Influences of sediment characteristics and land utilization on the behavior of groundwater arsenic (As) in the Kuitun River basin

• Published in: Desalination and water treatment Vol. 189; pp. 338 - 348
• Main Authors: Li, Qiao, Tao, Hongfei, Aihemaiti, Mahemujiang, Su, Yanpeng, Yuan, Hanqing, Jiang, Youwei, Yang, Wenxin
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-06-2020
• Subjects: Land utilization; Partition coefficient values; Sediment; The Kuitun River basin; The Kuitun River basin; As; Sediment; Partition coefficient values; Land utilization
• ISSN: 1944-3986; 1944-3986
• DOI: 10.5004/dwt.2020.25633

To better understand the formation and migration of high-arsenic groundwater, the influences of geochemical characteristics of sediments, and land utilization must be further studied. To better understand these dynamics, 76 groundwater samples from different scales of the landscape (alluvial–proluvial plain, downstream flood irrigation zone and downstream drip irrigation zone) were collected and tested to analyze the contents of their major and trace components. Forty-two sediment samples from two boreholes were collected and different variables such as particle size distribution, chemical composition, and concentrations of weakly (S1) and strongly (S2) bound As were tested for physiochemical index analysis. Results showed that high-As groundwater (As concentration >10 μg/L) was mainly distributed at depths of 20–36 m; the groundwater in the alluvial–proluvial plain had a generally low As concentration with an average concentration of 9.6 μg/L; and the groundwater in the flood irrigation zone and that in the drip irrigation zone had relatively high As concentrations with average concentrations of 36.0 and 151.45 μg/L, respectively. In the sediments, As content was positively correlated with Fe and Mn content, and its distribution was controlled by hydrodynamic conditions and lithology, with clay having a relatively high As content. The competitive adsorption by PO43– promoted the release of As in the sediments. As concentration in groundwater in the drip irrigation zone (known for growing cotton using drip irrigation, which demands high-phosphate fertilizer) was higher than that in the groundwater in flood irrigation zone (known for vegetable agriculture using flood irrigation, which demands high-potash fertilizer), suggesting that land use patterns have a significant influence on the distribution and migration of As.