Co-contaminationofatrazine(AT)andcadmium(Cd)onthesurficialsediments(SSs)andnaturalsufacecoatingsamples(NSCSs)wasinvestigatedviathermodynamicadsorptionexperiments.TheresultsshowthatsurfacecoatingshaveastrongerabilitytoadsorbATowingtotheirhigheractivecomponentscomparedwithsurficialsediments.SynergeticandantagonisticeffectsofCdontheadsorptionofATwereobserved.Cdatalowerconcentra-tion(≤4.0mg/L)inthesolid/liquidphaseenhancedATadsorptionontothesurficialsediments(surfacecoatings),whiletheadsorptionofATwouldbeinhibitedataCdconcentrationofmorethan8.0mg/L:ATcoordinatesstronglytoCd,andAT-CdcomplexesseemtobemorestronglyadsorbedonsedimentsthanATalone,andattheadsorptionofATcantakeplaceonthesiteswhereCdhasbeenpreviouslyadsorbedandCdactsasabridgefortheinteractionbetweensedimentsandAT.WiththeincreaseofCdconcentration,thesuperfluousCdmayholdmuchmoreadsorptionsitesandthusinhibitstheadsorptionofAT.Meanwhile,theeffectsofco-existedATonCdadsorptiononSSs(NSCSs)wereinsignificantsinceCdhasastrongercompetitiveabilitytobeabsorbedonSSs(NSCSs).Thepresentstudycouldbeusefulinpredictinginteractionsofthemetalionswithherbicidesandpotentiallyaidthedesignofremediationstrategiesforcontaminatedsedimentsandgroundwater.
