Pig carcass-derived biochar caused contradictory effects on arsenic mobilization in a contaminated paddy soil under fluctuating controlled redox conditions
Journal
Journal of Hazardous Materials
Journal Volume
421
Journal Volume
421
Start Page
126647
ISSN
03043894
Date Issued
2022-01-05
Author(s)
Yang, Xing
Hinzmann, Marvin
Pan, He
Wang, Jianxu
Bolan, Nanthi
Tsang, Daniel C.W.
Ok, Yong Sik
Shaheen, Sabry M.
Wang, Hailong
Rinklebe, Jörg
Abstract
Contamination of paddy soils by arsenic (As) is of great concern for human health and the environment. The impact of animal-derived biochar on As mobilization under fluctuating redox conditions in paddy soils has not been studied. Consequently, we investigated the effects of pig carcass-derived biochar (PB) on As (im)mobilization in a contaminated paddy soil under controlled redox potential (Eh) using a biogeochemical microcosm-setup. The addition of PB decreased the concentration of dissolved As at Eh = +100 and +200 mV by 38.7% and 35.4%, respectively (compared to the control), because of the co-precipitation of As with Fe-Mn oxides and the complexation between As and aromatic organic molecules. However, under reducing conditions (Eh = -300 mV), PB increased the dissolved As by 13.5% through promoting reduction and decomposition of As-bearing Fe minerals (e.g., ferrihydrite-As, Fe-humic-As). Under oxidizing conditions (Eh = +250 mV), PB increased the dissolved As by 317.6%, due to the associated increase of pH. We conclude that As mobilization in PB-treated paddy soils is highly affected by Eh. PB can be used to reduce the environmental risk of As under moderately reducing conditions, but it may increase the risk under highly reducing and oxidizing conditions in paddy soils.
Subjects
Biochar
Hazardous metal(loid)
Paddy soil contamination
Redox condition
Soil remediation
Publisher
Elsevier B.V.
Type
journal article