. . . . . . . "The competitive sorption behaviors of 1,2-DCB in binarysolute systems in four natural sorbents having naturalorganic matter (NOM) matrixes of different physicochemicalcharacters were investigated in batch reactors. Specifically,the study focused on investigating how the extent of 1,2-DCB competitive sorption depends on (i) the rigidity of NOMmatrixes as assessed by the efficiency of chemicaloxidation and (ii) the closeness of competitor structure tothat of the primary solute. The chemical oxidation andelemental composition results suggest that the shale NOMis the most reduced and condensed, the peat was themost oxidized and amorphous, and two surface soils hadintermediate NOM structures. Four chlorinated benzenes andphenanthrene were used as competing solutes. All fivechemicals exhibited competition against 1,2-DCB inall sorbents, including the peat, but the extent of competitionvaried significantly. Little difference in the extent ofcompetition with 1,2-DCB was observed for the variouschlorinated benzenes even though some were liquids andsome were solids at the experimental temperature. Allof the chlorobenzenes were more effective competitors thanphenanthrene. The shale showed markedly differentcompetition features from the other sorbents, with a muchsmaller competitive effect at a given sorbed volume ofcompetitor. However, normalizing sorbed competitor volumesby the capacity of the adsorption domain in the Polanyi\u2212Manes single-solute partition\u2212adsorption model (VO)produced qualitatively similar competitive behavior foreach solute; displacement of 1,2-DCB increased withincreasing sorbed competitor volumes up to VO, and littleadditional competition occurred beyond that point. Theextent of competition was positively correlated with themaximum adsorption capacity and the fraction of \u201Chard\u201D and\u201Csoot\u201D carbon contents as assessed by chemical andthermal oxidation methods. These findings indicate thatcompetition is associated with voids in the NOM structure,that these voids are likely present within the condensed(\u201Chard\u201D plus \u201Csoot\u201D) carbon domain, and therefore thatdiagenetic alteration of NOM plays a central role indetermining competitive sorption characteristics forhydrophobic contaminants." . . "Effects of Competitor and NaturalOrganic Matter Characteristics onthe Equilibrium Sorption of1,2-Dichlorobenzene in Soil andShale" . . . . .