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PUBLIC HEALTH ASSESSMENT

LOWER DUWAMISH WATERWAY
SEATTLE, KING COUNTY, WASHINGTON


APPENDIX C: EXPOSURE ASSUMPTIONS (Cont.)

Table C7.

Cancer dose calculations for consumption of fish groups from the Lower Duwamish Waterway, Seattle, Washington
Receptor Population Fish Group Contaminant Concentration a Estimated Dose (mg/kg-day) Cancer Slope Factor
(mg/kg-day-1)
Cancer Risk
Average API High-end Average API High-end Average API High-end
Fish Consumers Anadromous Arsenic 1 1.2 1.2 2e-05 3e-05 2e-04 1.5 2e-05 4e-05 2e-04
cPAHs 41 44 44 6e-06 1e-05 6e-05 7.3 4e-05 7e-05 4e-04
Chlordane 1.2 1.3 1.3 2e-07 3e-07 2e-06 0.35 6e-08 1e-07 6e-07
DDE 19 22 22 6e-06 1e-05 6e-05 0.34 2e-06 3e-06 2e-05
Total PCBs 55 56 56 8e-06 1e-05 8e-05 2 2e-05 3e-05 2e-04
Sum of Cancer Risks 9e-05 1e-04 9e-04
Pelagic Arsenic 1.3 1.4 1.4 4e-06 5e-05 4e-05 1.5 6e-06 7e-05 7e-05
cPAHs NA NA NA NA NA NA 7.3 NA NA NA
Chlordane NA NA NA NA NA NA 0.35 NA NA NA
DDE NA NA NA NA NA NA 0.34 NA NA NA
Total PCBs 111 140 140 3e-06 5e-05 4e-05 2 6e-06 1e-04 9e-05
Sum of Cancer Risks 1e-05 2e-04 1e-04
Benthic Arsenic 10.9 12.1 12.1 2e-05 1e-04 4e-04 1.5 3e-05 2e-04 6e-04
cPAHs 26 41 41 5e-07 5e-06 1e-05 7.3 3e-06 3e-05 9e-05
Chlordane 1.1 1.3 1.3 2e-08 2e-07 4e-07 0.35 7e-09 5e-08 1e-07
DDE 2.7 5.9 5.9 5e-08 7e-07 2e-06 0.34 2e-08 2e-07 6e-07
Total PCBs 267 312 312 5e-06 4e-05 1e-04 2 1e-05 7e-05 2e-04
Sum of Cancer Risks 4e-05 3e-04 8e-04
Shellfish Arsenic 0.8 0.9 0.9 3e-05 7e-05 3e-04 1.5 4e-05 1e-04 5e-04
cPAHs 42 43 43 1e-05 3e-05 1e-04 7.3 1e-04 2e-04 1e-03
Chlordane 3.4 3.4 3.4 1e-06 3e-06 1e-05 0.35 4e-07 9e-07 4e-06
DDE 0.7 0.7 0.7 2e-07 5e-07 3e-06 0.34 8e-08 2e-07 9e-07
Total PCBs 29 34 34 9e-06 3e-05 1e-04 2 2e-05 5e-05 2e-04
2e-04 4e-04 2e-03

Note - Doses are reported in scientific notation format. For example, 1e-02 is the same as 1 x 10-2 or 0.01.

Fish Consumption Limits

Several contaminants of concern are present in fish from the LDW; therefore, the most conservative recommended fish ingestion rate is the amount of a fish that one can consume that results in a hazard index of 1.0. However, all the contaminants of concern in fish do not have the same toxic effects, so it may not be appropriate to determine consumption limits based on the hazard index for all COCs. Therefore, consumption limits were calculated based on developmental and immunologic endpoints for PCBs, mercury, and DDE. Consumption rates were calculated for both average and high-end estimates of contaminant concentration for each species using Equation C3 in conjunction with the MRL or RfD as the target risk value and the exposure parameters provided in the table below. The developmental and immunologic endpoints are based on the additive effects of PCBs, mercury, and DDE as recommended in the draft ATSDR interaction profile for toxic contaminants found in fish. Table C9 provides fish consumption rates that would be protective of people who eat fish from the LDW.

Recommended fish consumption (meals per month) equals RfD or MRL times 30.4 times BW divided by meal size times C

Table C8.

Exposure parameters used to calculate recommended Lower Duwamish Waterway fish consumption limits
Exposure Parameter Endpoint Units
Developmental Immunologic
Concentration ) variable variable ug/kg
Minimal Risk Level (MRL) -PCBs 0.03 0.02 ug/kg/day
mercury 0.1 0.3
DDE 2 2
Days per month 30.4 30.4 days/month
Body Weight (BW) 60 70 kg
Meal size 0.227 0.227 kg

Many factors must be considered when recommending limits on the consumption of fish including the very real health benefits of eating fish, quality and comprehensiveness of environmental data and availability of alternate sources of nutrition. In addition, these limits do not consider that multiple species are consumed, which would require weighting of the percent of each species consumed. These allowable ingestion rates do not consider the fact that cooking reduces exposure to contaminants in fish. Therefore, allowable consumption limits for prepared fish would be greater than those shown in the tables below.

