Mercury levels in the ocean have been increasing steadily for the past century. The industrial revolution, coal burning, and mining have contributed greatly to rising mercury levels.
The article “Sources to Seafood: Mercury Pollution in the Marine Environment” in the Environmental Research journal— a companion report by the Dartmouth-led Coastal and Marine Mercury Ecosystem Research Collaborative (C-MERC), reports that mercury released into the air makes it way to oceans and rivers and contaminates the very seafood that makes its way into the global food supply.
This is the first study where scientists have collaborated to determine exactly how mercury moves from point of origin to various areas in the ocean and then up the food chain to the consumer. The conclusion C-MERC has made is that mercury from the atmosphere ranges from 56% of the mercury to approximately 90% in the open ocean.
It has long been known that tuna and swordfish are highly affected by mercury and can have dangerously high levels. In fact, these fish account for more than 50% mercury intake from seafood. The report’s model estimates as mercury inputs decrease, so too will methylmercury concentrations in fish. In other words, the fewer toxins generated in the first place, the fewer toxins in the food supply.
In some estuaries, river inputs can account for up to 80% of the mercury contamination. The problem is these estuaries are often hot spots for local fisherman and anglers who then introduce the contaminated seafood into the food supply.
There is a silver lining. It’s estimated that 33% of all mercury emissions are linked to industrial sources and other human activities. This means if mercury inputs are lowered intentionally the mercury levels in fish will decline correspondingly.
