Friday, April 21, 2017

Dangerous Levels of Mercury in Fish

          Every year, after school lets out, a friend and I go out to a dock on the Allegheny River north of Pittsburgh, and throw a line in the water. We have had a good amount of success fishing from that dock, usually pulling in a few 10-15 pound catfish from the bottom of the river. Unfortunately, we have always had to throw those fish back because of the mercury levels in them, and the regulations saying that they would not be healthy to eat. This problem reaches further than western Pennsylvania though. Mercury is becoming a common problem (due to toxicity and persistence in the environment) in fish populations in both fresh water and salt-water biomes, creating a situation where there are too high of levels in them to be safe to eat. Changes need to be made so that there is less mercury being introduced into the environment, and so the fish that so many people rely on will be healthy to eat.
            Mercury is a metallic element that is released through a few human processes such as coal manufacturing and gold mining, or through natural processes like volcanic eruptions, or the weathering of rocks (Bradford) (Freshwater). The natural processes produce an acceptable level of mercury that was not a major environmental concern in general, but the human processes have increased those levels (Bradford), making it something that needs to be watched, and regulated. The increased levels are dangerous because the mercury is getting into the water and is bio-accumulating in commonly consumed fish species (Scheer). Some of the top predator fish that we need to watch our consumption on are: Bluefin Tuna, Mackerel, and Walleye to name a few (Scheer). There are other fish noted by Scheer for their high levels, but the ones mentioned have the highest levels of concern based on the popularity of the fish.
These levels need to be watched because of the negative health effects that they have on humans when in high doses. Mercury poisoning has many effects including: Blindness, seizures, memory issues and eventually will lead to death (Bradford). These are obviously the effects someone would see after a decent amount of exposure, but these are some scary things to deal with. For pregnant women there is even more of a concern because unborn babies are even more susceptible to the issues and it can lead to miscarriages or cause mental issues that the children will deal with the rest of their lives (Bradford).

On the global level, there is good and bad news. Over the past 40 years, there have been studies on how high concentrations of certain toxic compounds (including mercury and DDT) were in ocean fish populations. A recent report says that over this 40-year period, there has been a massive drop in levels in the chemicals (Smith). It also says that the lawsuits and regulations that have been put out have ben playing a major role in the decreasing levels of pollution from the chemicals (Smith). That is the good news. The bad news is that there are still many fish that have dangerous levels for consumption in them. China is the main culprit here. The US and Canada have cut their emissions down thanks to the activity of the EPA and citizens bringing the problems to light, but while we have been reducing our bad activities, China had been building theirs up (Flesher). There are reports of mercury pollution coming from China in the Great Lakes region (Flesher). They know the pollution is from China based on the exact chemical fingerprint being observed matching the mercury fingerprint observed in areas of China (Flesher).

There has been major progress, but there is still a lot that needs to be done so that the people that rely on these fish to survive will not suffer because of the big polluters that refuse to cut down their emissions. Hopefully one day the rivers will be clean enough that the fish I pull out of the river will be clean enough for me to eat them.

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