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Mercury Accumulation

wobs

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wobs
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I’ve been looking at mercury in the environment recently, and have hit a brick wall on how it accumulates.

Does anyone know what mechanisms are required for mercury accumulation in a water system. I am talking about bacterial level, so not fish, or other higher life forms. Sediments, organic matter, fats, ammonia and bacteria in water are the main mediums I am looking at.

Basically, what specific conditions for bacteria or substances are found to promote mercury accumulation in such environments.

I have found some studies, but nothing that quite hits what I’m after.
 
wobs said:
I’ve been looking at mercury in the environment recently, and have hit a brick wall on how it accumulates.

Does anyone know what mechanisms are required for mercury accumulation in a water system. I am talking about bacterial level, so not fish, or other higher life forms. Sediments, organic matter, fats, ammonia and bacteria in water are the main mediums I am looking at.

Basically, what specific conditions for bacteria or substances are found to promote mercury accumulation in such environments.

I have found some studies, but nothing that quite hits what I’m after.
Click to expand...

Suggestion: check out the work of Tamar Barkay, and her team, of Rutgers University. I think you'll get some good leads, if not direct answers.
 
I'm not entirely certain what you are asking.

How does mercury get into a water system? Mostly through atmospheric deposition.

As for bio-accumulation, the important form of mercury for that is methyl mercury. As I recall, inorganic forms of mercury are less toxic and will be passed out of the body where methyl mercury will not.

Mercury accumulates in biological tissue through complex reactions (bioaccumulation), many of which are still unknown. We do know that several bacteria incorporate environmental inorganic mercury into their bodies through chemical conversion to several organic mercury compounds, collectively called methyl mercury (Me-Hg). This Me-Hg form is more toxic and more difficult to remove from bacterial systems than inorganic mercury. Any higher-level organisms that consume these bacteria also consume the Me-Hg. This cycle repeats up the food chain, with each higher predator consuming more and more Me-Hg, ultimately arriving in fish. Estimates suggest that Me-Hg can accumulate more than a million-fold in the aquatic food chain.
Click to expand...
http://nadp.sws.uiuc.edu/MDN/why.aspx
 
There is a very extensive literature on the mechanisms by which inorganic mercury is converted to organic forms (primarily methyl and dimethyl mercury) and as noted above these are the really toxic and dangerous versions. It can get fairly complex because different types of bacteria are involved in different places, it depends on the environmental conditions, and different bacteria can interact with one another in doing so. And, again as noted up thread, a lot remains unknown.

What level of information do you wish, and do you want general summaries, detailed expert reviews in the research literature, or the actual "primary" research publications themselves?
 
I would suspect that most mercury in the oceans is from natural sources- volcanoes, etc. Maybe wood ash after a forest fire gets washed down stream? Dunno, but coal buring does liberate mercury, where the coal get it?

I've heard that our oldest specimens of pelagic fish have just as much mercury as today's tuna.

And there has only been three cases of non-occupational mass poisonings- Iraq from eating seed wheat that had been treated with a pesticide, a cove in japan where the industrial pollution form the village poisoned the villages food supply, and a fishing village (Faralons?) that ate mass quantities of small whales.

Otherwise, NOBODY eats enough canned tuna to cause any disease.
 
Apologies for the delay in replying.


Giordano said:
There is a very extensive literature on the mechanisms by which inorganic mercury is converted to organic forms (primarily methyl and dimethyl mercury) and as noted above these are the really toxic and dangerous versions. It can get fairly complex because different types of bacteria are involved in different places, it depends on the environmental conditions, and different bacteria can interact with one another in doing so. And, again as noted up thread, a lot remains unknown.

What level of information do you wish, and do you want general summaries, detailed expert reviews in the research literature, or the actual "primary" research publications themselves?
Click to expand...

Some pointers towards any studies or further info would be helpful. As I feared, it all seems rather complicated in how it can accumulate.

If you know of any information on the environmental factors, that would helpful.

Tamar Barkay sounds like a good start, thank you JeanTate.
 
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