerably more than the officially recorded 12,242 SDDWs. Improved estimates of the locations of these properties, can help national and local government assess, and prioritise, risks arising from geospatially controlled factors (e.g. high metal concentration and vulnerability to drought). Recent NERC-funded research has built a spatially resolved, predictive model of the likely occurrence of PWS in Wales. In order to fulfil its potential impact, this work now needs to be shared with the key stakeholders at regional and national level. Specific examples will be developed that indicate regions where large numbers of PWS users coincide with expected high risks of events (e.g. flooding, drought) under future weather scenarios, and allow an improved understanding of pressures on marginal aquifers.Sustained inter-organisational and inter-personal communication will ensure the successful progress of this project. At an overarching level this will be achieved through active participation in an existing national forum, the Water Health Partnership, and by undertaking short-term secondments into key Local Authority and public body offices (Public Health Wales, Dwr Cymru Welsh Water, Natural Resources Wales, Powys County Council). Outward facing communication, of agreed key messages, is embedded into later activities. Web, mobile and selected more traditional mechanisms will be used to ensure that outreach is as equitable and widespread across private water supply users as possible. Project reports will be available in both English and Welsh.KEYWORDS: private water supply; lead; drought; flooding; manganese; public health.