Effects of different additives and aerobic composting factors on heavy metal bioavailability reduction and compost parameters: A meta-analysis. (15th August 2022)

• Record Type: Journal Article
• Authors: Yousif Abdellah, Yousif Abdelrahman; Shi, Zhao-Ji; Luo, Yu-Sen; Hou, Wen-Tao; Yang, Xi; Wang, Rui-Long
• Is Part Of: Environmental pollution. Volume 307(2022)
• Publication Date: 2022-08-15
• Subjects: Composting process -- Heavy metals -- Additives -- Zeolites -- Bioavailability -- Meta-analysis; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2022.119549
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Additives are considered a promising approach to accelerate the composting process and alleviate the dissemination of pollutants to the environment. However, nearly all previous articles have focused on the impact of additive amounts on the reduction of HMs, which may not fully represent the main factor shaping HMs bioavailability status during composting. Simultaneously, previous reviews only explored the impacts, speciation, and toxicity mechanism of HMs during composting. Hence, a global-scale meta-analysis was conducted to investigate the response patterns of HMs bioavailability and compost parameters to different additives, composting duration, and composting factors (additive types, feedstock, bulking agents, and composting methods) by measuring the weighted mean values of the response ratio "[ln (RR)]" and size effect (%). The results revealed that additives significantly lessened HMs bioavailability by ≥ 40% in the final compost products than controls. The bioavailability decline rates were −40%, −60%, −57%, −55%, −42%, and −44% for Zn, Pb, Ni, Cu, Cr, and Cd. Simultaneously, additives significantly improved the total nitrogen (TN) (+16%), pH (+5%), and temperature (+5%), and decreased total organic carbon (TOC) (−17%), moisture content (MC) (−18%), and C/N ratio (−19%). Furthermore, we found that the prolongation of composting time significantly promoted the effect of additives on declining HMs bioavailability ( p < 0.05). Nevertheless, increasing additive amounts revealed an insignificant impact on decreasing the HMs bioavailability ( p > 0.05). Eventually, using zeolite as an additive, chicken manure as feedstock, sawdust as a bulking agent, and a reactor as composting method had the most significant reduction effect on HMs bioavailability ( p < 0.05). The findings of this meta-analysis may contribute to the selection, modification, and application of additives and composting factors to manage the level of bioavailable HMs in the compost products. Graphical abstract: Image 1 Highlights: Composting additives significantly minimized heavy metals (HMs) bioavailability by ≥ 40%. Increasing additives amount revealed an insignificant impact on declining HMs' bioavailability. Zeolite indicated the maximum significant (P < 0.002) HMs bioavailability reduction. Application of zeolite and reactor with extending composting time is highly recommended.