Mercury Contamination in Amazon Region

A study was done in Santarém, Pará, Brazil about mercury contamination in fish. In this region of the Amazon lots of mercury is released into the atmosphere. It is generally accepted that the mercury comes from the goldmining activity in the area. The amount of mercury in the region is predicted to be as much as 70 to 130 tons per year based on the gold production from this area. Organic methyl mercury is the most toxic and is accumulated mostly by the large predator fish. This town this study was done in, is not that close to mining activity. However there is other commercialization there. The main questions that were trying to be answered were: What is the difference in contamination in the different species of fish? And what is the correlation between weight of fish and mercury concentration?
Santarém is located in Pará State, which as a whole has the most goldmining sits in the Amazon region. Furthermore, there are six rivers surrounding Santarém. Fishing is one of the most important economic activities in this area so whether or not the fish are safe for human consumption is very important. The fish that were used came from the local markets. The locality of the fish was possible to be determined by asking the specific farmers where they came from. There were 109 fish in total, both carnivorous and non carnivorous.
After the fish were tested, it was discovered that carnivorous species of fish have about five times more mercury in them than both herbivores and omnivores. One species in particular, Tucunaré, tested 2% above the legal limit for safe eating. The highest level in this species was 700 ng.g-1 of methyl mercury. In total, about 1% of fish had mercury levels above 500 ng.g-1 .
What the people in this region need to realize is consuming these fish on a daily basis may have a detrimental effect to their health. Particularly considering that about 90% of the mercury in these fish is toxic methyl mercury. Now that the high levels of mercury have been discovered, there will be more attention paid to the bioaccumulation process of mercury in the fish. It is not easy to avoid just the species of fish with high mercury levels because the area has so much biodiversity. Also, due to the amount that fish effect the Amazonian culture, from food to economy, limiting how much fish they consume is hardly an option. The best way to deal with this problem is by involving environmental politics. (de Souza et. al)

This just shows another way that anthropogenic effects are harming the environment. This is a particularly bad case since there are very few practical uses for gold in comparison to how much it is used solely for jewelry. The gold miners must be held accountable for what they are doing to the surrounding people. I would imagine that these miners are also eating the fish with mercury in them since they probably live somewhat close to where they work, and that makes even less sense.

-Rebecca Teel

de Souza, A, R Sarkis, de Souza, J, Nahum, C, da Silva M, Brabo, E, and de Oliveira E. "Mercury Contamination in Fish from Santarem, Para, Brazil." Environmental Research Section. A.83 (2000): 117-122. Print.