Analysis of spatial variability and influencing factors of arsenic in groundwater of Hetao Plain, Inner Mongolia

Abstract

Hetao Plain is one of the most serious area of local arsenic poisoning in China.Based on shallow groundwater arsenic samples, the paper used the semivariogram to reveal the spatial distribution and heterogeneity of groundwater arsenic concentration, and further discussed the influencing factors.The results show that the arsenic concentration in groundwater generally increases from south to north in the Hetao Plain.The residual groundwater arsenic concentration is fitted to the pure nugget effect model under the assumption of isotropic conditions, which means it is random on the measured scale, so there is no spatial autocorrelation and the variance is great in short distances.The fractal dimension value is large(D=1.999), further indicating the distinct variation of groundwater arsenic concentration within the measured scale.Groundwater arsenic is closely related to organic matters in sediments.Since the Late Quaternary, the tectonic movements of the northern mountains and changes in the sedimentary environment of the basin has caused multiple sedimentary facies, resulting in a high degree of spatial variability in burial conditions of organic matters.The high spatial variability of organic matters characteristics further leads to high spatial variability of groundwater arsenic concentration.The slow groundwater flow plays an important role in maintaining this pattern.This article focuses on the spatial heterogeneity of groundwater arsenic in the Hetao area, which has scientific significance for effectively predicting the potential risk of arsenic exposure in drinking water in unknown areas, accurately preventing endemic diseases and ensuring water supply safety.

Keywords

• arsenic concentration
• groundwater
• spatial variability
• organic matters
• hetao plain