Chemical speciation of cadmium: An approach to evaluate plant-available cadmium in Ecuadorian soils under cacao production

• Published in: Chemosphere (Oxford) 2016-05, Vol.150, p.57-62
• Main Authors: Chavez, E., He, Z.L., Stoffella, P.J., Mylavarapu, R.S., Li, Y.C., Baligar, V.C.
• Format: Article
• Language: English
• Subjects: Available Cd; Beans; Cacao; Cacao - chemistry; Cacao - growth & development; Cacao - metabolism; Cadmium; Cadmium - chemistry; Cadmium - metabolism; Chemical Fractionation; chemical speciation; Chocolate; cocoa beans; Consumption; correlation; crop production; Ecuador; Environmental Pollution; Fractionation; hydrochloric acid; organic matter; polluted soils; Pools; Remediation; Soil - chemistry; Soil contamination; soil depth; soil nutrients; Soil Pollutants - chemistry; Soil Pollutants - metabolism; soil pollution; soil separates; soil-plant interactions; Soils
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2016.02.013

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