Abstract: Heavy metal pollution in the mining area is a severe problem in developing countries like Vietnam. This study collected 17 surface soil samples from a lead/zinc mining area in Thai Nguyen Province, Vietnam. The concentrations and chemical fractions of heavy metals (copper (Cu), lead (Pb), cadmium (Cd), zinc (Zn), chromium (Cr), and arsenic (As)) were investigated. Environmental indices such as geo-accumulation index, enrichment factor, contamination factor, risk assessment code, and individual contamination factor were used to assess the studied metals' risk and degree of contamination. Multivariable statistics were applied to ascertain the relationship between the metals and their deriving sources. The average concentrations of the heavy metals were found in the following order Zn > Pb > Cd > Cu > As > Cr. The quantity of these elements was distributed in the five chemical fractions in the order: bound to carbonates (F2) > bound to Fe–Mn oxides (F3) > residual (F5) > exchangeable (F1) > bound to organic matter (F4). The pollution indices showed that Pb, Zn, Cd were from high to intense contamination, while Cu, As, and Cr were at a mild and moderate pollution level. Statistics showed that Cu, Pb, Cd, Zn, and As metals were strongly related to each other, whereas Cr had a weak relationship with the other five metals. It is speculated that the five metals might stem from human activities while Cr might originate from natural sources. The result of this study can provide helpful information for local land managers and environmental protectors.

More information http://doi.org/10.1007/s13762-022-04339-w. 

Free full text https://doi.org/10.1007/s13762-022-04339-w.