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How Clean is Clean?

November 15, 2018
By: 
Matt Dodd

Generally the clean-up of a contaminated site is based on environmental soil quality standards that are derived from the total concentration of the contaminants in the soil. In a risk assessment approach the answer to “how clean is clean” includes an assessment of what portion of the contaminants at the site can become biologically available to humans and other organisms (bioavailable) rather than just the total amount of the contaminant. Incorporation of bioavailability data into establishing clean-up levels leads to a more accurate estimation of the risk associated with the contaminated site and better use of limited resources.

I recently participated in the Society of Environmental Toxicology and Chemistry (SETAC) Central/West Africa conference at the University of Ghana, Legon, where I gave a keynote talk on incorporating bioavailability data into the decision making framework for contaminated sites clean-up.  Following a brief overview of the use of bioavailability in risk assessment, I used examples of research conducted in our laboratory for illustration including work done in collaboration with researchers from the Kwame Nkrumah University of Science and Technology (KNUST). One of the KNUST students I have been co-supervising presented a poster on the impacts of small scale mining on a local community (photo below).

I spent the weekend after the conference in Accra playing tourist with a visit to the carving shops and the Kwame Nkrumah Mausoleum and Memorial Park (selfie above), among others. Kwame Nkrumah is one of the founders of Ghana, the first president and an advocate of Pan-Africanism. The university in Ghana that I’ve been collaborating with is named after him.