Oregon and Washington health officials this week issued fish consumption advisories for certain species from two sections of the Columbia River due to elevated levels of mercury and polychlorinated biphenyls (PCBs) found in fish tissue.
Migratory fish like salmon, which pass down the big river as juveniles on their way to the Pacific and then again upstream as adults to spawn, should still be on the menu.
But so-called “resident fish” – stocks like bass, walleye and sturgeon that spend their entire life in the river section near Bonneville Dam – should not be eaten, while consumption of the fish living farther upstream between Bonneville and McNary Dam, should be limited. Resident fish are more likely to absorb contaminants in the water and river bottom sediments.
Tribal leaders immediately called for state and federal responses to the fish contaminant issues. Salmon and steelhead are core to the tribes’ high fish-consuming diets, but so are resident fish, particularly sturgeon.
Together, the two advisories, jointly issued Monday by the Oregon Health Authority and the Washington Department of Health, extend from Bonneville Dam at river mile 146 upstream 150 miles to McNary Dam. Public health officials do not know how long the advisories will last.
“Their hallmark is their persistency,” the OHA’s health toxicologist, David Farrer said of toxic chemicals such as PCBs that were engineered to last and used primarily in industrial applications.
“They were banned in the 1970s and we’re still dealing with their effects,” said the Oregon Department of Environmental Quality’s Aaron Borisenko. And PCBs also linger in long-lived fish such as the sturgeon.
The reason for the advisories is that mercury and PCBs built up in resident fish like bass, bluegill, yellow perch, crappie, walleye, carp, catfish, suckers and sturgeon that stay in the area and are exposed over their lifecycles. People who eat too much contaminated fish can suffer negative health effects over time such as damage to organs, the nervous system and reproductive system.
The advisories do not affect migratory fish species such as salmon, steelhead, American shad and lamprey, which should remain part of a healthy diet, the state health organizations say.
The advisories are as follows:
-- Bonneville Dam – OHA and WA Health recommend no consumption of any resident fish species taken from Bonneville Dam to Oregon’s Ruckel Creek, one mile upstream from Bonneville Dam.
-- Middle Columbia River – OHA and WA Health recommend eating no more than one meal per week – four meals per month – of any resident fish species taken from the river between Ruckel Creek and McNary Dam.
The Bonneville Dam advisory was derived from smallmouth bass testing. The advisory was applied to all resident fish as a precaution because the PCB concentrations were so high in the smallmouth bass.
The middle Columbia advisory was based on smallmouth bass and largescale suckers sampling and analysis. They represent the two major categories of game fish: predatory fish that eat smaller fish (bass) and bottom feeders (suckers).
PCB contamination in fish sampled upstream of Ruckel Creek was much lower than those found in the Bradford Island area. Those above-Ruckel studies were conducted in 2009 by the ODEQ with funding help from the Environmental Protection Agency. The ODEQ study, summarized in a 2011 report, sampled 23 sites from Bonneville up to McNary Dam for ecological conditions and water quality in the water column as well as for fish contamination.
The studies of contamination in the Bonneville to Ruckel Creek area were conducted for the U.S. Army Corp of Engineers. Bonneville’s “backwater” essentially extends that one mile.
The source of much of the PCB contamination in the Bonneville area is believed to be an unregulated landfill maintained by the Corps at the east tip of Bradford Island for approximately 40 years until 1983. Bradford Island is amidst the Bonneville Dam complex. The Corps operates the dam.
During a 1996 internal environmental audit of Bonneville Dam, the Corps determined that the former unregulated landfill could pose threats to human health and the environment. A variety of assessment and cleanup activities have been conducted since.
Research conducted by the Corps in 2011 included the sampling of 19 bass collected in the dam forebay (near Bradford Island). Another 19 bass were collected in an upstream reference zone in the Cascade Locks, Ore.,-Stevenson, Wash., area.
The results showed that, as in the past, PCBs are the primary contaminants of concern. Of the 19 fish samples collected from the forebay, PCB concentrations in four of the fish were extremely high, up to 183 parts per million, according to data released in late July.
A safe level is considered less than one part per billion, according to environmental cleanup site information posted on the Oregon Department of Environmental Quality web site http://www.deq.state.or.us/lq/ECSI/ecsidetailfull.asp?seqnbr=2010.
The other 15 fish from the forebay had PCB concentrations ranging from 15 to 277 parts per billion. These concentrations are above the safe level, but are similar to PCB concentrations in the 19 fish found in a reference area.
The Corps, which operates the dam, used the east end of the island as a landfill and dumped electrical components and other debris in the river near the northeast corner of the island. Some of the equipment was highly toxic, containing chemicals that do not break down readily and can bioaccumulate in resident fish.
The last cleanup activity at the site was in 2007 when the Corps removed PCB-contaminated sediments from the river. The agency also removed PCB-containing electrical equipment from the river in 2000 and 2002. The most recent sampling of sediments, clams and smallmouth bass indicate that PCB concentrations are still too high to protect fish living nearby, and people who eat the fish.
“The highest fish (levels of contamination) were at least two times higher” around the Bradford site in 2011 than found in the most contaminated fish tested in 2006 for PCB levels, said Mike Gross, the Corps’ technical lead on the Bradford Island cleanup project.
“We expected the levels to go down, but they did not,” Gross said. Levels in the reference area upstream remained about the same. Mercury levels were above the state threshold but about the same in 2006 and 2011.
