Heavy Metal Pollution Status and Human Health Risk Assessment of Farmland around the Karst Mining Area in Central Guizhou

PurposeTo clarify the heavy metal pollution and human health risks of farmland around the karst mining area in central Guizhou.

MethodsThe pollution status, ecological risk and human health risk of Cd, Hg, As, Pb and Cr in soil samples were evaluated by Nemerow comprehensive pollution index, geoaccumulation pollution index, potential ecological risk index and human health risk model.

ResultsThe contents of Hg, As, and Pb were higher than the background value, the excess rate of Hg element content was 98.04%, and the contents of other elements were all lower than the background value, and the spatial variation was medium; the single factor pollution of each element was Hg>Pb>As>Cd>Cr, the main pollution factor was Hg, and the whole area was dominated by comprehensive moderate pollution; Hg had accumulated pollution, with 91.83% of the pollution points, and the rest of the elements had no accumulated pollution, which were in a clean state. Ecological risks were mainly moderate risks, accounting for 81.80%; oral intake was the main way for the human body to produce health risks, and the health risk value of children was greater than that of adults. As and Pb were the main factors causing non-carcinogenic risk in this area, and Cr was the main influencing factor of carcinogenic risk in this area.

ConclusionThe heavy metal pollution in the farmland around the mining area in central Guizhou is mainly Hg element, followed by As and Pb; the farmland is polluted compositely by a variety of heavy metals, and there is a moderate potential ecological risk; the health risk level is within the acceptable range for the human body, As, Pb and Cr elements are the main factors that cause human health risks in the area.