Mercury Pollution in Fish Admin Note: There was a Question in the forum about Mercury in Fish…So I hunted up this info and thought I would also run it on the front page. This information came from several places. It is good reading, Be sure to check it out by hitting the “Read More” button. How does mercury get into fish? 1. What is mercury and methylmercury? Mercury occurs naturally in the environment and can also be released into the air through industrial pollution. Mercury falls from the air and can accumulate in streams and oceans and is turned into methylmercury in the water. It is this type of mercury that can be harmful to your unborn baby and young child. Fish absorb the methylmercury as they feed in these waters and so it builds up in them. It builds up more in some types of fish and shellfish than others, depending on what the fish eat, which is why the levels vary. 2. I’m a woman who could have children but I’m not pregnant – so why should I be concerned about methylmercury? If you regularly eat types of fish that are high in methylmercury, it can accumulate in your blood stream over time. Methylmercury is removed from the body naturally, but it may take over a year for the levels to drop significantly. Thus, it may be present in a woman even before she becomes pregnant. This is the reason why women who are trying to become pregnant should also avoid eating certain types of fish. 3. Is there methylmercury in all fish and shellfish? Nearly all fish and shellfish contain traces of methylmercury. However, larger fish that have lived longer have the highest levels of methylmercury because they’ve had more time to accumulate it. These large fish (swordfish, shark, king mackerel and tilefish) pose the greatest risk. Other types of fish and shellfish may be eaten in the amounts recommended by FDA and EPA.
Most mercury pollution is released into the air and then falls directly into water bodies or onto land, where it can be washed into waterways. When mercury gets into water, bacteria can change it into a form called methylmercury, which is absorbed by tiny aquatic organisms. When fresh water and ocean fish eat those organisms, the mercury begins to build up in their bodies. When larger fish eat smaller fish, mercury can build up to high levels in the tissues of the big fish. Because it binds to the protein in fish muscles – the ‘meat’ of the fish – mercury cannot be removed by cooking or cleaning the fish.
4. I don’t see the fish I eat in the advisory. What should I do?
If you want more information about the levels in the various types of fish you eat, see the FDA food safety web site
FPRIVATE “TYPE=PICT;ALT=exit EPA”
or the
EPA Fish Advisory website.5. What about fish sticks and fast food sandwiches?
Fish sticks and “fast-food” sandwiches are commonly made from fish that are low in mercury.
6. The advice about canned tuna is in the advisory, but what’s the advice about tuna steaks?
Because tuna steak generally contains higher levels of mercury than canned light tuna, when choosing your two meals of fish and shellfish, you may eat up to 6 ounces (one average meal) of tuna steak per week.
7. What if I eat more than the recommended amount of fish and shellfish in a week?
One week’s consumption of fish does not change the level of methylmercury in the body much at all. If you eat a lot of fish one week, you can cut back for the next week or two. Just make sure you average the recommended amount per week.
8. Where do I get information about the safety of fish caught recreationally by family or friends?
Before you go fishing, check your Fishing Regulations Booklet for information about recreationally caught fish. You can also contact your local health department for information about local advisories. You need to check local advisories because some kinds of fish and shellfish caught in your local waters may have higher or much lower than average levels of mercury. This depends on the levels of mercury in the water in which the fish are caught. Those fish with much lower levels may be eaten more frequently and in larger amounts.
Mercury
Mercury is an odorless, silver-white metal that is found naturally in the environment. Industrial sources such as coal burning industries, municipal and medical waste incinerators and chlor-alkali plants release mercury into the air. That mercury is spread through the air and may be deposited in water. Mercury builds up in fish tissue and other aquatic life. As bigger fish eat smaller fish, the bigger fish get higher levels of mercury. That’s why many advisories related to mercury warn against eating large fish like bowfin or largemouth bass or ocean fish like shark or king mackerel.
Exposure to high levels of mercury can damage the brains of unborn children and young children. Prenatal exposure to mercury can affect the way children think, learn, and problem-solve later in life. That’s why many of the advisories are stronger for pregnant women and young children who are more sensitive to the toxic effects of mercury.
In adults, the earliest obvious signs of mercury poisoning are numbness of lips, fingers or toes, fatigue and blurred vision.
Lower-mercury fish and shellfish that are safer to eat**
Ocean fish: Freshwater fish: Shellfish:
Spot
Croaker
Kingfish (sea mullet)
Speckled trout (spotted trout)
Cod
Whitefish
Pollock
Mahi-mahi
Ocean perch
Halibut
Haddock
Flounder
Herring
Canned tuna and other canned fish
For More Info….
http://www.epi.state.nc.us/epi/fish/