Effect and potential mechanisms of sludge-derived chromium, nickel, and lead on soil nitrification: Implications for sustainable land utilization of digested sludge

• Published in: Journal of hazardous materials Vol. 466; p. 133552
• Main Authors: Li, Jianju, Ma, Hao, Yu, Hang, Feng, Likui, Xia, Xinhui, He, Shufei, Chen, Xinwei, Zhao, Qingliang, Wei, Liangliang
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.03.2024
• Subjects: Ammonia - metabolism; Ammonia oxidation capacity; Archaea - metabolism; Bacteria - metabolism; Chromium - metabolism; Chromium - toxicity; Digested sludge; Heavy metals fractionation; Land application; Lead - metabolism; Metals, Heavy - metabolism; Metals, Heavy - toxicity; Nickel; Nitrification; Nitrification functional gene; Nitrites - metabolism; Oxidation-Reduction; Oxidoreductases - metabolism; Sewage - chemistry; Soil - chemistry; Soil Microbiology; Digested sludge; Heavy metals fractionation; Nitrification functional gene; Ammonia oxidation capacity; Land application
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2024.133552

Increasing occurrence of heavy metals (HMs) in sewage sludge threatens its widespread land utilization in China due to its potential impact on nutrient cycling in soil, requiring a better understanding of HM-induced impacts on nitrification. Herein, lab-scale experiments were conducted over 185-day, evaluating the effect of sludge-derived chromium (Cr3+), nickel (Ni2+), and lead (Pb2+) on soil nitrification at different concentrations. Quantitative polymerase chain reaction and linear regression results revealed an inhibitory sequence of gene abundance by HMs’ labile fraction: ammonia-oxidizing bacteria (AOB)-ammonia monooxygenase (amoA)> nitrite oxidoreductase subunit alpha (nxrA)> nitrite oxidoreductase subunit beta (nxrB). The toxicity of HMs’ incremental labile fraction decreased in the order of Ni2+>Cr3+>Pb2+, with respective threshold values of 5.01, 24.03 and 38.42 mg·kg−1. Furthermore, extending incubation time reduced HMs inhibition on ammonia oxidation, mainly related to their fraction bound to carbonate minerals. Random Forest analysis, variation partitioning analysis, and Mantel test indicated that soil physicochemical properties primarily affected nitrification genes, especially in the test of Cr3+ on AOB-amoA, nxrA, nxrB, Ni2+ for complete ammonia-oxidizing bacteria-amoA, and Pb2+ for nxrA and nxrB. These findings underline the importance of labile HMs fractions and soil physicochemical properties to nitrification, guiding the establishment of HM control standards for sludge utilization. [Display omitted] •Bioavailable heavy metals inhibit nitrifying gene abundance: AOB-amoA>nxrA> nxrB.•Soil’s labile Ni, Cr, Pb incremental thresholds (mg·kg-1) are 5.01, 24.03, 38.42.•Bound to carbonate mineral of Cr, Ni, Pb affect ammonia oxidation capacity in soil.•Cumulative importance of soil properties for nitrifying gene abundance exceed 90%.