23 December 2013
Environmental geochemist Dr Kate Spencer from Queen Mary School of Geography told the BBC World Service there was growing concern about the amount of methylmercury entering the food chain in an interview with the Business Daily show.
Dr Spencer – who teaches on the School’s geography and environmental science programmes – explained the way in which the highly toxic metal enters the environment from industrial waste.
“Mercury is volatile. Whether we are talking about a natural source of mercury – such as volcanic eruptions – or emissions from coal-burning power stations, once released mercury goes up into the atmosphere and travels long distances before it falls out as deposition, in rain for example, and into the ocean,” she said.
“Mercury transforms from elemental mercury and inorganic mercury into methylmercury (organic). This is far more toxic and very bioavailable. It is easily absorbed and can transfer from the water column across tissue membranes, so you find the primary producers at the bottom of the food chain – such as algae – can bioconcentrate, or accumulate, the mercury,” Dr Spencer explained. “The algae, or phytoplankton, are a food source for other organisms, such as small fish, and the concentration of methylmercury increases – or biomagnifies – all the way up to the higher predators, so we’re most concerned about fish which are at the top such as Sword fish. By the time you get to these types of species, the concentration of methylmercury is increased many thousands of times.”
Interviewed for the programme in fishmongers Steve Hatt in Islington, Dr Spencer’s research provided the interviewer with an insight into the cycling and behaviour of mercury in the aquatic environment.
“Understanding how contaminants behave in estuarine and coastal environments is a key area of my research and informs teaching in undergraduate and postgraduate modules such as Earth System Cycles, Environmental Management Applications and Biogeochemistry,” Dr Spencer added. “Students learn about the source, fate and transport of contaminants, and how to manage aquatic environments to protect water quality and ecological health. This prepares them for careers in environmental protection, environmental consultancy and conservation.”
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