制革污泥渗滤液中特征污染物对土壤氨氮转化及微生物群落结构的影响

孔祥科; 李义; 王平; 韩占涛; 刘圣华; 张兆吉; 王妍妍

doi:10.12029/gc20220312001

制革污泥渗滤液中特征污染物对土壤氨氮转化及微生物群落结构的影响

Effects of characteristic pollutants in leather sludge leachate on soil ammonia nitrogen transformation and microbial community structures

摘要

摘要:
研究目的 查明制革污泥渗滤液中特征污染物（Cr(III)、盐分、有机质）对土壤NH₄⁺−N转化和微生物群落结构的影响，为制革污泥的安全农用及土壤NH₄⁺−N的污染防控提供理论依据。
研究方法 通过土壤培养实验，研究不同污染物影响下土壤中NH₄⁺−N向NO₃⁻−N的转化规律，并利用高通量测序对比分析不同条件下的微生物群落组成和结构变化特征。
研究结果 制革污泥渗滤液中特征污染组分对土壤中NH₄⁺−N硝化过程的抑制程度排序为：Cr(III)>盐分>有机质。外源Cr(III)进入对土壤中NH₄⁺−N的转化速率和转化量具有明显抑制作用，而土壤中盐分和有机质主要影响硝化作用的启动时间和降低硝化速率。随着土壤中Cr(III)含量由100 mg/kg增加到250 mg/kg，培养90 d后NH₄⁺−N的转化量由94.23%降低到19.38%。高浓度Cr(III)和盐分在污染初期对土壤中微生物丰度和群落结构影响显著，随土壤老化过程中Cr(III)生物有效性降低及微生物适应性增强，不同污染特征土壤中微生物群落结构和组成逐渐趋同，硝化功能菌（Nitrosospira、Nitrosomonas和Nitrosospira）丰度增加明显。
结论冗余（RDA）分析结果表明，影响制革污染土壤中微生物群落结构演变的主要特征因子是Cr(III)（R²=0.53，P<0.01）、NH₄⁺−N（R²=0.59，P<0.005）和NO₃⁻−N（R²=0.53，P<0.01）。

Abstract:
This paper is the result of soil environmental survey engineering.
Objective The objective is to identify the impact of characteristic pollutants (Cr (III), salt, organic matter) in the leachate of tannery sludge on the conversion of soil NH₄⁺−N conversion and microbial community structure. It provides a theoretical basis for the safe agricultural use of tannery sludge and soil pollution prevention and control.
Methods The transformation of NH₄⁺−N to NO₃⁻−N in soil was studied through soil cultivation experiments under different pollution conditions, and the high−throughput sequencing is used to analyze the composition and structure characteristics of microbial community in soil.
Results The characteristic pollution components in the tannery sludge leachate inhibit the nitrification process of NH₄⁺−N in the soil, and the influence factors are sorted as follows: Cr(III)>saltness>organic matter. The exogenous Cr(III) pollution has a significant inhibitory effect on the transformation rate and amount of NH₄⁺−N, whereas the saltness and organic matter only delay the start time of nitrification and reduce the nitrification rate in soil. With the increase of Cr(III) content from 100 mg/kg to 250 mg/kg, the transformation amount of NH₄⁺−N decreases from 94.23% to 19.38% after 90 days of culture. The high Cr(III) and salinity in the leachate have a significant impact on the microbial community structure and distribution in the soil at the initial stage of pollution. With the decrease of the bioavailability of Cr(III) and the enhancement of microbial adaptation in soil aging process, the microbial community structure and composition in Cr(III), salinity, and organic matter contaminated soils become similar, and the abundances of nitrifying bacteria (Nitrosospira, Nitrosomonas and Nitrosospira) also have an obvious increase.
Conclusions The results of RDA analysis show that the main characteristic factors affecting the evolution of microbial community structure in tanning contaminated soil are: Cr(III) (R²=0.53, P<0.01), NH₄⁺−N (R²=0.59, P<0.005) and NO₃⁻−N(R²=0.53, P<0.01).

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