Mobility of arsenic, chromium and copper arising from soil application of stabilised aggregates made from contaminated wood ash

TY - JOUR

T1 - Mobility of arsenic, chromium and copper arising from soil application of stabilised aggregates made from contaminated wood ash

AU - Mitchell, Kerry

AU - Moreno-Jimenez, Eduardo

AU - Jones, Rod

AU - Zheng, Li

AU - Trakal, Lukas

AU - Hough, Rupert

AU - Beesley, Luke

N1 - The authors acknowledge the financial support the Scottish Government’s Rural and Environmental Sciences and Analytical Services (RESAS) for sample analysis.

PY - 2020/7/5

Y1 - 2020/7/5

N2 - Stabilized cementitious aggregates AG were produced from wood ashes containing ∼10,000 mg kg−1 As, Cr and Cu, then amended to two agricultural pasture soils. Metal(loid) leaching (column tests), mobility (pore water extracts) and uptake to ryegrass was determined, comparing raw ashes with aggregates. Risk modeling was applied to selected data to inform wider discussion of the experimental results. Under rapid leaching (7 h) AG 2 (pre-strengthened with CO2) outperformed AG 1 in suppressing soluble metal(loid) removal. During prolonged leaching (12d) both aggregates were susceptible to mild dissolution/release of metal(loid)s upon acidification. Pore water sampled from the pot test indicated that Cr was generally most mobile, As least so, reduced furthest by AG 2. Risk modelling, based on pot experimental data, demonstrated soil specific accumulation of As in beef muscle and milk, being furthest reduced (compared to the raw ash addition) by AG 2 in soil A, but increased in soil B by the same treatment. The results of this study indicate that a reduction in soluble As, Cr and Cu can be achieved through cementitious aggregation of wood ashes, though the extent is metal(loid) specific when amended to soils. Pre-testing under local soil conditions before field application would be required to ensure that metal(loid) mobility remained suppressed.

AB - Stabilized cementitious aggregates AG were produced from wood ashes containing ∼10,000 mg kg−1 As, Cr and Cu, then amended to two agricultural pasture soils. Metal(loid) leaching (column tests), mobility (pore water extracts) and uptake to ryegrass was determined, comparing raw ashes with aggregates. Risk modeling was applied to selected data to inform wider discussion of the experimental results. Under rapid leaching (7 h) AG 2 (pre-strengthened with CO2) outperformed AG 1 in suppressing soluble metal(loid) removal. During prolonged leaching (12d) both aggregates were susceptible to mild dissolution/release of metal(loid)s upon acidification. Pore water sampled from the pot test indicated that Cr was generally most mobile, As least so, reduced furthest by AG 2. Risk modelling, based on pot experimental data, demonstrated soil specific accumulation of As in beef muscle and milk, being furthest reduced (compared to the raw ash addition) by AG 2 in soil A, but increased in soil B by the same treatment. The results of this study indicate that a reduction in soluble As, Cr and Cu can be achieved through cementitious aggregation of wood ashes, though the extent is metal(loid) specific when amended to soils. Pre-testing under local soil conditions before field application would be required to ensure that metal(loid) mobility remained suppressed.

KW - Bioavailability

KW - Heavy metal leaching

KW - Pore water

KW - Stabilized aggregate

KW - Wood ash

UR - https://www.scopus.com/pages/publications/85082866280

U2 - 10.1016/j.jhazmat.2020.122479

DO - 10.1016/j.jhazmat.2020.122479

M3 - Article

C2 - 32369890

AN - SCOPUS:85082866280

SN - 0304-3894

VL - 393

SP - 1

EP - 10

JO - Journal of Hazardous Materials

JF - Journal of Hazardous Materials

M1 - 122479

ER -