Contaminants at the Estuary Interface

Jon Leatherbarrow1

Rainer Hoenicke2

Lester McKee1

1San Francisco Estuary Institute

2California Resources Agency

Estuary Interface Pilot Study History

• EIP study 1996-1999

initiated with the goal of describing how surface runoff from local watersheds might influence water quality in the Bay.

• Final report – Available soon

Objectives

• Relate patterns of contamination near the bottom of the watersheds to patterns in the receiving waters of the Lower South Bay

• Explore what kinds of water quality parameters and watershed characteristics should be measured or described to improve tributary monitoring methodology

Sampling Design• Water - three samples per year

• Sediment - two samples per year

Parameters• Trace Elements

• Organics – PCBs, PAHs, Pesticides

• Water and sediment quality parameters

Total PCBs in Water (pg/L)

0

1000

2000

3000

4000

5000

6000

7000Wet seasonDry Season

Total Mercury in Water (µg/L)

0.001

0.01

0.1

1 Wet SeasonDry Season

Particulate Mercury and TSSWinter 1997-1999

TSS (mg/L)

10 100

Par

ticu

late

Mer

cury

(µ

g/L

)

0.001

0.01

0.1

1 Guadalupe River (BW15)Standish Dam (BW10)Bay Stations

Particulate p,p'-DDE and TSSWinter 1997-1999

TSS (mg/L)

1 10 100 1000

Par

ticu

late

p,p

'-D

DE

(pg/L

)

10

100

1000

10000 EIP StationsBay Stations

Particulate PCBs and TSSWinter 1997

TSS (mg/L)

0 50 100 150 200 250 300

Par

ticu

late

P

CB

s (p

g/L

)

0

1000

2000

3000

4000

5000EIP StationsSouth BayNorthern Estuary

Mercury in RMP Sediment (mg/kg)1996-1999

% Fines

0 20 40 60 80 100

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Guadalupe RiverStandish DamBay Stations

Conclusions• Concentrations of PCBs, PAHs, mercury, selenium,

DDTs, and chlordanes were high in water and/or sediment collected from one or both of the EIP stations relative to several other Bay segments.

• High wet-season concentrations in EIP water samples suggest that the tributaries were a likely pathway for all of these contaminants to the Lower South Bay.

• Mercury concentrations in Guadalupe River (BW15) water and sediment were most likely influenced by the historic mining activities in the New Almaden district.

• Several independent factors, such as TSS in the water column and grain size effects in sediment, account to some extent for variability in contaminant concentrations.

RMP Five-Year Review

• New RMP Objective“Describe general sources and loadings

of contamination to the Estuary”

• RMP Sources Pathways and Loadings Workgroup

Further Questions• How do contaminant concentrations vary during

conditions of peak streamflow and sediment transport?

• What is the magnitude of contaminant loading from the local watersheds?

• How does loading from the tributaries compare to other pathways of contamination?

• What are the specific sources of contamination in the local watersheds?

• What are the most effective management actions?

Next Steps• Develop network of tributary monitoring locations in

the fresh water reaches of selected watersheds.• Prioritize locations based on conceptual models,

recent and historic contaminant data, and watershed characteristics.

• Design monitoring to capture contaminant response to peak flow and sediment transport and quantify loading from the watersheds.

• Explore and develop indicators for determining sources and temporal trends in contaminant concentrations and loading.

• Compare watershed loading with other pathways of contamination in the context of refined mass budgets for contaminants of concern.

Acknowledgments• City of San Jose and Santa Clara Valley Urban

Runoff Pollution Prevention Program (SCVURPPP)• RMP Principal Investigators and Contractors

Applied Marine Sciences

Brooks Rand LaboratoriesCity and County of San FranciscoEast Bay MUDTexas A&M – Geochem. and Environ. Research Group UC Santa Cruz – Dept. of Environmental ToxicologyUniversity of Utah – Energy and Geoscience Institute

• Jay Davis, Don Yee, and members of the RMP Sources, Pathways, and Loadings Workgroup

• All reviewers of the EIP Study report