Publisher © Czech Geological Survey, ISSN: 2336-5757 (online), 0514-8057 (print)
PGE metal-rich black shales in south China: mechanism of metal enrichment and environmental aspects
Abstract
The Zunyi region in Guizhou province /south China) is well known by the occurrences of Mo-Ni-polyelement black shales that are locally mined and processed for Mo. The preliminary results of our study covering the vicinity of the Xiao-Zhu mine, Jiepo-Ling and Tien Shan Bao Mo-Ni prospects can be summarized as follows: (1) Studied soil samples from all three Ni-Mo prospects are characterized by increased Mo, Ni, As, Cd, Zn and Cu concentrations and lower Pb values when compared to the orlide averages for normal soil (BOWEN 1979). Mo, As, and Ni values in our soil samples are very often above permissible levels suggested by KLOKE (1979). (2) Maximum Mo concentration as found in rice stalk and maximum As concentration in the bulb of edible wwater plant close to the Xiao-Zhu Mo-Ni mine. Peak Ni, Zn and Hg concentrations were detected in corn grain of the Jiepo-Ling area. Cd seems to accumulate preferentially into tobacco leafs where it reaches maximum values. This mechanism is also supported by extremely high biological absorption ratios between Cd and tobacco leafs (11.49 and 24.98) in both Xiao-Zhu area contains anomalous concentrations of Cd and rice grain from the Tien Shan Bao area contains anomalous concentrations of Cd, Cu and Zn. (4) Corn grain from the Jiepo-Ling area bears anomalous concentrations of Zn, Cd, Cu, Mo and Ni.
