A Colorful PCB Problem
by Lauren Heine
Originally published in the Green Science Poly Insititute September 2023 Newsletter
Though the U.S. EPA banned polychlorinated biphenyls (PCBs) in 1979 for hundreds of applications, exposure persists. In addition to communities burdened with persistent contamination, PCBs still linger in the food chain and in many old buildings, including schools.
Compounding this exposure to legacy PCBs, the U.S. EPA allows for inadvertent generation of PCBs to occur in certain manufacturing processes. Known as inadvertent PCBs (iPCBs), they are produced when manufacturing pigments and dyes, silicones, and vinyl chloride.
iPCBs are allowed at a maximum concentration of 50 ppm. While this does not sound like much, it is becoming increasingly problematic for paper recycling facilities. Recyclers concentrate effluent from waste paper contaminated by iPCB-containing pigments and become PCB emitters. Even the most modern specialty paper mills in the world cannot remove enough of the iPCBs to meet water quality standards designed to protect public health, including the health of tribal communities relying on fish consumption.
Will the circle be unbroken? Not while pigments contain PCBs
In search for solutions the NGO ChemFORWARD was funded by the Spokane River Regional Toxics Task Force to create the iPCB Pigment Resource, a freely available, searchable dataset. This tool tracks nearly 400 pigments organized by chemical name, CAS#, color index number, application, availability in the U.S. market, and whether they were manufactured using chlorinated solvents or are organochlorine molecules themselves (indicators of potential iPCB generation). The pigments most likely to contain iPCBs are diarylide yellows and phthalocyanine greens and blues.
This iPCB Pigment Resource is being used for a supply chain pilot project to identify which currently used inks should be tested for iPCBs. The goal is to help shift the market towards iPCB-free pigments, which would be a win for public health and the planet.
