Lyndal Johnson a fisheries biologist and toxicologist with the National Oceanic and Atmospheric Administration and her team of scientists were sampling English sole, a flatfish common to the sound’s Elliott Bay, when they noticed something. “These fish in Elliott Bay, when all the other fish had completed spawning, ready to go home, it’s all over for them, the Elliott Bay were still ripe and still had eggs that they had not yet spawned.”
The team went back and sampled more fish around Puget Sound and found some male fish were producing a protein called vitellogenin. Vitellogenin is a protein used to make egg yolks. That’s not something you want to see in male fish, says Jim West, a senior scientist with the Washington Department of Fish and Wildlife. West was with Lyndal Johnson when they found the fish. “It’s an indication that they’ve been exposed to something, some chemical, that is essentially feminizing them. They didn’t look different, but there were striking changes going on inside them.
The team took more samples. The results: almost half of the 49 male English sole they tested at the Elliott bay sight on the Seattle waterfront were producing the female egg yolk protein. Elevated egg protein levels were also found at sample sites in Tacoma’s Commencement Bay and near Everett. Perhaps more disturbingly, the researchers found similar results in the endangered juvenile chinook salmon they tested at the Elliott Bay site.
Pinpointing the exact chemicals that are causing this feminization and intersex development has been the biggest challenge for scientists so far. But many believe a group of chemicals known as endocrine disruptors are to blame.
They’re sort of like hormone imposters. They act like normal hormones – estrogen or testosterone for example – and mess with the body’s natural hormonal messaging system. Bisphenol A is probably the most well-known chemical in this family. It’s commonly referred to as BPA. You’ll find it in certain plastics, the liners of canned goods, epoxies – even kids toys. Synthetic estrogen from birth control pills has also been shown to feminize fish.
These chemicals get into our bodies and then end up in wastewater. Tillitt says that wastewater, even though it’s been treated, carries some of them into nearby waterways, and can negatively affect immune system response and reproductive health in fish.“It’s not surprising,” he notes, “that in certain locations, downstream from wastewater treatment plants, are some of the most common locations where we can find intersex (fish).”
A major national health study found Bisphenol A in the urine of more than 90 percent of Americans. It’s also prevalent in stormwater samples collected in King County, Washington. After years of debate the federal government banned the use of bisphenol A in baby bottles and sippy cups this summer. It’s too soon to say if that ban has had any effect.