TY - JOUR
T1 - Metal release from serpentine soils in Sri Lanka
AU - Vithanage, Meththika
AU - Rajapaksha, Anushka Upamali
AU - Oze, Christopher
AU - Rajakaruna, Nishanta
AU - Dissanayake, C. B.
N1 - Funding Information:
Acknowledgements International Foundation for Science (Sweden) and Organization for the Prohibition of Chemical Weapons, The Hague, are kindly acknowledged for their funding (grant number W/5068-1). Authors thank Dr. J.C. Bailey at the Institute for Geography and Geology, University of Copenhagen and Dr. Steen Christensen and colleagues at the Department of Earth Sciences, University of Aarhus, Denmark for providing XRF results and Prof. Y. S. Ok at the Department of Biological Environment at Kangwon National University, South Korea for EPMA analysis.
PY - 2014/6
Y1 - 2014/6
N2 - Ultramafic rocks and their related soils (i.e., serpentine soils) are non-anthropogenic sources of metal contamination. Elevated concentrations of metals released from these soils into the surrounding areas and groundwater have ecological-, agricultural-, and human health-related consequences. Here we report the geochemistry of four different serpentine soil localities in Sri Lanka by coupling interpretations garnered from physicochemical properties and chemical extractions. Both Ni and Mn demonstrate appreciable release in water from the Ussangoda soils compared to the other three localities, with Ni and Mn metal release increasing with increasing ionic strengths at all sites. Sequential extraction experiments, utilized to identify "elemental pools," indicate that Mn is mainly associated with oxides/(oxy)hydroxides, whereas Ni and Cr are bound in silicates and spinels. Nickel was the most bioavailable metal compared to Mn and Cr in all four soils, with the highest value observed in the Ussangoda soil at 168±6.40 mg kg-1 via the 0.01-M CaCl2 extraction. Although Mn is dominantly bound in oxides/(oxy)hydroxides, Mn is widely dispersed with concentrations reaching as high as 391 mg kg-1 (Yudhaganawa) in the organic fraction and 49 mg kg-1 (Ussangoda) in the exchangeable fraction. Despite Cr being primarily retained in the residual fraction, the second largest pool of Cr was in the organic matter fraction (693 mg kg-1 in the Yudhaganawa soil). Overall, our results support that serpentine soils in Sri Lanka offer a highly labile source of metals to the critical zone.
AB - Ultramafic rocks and their related soils (i.e., serpentine soils) are non-anthropogenic sources of metal contamination. Elevated concentrations of metals released from these soils into the surrounding areas and groundwater have ecological-, agricultural-, and human health-related consequences. Here we report the geochemistry of four different serpentine soil localities in Sri Lanka by coupling interpretations garnered from physicochemical properties and chemical extractions. Both Ni and Mn demonstrate appreciable release in water from the Ussangoda soils compared to the other three localities, with Ni and Mn metal release increasing with increasing ionic strengths at all sites. Sequential extraction experiments, utilized to identify "elemental pools," indicate that Mn is mainly associated with oxides/(oxy)hydroxides, whereas Ni and Cr are bound in silicates and spinels. Nickel was the most bioavailable metal compared to Mn and Cr in all four soils, with the highest value observed in the Ussangoda soil at 168±6.40 mg kg-1 via the 0.01-M CaCl2 extraction. Although Mn is dominantly bound in oxides/(oxy)hydroxides, Mn is widely dispersed with concentrations reaching as high as 391 mg kg-1 (Yudhaganawa) in the organic fraction and 49 mg kg-1 (Ussangoda) in the exchangeable fraction. Despite Cr being primarily retained in the residual fraction, the second largest pool of Cr was in the organic matter fraction (693 mg kg-1 in the Yudhaganawa soil). Overall, our results support that serpentine soils in Sri Lanka offer a highly labile source of metals to the critical zone.
KW - Chemical extractions
KW - EPMA
KW - Labile toxic metals
KW - Natural attenuation
KW - Serpentine geoecology
UR - http://www.scopus.com/inward/record.url?scp=84900831966&partnerID=8YFLogxK
U2 - 10.1007/s10661-014-3626-8
DO - 10.1007/s10661-014-3626-8
M3 - Article
C2 - 24464398
AN - SCOPUS:84900831966
SN - 0167-6369
VL - 186
SP - 3415
EP - 3429
JO - Environmental Monitoring and Assessment
JF - Environmental Monitoring and Assessment
IS - 6
ER -
