HEAVY METAL CONTENT AND HEALTH RISK ASSESSMENT OF KARST CAVE WATER IN GUIZHOU

In order to understand the heavy metal pollution status and health risk level of karst cave water in Guizhou, the concentration of six heavy metals in 32 water samples from 10 caves was analyzed and tested, and the health risk assessment model recommended by US EPA was used to study the risk evaluation of different types of cave water. The results show that the average concentration of heavy metals is: Zn>Ni>Cr>Cu>As>Hg. Ni exceeded the limit of the Class III standard (GB/T14848-2017) of the "Groundwater Quality Standard", and the over-standard rate was 3.13%. The remaining heavy metals did not exceed the standard. Spearman correlation coefficient analysis shows that Zn has homology with Cr, Cu, Ni, Hg, and there is no same source between Cr and As. Health risk assessment showed that the total health risk order was Cr>As>Hg>Ni> Zn>Cu. The total health risks for adults and children were 7.05 x10(-6) similar to 3.18x10(-4)a(-1) and 8.83 x10(-6) similar to 3.97 x 10(-4)a(-1), respectively. 28.1% and 50% of the samples exceeded US, respectively. The maximum acceptable risk level recommended by the EPA (1x10(-4)a(-1)) is distributed in tourist caves (Jiulong cave, Zhijin cave) and mining caves (Yanyingwo Cave, Yanrong Cave, and Laizi Cave). The health risk caused by non-carcinogenic heavy metals is 10(-13) similar to 10(-10), and the risk of carcinogenic heavy metals is 10(-7) similar to 10(-4). The total health risk is mainly caused by carcinogenic heavy metals and carcinogenic risk caused by Cr. It accounts for 85.5% of the total risk of cancer, which is greater than the carcinogenic risk caused by As. Cr and As are the pollutants controlled by the research area, especially Cr should be the priority of risk decision management. In addition, children have a greater health risk than adults.