The Dalles Wastewater Treatment Plant has discharged effluent into the Columbia River that exceeds the plant’s limit for E. Coli due to incomplete disinfection.  The Dalles Public Works Department says sample test results received Saturday confirmed that.  The cause is unknown at this point, and the frequency of sampling is being increased until E. Coli counts are back within permit limits.  Warning signs indicating contaminated water and advising no water contact are being placed at public river access points on the Oregon shore of the Columbia River from The Dalles Riverfront Park to the West Mayer Park boat launch.