Groundwater nitrate contamination in China: Spatial distribution, temporal trend, and driver analysis

Area of Science:

• Environmental Science
• Hydrogeology
• Water Quality Analysis

Background:

• Groundwater nitrate pollution poses a significant environmental and health risk.
• China's extensive agricultural practices and industrial development contribute to water contamination.
• Understanding nitrate distribution and trends is crucial for effective water resource management.

Purpose of the Study:

• To analyze the spatiotemporal distribution and trends of groundwater nitrate pollution in China from 1990 to 2020.
• To identify the primary drivers of increasing groundwater nitrate concentrations across different regions.
• To inform the development of targeted water management strategies.

Main Methods:

• Analysis of 2348 regional groundwater surveys conducted between 1990 and 2020.
• Statistical examination of nitrate concentration data to determine median levels and trends.
• Identification of contributing factors including agricultural activity, groundwater exploitation, domestic pollution, and industrial production.

Main Results:

• Median groundwater nitrate levels in China increased from 3.84 mg/L in 1990 to 6.94 mg/L in 2020.
• Northern China exhibits significantly higher median nitrate concentrations (8.54 mg/L) compared to southern China (7.15 mg/L).
• Agricultural activity was identified as the dominant driver of nitrate pollution, with other factors playing secondary roles.

Conclusions:

• Groundwater nitrate pollution is a worsening issue in China, necessitating immediate attention.
• Regional disparities in pollution levels require tailored management approaches.
• Urgent implementation of region-specific policies is needed to mitigate nitrate contamination and protect water resources.