title: Chemical speciation of cadmium: An approach to evaluate plant-available cadmium in Ecuadorian soils under cacao production.
abstract: Elevated concentration of cadmium (Cd) in cacao beans has raised serious concerns about the chocolate consumption on human health. Accumulation of Cd in cacao bean in southern Ecuador has been related to soil contamination. In this study, soil fractionation approach was used to identify available Cd pools in the soils and to correlate these Cd pools with bean Cd concentration and soil test indexes. The distribution of soil Cd fractions decreased in the order: oxidizable > acid-soluble > residual > reducible >> water-soluble (+exchangeable). Oxidizable and acid-soluble fractions accounted for 59 and 68% of the total recoverable Cd for the 0-5 and 5-15 cm soil depth, respectively. Acid-soluble fraction was closely related to bean-Cd, with correlation coefficients (r) of 0.70 and 0.81 (P < 0.01) for the 0-5 and 5-15 cm soil depth, respectively. Acid-soluble Cd was significantly correlated with 0.01 M HCl- (r = 0.99, P < 0.01) or Mehlich 3- extractable Cd (r = 0.97, P < 0.01). These results indicate that acid-soluble Cd fraction is an important part of available Cd pool. Since approximately 60% of Cd in the cacao-growing soils is related to the acid-soluble fraction and bound to organic matter, remediation of the contaminated soils should consider to the dynamics of soil pH and organic matter content.
authors.affiliation: University of Florida, Institute of Food and Agricultural Science, Indian River Research and Education Center, 2199 South Rock Road, Fort Pierce, FL 34945, USA; Escuela Superior Politecnica del Litoral, Facultad de Ciencias de la Vida, Centro de Investigaciones Biotecnologicas del Ecuador, Km 30.5 Via Perimetral, Guayaquil, Guayas, Ecuador.
authors.forename: E
authors.initials: E
authors.lastname: Chavez
authors.affiliation: University of Florida, Institute of Food and Agricultural Science, Indian River Research and Education Center, 2199 South Rock Road, Fort Pierce, FL 34945, USA. Electronic address: zhe@ufl.edu.
authors.forename: Z L
authors.initials: ZL
authors.lastname: He
authors.affiliation: University of Florida, Institute of Food and Agricultural Science, Indian River Research and Education Center, 2199 South Rock Road, Fort Pierce, FL 34945, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Stoffella
authors.affiliation: University of Florida, Institute of Food and Agricultural Science, Soil and Water Science Department, 171 McCarty Hall, Gainesville, FL 33611, USA.
authors.forename: R S
authors.initials: RS
authors.lastname: Mylavarapu
authors.affiliation: University of Florida, Institute of Food and Agricultural Science, Tropical Research and Education Center, 18905 SW 280 Street, Homestead, FL 33031, USA.
authors.forename: Y C
authors.initials: YC
authors.lastname: Li
authors.affiliation: United State Department of Agriculture, ARS, 10300 Baltimore Ave., Beltsville, MD 20705, USA.
authors.forename: V C
authors.initials: VC
authors.lastname: Baligar
mesh_terms: D002099:Cacao / Q000737:chemistry* / Q000254:growth & development / Q000378:metabolism; D002104:Cadmium / Q000737:chemistry* / Q000378:metabolism; D005591:Chemical Fractionation; D004484:Ecuador; D004787:Environmental Pollution; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000737:chemistry* / Q000378:metabolism
chemical_list: D012987:Soil; D012989:Soil Pollutants; D002104:Cadmium
keywords: Available Cd; Cacao; Cadmium; Ecuador; Fractionation; Soil contamination