... metal contaminationincluding site remediation, modeling, and risk assessment.Several studies have also included the effects of Ca on the binding and dissolution behavior of OM in soils and aquatic ... Mandal et al. (2000) examined the effects of Ca and Mg on Ni binding by FA. They concluded thatbound Ni tends to be relea sed in the form of Ni2+ion in the presence of Ca and Mg as these ions ... fractionate the DOC in water extractions of the soils, (2) examine the concentrations of the operationallydefined DOC fraction s in the extract s as a function of systempH ,and( 3)correlateCd,Cu,Ni,PbandZnconcentrations...