地质科技通报 (Mar 2024)
Pollution characteristics and health risk assessment of volatile organic compounds in groundwater in a decommissioned oil refinery in Northwest China
Abstract
Objective Volatile organic compounds (VOCs) can exist in groundwater for a long time, thus causing harm to human body. Methods To characterize the volatile organic compounds (VOCs) pollution in the organic-contaminated phreatic zone beneath a decommissioned oil refinery in Northwest China, investigations and sample testing were carried out and possible health risks were assessed in the study area. Results A total of 18 VOCs were detected in the groundwater at the site, with detection rates ranging from 6.25% to 56.25%. Benzene and 1, 2, 4-trimethylbenzene were the main characteristic pollutants, with adetection rate being 56.25%, both of which exceeded the class Ⅲ standard of the Groundwater Quality Standard (GB/T14848-2017) in China by 50%. The pollutants at the site mainly originated from the vertical seepage from the former liquefied gas storage tank area and the former diesel oil irrigation area, indicating that these two areas may be the main pollution sources of groundwater at the site. The distribution of pollutants was influenced by hydrogeological conditions and groundwater flow direction, with pollution occurring in groundwater downstream of the site.The results of the health risk assessment showed a predominant health risk posed by drinking water. 83.3% of the points had a cancer risk (CR) value greater than 10-6, indicating a possible cancer risk. The CR value for GW11 located in the residual oil tank area was greater than 10-4, indicating a significant cancer risk. 50% of the points had a hazard quotient (HQ) greater than 1, which would pose a noncarcinogenic risk and influence human health. Conclusion Therefore, the attention and control of regional drinking water issues should be strengthened in the future.
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