Heavy Metal Content and Health Risk Assessment in Water of Karst Cave in Libo, Guizhou.

In order to understand the heavy metal content and health risk level in water of kasrt cave in Libo, Guizhou Province, the concentration of 8 heavy metals in water from 13 caves was analyzed and detected, and the health risk assessment model recommended by US EPA was used to estimate the health hazard risk level of heavy metal pollutants in drinking water. The results showed that the average concentration of heavy metals is Zn>Cr>Cu>As>Ni>Cd>Pb>Hg, which did not exceed the class III water standard of Quality Standard for Ground Water (GB/T 14848-2017). The content of heavy metals in cave water in Libo is generally lower than (or only a little close to) surface water and groundwater outside the cave. Spearman correlation analysis showed that Zn was significant positive correlation between Pb and Cu, Cd was significant positive correlation with Hg, As was significant negative correlation with Cr and Hg. The health risk assessment showed that the mean values of the total health risk of adults and children caused by heavy metals in cave water were Cr>As>Cd>Cu>Hg>Ni>Pb>Zn. The average annual health risk for both adults and children caused by Cr and As (85% of caves) exceed the maximum acceptable risk for the Swedish Environmental Protection Agency, the Dutch Construction Environmental Protection Agency and the Royal Society of the United Kingdom. This indicates that drinking cave water for a long period of time may lead to a certain risk of carcinogenesis. The average contribution rate of Cr and As to the total health risk of adults and children is 99.60%, so Cr and As should be regarded as the priority control and management of pollutants of cave water in Libo. The total health risks of adults and children were 4.80x10^-6~3.51x10^-5 a^-1 and 5.46x10^-6~3.97x10^-5 a^-1, respectively, indicating that children are more sensitive risk receptors than adults, and the control and management of children's drinking water safety should be strengthened. [ABSTRACT FROM AUTHOR]