The report, Evaluation of Fish Hatcheries as Sources of PCBs to the Spokane River, is now available at https://fortress.wa.gov/ecy/publications/SummaryPages/1803014.html 

Sections of the Spokane River, Little Spokane River, and Lake Spokane are currently listed as impaired for polychlorinated biphenyls (PCBs) on Section 303(d) of the Clean Water Act. To address the problem, the Spokane River Regional Toxics Task Force has been working with local entities to determine PCB sources and implement strategies to reduce PCBs in the system. One of the data gaps identified was the contribution of fish hatcheries to PCBs in the Spokane River via wastewater discharges and fish stocking. Previous studies have shown that hatchery fish can contain PCBs. 

The Department of Ecology undertook a screening-level study to evaluate hatchery contributions of PCBs to the Spokane River. The primary study objectives were to (1) characterize PCB concentrations in hatchery discharges and hatchery-raised rainbow trout and (2) estimate PCB loads from hatchery operations to the Spokane River. In 2016, we sampled discharges from the Spokane Hatchery and collected fish from the two hatcheries that stock trout to the river (Spokane Hatchery and a private hatchery in the town of Soap Lake). Water, whole fish tissue, fish feed, and sediment samples were analyzed for the 209 PCB congeners. 

PCBs were detected in all samples. PCB concentrations in hatchery discharges ranged from 147–219 pg/L. In feed samples, PCB concentrations ranged from 3.9–31.5 ug/kg. PCB concentrations in fish caught from Lake Spokane four months after their release were higher (20.5–28.7 ug/kg) than in pre-released fish (4.0–11.3 ug/kg), suggesting that most of the PCB body burden in post-released fish was accumulated after being released into the environment. The mean PCB load from hatchery operations was estimated to be 7.8 mg/day, most of which was represented by discharges from the Spokane Hatchery. 

If you have questions, contact Siana Wong at 360-407-6432 or swon461@ecy.wa.gov.