Most mercury researchers have believed that microbes could not convert elemental mercury — which is volatile and relatively inert — into methylmercury. Instead of becoming more toxic, they reasoned that elemental mercury would bubble out of water and dissipate. That offered a solution for oxidized mercury, which dissolves in water. By converting oxidized mercury into elemental mercury, they hoped to eliminate the threat of methylmercury contamination in water systems.
ORNL’s study and a parallel study reported by Rutgers University, however, suggest that elemental mercury is also susceptible to bacterial manipulation, a finding that makes environmental cleanup more challenging.
“Communities of microorganisms can work together in environments that lack oxygen to convert elemental mercury to methylmercury,” study leader Baohua Gu said. “Some bacteria remove electrons from elemental mercury to create oxidized mercury, while others add a methyl group to produce methylmercury.”
Mercury is a toxin that spreads around the globe mainly through the burning of coal, other industrial uses, and natural processes such as volcanic eruptions, and various forms of mercury are widely found in sediments and water. Methylmercury bioaccumulates in aquatic food chains, especially in large fish.
- ORNL research reveals new challenges for mercury cleanup (oddonion.com)
- Misunderstood skull and crossbones label caused mass poisoning in Iraq (mysafetysign.com)
- Research reveals new challenges for mercury cleanup (phys.org)