Wood product contamination found at numerous Clark Fork sites

Laura Lundquist

(Missoula Current) The first results of possible sawmill pollution in the Clark Fork River are in, and while the Smurfit Stone mill site could be a source, pollution is showing up elsewhere as well.

During the Thursday meeting of the Frenchtown Smurfit Stone Community Advisory Group, Fish, Wildlife & Parks pollution control biologist Trevor Selch presented water quality results collected by passive water samplers in local rivers last summer.

While pollution concentrations near the Smurfit site increased, pollution spikes were also found at other locations.

“We were looking for dioxins, furans and coplanar PCBs,” Selch said Thursday. “Dioxins are much more toxic than PCBs. I also looked at the biotic sediment accumulation factor, which is how easily they accumulate in the biota and in the fish in particular. Coplanar PCBs are so much more bioaccumulative than the dioxins, so that was the driving force behind the fishing advice.”

Dioxins, furans and dioxin-like PCBs often occur together, as a byproduct of pulp, paper or pesticide production, and can cause reproductive and developmental problems, damage the immune system and cause cancer in humans, fish and wildlife.

The Smurfit-Stone pulp mill produced bleached pulp for 39 years and the site contains more than one million tons of bleached pulp waste, which is a source of dioxins and furans. Groundwater and soil samples taken at the site contained dioxins and furans.

After fish were collected from the Clark Fork River in 2018 and 2019, fish tissue data showed that rainbow trout and northern pike carried enough toxins that FWP had to issue a new fish consumption advisory. A 2013 advisory warned people to avoid pike from the river below Missoula and limit trout to four meals a month. The 2019 advisory warned people to avoid all pike and rainbow trout in the Clark Fork River, from Bonner to St. Regis.

Since then, state administrators and the Community Advisory Group have asked the Environmental Protection Agency for more samples to learn more about whether the Smurfit Stone site is contributing to pollution in the Clark Fork River, which is contaminating fish.

In late 2022, Trout Unlimited received an EPA Columbia River Basin Restoration Funding Assistance Program grant worth more than $304,000 for additional water and fish tissue sampling in the Clark Fork River and beyond. Several organizations are involved in the effort, including FWP, the Department of Environmental Quality, Natural Resources Damages Program, Confederated Salish and Kootenai Tribes and the Clark Fork Coalition.

So last summer, biologists collected fish and water samples to assess contamination beyond what might have come from the Smurfit site. Selch said the fish tissue data is not yet available due to quality control procedures, but the data from the passive water samplers is.

In mid-July, technicians deployed passive water samplers at 19 locations, from the upper Clark Fork River above Anaconda to the Flathead River near Cabinet Gorge, and left them in the water for 30 days. Although they expected to lose a number of samplers due to vandalism or environmental factors, they managed to get eighteen back.

Passive water samplers are essentially lipid or fat pockets with semi-permeable membranes that slowly sample water, so they are better than a one-time sample for simulating how fish absorb pollutants in the water. This is especially important on free-flowing rivers where flows change and pollutants can be released at different times.

When Selch calculated the relative toxicity of the three types of pollutants at each site, he found peaks for dioxins and furans in the Clark Fork River downstream from Butte — which had the highest concentration — at Bearmouth and at Thompson Falls Reservoir.

High readings were also recorded at Harpers Bridge just above the Smurfit site and two locations downstream of the Smurfit site. Spikes also appeared on the Blackfoot River at Scotty Brown Bridge and on the Bitterroot River near Hamilton.

Selch said he could not explain the high readings upstream of the Smurfit site.

When Selch looked only at PCBs, the highest values ​​were in the Blackfoot River, just above the confluence with the Clark Fork, and on the Clark Fork River between Paradise and Plains. But there were significant readings just above the Smurfit site at Harpers Bridge, with readings increasing downstream to St. Regis, that could not be explained by upstream sources.

“The Blackfoot site is across from the Bonner Mill, so there may be a spring there. But by the time we get to Missoula, we just don’t see any signatures anymore,” Selch said.

As the Clark Fork River progresses from its headwaters west toward the Montana border, the river grows as more streams are added to its flow. Higher flows can dilute the concentration of pollutants, but fish can still be affected. To compensate for the flow, Selch calculated the pollution load (how many pounds of a contaminant is pushed downstream per day) at each location.

“As we go downstream, flows increase and overall concentration may decrease. But when we calculate the load, the load increases as we go downstream,” Selch said.

While it appears the Smurfit site may be contributing to the dioxins, furans and PCBs in the Clark Fork, Selch said the fish tissue data would provide more information. He hopes to release that information soon, perhaps at the next Community Advisory Group meeting.

In 2021, Jamie Holmes, consulting scientist and vice president of Abt Associates, told the Community Advisory Group that the primary PCB found in the EPA fish samples was PCB 126, the most toxic of 209 congeners. The US banned all PCB congeners in 1978 after their environmental toxicity and longevity were discovered.

Montsanto was the only American manufacturer and produced a number of PCBs under the trade name Aroclor for almost 50 years.

Contact Laura Lundquist at [email protected].