Mercury Flashcards
(15 cards)
What are some uses of Hg?
in dyes
burning fossil fuels - gas, coal, natural gas
switches, lamps
flooding of vegetated lands
What does cycle mean?
movement/change that ends up in the same place (in and out)
What does pool mean?
Rate of exchange/movement
What is elemental mercury?
Hg^2+
Hg^0
HgS
H2S
Hg^0
How does elemental mercury change into Hg^2+? What are some properties of Hg^2+
The first state change of elemental mercury to Hg^2+ is induced by sunlight, therefore it happens in the atm.
Hg2+ has a higher solubility than Hg0, which means that Hg2+ can be dissolved in h2o which means that rain can pick it up and wash it out.
Hg2+ is also more volatile
What is the lifetime of Hg and Hg2+
Hg- about a year
Hg2+ - few weeks
What does the movement of an element depend on? what does Hg0 prefer and Hg2+?
The movement of an element depends strongly on its state, so it favours on change strongly.
Hg0 - favours volatilization
Hg2+ - favours condensation
What is HgS? What is it’s residence time?
HgS is cinnabar, and it has a solid residence time
What is residence time?
How long an atom is going to stay in a pool before fluxing out
What is CH3Hg+, and CH3HgCH3? Which is more toxic?
methylmercury - more toxic
dimethylmercury
Why is the entry of methylmercury into cells toxic?
The sulfur in the cells makes it really easy for Hg to move in the body, by jumping from one culture containing compound to another. Hg can mess with exposed S in sulfur-containing compounds therefore limiting the effectiveness to work with its cofactor. As a result, the compound is not doing its function
Define biomagnification
Methyl that is present in an organism will not be secreted out, but the next organism will have in increase in the concentration of Hg. Basically once it enters the body there is no way to get rid of it
What bacteria reverse the process of methylmercury formation?
MerA and MerB
What does MerA do?
MerA reverses the light-driven oxidation of elemental Hg
How does HgC contribute to food safety risk to fisherman?
When Hg2+ is in the water, HgC converts it to methylmercury by adding a methyl group onto Hg2+. This in turn creates a toxic form of Hg that fish, for example, can ingest and now have mercury in their system. Bigger fish can eat smaller fish and accumulate the Hg and when fisherman catch these fish with high levels of mercury, it poses a food safety risk
