Cadmium sorption in biosolids amended soils: results from a field trial.
The effect of biosolids amendment on cadmium sorption coefficient (K(d)) was determined for soils in a biosolids field trial. The sorptive properties of biosolids are thought to have a significant controlling effect upon the availability/uptake and mobility of potentially toxic metals. K(d) values for the three biosolids were 10-30 times greater than those for unamended soil. Elevated K(d) values were still apparent 1 and 2 years after biosolids amendment (100 t ha(-1)) for two of the three biosolids. Chemical extractants (sodium hypochlorite and hydrofluoric acid, respectively) were used in an attempt to determine K(d) values of isolated inorganic and organic fractions. For both biosolids amended soils and unamended controls, Cd sorption appeared to be dominated by the inorganic fraction, potentially indicating the overriding importance of this fraction in controlling metal mobility. However, for the biosolids themselves, the sum of inorganic and organic fraction contributions to K(d) accounted for less than half the K(d) of the whole biosolids. This discrepancy was attributed to the loss of highly sorptive water soluble species in both chemical extractions.
Merrington
G
G
Environment Agency, National Centre for Ecotoxicology and Hazardous Substances, Howbery Park, Wallingford, Oxfordshire, OX10 8BD, UK. graham.merrington@environment_agency.gov.uk
Smernik
R J
RJ
D000327:Adsorption; D002104:Cadmium / Q000737:chemistry*; D002106:Cadmium Radioisotopes; D006851:Hydrochloric Acid; D006858:Hydrofluoric Acid; D017942:Nitric Acid; D012722:Sewage / Q000737:chemistry*; D012965:Sodium Chloride; D012973:Sodium Hypochlorite; D012987:Soil / Q000032:analysis*; D013021:South Australia
D002106:Cadmium Radioisotopes; D012722:Sewage; D012987:Soil; D002104:Cadmium; D017942:Nitric Acid; D012965:Sodium Chloride; D012973:Sodium Hypochlorite; D006851:Hydrochloric Acid; D006858:Hydrofluoric Acid; C022102:aqua regia