Table 11. Estrogenicity in wastewater-treatment-plant effluent samples, instantaneous loadings, and calculated concentrations in the Columbia River, Columbia River Basin, Washington and Oregon, December 2008.


[Station names are shown in table 2. Slight, estrogenic response was observed above the 99 percent confidence limits, but below a measurable threshold. A 7Q10 flow is not available for Umatilla, so 78,000 ft³/s is used for these calculations. Abbreviations: EEQ, estimated estradiol equivalents; ng E2/L, nanograms of 17β-estradiol per liter; ng E2/g, nanograms of 17β-estradiol per gram; Mgal/d, million gallons per day; 7Q10, the lowest streamflow for 7 consecutive days that occurs on average every 10 years; ft³/s, cubic foot per second; g/d, gram per day; –, not detected]


First posted April 25, 2012