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| Effects of minerals with different immobilization mechanisms on heavy metals availability and soil microbial response |
| Received:December 14, 2020 |
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| KeyWord:heavy metals;limestone;montmorillonite;bioavailability;microbial community;passivation |
| Author Name | Affiliation | | REN Lulu | Guangdong Vocational College of Environmental Protection Engineering, Foshan 528216, China | | CAI Zongping | Guangdong Vocational College of Environmental Protection Engineering, Foshan 528216, China | | WANG Guning | Guangdong Vocational College of Environmental Protection Engineering, Foshan 528216, China | | YE Zhijun | Guangdong Vocational College of Environmental Protection Engineering, Foshan 528216, China | | ZHANG Yanlin | Guangdong Vocational College of Environmental Protection Engineering, Foshan 528216, China | | CAO Meiyuan | Guangdong Vocational College of Environmental Protection Engineering, Foshan 528216, China |
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| Abstract: |
| The goals of this study are to elucidate the effects of minerals, including limestone and montmorillonite, on the heavy metal availability and soil health. A pot trial was conducted to examine the effects of the two aforementioned minerals on heavy metals availability, enzyme activities, and microbial community structure in metal-contaminated farmland soils by traditional testing methods and 16S rRNA high throughput sequencing. Additionally, their effects on biological concentrations and translocation factors of heavy metals in rice, the relationships between microbial community structure and physicochemical properties, and factor regulating them were analyzed. The results showed that limestone application decreased the availabilities of Cd, Cu, Pb, and Zn, with decreases of 99.1% for Zn, 91.4% for Cd, 85.6% for Cu, and 46.1% for Pb. Moreover, limestone application also significantly reduced the biological concentration factors （43.4%~85.5%） and translocation factors（Cd 62.5% and Zn 30.0%）. In contrast, the application of montmorillonite decreased the availability of only Pb（19.5% decrease）. Consistently, urease and catalase activities in the limestone treated soil were 1.6 times higher than those of the control, whereas catalase activity in the montmorillonite amended soils also increased 1.4 times, although urease activity did not increase significantly. Additionally, the application of montmorillonite did not affect the microbial community structure significantly, whereas the application of limestone significantly increased microbial community diversity. The beneficial bacterial genera f_Gemmatimonadaceae, f_BIrii41, and c_KD4-96, which are vital for phosphate dissolution and microbial nitrogen metabolism, were also enriched. Overall, our study shows that the limestone application decrease the availabilities of Cd, Cu, Pb, and Zn, and improve soil health. The soil microbial community is determined by soil pH, and available P and soil organic matter contents. |
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