1 Trace element loads in urbanized watersheds and the potential for treatment of NPS loads Lester McKee Sources Pathways and Loadings Workgroup May 22 nd 2007 San Francisco Estuary Institute Item #1

2 History 2000 – 2002: Study design and location developed and recommended by SPLWG WY 2003:CEP ($150k) WY 2004:RMP and CEP ($50k+75k) WY 2005:RMP, USACE/SCVWD, SCVURPPP ($50k + $100k + $23k) San Francisco Estuary Institute Item #1

3 Impetus May 15 th 2006 WG meeting. May 15 th 2006 WG meeting. Members asked about the trace metals data for Guadalupe and remarked they did not remember it being reported – Lester responded that there was three years of data and that we only reported it once (year 2). Members asked about the trace metals data for Guadalupe and remarked they did not remember it being reported – Lester responded that there was three years of data and that we only reported it once (year 2). Mike C asked what inter-annual variability might look like for contaminants other than Hg. Lester said that he thinks the Hg in the Guadalupe River would be more variable than sediment but he cannot say for other metals or the organics. Mike suggests that Lester do the analysis for the others. WG agreed it would be informative. Mike C asked what inter-annual variability might look like for contaminants other than Hg. Lester said that he thinks the Hg in the Guadalupe River would be more variable than sediment but he cannot say for other metals or the organics. Mike suggests that Lester do the analysis for the others. WG agreed it would be informative. Nov 13 th WG meeting. Nov 13 th WG meeting. Try to write future reports so that there is a better connection to management alternatives as an endpoint Try to write future reports so that there is a better connection to management alternatives as an endpoint San Francisco Estuary Institute Item #1

4 Sampling Location Area: 414 km 2 4 th largest watershed (8.4%) 178 km 2, upstream from reservoirs leaving 236 km 2 of which >78% is urban land use Population: 486,500 (7.2% of Bay Area) Highest elevation: Loma Prieta (1,155 m) Precipitation varies from 300-1,100mm and falls during winter (Nov-April: 89%) Annual Q: Mm 3 or approximately 1-640mm San Francisco Estuary Institute Item #1

5 Sampling Methods San Francisco Estuary Institute Item #1 USGS flow gage at Hwy 101 adjacent to SJ Airport Sampling based on hypothesis that SSC is a surrogate for predicting TE concentrations FTS Ltd. DTS 12 turbidity probe with wiper Water samples collected using D74 or DH48 and analyzed for SSC and GS LOESS regression used to generate continuous 15-minute SSC Water samples collected during floods using D95 and analyzed for total Ag, As, Cd, Cr, Cu, Ni, Pb, and Zn

6 QA/QC All samples run through the RMP QA/QC program 2, 3. Silver concentrations in these batches were considered marginally acceptable as the matrix spike and duplicate recoveries were within the data quality objectives. 4. These samples were not rejected because the matrix spike and duplicate recoveries were within the data quality objectives and more importantly they were not anomalous with respect to SSC San Francisco Estuary Institute Item #1

7 Loads Estimation Linear interpolation when storms are well samples Linear interpolation when storms are well samples Stratified regression estimator during other storms depending on the predominant source of runoff based on rainfall and runoff gauging information from further up the watershed: Stratified regression estimator during other storms depending on the predominant source of runoff based on rainfall and runoff gauging information from further up the watershed: Used lower watershed urban regression when water from there Used lower watershed urban regression when water from there Used upper watershed non-urban regression when water from there Used upper watershed non-urban regression when water from there Base flow: used upper watershed regression but choice made little difference to the annual loads estimation Base flow: used upper watershed regression but choice made little difference to the annual loads estimation San Francisco Estuary Institute Item #1

8 Error Analysis Errors accounted for during loads estimation were: Errors accounted for during loads estimation were: flow ( 10%) flow ( 10%) SSC ( 2%) SSC ( 2%) SSC-Turbidity regressions ( 2%) SSC-Turbidity regressions ( 2%) Interpolation / SSC-trace element specific regressions: Interpolation / SSC-trace element specific regressions: Ag: 23% Ag: 23% As: 31% As: 31% Cd: 13% Cd: 13% Cr: 13% Cr: 13% The mean coefficient of variation (CV) of duplicate field samples was: The mean coefficient of variation (CV) of duplicate field samples was: Ag: 46% Ag: 46% As: 4.9% As: 4.9% Cd: 13% Cd: 13% Cr: 7.3% Cr: 7.3% We did not include an error for variation in the cross section because this was accounted for within the USGS SSC records The total estimated errors for loads calculations were: SSC: 10% Ag: 52% As: 33% Cd: 21% Cr: 18% Note, that we have found no other papers that have quantified errors in loads calculations, yet clearly, claims of loads variation between years may not be valid San Francisco Estuary Institute Item #1 Cu: 10% Cu: 10% Ni: 13% Ni: 13% Pb: 7% Pb: 7% Zn: 14% Zn: 14% Cu: 4.3% Cu: 4.3% Ni: 6.2% Ni: 6.2% Pb: 3.6% Pb: 3.6% Zn: 2.3% Zn: 2.3% Cu: 15% Cu: 15% Ni: 17% Ni: 17% Pb: 13% Pb: 13% Zn: 17% Zn: 17%

