A multi-approach assessment of land use effects on groundwater quality in a karstic aquifer

Tracing the land use specific impacts on groundwater quality: a chemometric, information entropy WQI and health risk assessment study

Understanding the nexus of land use and water quality can potentially underline the influences within the groundwater management. The study envisages land use-specific qualitative assessment of the groundwater resources in Ghaziabad district, in western Uttar Pradesh, India. For encountering the relative impacts of land use on the groundwater quality, chemometric analysis has been employed to apportion the pollution sources. The integration of quality parameters, in the information entropy index modeling, has segregated the quality classes and visualized the seasonal suitability trends as per potability standards along with non-carcinogenic health hazard risk assessment (HHRA). The qualitative assessment of the groundwater resources, along with spatial distribution, has deciphered a polluting impact, specifically in western and south western parts of district, and observed the linkages with direct and indirect discharges/seepages from densely populated residential and industrial land use types localized in urbanized areas. Statistically significant annual and seasonal variations have been found exclusively for EC, Mg2+, F-, Cd, Cr(total), Ni, and Pb which inferred variable concentrations, whereas land use types showed a non-significant variation within groundwater quality. Chemometric-based source apportioning and hierarchical cluster analysis (HCA) have derived salinization and enrichment of dissolved salts, arising from mixed sources and contributes to metal pollution, i.e., mainly from anthropogenic sources. Information EWQI derived poor to extremely poor category represented degraded potability specifically for fewer sites located within western and southern parts on the Yamuna-Hindon flood plains for limited sites of residential, industrial, and agricultural in an urbanized region. However, majority of the samples fall under excellent to good groundwater quality, recommendable in the north and north-eastern (peri-urban) regions. Non-carcinogenic HHRA has shown that majority of the samples categorized under unsafe value for hazard index (HI > 1), for females and children and thus, presumed probable health hazard risk from metal groundwater pollution in south-western part, eastern, and northern regions.

Hydrochemical characteristics and quality assessment of groundwater in Guangxi coastal areas, China

Groundwater is a main source of water supply in Guangxi Province, China. The urbanization expansion and ocean dynamic may change the groundwater quality, which is an important issue due to its effects on human health. In this paper, the influence of seawater intrusion and anthropogenic activity on the Guangxi coastal aquatic environment was assessed by geochemical and multivariate statistical methods. The result indicated that the chemical composition of groundwater in the study area is obviously associated with seawater and the main groundwater types were Ca·Na-Cl, Ca·Na-HCO₃, and Ca-HCO₃·Cl_. The groundwater evolution path from land to sea in Guangxi is Ca-HCO3 → Na·Mg-Cl. The origin of salts in the study area is mainly controlled by mineral weathering, the hydrogen and oxygen isotopes contents point to the aqueous source of atmospheric precipitation. According to the results of PCA, seawater intrusion and pollution caused by human activities play an increasingly important role in the evolution of groundwater characteristics. Seawater intrusion is the main factor for the increase of groundwater salinity in Guangxi, while domestic sewage, industrial waste, fertilizers, and pesticides may contribute to the nitrate pollution of groundwater, especially in Beihai. The degree of groundwater nitrate pollution is as follows: Fangchenggang < Qinzhou < Beihai, which is associated with the degree of urbanization in the coastal area. Finally, the results of the water quality index (WQI) assessment show that 82.8 % of the samples were classified as excellent, while there is still a need to be vigilant about groundwater pollution caused by seawater intrusion and groundwater pollution. The results will be valuable for sustainable groundwater resource management in Guangxi coastal zone.

Comprehensive assessment of the impact of land use and hydrogeological properties on the groundwater quality in Taiwan using factor and cluster analyses

This study aims at making a comprehensive assessment of the impact of land use and the hydrogeological properties on groundwater quality. First, factor analysis (FA) is applied to reveal the main pollutant sources and hydrogeological processes controlling the groundwater quality. FA identifies the four most important factors. Factor 1 (seawater salinization) is characterized by a medium loading of land use type of aquaculture. It is recognized that the high scores for factor 1 in coastal areas are due to over-pumping from aquafarms. Focused land use management is required to prevent saline-water intrusion in coastal aquifers. Factor 3 (nitrate pollution) shows high correlations with the land use type of fruit farming and the gravel thickness in unsaturated layers. High scores for factor 3 are also found in the proximal area of the Chuoshui River Alluvial Fan and the northeastern mountain area in the Pingtung Plain. Fruit farmers should be educated to reduce the application of fertilizers and promote the organic fruit farming. The impacts of land use and the hydrogeological properties on both Factor 2 (arsenic enrichment) and Factor 4 (reductive dissolution of Fe²⁺ and Mn²⁺) are negligible. Second, cluster analysis (CA) is performed on computed scores of the four main factors to separates 123 monitoring wells into cluster 1 (low polluted zone), cluster 2 (nitrate polluted zone) and cluster 3 (hybrid polluted zone). The results obtained from CA provide practical applications such as reduce agrichemical use in the areas of cluster 2 and enforce intensive monitoring in the prioritizing areas of cluster 3. This study successively uses the FA and CA to extract the meaningful information present by geographical visualization of scores for 4 main factors and 3 distinct clusters zones. The results are essential for formulating sound groundwater resource and land use management policies to ensure groundwater sustainability.

