Assessment of Heavy Metal Uptake in Potatoes Cultivated in a Typical Karst Landform, Weining County, China

The average content of heavy metals in Weining soil of karst landforms is generally higher than that of other agricultural regions. The aim of this study was to evaluate the heavy metal content in potatoes from Weining county and to analyze the correlation between the content of heavy metals in potatoes planted in the soil of karst landform and the soil’s environmental factors (soil heavy metals, soil pH, soil organic matter, altitude). Weining county (Guizhou province, China) is a typical karst landform, and has a potato production yield of 2.7 million tons. In this study, 56 soil and potato samples were collected from Weining county and the heavy metal content in the soils and potatoes was detected by inductively coupled plasma atomic mass spectrometry (ICP-MS). The content of Cr, Ni, and As in the soil was found to be higher, with almost half of the samples exceeding the maximum allowable levels. A total of 9 of the 56 samples tested had pollution load index values greater than 1.0, which indicates serious soil pollution. It was found that the ability of the potato to absorb heavy metals from the soil was very low, with the average bio-concentration factors of the metals Zn, Cu, Pb, Cr, Ni, and As being 0.087, 0.088, 0.0028, 0.0034, 0.0066, and less than 0.001, respectively. The content of the six heavy metals in the potatoes were all lower than the maximum permissible limit. The results show that a high As content in the soil could increase the content of Pb in potatoes, that a lower pH was beneficial to the bioaccumulation of Cr and Ni in potatoes, and that a high altitude is detrimental to the bioaccumulation of zinc and copper in potatoes. The HRI ranged between 1.12 × 10−2 and 5.92 × 10−2.