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| Title | Quality Assurance Project Plan: Okanogan River DDT and PCB Total Maximum Daily Load Effectiveness Monitoring | |
| Month-Year Published | April 2009 | |
| Online Availability |
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| Short Description |
This is the plan for the Okanogan River DDT and PCB Total Maximum Daily Load Effectiveness Monitoring study. (Also see abstract below) | |
| Publication Number | 09-03-107 | |
| Author(s) | Coffin, C. | |
| Print Availability | ||
| Number of pages | 44 pp. | |
| Keywords | DDT, monitoring, Okanogan River, quality, quality assurance, quality assurance project plan, river, Total Maximum Daily Load | |
| Abstract | Long Description |
In 2003, the Washington State Department of Ecology (Ecology) published a Total Maximum Daily Load (TMDL) report for DDT and PCBs in the lower Okanogan River basin. The 2001-2002 sampling for the TMDL examined DDT and PCB concentrations in the water column of the mainstem Okanogan River and its tributary streams, in sewage treatment plant (STP) effluent and sludge, and in stream and lake bottom sediments. Composite samples of three fish species--carp (Cyprinus carpio), mountain whitefish (Prosopium williamsoni), and smallmouth bass (Micropterus dolomieui)-- were also analyzed for DDT and PCBs. Data from these samples and historical data were used to develop the TMDLs. Sampling results suggested that only small loads of DDT and PCBs are delivered to the lower Okanogan River through tributaries and STPs. No other specific sources of these pollutants were identified during the TMDL investigation. However, the small loads found in the water entering the lower Okanogan River contrast sharply with the actual measured loads found in fish from several reaches of the lower river. The TMDL loading analysis indicated that the bulk of pollutant loading was internal, presumably isolated in the bottom sediments of the river and Osoyoos Lake and eventually processed up through the food chain by smaller organisms to fish. Since all reasonable implementation activities to prevent the entry of these two legacy pollutants into the river system were already in place, the TMDL recommended continued monitoring of fish tissue for concentrations of DDT and PCBs. The concentrations in fish tissue will serve as a surrogate indicator of pollutant concentrations in the river and provide information to track trends over time. This document is a plan of how the monitoring of total DDT and PCBs in fish tissue from the lower Okanogan River was to be carried out in the summer of 2008. |
Copyright © Washington State Department of Ecology. See http://www.ecy.wa.gov/copyright.html.
