Lower Duwamish

Waterway Superfund Site

Proposed PlanApril 15, 2013

ESC, LLC

Dr. Peter deFur

Four Cleanup Objectives

Protect people from contaminated fish

Protect people from contaminated sediment

Protect wildlife from contamination

Protect bottom dwelling animals

http://bioweb.uwlax.edu/bio203/s2009/lu

chterh_wesl/dungcrab.jpg

Protect Wildlife from Contaminants

Protect animals that live on the bottom

Proposed Plan pg. 49

Dredging: removal

Enhanced recovery: additives

Capping: cover

Natural recovery: Let It Be

Institutional Controls – no fishing

Few options to clean up the river...

The Preferred Alternative (5C Plus) will address approx. 412 acres

Not including 29 acres of cleanup in Early Action Areas (EAAS)

?Institutional Controls – such as fish advisories?

Preferred Alternative Remediation Elements

84

24

48256

Dredging

Capping

Enhanced NaturalRecovery

Monitored NaturalRecovery

For more

comparison of

alternatives see

Proposed

Plan, Figure 14

pg. 63

62%

20%

6%

12%

Permanence

Certa

inty

Dredge

Cap

Enhanced natural recovery

Monitored natural recovery

1E-08

1E-07

1E-06

1E-05

1E-04

1E-03

1E-02

1 meal every other month

1 meal per month

1 meal per week

3 meals per week*

Excess C

an

cer

Ris

ks f

or

PC

Bs

Risks at LDW baseline concentrations

The shaded area indicates EPA's acceptable excess

cancer risk range under CERCLA. The dotted line

indicates the MTCA threshold for individual carcinogens.

1 in 100

1 in

100,000,00

0

1 in

1,000,00

0

1 in

10,000

Excess Cancer Risks for PCBs for Tribal Child

Source: EPA, Hiltner, April 5, 2013

0

2

4

6

8

10

12

14

1 meal every other month

1 meal per month

1 meal per week

3 meals per week*

No

n-C

an

cer

HQ

s f

or

PC

Bs HQ at LDW baseline concentrations

HQ at model-predicted steady-state concentration

The dotted line indicates the CERCLA

and MTCA non-cancer threshold.

8127

Non-cancer hazard quotients for PCBs for Tribal child

Source: EPA, Hiltner, April 5, 2013

Source Control from many places

Proposed Plan pg. 4

Figure 1

Lower Duwamish Waterway and Early Action Areas

Sources from the Green River

Map of relevant locations on the Green River upstream of the Lower Duwamish Waterway Superfund Site in Seattle, WA

Quality Assurance Project Plan (QAPP) pg. 11

Questions?????

At the end