1 PCBs and PBDEs on the Guadalupe River WYs 2003 – 2006 John Oram, Jon Leatherbarrow, and Lester McKee Sources Pathways and Loadings Workgroup November 13 th 2006 Item #2b

2 Methods for Estimating Loads of PCBs and PBDEs 1.Examine relationship between instantaneous SSC and contaminant conc. 2.Examine spatial/temporal patterns of precip and Q at various locations in watershed to determine source. 3.Use 1 and 2 to build regression model(s) where appropriate. 4.Use regression model to estimate 15-minute concentrations. 5.Use 15-minute Q and 15-minute conc to calculate loads. Iterative Process Item #2b

3 WY 03 (n=21) WY 04 (n=19) WY 05 (n=13) WY 06 (n=14) Sampling Frequency Item #2b

4 Sampling Frequency Item #2b

5 PCBs vs SSC (previous water years) WY 2005 Item #2b

6 PCBs vs SSC WY 2006 Did not see split regression this water year. Item #2b

7 PBDEs vs SSC WY 2005 Item #2b

8 PBDE Concentrations, Discharge, and Instantaneous SSC Item #2b

9 PBDEs vs SSC WY 2006 Attempted to split regression by upper/lower/base flow designations. –Didnt work this year for PBDEs or PCBs Two Regressions: –All data –No Outlier Item #2b

10 Previously Reported Loads Item #2b

11 WY 2006 Loads Item #2b

12 Source ID by PCB Homologs? From WY05 Report Source activation of new PCBs during high flow? Transport of weathered material? Item #2b

13 Source ID by PBDE Homologs? Item #2b

14 How did WY05 and WY06 compare to previous years? Item #2b

15 How did WY05 and WY06 compare to previous years? Item #2b

16 April Kg PBDEs (52% of Seasonal Load) 30% of 2.21 kg delivered on April 4 th = 0.73 kg. Item #2b

17 PBDEPCB Source(kg/yr) Wastewater372.5 Small tributaries~ Delta~ Atmosphere1-2-7 Total~ Sources: RMP special study on wastewater discharges; L. McKee; CARB (2005); D. Yee Annual Loading Estimates PBDE loads are 3-11x PCB loads. Estimates or Preliminary! Item #2b

18 Modeling PBDEs *Predicted inventories are consistent with those estimated from monitoring. Source: J. Oram, SFEI Model predictions are preliminary. Loads Item #2b