Predicting plant uptake and toxicity of lead (Pb) in long-term contaminated soils from derived transfer functions.
Regulatory assessment of lead (Pb) in contaminated soils is still expressed primarily as total Pb concentrations in soil. In this study, we estimated effective concentrations (ECx) of Pb to Cucumis sativa L. (cucumber) focusing primarily on pore-water Pb data from 10 different soils after 12 weeks ageing. Phytotoxicity expressed in terms of Pb(2+) was observed to occur in the nanomolar range in neutral to alkaline soils (EC50 values 90 to 853 nM) and micromolar levels for acidic soils (EC50 values 7.35 to 9.66 μM). Internal Pb concentrations relating to toxicity (PT50) in roots and shoots also decreased with increasing pore-water pH (R (2) = 0.52 to 0.53). From a series of dose-response studies, we developed transfer functions predicting Pb uptake in C. sativa and we validated these functions with long-term Pb contaminated soils. The significant independent parameters were pore-water Pb(2+) and dissolved Pb plus dissolved organic carbon (DOC). The observed RMSE for the Pb-DOC model and Pb(2+) were 2.6 and 8.8, respectively. The Pb-DOC model tended to under-predict Pb, whilst Pb(2+) tended to over-predict accumulation despite reasonable RMSE values. Further validation is needed in soils with higher pore-water Pb solubility.
Global Centre for Environmental Remediation (GCER), The University of Newcastle (UoN), Callaghan, NSW, 2308, Australia. mohammed.kader@uon.edu.au.|Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), Advanced Technology Building, Callaghan, NSW, 2308, Australia. mohammed.kader@uon.edu.au.
Mohammed
M
Kader
Global Centre for Environmental Remediation (GCER), The University of Newcastle (UoN), Callaghan, NSW, 2308, Australia.|Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), Advanced Technology Building, Callaghan, NSW, 2308, Australia.
Dane T
DT
Lamb
Global Centre for Environmental Remediation (GCER), The University of Newcastle (UoN), Callaghan, NSW, 2308, Australia.|Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), Advanced Technology Building, Callaghan, NSW, 2308, Australia.
Khandaker Rayhan
KR
Mahbub
Global Centre for Environmental Remediation (GCER), The University of Newcastle (UoN), Callaghan, NSW, 2308, Australia.|Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), Advanced Technology Building, Callaghan, NSW, 2308, Australia.
Mallavarapu
M
Megharaj
Global Centre for Environmental Remediation (GCER), The University of Newcastle (UoN), Callaghan, NSW, 2308, Australia.|Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), Advanced Technology Building, Callaghan, NSW, 2308, Australia.
Ravi
R
Naidu
D001315:Australia; D018553:Cucumis sativus / Q000737:chemistry* / Q000254:growth & development / Q000378:metabolism; D007854:Lead / Q000032:analysis* / Q000378:metabolism / Q000633:toxicity; D008962:Models, Theoretical; D018517:Plant Roots / Q000737:chemistry; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis* / Q000378:metabolism / Q000633:toxicity; D012995:Solubility; D014867:Water / Q000737:chemistry*
D012987:Soil; D012989:Soil Pollutants; D014867:Water; D007854:Lead
Bioaccumulation; Partitioning; Phytotoxicity; Pore-water; Transfer function