9 Results – Precipitation and Runoff 30-year average (July 1st, June 30th, 2005): 388 mm and a coefficient of variation (CV) of year average (July 1st, June 30th, 2005): 388 mm and a coefficient of variation (CV) of 0.39 WY 2003: 100% WY 2003: 100% WY 2004: 90% WY 2004: 90% WY 2005: 164% WY 2005: 164% WY 2006: 150% WY 2006: 150% Storms were generally of low magnitude and duration with the exception of five storms (December 19th 2002; November 9th 2003; December 21st, 2003; December 27th, 2004; October 26th, 2004) Storms were generally of low magnitude and duration with the exception of five storms (December 19th 2002; November 9th 2003; December 21st, 2003; December 27th, 2004; October 26th, 2004) Runoff similar (MAR = 57.4 Mm 3 ): Runoff similar (MAR = 57.4 Mm 3 ): WY 2003: 106% WY 2004: 92% WY 2005: 128% WY 2006: 221% San Francisco Estuary Institute Item #1

10 Results – Concentration Statistics San Francisco Estuary Institute Item #1

11 Results – Concentration Scatter Plots San Francisco Estuary Institute Item #1

12 Results – Concentrations San Francisco Estuary Institute Item #1

13 Correlation Analysis San Francisco Estuary Institute Item #1 AsCdCrCuNiPb Cd 0.49**1 Cr Cu 0.33* 0.80**0.081 Ni **0.021 Pb 0.30* 0.79** ** Zn 0.39* 0.84** ** ** *p<0.01 **p<0.001 Groups: 1.Ag 2.As 3.Pb, Zn, Cd, Cu 4.Cr, Ni

14 Daily Loads San Francisco Estuary Institute Item #1

15 Annual Wet Season Loads San Francisco Estuary Institute Item #1

16 Guadalupe versus the World (Peer-reviewed Literature) San Francisco Estuary Institute Item #1 Ag – Hardly ever reported, Guadalupe similar Ag – Hardly ever reported, Guadalupe similar As – Reported previously in 9 urban watersheds, Guadalupe similar As – Reported previously in 9 urban watersheds, Guadalupe similar Cd – Reported previously in 19 urban watersheds, Guadalupe similar – but time trend in world literature Cd – Reported previously in 19 urban watersheds, Guadalupe similar – but time trend in world literature Cr – Reported previously in 29 urban watersheds, Guadalupe greater except 2 industrial watersheds Cr – Reported previously in 29 urban watersheds, Guadalupe greater except 2 industrial watersheds Cu – Reported previously in 34 urban watersheds, Guadalupe similar Cu – Reported previously in 34 urban watersheds, Guadalupe similar Ni – Reported previously in 20 urban watersheds, Guadalupe greater except 1 industrial watershed and 1 high density residential watershed – but time trend evident Ni – Reported previously in 20 urban watersheds, Guadalupe greater except 1 industrial watershed and 1 high density residential watershed – but time trend evident Pb – Reported previously in 39 urban watersheds, Guadalupe similar – but time trend in world literature Pb – Reported previously in 39 urban watersheds, Guadalupe similar – but time trend in world literature Zn – Reported previously in 29 urban watersheds, Guadalupe similar Zn – Reported previously in 29 urban watersheds, Guadalupe similar

17 Cadmium Item #1 San Francisco Estuary Institute

18 Chromium Item #1 San Francisco Estuary Institute Guadalupe

19 Nickel Item #1 San Francisco Estuary Institute Guadalupe

20 Lead Item #1 San Francisco Estuary Institute Lee and Bang, 2000 – Korea Choe et al., 2002 Buffleben et al., 2002

21 Mahler et al., Trends in metals in urban and reference lake sediments across the United States, (ET&C 25, ) Cd decreased by 29% Cd decreased by 29% Cr decreased by 15% Cr decreased by 15% Ni decreased by 22% Ni decreased by 22% Pb decreased by 46% Pb decreased by 46% San Francisco Estuary Institute Item #1

22 Treatment Potential? San Francisco Estuary Institute A. 1 st storm only B. 1 st storm and largest flood C. All rising stage D. Peak shaving Item #1