The concentrations of toxic flame retardants called PBDEs in fish tissues from the Spokane River are higher than any other tested area in Washington state, but recent studies indicate levels of those toxics may actually be dropping.
In addition, osprey eggs collected along the Spokane River in 2009 all contained PBDEs, but the amount was generally too low to harm the reproductive success of ospreys.
This is the conclusion of two studies conducted cooperatively by the Washington Department of Ecology and the U.S. Geological Survey that evaluated PBDEs in fish tissues and osprey eggs.
PBDEs, or polybrominated diphenyl ethers, are compounds that have been used since the 1970s as flame retardants in plastics, fabrics, motor vehicles, electronic circuitry and more. They persist in the environment and move up the food chain to accumulate in the tissues of fish, birds and people.
PBDEs also have been found at high levels in indoor dust, sewage sludge, and effluents from wastewater treatment plants. Human health concerns include thyroid hormone disruption and problems in the development of the central nervous system. PBDEs also have caused cancer in lab animals.
The Ecology study specifically looked at fish tissues from the Spokane River as part of a larger USGS osprey study in the Columbia River basin to determine whether PBDE levels were affecting the reproductive success of ospreys. Ecology researchers studied fish tissues from sport fish such as mountain whitefish and also from largescale suckers, the primary diet of osprey. They took their samples from six reaches of the river from the Idaho border through Lake Spokane.
“The mountain whitefish generally have more PBDEs in their tissues than suckers do,” said Chad Furl, the primary Ecology researcher on the fish tissue study project. “The ospreys usually go for the suckers, probably because they are slow and they hang out in shallow water, so they’re easier to catch.”
Fish tissue concentrations were highest in the Nine Mile area, downriver from Spokane. They were about six times higher than at Mission Park, east (upriver) of Spokane, and they were higher in sport fish than in largescale suckers. This suggests major contributions may be coming from Spokane.
But when compared with samples taken in 2005 at the same locations, the concentrations in the fish tissue samples collected in 2009 were lower, in some cases by more than 50 percent. Similar findings were reported for osprey eggs from other locations in the Columbia basin. Spokane River eggs were only collected in 2009.
The USGS found PBDEs in all 175 osprey eggs collected from the Columbia River basin between 2002 and 2009. Scientists consider that PBDE egg concentrations over 1,000 parts per billion (ppb) may reduce osprey reproductive success. Only two of the osprey eggs collected from the Spokane River sampled in 2009 contained more than 1,000 ppb PBDEs. This study appears in the journal Ecotoxicology.
In the study of Columbia River osprey, primary author Chuck Henny, a USGS research biologist in Corvallis, Ore., said: “We found no evidence that the egg concentrations in 2009 were harming the ospreys’ reproduction. Additional monitoring would help define trends with PBDE concentrations and provide additional understanding of the relationship between PBDEs and reproductive health in the osprey.”
PBDE levels have decreased in osprey eggs by 55 percent along the upper Willamette River between 2006 and 2008 and 46 percent between 2007 and 2009 in the lower Columbia River.
In Spokane, Ecology’s urban waters team is actively looking for sources of PBDEs by tracing pipes back from places on the river where testing has shown higher levels of PBDEs. In 2007, the state Legislature funded the Urban Waters Initiative to look for the sources of PBDEs and other harmful chemicals in the Spokane River.
Ecology urban waters specialist Arianne Fernandez said, “We are sampling the stormwater and combined sewer overflow that goes directly to the river to identify the areas of town where we should concentrate our efforts. The only way we can stop the pollution is to find where it’s coming from first.”
The urban waters team and Ecology’s Water Quality Program are working with the city of Spokane’s wastewater treatment plant staff on tracing PBDE sources in the city’s system.
In 2007, the Washington State Legislature passed legislation prohibiting certain PBDEs in products in Washington state. As of Jan. 1, 2011, all computers, televisions, and upholstered furniture sold in Washington must be PBDE-free. This ban on deca-BDE (a type of PBDE) was the first ban in the country. Two other forms of PBDEs (penta and octa) were voluntarily taken off the U.S. market in 2004.