Concentrations, Sources and Health Risk of Boron in Surface Water of Huaihe River Basin, China

Boron is an essential micronutrient for living organisms, yet excessive concentrations can become toxic and pose significant health risks. The presence of elevated boron levels in drinking and irrigation water has been identified as a potential threat to human health. This concern is particularly relevant for the Huaihe River Basin (HRB), a crucial agricultural region serving as one of China's primary grain and wheat production areas. To assess the water quality status, this study collected and analyzed 59 surface water samples from the HRB, focusing on boron concentrations along with anions, cations, and trace elements. The investigation aimed to determine boron levels, identify potential sources, and evaluate associated health risks across the basin. The analysis revealed boron concentrations ranging from 0.008 to 0.683 mg/L, with a mean value of 0.106 mg/L. While most samples showed boron levels within acceptable limits for both surface and drinking water standards, two samples (HR41 and HR42) exceeded these thresholds. The primary natural sources of boron in the HRB were identified as silicate and evaporite dissolution. Anthropogenic contributions were only evident in areas exhibiting higher boron concentrations. The HQ_ingestion for adults and children ranged from 0.001 ~ 0.084 and 0.001 ~ 0.088, with mean values of 0.013 and 0.014, respectively. The HQ_dermal for adults and children ranged from 0.007 ~ 0.584 and 0.015 ~ 1.201, with average values of 0.091 and 0.187, respectively. The HQ_dermal values were higher than the HQ_ingestion values for both groups, indicating that dermal exposure poses a greater risk than ingestion, and children face higher health risks than adults. Notably, in the Suzhou and Bozhou regions of Anhui Province, the HQ and HI of children exceeded the safety threshold of 1, indicating that children face potential non-carcinogenic health risks. These findings provide critical baseline data on boron pollution in this region, highlighting the urgent need for local authorities to implement targeted water treatment measures. Such actions are essential to reduce boron concentrations and safeguard public health, especially among vulnerable populations.