Most toxic pollution falling onto Puget Sound’s waters has decreased – some by as much as 99 percent – below earlier estimates, according to a region-wide study. Despite the overall decline, the study found that industrial areas like Tacoma still have the Puget’s Sound’s highest air-deposited contamination levels. The study, by researchers at the Department of Energy’s Pacific Northwest National Laboratory and Texas A&M University at Galveston, found the amount of trace metals like arsenic, lead and copper falling onto the Tacoma region have decreased significantly since PNNL last measured air-deposited pollution there in 1991. But other contaminants like mercury showed a more modest decline of just 35 percent.
“Regulations and increased public focus on pollution prevention appear to be paying off,” said the study’s lead researcher, PNNL marine chemist Jill Brandenberger. “But our awareness of some chemicals wasn’t very high when those initial laws were passed decades ago. As a result, chemicals like flame retardants weren’t included, allowing them to accumulate in the Puget Sound.”
The study is helping the Washington state Department of Ecology update its measurements of all toxic sources for Puget Sound. Gov. Christine Gregoire and the state Legislature charged the Department of Ecology and the Puget Sound Partnership with restoring the Sound, which is burdened with pollutants and other problems. To do that, officials need to know how much and where pollution is entering the Sound. This prompted the Department of Ecology to measure toxics in the entire Puget Sound through projects such as the PNNL-led study.