Hydrochemical characteristics and formation mechanisms of groundwater in west Zoucheng City, Shandong Province, China

Groundwater is an important water source for domestic, industrial, and agricultural use in the western part of Zoucheng, China. Understanding its hydrochemical characteristics and formation mechanisms is important for the sustainable development and utilization of groundwater. In this study, 36 water samples were collected during the wet and dry seasons, respectively, and the hydrochemical components such as K⁺, Na⁺, Ca²⁺, Mg²⁺, Cl^-, SO₄^2-, HCO₃^-, NO₃^-, F^-, TH, and TDS were analyzed. A graphical method, correlation analysis, and principal component analysis were applied to explore the hydrochemical characteristics and evolution mechanisms of groundwater in the study area. The results show that the orders of the anion and cation concentrations of karst groundwater and pore groundwater are Ca²⁺  > Na⁺  > Mg²⁺  > K⁺ and HCO₃^-  > SO₄^2-  > Cl^-  > NO₃^-  > F^-, respectively. On the whole, the karst groundwater quality is better than the pore groundwater quality, which in turn is better than the surface water quality. In addition, water quality in the dry season is better than water quality in the wet season for all the three water sources. The hydrochemical types of groundwater are complex and changeable. Compared with dry seasons, HCO₃ and SO₄ type water increase during the wet seasons, while the Cl type and Mg type water decrease. Na type is significantly more prevalent in pore groundwater than in karst groundwater. The chemical formations of karst groundwater and pore groundwater in the dry and wet seasons are mainly affected by water-rock interactions and human activities.

A comprehensive physico-chemical quality and heavy metal health risk assessment study for phreatic water sources in Narora Atomic Power Station region, Narora, India

An investigation of water quality and heavy metal distribution in the groundwater samples collected from the vicinity of Narora Atomic Power Station (NAPS), Narora, India, was conducted for the metals including Cu, Zn, Ni, Co, Cd, Pb, and Fe. A total of 16 water quality parameters were measured for all the groundwater samples, and TDS, TH, Mg²⁺, Ca²⁺, F^-, and turbidity were found to be on the higher side in comparison to the prescribed limits of Indian standards. Geometrical mean concentrations for these heavy metals were found to be 0.049, 0.213, 0.23, 0.135, 0.017, 0.061, and BDL for Cu, Fe, Zn, Pb, Cd, Co, and Ni, respectively. Pb and Cd were more than the permissible limits (0.01 mg/L for Pb and 0.003 for Cd) prescribed for safe drinking water while Cu and Fe were exceeding the permissible limits of 0.05 mg/L and 0.3 mg/L in 32% and 36% samples, respectively. Health risk assessment was done by calculating total hazard quotient (THQ), and the values for all the metals were below the threshold value of 1.0 beyond which they may pose a significant risk.

An Integrated Multi-Approach to Environmental Monitoring of a Self-Burning Coal Waste Pile: The São Pedro da Cova Mine (Porto, Portugal) Study Case

The São Pedro da Cova waste pile (Porto, Portugal) is composed of coal mining residues that have been self-burning since 2005 and is located close to an inhabited area and social infrastructures, further adding to effects on the environment and human health. Therefore, there is a great interest in the environmental monitoring of this waste pile. This work describes an integrative multi-approach that allows the environmental monitoring of several parameters of the waste pile, applying several technologies. The temperature measurements were obtained by a thermal infrared (TIR) sensor on board an unmanned aerial vehicle (UAV) and supplemented with field measurements. In order to evaluate the altimetric variations, for each flight, a digital elevation model (DEM) was generated considering a multispectral sensor also on board the UAV. The hydrogeochemical characterization was performed through the analysis of groundwater and surface water samples, with and without the influence of mine drainage. The soil monitoring included the analysis of waste material as well as the surface soil in the surrounding area of the waste pile. All the data were analyzed and integrated in a geographical information system (GIS) open-source application. The adopted multi-approach methodology, given its intrinsic interdisciplinary character, has proven to be an effective way of encompassing the complexity of this type of environmental problem.

Water Quality and Hydrogeochemical Characteristics of Some Karst Water Sources in Apuseni Mountains, Romania

Human activities and natural factors determine the hydrogeochemical characteristics of karst groundwaters and their use as drinking water. This study assesses the hydrogeochemical characteristics of 14 karst water sources in the Apuseni Mountains (NW Romania) and their potential use as drinking water sources. As shown by the Durov and by the Piper diagrams, the chemical composition of the waters is typical of karst waters as it is dominated by HCO3− and Ca2+, having a circumneutral to alkaline pH and total dissolved solids ranging between 131 and 1092 mg L−1. The relation between the major ions revealed that dissolution is the main process contributing to the water chemistry. Limestone and dolostone are the main Ca and Mg sources, while halite is the main Na and Cl source. The Gibbs diagram confirmed the rock dominance of the water chemistry. The groundwater quality index (GWQI) showed that the waters are of excellent quality, except for two waters that displayed medium and good quality status. The quality of the studied karst waters is influenced by the geological characteristics, mainly by the water–rock interaction and, to a more limited extent, by anthropogenic activities. The investigated karst waters could be exploited as drinking water resources in the study area. The results of the present study highlight the importance of karst waters in the context of good-quality water shortage but also the vulnerability of this resource to anthropogenic influences.