Abstract
Soil washing residue (SWR), which typically concentrates the washed toxic metals and is comprised of high contents of clay particles, may pose risks to the surrounding environment. This study aims to simulate accelerated ageing to assess the stability of selected metals (Cd2 + (132 mg/kg), Cu2 + (248 mg/kg) and Pb2 + (3470 mg/kg)) in a SWR (89.68% of clay) with and without biochar treatment. The soil was incubated under constant moisture and wet-dry cycles (accelerated ageing), respectively, and the mobility and fractions of heavy metals in the soils with and without biochar treatment were examined. Under the constant moisture condition, biochar addition at 5% w/w reduced the leached Cd2 + (by 1.81%) and Cu2 + (by 8.70%) from SWR at day 1 and the leached Cu2 + (by 51.08%) and Pb2 + (by 25.36%) from SWR at day 14; however, the leached metals in the TCLP solution from the biochar-amended soils still exceed the regulatory limits (1 mg/L for Cd2 +, 5 mg/L for Pb2 +, no regulatory limits for Cu2 +). Conversely, accelerated ageing (14 days) significantly increased the fractions of exchangeable Cd2 + (from 3.63–3.94% to 6.21–6.29%) and Pb2 + (from 0.025–0.027% to 0.034–0.041%) as well as the TCLP leachabilities of Cd2 + (from 2.91–3.28% to 3.46–3.73%), Cu2 + (from 0.08–0.10% to 0.03–0.06%) and Pb2 + (from 0.25–0.35% to 0.52–0.57%) in the soils, as compared with those incubated under constant moisture, regardless of biochar addition. This study reveals challenges associated with stabilising SWR due to the presence of residual fine-grained particles.
| Original language | English |
|---|---|
| Pages (from-to) | 185-193 |
| Number of pages | 9 |
| Journal | Science of the Total Environment |
| Volume | 619-620 |
| DOIs | |
| Publication status | Published - 2018 Apr 1 |
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Keywords
- Accelerated ageing
- Biochar
- Black carbon
- Leaching
- Soil remediation
- Soil washing
ASJC Scopus subject areas
- Environmental Engineering
- Environmental Chemistry
- Waste Management and Disposal
- Pollution
Cite this
Stability of heavy metals in soil washing residue with and without biochar addition under accelerated ageing. / Shen, Zhengtao; Hou, Deyi; Zhao, Bin; Xu, Wendi; Ok, Yong Sik; Bolan, Nanthi S.; Alessi, Daniel S.
In: Science of the Total Environment, Vol. 619-620, 01.04.2018, p. 185-193.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Stability of heavy metals in soil washing residue with and without biochar addition under accelerated ageing
AU - Shen, Zhengtao
AU - Hou, Deyi
AU - Zhao, Bin
AU - Xu, Wendi
AU - Ok, Yong Sik
AU - Bolan, Nanthi S.
AU - Alessi, Daniel S.
PY - 2018/4/1
Y1 - 2018/4/1
N2 - Soil washing residue (SWR), which typically concentrates the washed toxic metals and is comprised of high contents of clay particles, may pose risks to the surrounding environment. This study aims to simulate accelerated ageing to assess the stability of selected metals (Cd2 + (132 mg/kg), Cu2 + (248 mg/kg) and Pb2 + (3470 mg/kg)) in a SWR (89.68% of clay) with and without biochar treatment. The soil was incubated under constant moisture and wet-dry cycles (accelerated ageing), respectively, and the mobility and fractions of heavy metals in the soils with and without biochar treatment were examined. Under the constant moisture condition, biochar addition at 5% w/w reduced the leached Cd2 + (by 1.81%) and Cu2 + (by 8.70%) from SWR at day 1 and the leached Cu2 + (by 51.08%) and Pb2 + (by 25.36%) from SWR at day 14; however, the leached metals in the TCLP solution from the biochar-amended soils still exceed the regulatory limits (1 mg/L for Cd2 +, 5 mg/L for Pb2 +, no regulatory limits for Cu2 +). Conversely, accelerated ageing (14 days) significantly increased the fractions of exchangeable Cd2 + (from 3.63–3.94% to 6.21–6.29%) and Pb2 + (from 0.025–0.027% to 0.034–0.041%) as well as the TCLP leachabilities of Cd2 + (from 2.91–3.28% to 3.46–3.73%), Cu2 + (from 0.08–0.10% to 0.03–0.06%) and Pb2 + (from 0.25–0.35% to 0.52–0.57%) in the soils, as compared with those incubated under constant moisture, regardless of biochar addition. This study reveals challenges associated with stabilising SWR due to the presence of residual fine-grained particles.
AB - Soil washing residue (SWR), which typically concentrates the washed toxic metals and is comprised of high contents of clay particles, may pose risks to the surrounding environment. This study aims to simulate accelerated ageing to assess the stability of selected metals (Cd2 + (132 mg/kg), Cu2 + (248 mg/kg) and Pb2 + (3470 mg/kg)) in a SWR (89.68% of clay) with and without biochar treatment. The soil was incubated under constant moisture and wet-dry cycles (accelerated ageing), respectively, and the mobility and fractions of heavy metals in the soils with and without biochar treatment were examined. Under the constant moisture condition, biochar addition at 5% w/w reduced the leached Cd2 + (by 1.81%) and Cu2 + (by 8.70%) from SWR at day 1 and the leached Cu2 + (by 51.08%) and Pb2 + (by 25.36%) from SWR at day 14; however, the leached metals in the TCLP solution from the biochar-amended soils still exceed the regulatory limits (1 mg/L for Cd2 +, 5 mg/L for Pb2 +, no regulatory limits for Cu2 +). Conversely, accelerated ageing (14 days) significantly increased the fractions of exchangeable Cd2 + (from 3.63–3.94% to 6.21–6.29%) and Pb2 + (from 0.025–0.027% to 0.034–0.041%) as well as the TCLP leachabilities of Cd2 + (from 2.91–3.28% to 3.46–3.73%), Cu2 + (from 0.08–0.10% to 0.03–0.06%) and Pb2 + (from 0.25–0.35% to 0.52–0.57%) in the soils, as compared with those incubated under constant moisture, regardless of biochar addition. This study reveals challenges associated with stabilising SWR due to the presence of residual fine-grained particles.
KW - Accelerated ageing
KW - Biochar
KW - Black carbon
KW - Leaching
KW - Soil remediation
KW - Soil washing
UR - http://www.scopus.com/inward/record.url?scp=85033581647&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85033581647&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2017.11.038
DO - 10.1016/j.scitotenv.2017.11.038
M3 - Article
AN - SCOPUS:85033581647
VL - 619-620
SP - 185
EP - 193
JO - Science of the Total Environment
JF - Science of the Total Environment
SN - 0048-9697
ER -