PCB Congener Distributions of Commercial Pigments As a Function of Their Color

Polychlorinated biphenyls (PCBs) are a family of 209 congeners, some of which were produced commercially as Aroclors by chlorination of biphenyl in the years between 1930 and 1979, when their production was banned under the Toxic Substances Control Act (TSCA). Since then, lesser-known PCB congeners have continued being legally produced as unintentional byproducts of manufacturing processes used to make pigments. These non-Aroclor congeners, most notably 3,3’-dichlorophenyl (PCB11), have emerged as markers of environmental contamination from inadvertent production of PCBs in recent years after they were discovered in Chicago air and were believed to have volatilized from painted surfaces. Subsequent findings have shown that PCBs of all chlorination levels are prevalent in diarylide and phthalocyanine pigments that are used to color inks, dyes, paint, paper, textiles, plastics, leather, cosmetics, and foods, among other materials and products. The different pigments have different PCB distribution profiles due to variance in their chemical manufacturing processes. Lower chlorinated PCB congeners dominate in most pigments – especially yellow and orange, while higher chlorinated PCB congeners, including decachlorobiphenyl (PCB209), are found in green and blue pigments. We hypothesize that the distribution of PCB congeners in the air of a recently painted room is a function of the color of the paint. This will be examined by determining the mixtures of pigments used to make common colors, by calculating the resulting distribution of PCB congeners for those mixtures, and by showing that the mixture would look distinctly different as a mixture of congeners in air exposed to commercial Aroclors that volatilize from caulking and other old building materials.