Back in the mid-1950s in a Japanese town called Minamata, pets started behaving strangely. Household cats started to convulse mysteriously and eventually die. Shortly thereafter, people in the village suffered from symptoms such as losing the ability to speak, move and think.
It turned out that a Japanese chemical company, Chisso Corp., dumped 600 tons of mercury into the bay between 1932 and 1968. The slow deaths of 1,784 people puzzled doctors over the following years as the deaths caused by uncanny symptoms baffled them.
The Minamata Bay Disease
This methylmercury poisoning has caused a neurological illness now called Minamata Bay disease. The sickness causes long-term central nervous system impairment. In early 2013, the Minamata Convention on mercury emerged. Their goal was to have an international environmental treaty to limit global mercury poisoning in 112 countries.
Government organizations and environmental protection agencies have since limited mercury entering surface waters from power plants and other industries.
The concentration of mercury in the surface level of the ocean is probably three or four times higher today than it was 500 years ago, commented Dr. Carl Lamborg, an associate professor from the ocean sciences department at the University of California Santa Cruz.
Methylmercury finds its way to our dinner plate from the marine ecosystem’s smallest organisms—phytoplankton and zooplankton—from fish to humans.
Ocean Plastic Pollution More Than an Eyesore!
Ocean plastic pollution is a powerful toxic avenue to neurologic toxins in the human brain, according to Dr. Katlin Bowman, a postdoctoral research scholar at UCSC. “Plastic has a negative charge, mercury has a positive charge. Opposites attract so the mercury sticks,” Bowman said.
Mercury in the ocean mutates into methylmercury, which is an organic form of mercury. It is far more dangerous because it easily concentrates during its journey up the food chain. Heavy metal toxins naturally cling to plastics in the water; Since plastic has a negative charge and mercury a positive one, the two attract. This process creates toxic food consumed by fish that eventually ends up on our dinner plates.
“We Define microplastics as a piece of plastic that is less than five millimeters in size,” said Abigail Barrows, a marine research scientist from the College of the Atlantic. “They Cover a whole suite of things.” These include microbeads in personal care products and microfibers that break off clothing. As plastic bags, bottles, and utensils degrade over time, they become microplastics.
“If microplastics increase the rate of methylmercury production, then microplastics in the environment could indirectly increase the amount of mercury that accumulates in fish,” Bowman said.
Ocean Plastics Pollute The Food Chain
There are two key concepts that worsen methylmercury’s impact, they are bioaccumulation and bio-magnification.
With bioaccumulation, methylmercury never leaves the body, instead, it builds up slowly.
“The longer the fish lives, it just keeps eating mercury in its diet, and it doesn’t lose it, so it ends up concentrating very high levels of mercury in its tissues,” said Dr. Nicholas Fisher, a distinguished professor at the State University of New York Stony Brook. “The methylmercury also bio-magnifies, so the concentration is higher in the predator than it is in the prey.”
According to the European Commission’s Mercury Issue Briefing of 2012, top-level predators have over 100,000 times more methylmercury stored in their system compared to their surrounding waters.
Barrows concluded:
Our focus should be on the plastic pollution issue rather than on mercury discharge. The plastic produced in this process expected to double in the next two decades. Researchers strongly suggest that we need to focus on this issue in terms of our environment and eventual well-being.
