Why Only Mercury?

[Blue Stocking]

Didn't want to mix this in with the other Anti-fouling discussions currently running, but am interested to hear points of view on the following.
I know the arguments relating to the concentrations of AF heavy metals in shallow bays, and the purported effects of TBT in these areas.
I also am familiar with the story on commercial ships not fouling these areas, and therefore can use more toxic paints.
So, from the point of view of how detrimental these heavy metals are, in relation to the food chain, and how we consume the ocean food supply, why do we only hear, in the media mainstream, about Mercury levels.

[Stu Jackson]

Because they can only deal with one thing at a time?

[skipmac]

Well, here's a semi-educated guess.

From an environmental standpoint, mercury is the only heavy metal I can think of that is commonly released into the general environment. Comes from burning coal in power plants so where the smoke and dust settles there is a build up of mercury. This is very common in areas where people live so generates attention.

Other heavy metals are no longer used in common commercial applications like lead paint, tetra-ethyl-lead in gasoline, etc which put the metals into areas where you find a lot of people so are not as much of an immediate concern, don't usually show up in your house, food or other human contact so don't generate the interest from the news.

Then mercury is cumulative in the food chain and the human body so gives another point to put in the news bites to excite the reader.

[Celestialsailor]

I know tons of mercury was released into the SF Bay during gold mining well into the late 1900's. It's really something when they tell you it's safe to eat one fish a week with a smile on their face. I think all the Oceans of the world have toxic fish now because there is almost zero break down of these metals in fish. Fish eat fish. Crab eats dead fish and on and on it goes. Now they are finding small plastics in fish.

[Cheechako]

Mercury also a result of gold mining... down the rivers to the sea! Lead is also released commonly. The release was huge prior to unleaded gas.

Good question though, why is there mercury in so many fish ... pretty much throughout the world..? How does the Mercury get into the offshore large fish like tuna , wahoo, mahi? These fish dont eat reef fish much right? They eat offshore small fish. Is it possible that the mercury content in the ocean and land has always been there? I know up here in Wa state, there are areas where the natural chromium content in the soil is higher than the EPA allows!

[Bash]

In a word, it's because of how mercury bioaccumulates at higher trophic levels. Elemental mercury is a pervasive, toxic pollutant that transports globally as a gas and can be absorbed at microbial levels. Bad stuff.

http://www.princeton.edu/geosciences...elARES1998.pdf

[Cheechako]

but it is curious..... my mouth is full of Mercury/almalgam fillings... I feel no ill effects and some has been in there for about 50 years.... othe...r than that occasional twitch and the blackouts anyway... :>)

a quik search: Sources of mercury in the environment: Coal burning, Cement plants, Gold mining, Vinyl products purses etc, chlorine bleach. China is putting huge amounts of mercury in the atmosphere due to coal burning... settles in the ocean and the fish.
and more:
LEAST MERCURY
Enjoy these fish:
Anchovies, Butterfish Catfish Clam Crab (Domestic) Crawfish/Crayfish Croaker (Atlantic)
Flounder* Haddock (Atlantic)* Hake Herring Mackerel (N. Atlantic, Chub) Mullet Oyster
Perch (Ocean) Plaice Pollock Salmon (Canned)** Salmon (Fresh)** Sardine Scallop*
Shad (American) Shrimp* Sole (Pacific) Squid (Calamari) Tilapia Trout (Freshwater)
Whitefish Whiting
MODERATE MERCURY
Eat six servings or less per month:
Bass (Striped, Black) Carp Cod (Alaskan)* Croaker (White Pacific) Halibut (Atlantic)*
Halibut (Pacific) Jacksmelt (Silverside) Lobster Mahi Mahi Monkfish* Perch (Freshwater)
Sablefish Skate* Snapper* Tuna (Canned chunk light) Tuna (Skipjack)* Weakfish (Sea Trout)
HIGH MERCURY
Eat three servings or less per month:
Bluefish Grouper* Mackerel (Spanish, Gulf) Sea Bass (Chilean)* Tuna (Canned Albacore)
Tuna (Yellowfin)*
HIGHEST MERCURY
Avoid eating:
Mackerel (King) Marlin* Orange Roughy* Shark* Swordfish* Tilefish* Tuna (Bigeye, Ahi)*

[Knowazark]

Partly the talk about mercury is because it made its effects known in a dramatic way in the Japanese fishing town of Minimata. Mercury poisoning was known as Minimata disease at one point.

It kinda became a hot topic at one point and hasn't really gone away that much .... in a similar way to mercury itself. It doesn't break down, it doesn't get metabolised or eliminated from the food chain, it just accumulates until it reaches a critical point where it has some serious deliterious effects.

[Bash]

Originally Posted by Knowazark

Mercury poisoning was known as Minimata disease at one point.

Minimata disease is only one of several diseases that can be caused by mercury poisoning. As a toxin, mercury can have a deleterious effect on several organs, including the brain, the kidneys and the lungs.

[forsailbyowner]

I saw a website of chemicals of concern by US govt. Was really scary all the chemicals that were at one time legal that are still present in substantial amounts. Almost one of those you don't want to know lists.

[Bash]

Originally Posted by forsailbyowner

I saw a website of chemicals of concern by US govt. Was really scary all the chemicals that were at one time legal that are still present in substantial amounts. Almost one of those you don't want to know lists.

Yeah. But here's the difference. Most of those chemicals will break down at some point, or dilute sufficiently to cease being a problem. When we understand how those chemicals are harming the environment, we can usually stop producing them. DDT? We don't manufacture that anymore. While there's still some out there, it's going away over time.

That's not the situation with mercury. It's an element, straight off the periodic table, not a synthetic formulation. It will never dissolve or biodegrade. And even when we stop mining it, we will still be pumping it into the environment, at least until the point that we stop burning coal to produce energy.

[DeepFrz]

Mercury can be released into the water system by shore/bank erosion, other mining activities (other than coal), water diversion projects, damming rivers for electrical generation, etc.

[Khagan1227]

Originally Posted by Bash

Yeah. But here's the difference. Most of those chemicals will break down at some point, or dilute sufficiently to cease being a problem. When we understand how those chemicals are harming the environment, we can usually stop producing them. DDT? We don't manufacture that anymore. While there's still some out there, it's going away over time.

That's not the situation with mercury. It's an element, straight off the periodic table, not a synthetic formulation. It will never dissolve or biodegrade. And even when we stop mining it, we will still be pumping it into the environment, at least until the point that we stop burning coal to produce energy.

I agree with everything except the last line.

Many coal fired power plants are installing new equipment to "capture" mercury from coal prior to it's release. SO2 and NOX used to be the big concerns, but are managed by the utilities. Next up is CO2.