Clays, Limestone and Biochar Affect the Bioavailability and Geochemical Fractions of Cadmium and Zinc from Zn-Smelter Polluted Soils
College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China
Department of Environmental Sciences, Sindh Madressatul Islam University, Karachi 74000, Pakistan
Department of Agricultural and Environmental Chemistry, University of Agriculture in Krakow, al. Mickiewicza 21, 31-120 Krakow, Poland
Department of Mineralogy, Petrography and Geochemistry, al. Faculty of Geology, Geophysics and Environmental Protection, AGH University of Science and Technology, Mickiewicza 30, 30-059 Krakow, Poland
Department of Agro-Environment and Ecology, Faculty of Agriculture and Environment, Agriculture University of Tirana, Tirana 1029, Albania
Cerema, Project-Team DIM, 120 Rue de Paris, BP 216 Sourdun, 77487 Provins CEDEX, France
Institute of Ecology and Biological Resource, Vietnam Academy of Science and Technology (VAST), No. 18 Hoang Quoc Viet, Caugiay, Hanoi 100000, Vietnam
Vietnam–Russia Tropical Centre, 63 Nguyen Van Huyen, Nghia Do, CauGiay, Hanoi 100000, Vietnam
Department of Economics, Abdul Haq Campus, Federal Urdu University of Arts, Science & Technology, M.A. Jinnah Road, Karachi 75300, Pakistan
Authors to whom correspondence should be addressed.
Sustainability 2020, 12(20), 8606; https://doi.org/10.3390/su12208606
Received: 27 September 2020 / Revised: 14 October 2020 / Accepted: 15 October 2020 / Published: 17 October 2020
(This article belongs to the Special Issue Soil Use Management and Soil Health)
Ca-bentonite (CB) alone and in a mixture with limestone (L), tobacco biochar (TB) and zeolite (Z) on the fixation, geochemical fractions and absorption of Cd and Zn by Chinese cabbage in smelter heavily polluted (S-HP) and smelter low polluted (S-LP) soils were investigated. The results showed that the CB + TB and CB + L + TB treatments significantly immobilized Cd up to 22.0% and 29.7%, respectively, and reduced uptake by Chinese cabbage shoot to 36.0% with CB + Z + L and 61.3% with CB + L in S-HP and S-LP soils compared with the control. The CB + Z + L + TB treatment mobilized Cd up to 4.4% and increased absorption in the shoot by 9.9% in S-HP soil. The greatest immobilization of Zn was 53.2% and 58.2% with the CB + Z + L + TB treatment, which reduced Zn uptake in the plant shoot by 10.0% with CB + L and 58.0% with CB + Z + L + TB in S-HP and S-LP soils. The CB + Z + TB and CB + TB treatments mobilized Zn up to 35.4% and 4.9%, respectively, in both soils. Furthermore, the uptake of Zn in plant shoot was observed by 59.0% and 7.9% with application of CB + Z and CB + TB treatments, respectively, in S-HP and S-LP soils. Overall, our results suggest that Ca-bentonite alone and in mixtures with different amendments can be used to reduce the phyto-extraction of Cd and Zn in Zn-smelter polluted soils.