Abstract
Mercury pollution in soil poses serious risks to human health through consumption of contaminated vegetables. We used a meta-analysis to examine the mercury enrichment ability of different vegetables and the main factors affecting mercury uptake. We drew the following conclusions. (1) Plants with a lower bioconcentration factor (BCF) include cowpea, long bean, and radish, whereas plants with a higher BCF include green pepper, spinach, cabbage, and Chinese cabbage. (2) Leaf and cucurbit have the highest and lowest capacity, respectively, for mercury enrichment. (3) When soil pH is <6.5, mercury level uptake by the plant increases, whereas it decreases when the pH is >7.5, meaning that increased soil pH reduces mercury uptake in soil. (4) When soil organic matter (SOM) is lower than 20 g/kg, tuber plants have the highest and eggplant has the lowest mercury adsorption capacity, respectively. When SOM is 20–30 g/kg, cucurbit has the lowest and leaf the highest adsorption capacity, respectively. When SOM is higher than 30 g/kg, however, eggplant has the highest mercury adsorption capacity, but there were no significant differences among the five types of vegetables. We argue that this meta-analysis aids in selecting vegetables suitable for absorption of heavy metals from polluted soil.
Highlights
Mercury pollution in soil poses serious risks to human health through consumption of contaminated vegetables
The soil chemical behavior of heavy metal ion adsorption is mainly affected by soil pH, organic matter content, and cation exchange capacity, affecting the effective concentration of Hg and thereby indirectly affecting the concentration of Hg uptake from the soil[18]
Based on a meta-analysis of the role of soil Hg in vegetable absorption, enrichment coefficients of long beans, cowpea, and radish were found to be lower than the national standard for effect size (ES) = ln bioconcentration factor (BCF) = −2.7076
Summary
Mercury pollution in soil poses serious risks to human health through consumption of contaminated vegetables. When SOM is higher than 30 g/kg, eggplant has the highest mercury adsorption capacity, but there were no significant differences among the five types of vegetables. We argue that this meta-analysis aids in selecting vegetables suitable for absorption of heavy metals from polluted soil. Research into the effects of different vegetable varieties on soil Hg adsorption capacity has an important role in making it feasible to control the human intake of HMs. Currently, most suburban soils of cities of our country demonstrate varying degrees of Hg pollution, and in many local vegetables, fruits, and other foods, the heavy metal content exceeds the standard or is close to the critical value.
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