Jan2010_ES&E_ES&E 27/01/10 9:02 PM Page 43 Health nanoparticle size, it can easily collect on the surface of microbes where any mercury that dissolves can be taken in by the microbes,â€? Deonarine said. â€œWithout the organic matter, the mercury sulfide nanoparticles would grow too large and become insoluble, thus reducing the availability of mercury for microbial methylation.â€? It is while inside the microbe that the mercury is converted into the harmful methylmercury form, the researchers said. These reactions can only take place in cold water environments with little to no oxygen, such as the zone of sediment just below the bottom of a body of water. Other such anaerobic environments can also be found in wastewater and sewage treatment systems, the researchers said. â€œThese initial laboratory findings could have far-reaching implications,â€? Hsu-Kim said. â€œThat these reactions can take place in anaerobic environments suggests that the old paradigm of testing for toxic metals in sediments may provide an incomplete picture of how much methylmercury is there.â€? The researchers plan to continue their studies with other types of organic matter and for longer periods of time. For her presentation and paper, Deonarime was one of six recipients of the C. Ellen Gonter Environmental Chemistry Award, given annually to graduate students. The research was supported by the federally funded Center for the Environmental Implications of NanoTechnology (CEINT), which is based at Duke, and the ACSâ€™s Petroleum Research Fund. For more information, E-mail: amrika.deonarine@duke.edu That these reactions can take place in anaerobic environments suggests that the old paradigm of testing for toxic metals in sediments may provide an incomplete picture of how much methylmercury is there. â€œThe exposure rate of mercury in the US is quite high,â€? said Heileen HsuKim, Duke assistant professor of civil and environmental engineering and senior member of the research team. â€œA recent epidemiological survey found that up to 8 percent of women had mercury levels higher than national guidelines. Since humans are on top of the food chain, any mercury in our food accumulates in our body.â€? Because fish and shellfish have a natural tendency to store methylmercury in their organs, they are the leading source of mercury ingestion for humans. There are many ways mercury gets into the environment, with the primary sources being the combustion of coal, the refining of such metals as gold and other non-ferrous metals, and in the gases released during volcanic eruptions. The air-borne mercury from these sources eventually lands on lakes or ponds and can remain in the water or sediments. www.esemag.com -)8:714/ 9-+04525/> .57 8).- -.@ +1-49 <)9-7 )4, <)89-<)9-7 97-)93-49 A 4)2>?-78 )4, 8-48578 +:89531?-, 95 >5:7 8>89-38 675+-88-8 A $ -791@ -, 25< 852:91548 A '1,- 7)4/- 5. -;-2 14897:3-49)9154 A ")6-72-88 #-+57,-78 ;18:)2 8).-9> ,)9) 3)4)/-78 A :953)9-, 675+-88 $52:91548 A )21*7)9154 &-71@ +)9154 $-7;1+-8 18 1.-+>+2- )4)/-3-49 %7> 54- 5. 198 .:4+91548 .57 <<< +) -4,7-88 +53 ,-;1+-;1-<-7 4,7-88 ):8-7 )4),) 9, $:9954 71; :7214/954 !49)715 ( %-2 )= 14.5 +) -4,7-88 +53 <<< +) -4,7-88 +53 January 2010 | 43