Polycyclic aromatic hydrocarbons (PAH) are among the most widely investigated and monitored compounds in the environment. Much work is centered on a list of 16 PAHs as priority pollutants that was introduced by the Environmental Protection Agency (EPA) in 1976 to monitor the quality of U.S. waterways. However, since then this compilation of PAHs has become the standard even for toxicological assessments of environmental samples, a task for which it was never intended and is not particularly well suited. A scientific discussion on adding more relevant compounds is ongoing. Such compounds would belong to classes so far not represented, i.e., larger PAHs, heterocyclic aromatic compounds and substituted PAHs of well-recognized carcinogenicity. A strong case can be made for including several isomers of the dibenzopyrenes. They frequently are found in environmental samples and some of them are known to be much stronger carcinogens that benzo[a]pyrene. Their toxic equivalence factors vary between 1 and 100, i.e. they are 1-100 times as potent as dibenzo[a]pyrene. Thus they would have a decisive influence on the toxic equivalence (TEQ) of the sample but despite that they are not routinely measured today. Literature examples of environmental samples indicate that they can be contribute twice as much of the TEQ than the sum of the 16 EPA PAHs. Benzo[c]fluorene is another PAH with similar characteristics as the dibenzopyrenes; it shows a toxic equivalence factor of 20 and may therefore, from a toxcicological standpoint, be of major concern. Besides the toxicity, other factors should also be considered before deciding on an extension of a mandated list. Analyzability is among them and so is the bioavailability that strongly influences the relative amount of a compound that an organism actually takes up from the sample and thus exerts an adverse health effect.

Dibenzopyrenes and Benzo[c]fluorene as strong candidates for an extended list of priority pollutants

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.