The waters of Lake Michigan, food and humans all hold a growing amount of a compound used as a flame retardant banned in several European countries, according to University of Wisconsin professors.
The two UW professors, Jon Manchester and William Sonzogni, were the principal investigators in a recent study sponsored by the National Oceanic and Atmospheric Administration. They found increasing concentrations of PBDEs, or polybrominated diphenyl ethers, deep in the subterranean ecosystem of Lake Michigan.
PBDEs were originally designed to protect upholstery, textiles and other plastic products from flammability. The scientists speculated the chemicals might have slipped into the Great Lakes when the plastic vented PBDEs into the atmosphere or when the products fragmented into small parts.
Three years ago, Manchester and Sonzogni looked for the PCB contaminants, or polychlorinated biphenyls, in Great Lakes’ Coho and Chinook salmon fish. They found unusually high levels of PBDEs in addition to PCBs in the lake’s predator fish.
Manchester said the presence of PBDEs in the salmon is a warning that these chemicals are circulating throughout the world.
“PBDEs in top-level predators means the chemicals have moved up the food chain and made their way to Lake Michigan,” Manchester said. “They are moving from where they should be to where they shouldn’t. These chemicals do not belong to living things, they belong in plastics.”
Wisconsin Sea Grant Communications Coordinator Stephen Wittman said this finding prompted the three-year study that found PBDEs at one part per billion in the lake’s sediment, a number that is steadily rising.
Animals store pollutants from their environments in their fat cells, which people eat. This concerns the two scientists because PBDEs have a very similar genetic structure to the toxic PCBs.
Laboratory animals have substituted their human counterparts in studies that are difficult and dangerous to perform on people. The chemicals affected mice and rats by attacking their thyroid hormone, which regulates the body’s temperature and immune responses. One of the heavier formulations of PBDEs might cause cancer and cognitive impairments in newborn mice.
But no study has shown a direct correlation between PBDEs and specific damage in humans.
Even so, Sonzogni said he insisted if the unnatural compounds continue to build in our environment, and hence our bodies, certain internal enzymes would eventually suffer.
“I maintain that PBDEs shouldn’t be [in the lake] even if we think their toxicity is not well-established,” Sonzogni said.
Some researchers around the country and the world seem to share Sonzogni’s and Manchester’s concerns. A California study found that San Francisco bay area women had three to 10 times more of the chemicals in their breasts than European or Japanese women. Indiana and California women and infants held 20 times more of the chemical than what studies found in their Norwegian and Swedish equivalents. Germany, Great Britain and Italy have done similar research.
As a result, the European Union proposed to curb the use of some of the three forms of PBDEs in 2003. California will become the first state to ban two of the chemical’s variations in 2008.
Although some companies have stopped producing the two forms of PBDEs, the third form is still mass-produced.
Human health might not be the only victim of the chemical’s increase in Wisconsin.
“It’s what the sports fishing industry hates to hear,” Sonzogni said, adding the multi-billion dollar fishing industry would feel the repercussions of more polluted fish.
