To be brief, we've mentioned that PAHs are carcinogenic, teratogenic, and immunogenic compounds, especially when they're being metabolized. It's those metabolites that are the toxic principles in those mixtures. With the fish, we're seeing increased incidence of liver tumours and neoplasm skin lesions that are scaring the community.
Basically, under current regulations and legislation, we usually focus on only 16 PAHs. Those are the parent compounds that are found on the U.S. EPA list of priority substances. Those are the compounds we're actually finding in lower quantities in the environment. When you're looking at any environmental sample, be it water, biota, or sediments, you're finding that over 95% of all PAHs are actually the alkylated forms of those compounds. With PAHs, there are thousands of different compounds, and we're finding the majority of them are currently not listed under priority substances lists.
Mikisew is working hard to recommend the inclusion of some of these compounds, especially the alkylated PAHs, on the priority substances list, and also more meaningful monitoring in addressing the complexities around exposure to these complex environmental mixtures of PAHs and other heavy metals, as they've presented.