1.Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems,South China Botanical Garden,Chinese Academy of Sciences;2.Southern Marine Science and Engineering Guangdong Laboratory Guangzhou;3.CAS Key Laboratory of Soil Environment and Pollution Remediation,Institute of Soil Sciences,Chinese Academy of Sciences;4.College of Natural Resources and Environment,Northwest A F University;5.College of Forestry,Guangxi University
Key Special Program for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou)（GML2019ZD0408）
Soil enzymes play a vital role in the biogeochemical cycling of key elements, maintenance of animal and plant health, and decontamination of environmental pollution. The activities of soil enzymes can find application in the environmental risk assessment of soil heavy metal pollution. However, the effects of heavy metals on soil enzyme activities varied with soil physicochemical and biological properties and the differences of research methods. Thus, these factors hinder the application of soil enzymes in the assessment of soil health and quality. This study systematically elaborates the eco-toxicological effects of heavy metal pollution on soil enzyme activities and the kinetic characteristics of soil enzyme catalytic reactions. We also constructed a conceptual diagram of soil enzymes in response to soil-heavy metals-microorganisms, proposed and discussed the future trends and directions in soil enzyme in the assessment of heavy metal pollution. Our results showed that soil enzymes are a potential biological index for the evaluation of soil heavy metal pollution, because the determination of soil enzyme activity is efficient and cheap, and soil enzyme activity is sensitive to heavy metal toxicity. However, soil enzyme activity may overestimate or underestimate the ecological toxicity of heavy metals as an individual indicator. Furthermore, there is no uniform standard on how to select soil enzyme as a general indicator to assess the toxicity of heavy metals in different soils. Also, it is difficult to establish a quantitative relationship between the ecological doses of heavy metals for soil enzyme activity and soil properties, which led to the arguments about its accuracy and applicability in the ecological risk of heavy metal pollution. Therefore, it is crucial to use new technologies and methods to uncover the reactive mechanisms of enzymes to heavy metal toxicity in different types of soils, and quantitatively analyze the relationship between soil properties and ecological doses of heavy metals based on kinetic parameters. This can strengthen the practical application of soil enzymes in the diagnosis of soil pollution by heavy metals.
TAN Xiangping, He Jinghong, Guo Zhiming, Wang Ziquan, Nie Yanxia, Ye Qing, He Wenxiang, Shen Weijun. Research progresses on soil enzymes as indicators of soil health and their responses to heavy metal pollution[J]. Acta Pedologica Sinica,,[In Press]