Immobilization of Cd, Pb and Zn through Organic Amendments in Wastewater Irrigated Soils

Sustainability

MohamedSoliman Elshikh¹  AbdullahAhmed Al-Ghamdi¹  AbdEl-Zaher M. A. Mustafa¹  MonaS Alwahibi¹  Motsim Billah²  Subhan Danish³  Saqib Bashir⁴  KhalidSaifullah Khan⁵  Ahmad Khan⁵  Saba Akbar⁵  Shah Rukh⁶  KouserMajeed Malik⁷ 

[1] Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia;Department of Life Sciences, Abasyn University Islamabad Campus, Islamabad 44000, Pakistan;Department of Soil Science, Bahauddin Zakariya University, Multan 66000, Pakistan;Department of Soil and Environmental Sciences, Ghazi University, DG Khan 32200, Pakistan;Institute of Soil Science, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi 46300, Pakistan;National Centre of Excellence in Geology, University of Peshawar, Peshawar 25130, Pakistan;Soil Fertility Survey and Soil & Water Testing Institute, Rawalpindi 46300, Pakistan;

关键词: microbial biomass carbon;    microbial activity;    chemical speciation;    toxic metals;    organic amendments;    wastewater irrigated soils;   

DOI  :  10.3390/su13042392

来源: DOAJ

【 摘 要 】

Due to the scarcity of water, raw sewage effluents are often used to irrigate arable suburban soils in developing countries, which causes soil contamination with toxic metals. Soil microorganisms involved in biochemical transformations are sensitive to heavy metals contamination. The study was designed to investigate the effect of organic amendments on the microbial activity of cadmium (Cd), lead (Pb) and zinc (Zn) fractions and their bioavailability in soils contaminated with wastewater irrigation. Three metal contaminated soils under wastewater irrigation were collected, ground, sieved and added to incubation jars. Two organic amendments: wheat straw and chickpea straw, were applied (1% w/w) to the soil before incubation for 84 days at 25 °C. The CO₂-C evolution after 1, 2, 3, 5, 7, 10 and 14 days was measured and thereafter was also measured weekly. Soil samples collected at 0, 14, 28, 42, 56, 70 and 84 days after incubation were analyzed for microbial biomass carbon (MBC). Sequential extraction for metal fractionation of samples was carried out collected at 0, 28, 56 and 84 days. Three soils differed significantly in evolved MBC and ∑CO₂-C. Chickpea straw addition significantly increased soil MBC as compared to the wheat straw. Organic amendments significantly increased ∑CO₂-C evolution from the soils, which was higher from chickpea straw. The addition of crop residues did not affect total Pb, Cd and Zn contents in soils. The concentration of exchangeable, carbonate bound and residual fractions of Pb, Cd and Zn decreased (6–27%), while the organic matter bound fraction increased (4–75%) with straw addition. Overall, the organic amendments improved microbial activity and reduce the bioavailability of toxic metals in wastewater irrigated soils. Furthermore, organic amendments not only reduce economic losses as they are cheap to produce but also minimize human health risks from heavy metals by hindering their entry into the food chain.

【 授权许可】

Unknown