August, 5, 2007 A small spill, but now a big problem
http://www.pensacolanewsjournal.com/apps/pbcs.dll/article?AID=/20070805/OPINION/708050307/1020
Carl Wernicke
cwernicke@pnj.com
It's hard to imagine a small chemical spill from the 1960s could cause so many problems today. But the legacy of that PCB discharge is raising concerns about eating Northwest Florida's "poster" fish — mullet.
According to University of West Florida researchers, an industrial plant on the river — at the time it was Monsanto — discharged one to three gallons a day of PCBs during the late 1960s.
Today, those PCBs are showing up like a rash throughout the Pensacola Bay system.
Last week, Dick Snyder, associate director of UWF's Center for Diagnostics and Bioremediation, at a meeting of the Bream Fishermen Association painted a picture of how this pollution moves around.
It serves as a primer for how pollution dumped in one place ends up permeating our planet and working its way into our bodies.
The PCBs that leaked from Monsanto (they were used in air compressors) ended up in sediments on the bottom of the lower Escambia River and upper Escambia Bay. (There are huge differences in the amount of PCBs found in fish above the spill, and below the spill.)
PCBs are known as a persistent pollutant, because they degrade very slowly, if at all, staying toxic for decades or longer.
Then along comes the innocent mullet.
Mullet are bottom feeders. They eat worms and other organisms that live in bottom sediments; in the process they ingest a lot of sediment (which is why mullet caught off sandy bottoms taste better than those off muddy bottoms).
PCBs love fat. They stick to body fat, and accumulate. They are not broken down or regularly discharged from the body, as many toxins are. It's why eating fish with even low levels of PCBs can lead to a problem over time — it stays with you.
For example, the fat in local blue crabs "is loaded" with PCBs, Snyder told the BFA. "I won't eat it anymore." That doesn't mean he won't eat crabs — but only if they have been cleaned, which removes most of the fat. But if you boil crabs without cleaning them, the fat — and the PCBs — melts into the water.
Meanwhile, as public relations executive Jim McClellen put it to me recently, "mullet are the french fries of the sea — everyone eats them."
Which makes them so important.
Small predators eat finger mullet, and larger predators (including us) eat larger mullet. That includes speckled trout, mackeral, snapper and grouper.
Mullet range far and wide. They travel from the bayous to the Gulf of Mexico, where they spawn. They get eaten by other fish both going and coming. ("PCBs love fat — lipids. And what are eggs but drops of lipids?" Snyder said. "Mullet go out into the Gulf and drop their eggs.")
Mullet are also eaten by perhaps everyone's favorite sea creature, the dolphin. Snyder paints a picture there that really shows how insidiously pollution can spread.
Dolphin live long lives, and so make valuable subjects for a study of persistent pollutants that bio-accumulate, like PCBs.
"Every dead dolphin we find is subject to an autopsy to measure heavy metals and other contaminants," Snyder said. "What we've found is that levels of PCB in male dolphins rise with age, but stay flat in females. The pups have high levels. Why?
"They (the females) are dumping their PCBs through their milk, which is full of fat, to their pups."
That is a depressing scenario. This pollutant inserts itself into the most fundamental of life functions, and rides it from mother to child, spreading its ugliness.
This ability to corrupt what is most critical to the furtherance of the life of a species is what makes pollution so ugly.
And PCBs are an ugly pollutant. They can cause cancer, and can act as a hormone "mimicker" that even at low levels can interfere with healthy development of an unborn baby — dolphin or human — or a newborn feeding on its mother's milk.
That's why Snyder says pregnant women should avoid eating fish contaminated with PCBs.
"We know the stuff is moving," Snyder says. "It's all one system. Nothing has made that as clear to me as this study. It is moving from the bay to the Gulf."
And it is moving its way up the food chain, one step at a time. We, of course, are standing on the top step.
Carl Wernicke is the Opinion editor for the News Journal. E-mail him at cwernicke @pnj.com.
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