Provenance of drinking water revealed through compliance sampling

Abstract

Understanding drinking water hydrochemistry is essential for maintaining safe drinking water supplies.Whilst targeted research surveys have characterised drinking water hydrochemistry, vast compliance datasets are routinely collected but are not interrogated amidst concerns regarding the impact of mixed water sources, treatment, the distribution network and customer pipework. In this paper, we examine whether compliance samples retain hydrochemical signatures of their provenance. We first created and subsequently undertook the first hydrochemical analysis of a novel national database of publically available drinking water compliance analyses (n ¼ 3 873 941) reported for 2015 across England and Wales. k-means cluster analysis revealed three spatially coherent clusters. Cluster 1 is dominated by groundwater sources, with high nitrate concentrations and mineralisation, and lower organic carbon, residual chlorine and THM formation. Cluster 2 was dominated by surface water sources and characterised by low mineralisation (low conductivity and major ion concentrations), low nitrate and high organic carbon concentrations (and hence residual chlorine and THM formation). Cluster 3 shows a mixture of groundwater overlain by confining layers and superficial deposits (resulting in higher trace metal concentrations and mineralisation) and surface water sources. These analyses demonstrate that, despite extensive processing of drinking water, at the national scale signatures of the provenance of drinking water remain. Analysis of compliance samples is therefore likely to be a helpful tool in the characterisation of processes that may affect drinking water chemistry. The methodology used is generic and can be applied in any area where drinking water chemistry samples are taken. Environmental signicanceUnderstanding drinking water hydrochemistry is essential for maintaining safe water supplies. We examined whether routine drinking water samples retain hydrochemical signatures of their provenance. We undertook the rst hydrochemical analysis of a novel national database of routine drinking water samples. Principal component analysis and cluster analysis revealed three spatially coherent clusters reecting groundwater and surface water sources. Despite treatment of drinking water, at the national scale signatures of the provenance remain. Analysis of routine compliance samples is therefore likely to be a helpful tool in the characterisation of environmental processes occurring that may affect drinking water quality.

Cumulative risk analysis of carcinogenic contaminants in United States drinking water

“…Further, contaminant occurrence in drinking water generally reflects the quality of the source water (Ascott et al., 2019). Across the U.S., arsenic is detected in 41 % of the wells sampled in aquifers used for drinking water at concentrations of 1 μg/L or more (United States Geological Survey, 2014b).…”

Waterlogging mitigation and safe water supply: lessons learnt from low-lying areas of Basirhat municipality, India

“…The peri-urban areas are the transitional zones and endure in a crossroad between the development furore and a decaying or destroyed ecosystem. These transitional zones located in city outskirts that are generally situated in low-lying back swamps behind the relatively elevated natural levees on which cities developed (Ascott et al , 2019; Brelih et al , 2018). Urbanization has brought in drastic changes in both the topography and adaptability of these peri-urban areas.…”

“…Urbanization has brought in drastic changes in both the topography and adaptability of these peri-urban areas. Cities fail to recognize the importance of peri-urban areas and their ecosystems as store house of resources, act to safeguard from floods and droughts are supposed to be kept as city buffer zones for long-term sustainability of the city and to give a range of ecosystem services to the urban communities (Ascott et al , 2019; Brelih et al , 2018). But unfortunately, these areas are becoming occupied by people and cause breakdown of physical/environmental integrity by bringing abrupt change in the pattern of land use.…”