Seasonal and Spatial Variability of Anthropogenic and Natural Factors Influencing Groundwater Quality Based on Source Apportionment

Abstract

Globally, groundwater resources are being deteriorated by rapid social development. Thus, there is an urgent need to assess the combined impacts of natural and enhanced anthropogenic sources on groundwater chemistry. The aim of this study was to identify seasonal characteristics and spatial variations in anthropogenic and natural effects, to improve the understanding of major hydrogeochemical processes based on source apportionment. 34 groundwater points located in a riverside groundwater resource area in northeast China were sampled during the wet and dry seasons in 2015. Using principal component analysis and factor analysis, 4 principal components (PCs) were extracted from 16 groundwater parameters. Three of the PCs were water-rock interaction (PC1), geogenic Fe and Mn (PC2), and agricultural pollution (PC3). A remarkable difference (PC4) was organic pollution originating from negative anthropogenic effects during the wet season, and geogenic F enrichment during the dry season. Groundwater exploitation resulted in dramatic depression cone with higher hydraulic gradient around the water source area. It not only intensified dissolution of calcite, dolomite, gypsum, Fe, Mn and fluorine minerals, but also induced more surface water recharge for the water source area. The spatial distribution of the PCs also suggested the center of the study area was extremely vulnerable to contamination by Fe, Mn, COD, and F−.

The Spatial and Temporal Variability of Groundwater Vulnerability and Human Health Risk in the Limin District, Harbin, China

“…Groundwater Fe concentration showed a considerably decrease from 2006 ( Figure 3e) to 2016 ( Figure 3f) and this change corresponded with the results of Sharma, et al [59] and the Kruskal-Wallis test (Table 4) It has been reported that high contents of Fe and Mn in groundwater are common in northeastern China, with high Fe concentrations generally occurring where Mn concentrations are high [55][56][57]. Especially in the center of the Songnen Plain, in which our study area occurs, contents of Fe and Mn are as high as 11.2-44.4 mg/g and 0.5-1.0 mg/g, respectively, due to the abundance of iron-manganese nodules in local Quaternary aquifer sediments [55,58]. Therefore, the background concentrations of Fe and Mn in the study area are very high and usually exceed the acceptable levels.…”

Hydrogeochemical Evolution of Interaction Between Surface Water and Groundwater Affected by Exploitation

“…Major ions of river water and groundwater show higher concentrations in the dry season than in the wet season, including Ca 2+ , Na + , Mg 2+ , HCO 3 − , SO 4 2− , Cl − , and TDS (Table S1). This is caused by strong seasonal evaporation, slow groundwater runoff with weaker water‐rock interaction in addition to some influences from human activities in the dry season (Hulan Water Authority ; Zhang et al ; Guo et al ).…”

Assessment of tea garden soils at An'xi County in southeast China reveals a mild threat from contamination of potentially harmful elements

“…The comparative medium coefficient of variation (CV) for all PHEs showed a fairly large geochemical variability in concentrations for each of two metals in the sampled soils. Generally, the degree of variation can be divided into three levels: CV < 10% is considered as weak variability, 10% < CV < 100% defines moderate variability, and CV > 100% is strongly variable [ 38 , 39 ]. The CV of all PHEs at An'xi was moderate variability, following an order of Cr > Cd > Pb > As > Hg, which indicated the concentration of elements showing moderate geochemical variation.…”

“…Generally, the degree of variation can be divided into three levels: CV , 10% is considered as weak variability, 10% , CV , 100% defines moderate variability, and CV . 100% is strongly variable [38,39]. The CV of all PHEs at An'xi was moderate variability, following an order of Cr .…”