Scientific research is designed to build knowledge and explore. Sometimes, that means changing previous ideas. In the US, we have a system that reviews and updates toxic chemicals. In 2017, benzo[a]pyrene (BaP) was updated. BaP is a polycyclic aromatic hydrocarbon (PAH) (https://superfund.oregonstate.edu/all-about-pahs). It is also a carcinogen. Exposure to a carcinogen may increase cancer risk.
The review of BaP found it to be 7 times less toxic than previously thought. However, it is still a carcinogen. This change may impact Superfund sites that have PAHs as pollutants. Why? Because BaP is used as a standard of toxicity for 6 other carcinogenic PAHs. When the toxicity of BaP changes, it changes these other PAHs. This means that BaP and 6 other PAHs will be considered 7 times less carcinogenic. We developed a one-page infographic describing this change (https://superfund.oregonstate.edu/sites/superfund.oregonstate.edu/files/image-album/infographics/infographics_0.jpg). The Portland Harbor Superfund site has BaP and other PAHs. Only BaP and 6 PAHs will be affected by the change in toxicity. Other PAHs will not be changed.
Want to learn more about PAHs? Check out our newest research: https://www.researchgate.net/project/Superfund-Research-Program-at-Oregon-State-University