TY - JOUR
T1 - Impact of sulfur-impregnated biochar amendment on microbial communities and mercury methylation in contaminated sediment
AU - Bailon, Mark Xavier
AU - Chaudhary, Dhiraj Kumar
AU - Jeon, Cheolho
AU - Ok, Yong Sik
AU - Hong, Yongseok
N1 - Funding Information:
This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Science, ICT & Future Planning ( 2018R1D1A1B07049757 ). This study was supported by the Ministry of Oceans and Fisheries through the Open Innovation Project ( 1525011792 ).
Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2022/9/15
Y1 - 2022/9/15
N2 - S-impregnation of biochar through elemental S streaming is known to increase its sorption performance against Hg and methyl mercury (MeHg). However, the effects of %S-loading on biochar's mechanism and sorption capacities for MeHg, and its consequent impact when used as an amendment material for Hg-contaminated sediments, are poorly understood, and thus, were investigated in this work. Our results showed that a minimum sulfur loading of 1% was the most effective in reducing MeHg levels in sediments. At higher %S-loading (3–20%), the reduction in surface area, pore blockage due to unreacted sulfur particles, and presence of poorly bound sulfur species resulted in lowered effectiveness for MeHg control. Increasing S-functionalization during impregnation shifted the sorption process of MeHg from Hg-O to Hg-S in S-impregnated biochar (BCS). Our 60-day slurry experiment showed a significant reduction in pore water THg (40–70%) and MeHg (30–55%), as well as sediment MeHg (50–60%) in biochar-amended sediments. The reduction in the bioavailable Hg resulted in lowered Hg methylation, as supported by the suppression of both the Fe- and SO42--reduction activities in the amended sediments. The microbial community structure in BCS-amended sediments showed a shift towards sulfur-consuming, iron-reducing, thiosulfate-oxidizing, and sulfate-reducing bacterial populations. At the genus level, the overall relative abundance of principal Hg methylators was also lower in the BCS treatment than in the unamended sediments. This study highlights the application of BCS as a promising strategy for remediation of Hg-contaminated sediments.
AB - S-impregnation of biochar through elemental S streaming is known to increase its sorption performance against Hg and methyl mercury (MeHg). However, the effects of %S-loading on biochar's mechanism and sorption capacities for MeHg, and its consequent impact when used as an amendment material for Hg-contaminated sediments, are poorly understood, and thus, were investigated in this work. Our results showed that a minimum sulfur loading of 1% was the most effective in reducing MeHg levels in sediments. At higher %S-loading (3–20%), the reduction in surface area, pore blockage due to unreacted sulfur particles, and presence of poorly bound sulfur species resulted in lowered effectiveness for MeHg control. Increasing S-functionalization during impregnation shifted the sorption process of MeHg from Hg-O to Hg-S in S-impregnated biochar (BCS). Our 60-day slurry experiment showed a significant reduction in pore water THg (40–70%) and MeHg (30–55%), as well as sediment MeHg (50–60%) in biochar-amended sediments. The reduction in the bioavailable Hg resulted in lowered Hg methylation, as supported by the suppression of both the Fe- and SO42--reduction activities in the amended sediments. The microbial community structure in BCS-amended sediments showed a shift towards sulfur-consuming, iron-reducing, thiosulfate-oxidizing, and sulfate-reducing bacterial populations. At the genus level, the overall relative abundance of principal Hg methylators was also lower in the BCS treatment than in the unamended sediments. This study highlights the application of BCS as a promising strategy for remediation of Hg-contaminated sediments.
KW - Bacterial community
KW - Elemental S streaming
KW - Methyl mercury
KW - Methylation
KW - Sulfur
UR - http://www.scopus.com/inward/record.url?scp=85134356559&partnerID=8YFLogxK
U2 - 10.1016/j.jhazmat.2022.129464
DO - 10.1016/j.jhazmat.2022.129464
M3 - Article
C2 - 35999716
AN - SCOPUS:85134356559
SN - 0304-3894
VL - 438
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
M1 - 129464
ER -