Juvenile sturgeon that ingested slag from Teck Resources’ Trail, B.C., smelter had chronic inflammation in their guts, according to a federal study.
Thirty-seven juvenile sturgeon were captured in the upper part of Lake Roosevelt in October 2008. Scientists from the U.S. Geological Survey examined their digestive tracts to see what they were eating. Slag was present in 76 percent of the sturgeons’ guts.
Analysis of the gut tissues showed the presence of chronic inflammation. Bigger fish had more inflammation, suggesting a long-term exposure to one or more stress factors, the study said. However, additional research is needed to determine if physical or chemical properties from the slag contributed to the chronic inflammation, the scientists said.
Slag is a byproduct of the smelting process, which extracts metals from ore. Teck stopped discharging slag into the Columbia River in 1995. The U.S. Environmental Protection Agency estimates that the smelter dumped at least 23 million tons of slag into the Columbia over the past century.
Slag contains 25 different compounds, including iron, zinc, aluminum, manganese, copper, chromium, cobalt, arsenic, nickel, lead, cadmium, silver and mercury.