Spatial-Temporal Changes in Shallow Groundwater Quality with Human Health Risk Assessment in the Luxi Plain (China)

Groundwater is an essential water source for drinking, domestic, irrigation and industrial production in Luxi Plain, Shandong Province, China. Understanding the spatial-temporal changes in groundwater quality and its influencing factors in the region were required for better utilization of groundwater resources and efficient design of groundwater management strategies. In this study, the hydrochemical characteristics of groundwater in the study area were analyzed, and significant evolution was found from 2018 to 2020 due to silicate and carbonate weathering, evaporation and human activities. Moreover, the entropy water quality index (EWQI) was used to assess groundwater quality from 2018 to 2020. The EWQI values in 2018-2020 were 129.5, 90.5 and 94.0, respectively, and 31.7% of the groundwater in 2019 and 20.0% in 2020 can be used directly for drinking in the study area; others can be used for domestic water or irrigation. The potable groundwater, with an EWQI value of <50 (ranked as class I or II water quality), was mainly distributed in the west and southeast of the study area. The potential health risk due to oral intake and dermal intake was further assessed based on the human health risk assessment (HHRA) model. The results showed that, 37.3%, 6.7% and 3.3% of the groundwater samples for adults exceeded the acceptable limit for non-carcinogenic risk of 1.0 in 2018-2020, while for children, they were 88.2%, 30.0% and 56.7%, respectively. The high non-carcinogenic risks virtually all occurred in the counties or districts with higher agricultural or economic values. This work may provide useful information for local groundwater conservation and management and help to ensure a sustainable and healthy water supply for drinking, domestic and agricultural needs.