Characteristics of sorption losses of polychlorinated biphenyl congeners onto glass surfaces

Sorption losses to glass surfaces of five polychlorinated biphenyl (PCB) co ngeners in aqueous solutions were investigated. Adsorption/desorption exper iments were conducted under conditions that simulated actual sample handlin g procedures for environmental samples. It was found that the adsorption lo ss is related to the degree of chlorination. PCB congener 180 lost the most onto glass surfaces, followed by congeners 138, 101/28, and 52, in decreas ing order. More PCB adsorption occurred onto glass under conditions of agit ation and higher temperature (22 degrees C) during the five-day experimenta l period. The salinity effect ("salting out effect") was also observed in t his work. The efficiency of desorption (rinsing three times with solvent) w as found to be ineffective in extracting adsorbed PCBs. It was necessary to use mechanical shaking for extraction. Storage of samples up to five days resulted in sorption losses as much as 30%, 17%, 30%, 40%, and 55% of PCB 2 8, 52, 101, 138, and 180, respectively. Sorption losses need to be consider ed when conducting water sampling or toxicological studies to avoid underes timation of the actual PCB concentrations and their toxic effects. (C) 2000 Elsevier Science Ltd. All rights reserved.