Risk assessment for Cd, Cu, Pb and Zn in urban soils: Chemical availability as the central concept

• Published in: Environmental pollution (1987) 2013-12, Vol.183, p.234-242
• Main Authors: Rodrigues, S.M., Cruz, N., Coelho, C., Henriques, B., Carvalho, L., Duarte, A.C., Pereira, E., Römkens, Paul F.A.M.
• Format: Article
• Language: English
• Subjects: 5 european cities; Availability; bioaccessibility; Bioavailability; Biological and medical sciences; cadmium; calcium chloride; Chemical and industrial products toxicology. Toxic occupational diseases; contaminated soils; Copper; Environmental Monitoring - methods; equations; extractability; extraction; heavy-metals; lead; Lead (metal); Mathematical analysis; Mathematical models; Medical sciences; Metals - analysis; Metals and various inorganic compounds; Mining; nitric acid; Oral bioaccessibility; pools; Potentially toxic elements; Reactivity; Risk assessment; Risk Assessment - methods; Soil - chemistry; Soil extraction; Soil Pollutants - analysis; soil properties; Soils; Toxicology; trace-elements; Urban soils; zinc
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2012.10.006

To assess the geochemical reactivity and oral bioaccessibility of Cd, Cu, Pb and Zn in urban soils from the Porto area, four extractions were performed including Aqua Regia (AR; pseudototal), 0.43 M HNO3 (reactive), 0.01 M CaCl2 (available), and 0.4 M glycine at pH = 1.5, SBET method (oral bioaccessible pool). Oral bioaccessibility in urban soils was higher than in samples from rural, industrial and mining areas which is most likely related to sources of metals and parent materials of corresponding soils. The availability and reactivity were described well by non-linear Freundlich-type equations when considering differences in soil properties. The resulting empirical models are able to predict availability and reactivity and can be used to improve the accuracy of risk assessment. Furthermore, a close 1:1 relationship exists between results from the 0.43 M HNO3 method and the SBET method which substantially facilitates risk assessment procedures and reduces analytical costs. ► Availability of PTEs in urban soils is described well by non-linear Freundlich-type equations. ► A 1:1 relationship was obtained between the 0.43 M HNO3 method and the SBET method. ► A single soil extraction indicates reactivity and bioaccessibility of metals in soils. ► The reactive pool is suitable to assess risks of Cd, Cu, Pb and Zn in urban soils. A single analysis of the reactive pool by dilute nitric acid is suitable to assess risks of Cd, Cu, Pb and Zn in urban soils related to leaching to (ground)water and exposure to human beings (bioaccessibility).