Abstract
Groundwater quality deterioration has become an environmental problem of widespread concern. In this study, we used a water quality index (WQI) and multivariate statistical techniques to assess groundwater quality and to trace pollution sources in the Hutuo River alluvial-pluvial fan, China. Measurement data of 17 variables in 27 monitoring sites from three field surveys were obtained and pretreated. Results showed that there were 53.09% of NO3−, 18.52% of SO42− and 83.95% of total hardness (TH) in samples that exceeded the Grade III standard for groundwater quality in China (GB/T 14848-2017). Based on WQI results, sampling sites were divided into three types: high-polluted sites, medium-polluted sites and low-polluted sites. The spatial variation in groundwater quality revealed that concentrations of total dissolved solids (TDS), Cl−, TH and NO3− were the highest in high-polluted sites, followed by medium-polluted and low-polluted sites. The temporal variation in groundwater quality was controlled by the dilution of rainwater. A principal component analysis (PCA) revealed that the primary pollution sources of groundwater were domestic sewage, industrial sewage and water–rock interactions in the dry season. However, in the rainy and transition seasons, the main pollution sources shifted to domestic sewage and water–rock interactions, nonpoint pollution and industrial sewage. According to the absolute principal component scores-multivariate linear regression (APCS-MLR), most water quality parameters were primarily influenced by domestic sewage. Therefore, in order to prevent the continuous deterioration of groundwater quality, the discharge of domestic sewage in the Hutuo River alluvial-pluvial fan region should be controlled.
Highlights
The availability of good-quality groundwater is vital for the physical health and socio-economic development of the local populations that depend on it
total hardness (TH) had mean values of 121.90 mg/L, 181.82 mg/L and 600.32 mg/L, respectively; 53.09% of NO3 −, 18.52% of SO4 2− and 83.95% of TH samples surpassed the Grade III standard for groundwater quality in China [20]. According to this set of results, the mean concentrations of NO3 −, SO4 2− and TH were very high in the Hutuo River alluvial-pluvial fan region. This indicated that its groundwater quality was generally impacted by human activity [6,13]
During the study period, we found that the villages and towns in the upstream of the Hutuo River area did not construct a network of sewage pipes, and large volumes of domestic sewage were drained directly into nearby rivers and ditches without treatment; this domestic sewage inevitably infiltrates into groundwater
Summary
The availability of good-quality groundwater is vital for the physical health and socio-economic development of the local populations that depend on it. The rapid growth in human populations and economic development has caused the severe deterioration of groundwater quality [1], especially in developing countries [2,3,4]. Groundwater quality is mainly controlled by two sets of factors: one is anthropogenic activity factors, such as domestic and industry sewage, agriculture fertilizer, urban development, exploitation of water resources and mining operations [4,5,6], while the other comprises natural processes, including. Res. Public Health 2020, 17, 1055; doi:10.3390/ijerph17031055 www.mdpi.com/journal/ijerph
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