Understanding the holistic approach to plant-microbe remediation technologies for removing heavy metals and radionuclides from soil

Qi-zhong

et al. 2022

Forests

Phytoremediation is an important solution to heavy metal pollution in soil. However, the impact of plants on microbial communities in contaminated soil also requires attention. Community-level physiological profiling (CLPP) based on the Biolog™ EcoPlate and high-throughput sequencing were used to study the soil microbial community in this article. The rhizosphere and bulk soil samples of six native species were collected from the iron mine tailings on Jiulong Mountain, Jiangxi Province. According to the average well color development (AWCD), all plants improved the activity and diversity of the contaminated soil microbial community to varying degrees. Cunninghamia lanceolate is considered to have good effects and led to the appearance of Cunninghamia lanceolata > Zelkova schneideriana > Toona ciliata > Alnus cremastogyne > Cyclobalanopsis myrsinifolia > Pinus elliottii. The Shannon–Wiener diversity index and principal component analysis (PCA) show that the evenness and dominance of soil microbial communities of several plants are structurally similar to those of uncontaminated soil (UNS). The results of high-throughput sequencing indicated that the bacterial community diversity of C. lanceolata, A. cremastogyne, and P. elliottii is similar to UNS, while fungal community diversity is different from UNS. C. lanceolata has a better effect on soil nutrients, C. myrsinifolia and P. elliottii may have a better effect on decreasing the Cu content. The objective of this study was to assess the influence of native plants on microbial communities in soils and the soil remediation capacity. Mortierellomycota was the key species for native plants to regulate Cu and microbial community functions. Native plants have decisive influence on microbial community diversity.

Section: The Relationship Between Microbial Metabolic Diversity and S...mentioning

confidence: 76%

Effects of Different Native Plants on Soil Remediation and Microbial Diversity in Jiulong Iron Tailings Area, Jiangxi

Qi-zhong

et al. 2022

Forests

“…The present study is one of the first attempts to evaluate amendments to remediate contaminated soils in critical agricultural areas coexisting with the mining industry in central Chile. We obtained promising results, but these are not enough to fulfill a holistic remediation approach as is required nowadays by research programs and legislation worldwide [66,67]. A holistic remediation approach must consider the potential human health risks, the interlinks between contaminant exposure, the remediation technology, and the ecological effects, including climate change.…”

Section: Towards a Holistic Remediation Approachmentioning

confidence: 95%

Remediation of Agricultural Soils with Long-Term Contamination of Arsenic and Copper in Two Chilean Mediterranean Areas

et al. 2022

Soil amendments may decrease trace element accumulation in vegetables, improving food security and allowing the recovery of contaminated farmlands. Despite some promising results in the laboratory, validation of soil amendments in field conditions are scarce, especially in aerobic soils. Here, we assessed the effect of different potential soil amendments on arsenic (As) accumulation in lettuces. Then, we compared them in terms of food security and the associated investment (efficacy and efficiency, respectively). We also hypothesized that the soil amendments do not lead to side effects, such as yield decrease, phytotoxicity of Cu, or undesired changes in soil properties. Thereby, we assessed lettuces grown on untreated contaminated soils (C+), treated contaminated soils, and untreated uncontaminated soils (C−) in two contrasting soil types (sandy and loamy soils). The treated contaminated soils consisted of multiple soil amendments. Soil amendments were: diammonium phosphate (DP), iron sulfate (IS), ferrous phosphate (FP), calcium peroxide (CP), and organic matter (OM). We found that phosphate amendments (DP and FP) reduced the As in edible tissues of lettuce in both areas, while CP only reduced As accumulation in the sandy soils area. The As intake through lettuces grown on these amended soils was about 30% lower than on the unamended ones. Cu concentrations in lettuces above 25 mg kg−1 grown in contaminated soils without reducing growth were found, a result that differed from non-field studies.

“…Phytoremediation, especially in-situ enhanced phytoremediation, is widely used for the bioremediation of heavy metal-contaminated soil ( Thakare et al, 2021 ). The growth of plants in contaminated soil can be facilitated by utilizing the biological nitrogen fixation (BNF) ability of legume-rhizobia symbionts ( Hao et al, 2014 ; Yu et al, 2017 ; Wang et al, 2019 ; Salmi & Boulila, 2021 ).…”

Section: Introductionmentioning

confidence: 99%

Nickel mine soil is a potential source for soybean plant growth promoting and heavy metal tolerant rhizobia

Han

Cui

Zhou

et al. 2022

PeerJ

Mine soil is not only barren but also contaminated by some heavy metals. It is unclear whether some rhizobia survived under extreme conditions in the nickel mine soil. Therefore, this study tries to isolate some effective soybean plant growth promoting and heavy metal resistant rhizobia from nickel mine soil, and to analyze their diversity. Soybean plants were used to trap rhizobia from the nickel mine soil. A total of 21 isolates were preliminarily identified as rhizobia, which were clustered into eight groups at 87% similarity level using BOXA1R-PCR fingerprinting technique. Four out of the eight representative isolates formed nodules on soybean roots with effectively symbiotic nitrogen-fixing and plant growth promoting abilities in the soybean pot experiment. Phylogenetic analysis of 16S rRNA, four housekeeping genes (atpD-recA-glnII-rpoB) and nifH genes assigned the symbiotic isolates YN5, YN8 and YN10 into Ensifer xinjiangense and YN11 into Rhizobium radiobacter, respectively. They also showed different tolerance levels to the heavy metals including cadmium, chromium, copper, nickel, and zinc. It was concluded that there were some plant growth promoting and heavy metal resistant rhizobia with the potential to facilitate phytoremediation and alleviate the effects of heavy metals on soybean cultivation in nickel mine soil, indicating a novel evidence for further exploring more functional microbes from the nickel mine soil.