Impairment Assessment and Conceptual Model of Legacy Pesticides:DDT, Chlordane, and Dieldrin

RMP Annual MeetingMay 4, 2004

Jon Leatherbarrow, Chris Werme, Mike Connor, Jay DavisSan Francisco Estuary Institute

Regulatory Status

Restricted/Banned

• DDT in the 1960s/70s• Chlordane and Dieldrin

in the 1970s/80s

SanPabloBay

SuisunBay

CentralBay

SouthBay

LowerSouthBay

Delta

CWA 303(d) List• 1994 Fish Advisory

(OEHHA)• All segments of SF Bay

listed as impaired

Carquinez Strait

Impairment Indicator – Fish2000 RMP Fish Monitoring Results

DDT

Pe

stic

ide

s in

Fis

h (

ng

/g)

0

20

40

60

80

100

120

Chlordane0

5

10

15

20

25

30

Dieldrin0

1

2

3

4

5

Fish Screening Value

POSSIBLEIMPAIRMENT

POSSIBLEIMPAIRMENT

IMPAIRMENTUNLIKELY

Impairment Indicator – Water2002 RMP Water Monitoring Results

No 2002 samples exceeded CTR water quality criteria for:

p,p’-DDEp,p’-DDDp,p’-DDTTotal ChlordaneDieldrin

0 10 20 30 40

Mas

s in

Bay

(kg

)

0

100

200

300

400

Years

60 kg

40 kg

20 kg

0 kg

DDT Forecast

1980 1990 2000

p,p'

-DD

E (

µg/

kg)

0

20

40

60

80

100

…and Historic Trends in Bivalves

Data Gaps and Potential Next Steps

1. Current trends in contamination? Sediment cores and continued fish monitoring

3. Pesticide loading & fate from tributaries? Central Valley; storms with Delta Outflow > 150,000 cfs Local Watersheds; clean-up, loading & BMP studies

4. Loading & fate of remobilized sediment in Bay? Further investigation; field studies, clean-up, bathymetry, modeling

2. Benefits from activities focused on reducing PCB contamination in the Bay?