The state study showed that mercury levels in bass and largescale suckers sampled had a maximum level of 0.77, with an average of 0.26. The threshold in that area up to McNary Dam is 0.2.
“There the mercury is driving it,” more so than PCB, Farrar said of the upriver advisory.
The Corps has said it will conduct a feasibility study to identify and evaluate future clean-up actions at the dam.
That feasibility study is expected to be completed by the end of fiscal year 2014, roughly a year from now, according to Gross.
The ODEQ report on which the above-Ruckel advisory was based “showed that while the river’s fish and bank habitat is degraded, its water quality is generally good, with low levels of metals and organic compounds known as polyacromatic hyrdrocarbons. Unfortunately, bass and largescale sucker fish fillets sampled from the river as part of this study show accumulation of potentially harmful levels of mercury, chlorinated pesticides and other toxic or cancer-causing chemicals, including dioxins, furans, and PCBs.”
PCBs in fish tested by the state averaged about 20 parts/million, much lower than the Bonneville area.
But even the 20 is high compared to the advisory threshold of 0.047, Farrer said.
Unborn fetuses, nursing babies and small children are most vulnerable to the health effects of PCBs and mercury, so it is especially important that pregnant and nursing women follow this advice, according to a press release issued Monday by the OHA. Fetuses and babies exposed to high levels of mercury and PCBs can suffer lifelong learning and behavior problems. The state health agencies recommend all women of childbearing age (18 to 45) follow fish advisories.
Anglers also should not give resident fish caught from the middle Columbia River to others unless the recipients are aware of where the fish were caught, and they understand the recommendations in these fish advisories, the press release says.
Washington already has a statewide fish advisory that warns women of childbearing age to not eat northern pikeminnow (a native fish found up and down the Columbia River) and advises them to limit largemouth and smallmouth bass consumption (based on harvest location) due to elevated mercury levels.
For a map of those harvest locations go to: http://www.doh.wa.gov/CommunityandEnvironment/Food/Fish/Advisories.aspx
By issuing the advisories, health officials hope to increase the public’s awareness of fish species they should avoid or limit consumption of, and those they can keep eating. While it is important for people to know about contaminants in fish, it is equally important to keep fish on the table.
Health officials from both states continue to encourage people, including pregnant women, to eat a variety of fish as part of a healthy diet. Migratory fish such as salmon and steelhead are an essential source of protein, omega-3 fatty acids and other nutrients, and are low in contaminants.
“Our iconic salmon, steelhead and other migratory fish are fine,” said Farrer. “People still need to eat at least two meals of fish per week. We just want people to pay attention to these advisories and continue to eat migratory fish from these stretches of the river.”
He said that migratory fish spend most of their lives in the ocean, which tends to be cleaner than contaminated rivers because pollutants are so much more diluted in the large volume of water.
When these fish come back up through the rivers they are just quickly passing through contaminated areas and not eating much, since they are mainly focused on reproduction and not food at that point in their life cycle.
Recent tests of salmon caught in the Portland Harbor Superfund site in the lower Willamette River have shown levels of contaminants were very much lower than in resident fish species caught in the same area.
“Because salmon spend most of their lives at sea, pollution measured in them is a reflection of conditions in the ocean as opposed to conditions in contaminated areas of the Columbia or Willamette rivers,” Farrar said. “This is also why salmon caught in the Willamette River can be thought of as representative of salmon one would expect to catch in the Columbia River” since they are both returning from the Pacific Ocean.
To learn more online about why fish is good for you and get information about fish consumption advisories in Oregon, visit www.healthoregon.org/fishadv.
For information about Washington’s fish consumption advisories, visit http://www.doh.wa.gov/fish.
Most of the mercury that contaminates fish comes from household and industrial waste that is incinerated or released during the burning of coal and other fossil fuels, according to WDH.
Products containing mercury that are improperly thrown in the garbage or washed down drains end up in landfills, incinerators, or sewage treatment facilities. The mercury then leaches into the ground and water.
Once mercury enters the water and soil, it is naturally converted to methylymercury by bacteria. In water, the bacteria are eaten by plankton and other small creatures, which in turn are eaten by small fish, then larger fish. Mercury doesn't easily leave the body of an organism, so the amount of mercury builds up in species as they go up the food. Larger, older fish accumulate more contaminants than smaller,
The Corps in October 2007 completed the removal of 65 tons of sediment from a 0.83-acre area along the shoreline of Bradford Island, an oblong piece of land near the Oregon shore that anchors the north end of the hydro project's first power house and the south end of its spillway.
From the 1940s until about 1982, a landfill on Bradford Island's upstream tip was used to dispose of project waste materials like oil and grease, paint and solvents, scrap metals, mercury vapor lamps, cables and sand blast grit, according to the Corps. Some electrical transmission components like switchgear, insulators and possibly light ballasts were also placed in the landfill. Household waste came from a small community of homes used by construction workers and later project personnel until 1976.
The 2007 effort involved suctioning 2.2 million gallons of water and sediment from the river bottom and filtering to remove contaminants. The resulting filtered water that was returned to the river was non-detectable for PCBs at five parts per trillion, the Corps said. The captured sediment that was taken to a licensed landfill was non-detectable for PCBs at 80 parts per billion, far lower than originally estimated.
For more information see, CBB, Jan. 21, 2011, “Corps Report On Bradford Island Cleanup Says Contaminants Exceed ‘Risk Screening Levels”’http://www.cbbulletin.com/404187.aspx