The consumption limits in the tables below also do not account for the fact that the majority of fish consumers are not likely to obtain all of their seafood from the LDW. Some fish from other areas of Puget Sound or the Pacific Ocean are likely to contain lower levels of contaminants; therefore, more fish meals than shown in the tables would be acceptable. Recommendations regarding consumption of fish can be found in the recommendations section of this health assessment.

Table C9.

Adult fish consumption limits for the Lower Duwamish Waterway, Seattle, Washington based on exposure to, PCBs, mercury, and DDE a
Fish Species Recommended 8 ounce meals per month
(Developmental Endpoint)
Recommended 8 ounce meals per month
(Immune Endpoint)
Average 95 UCL Average 95 UCL
English Sole 0.9 0.7 0.7 0.6
Rockfish 0.6 0.5 0.6 0.5
Coho 5.0 4.3 4.8 3.9
Chinook 2.9 2.4 3.2 2.6
Red Rock Crab 1.9 1.4 1.6 1.2
Dungeness Crab 1.5 1.1 1.4 1.0
Mussels 7.5 6.3 6.3 5.4
Perch 2.1 1.7 1.7 1.3

a = Consumption limit based on a target hazard index of 1.0.

Direct Contact with Sediment

Upper-bound exposure scenarios were evaluated for direct contact with sediment from the LDW site. Because recreational and crabbing activities occur at a few select areas, site specific sediment contaminant concentrations were used to estimate exposure. Exposure assumptions given in Table C10 below were used with the equations below to estimate contaminant doses associated with direct sediment contact. Doses received from the ingestion and dermal routes were summed to obtain a single dose associated with direct sediment contact.

Ingested Dose sub non-cancer (mg/kg-day) equals CS times IR times CF sub 1 times EF times ED divided by BW times AT sub non-cancer

Dermal Dose sub non-cancer (mg/kg-day) equals CS times AF times ABS times AD times CF sub 2 times EF times ED times SA divided by ORAF times BW times AT sub non-cancer

Ingested Dose sub cancer (mg/kg-day) equals CS times IR times CF sub 1 times EF times ED divided by BW times AT sub cancer

Dermal Dose sub cancer (mg/kg-day) equals CS times AF times ABS times AD times CF sub 2 times EF times ED times SA divided by ORAF times BW times AT sub cancer

Table C10.

Exposure assumptions used to estimate contaminant doses from direct contact with Lower Duwamish Waterway sediments
Parameter Units Tribal Netfishing Recreational a Shellfishing/Crabbing b
Sediment Concentration (CS) mg/kg 95th UCL of LDW sediments 95th percentile of site specific sediments 95th percentile of site specific sediments
Soil Ingestion Rate (IR) mg/day 50 200 50
Conversion Factor (CF1) kg/mg 0.000001 0.000001 0.000001
Exposure Frequency (EF) days 30/119c 41g 52
Exposure Duration (ED) years 10/44c 5 25
Body Weight (BW) kg 41/72d 15 41/72d
Averaging Time (AT) -non-cancer days 3650/16060 1825 9125
Averaging Time (AT) cancer days 27375 27375 27375
Surface Area (SA) cm2 2900/3850e 2000 2900 / 5700e
Adherence Factor (AF) mg/cm2 0.25f 0.2 0.25
24 hr Absorption Factor (ABS) unitless Chemical Specific:

SVOCs - 0.1
Arsenic 0.03
Inorganic - 0.01
PAHs - 0.13
PCBs - 0.14

Conversion Factor (CF2) kg/mg 0.000001 0.000001 0.000001
Adherence Duration (AD) days 1 1 1
Oral route adjustment factor unitless 1 1 1

a = Recreational exposure doses were calculated using concentrations terms specific to particular areas of the river accessed by the public based on community outreach information.
b = Shellfishing exposure doses were calculated using concentration terms specific to intertidal sediments surrounding Kellogg Island
c = 119 days of fishing for 44 years reported by Muckleshoot Tribe, and 30 days per year during childhood for 10 years (worst-case) based on communication with Suquamish and professional judgement.
d = Body weights an older child and adult used in scenario
e = Surface areas of older child and adult used in scenario
f = Adjusted from Reed Gatherer population (Exposure Factors Handbook EPA)
g = EPA comments to LDWG January 23, 2002

Many of exposure assumptions used in calculating exposure doses were based on default values provided in the Exposure Factors Handbook Volumes I and III. Adjustments were made to some of these assumptions based on site specific information and professional judgement. In the tribal netfisher exposure scenario, fisher people were adults participating in this occupation for 44 years over the period of their lifetime. It was assumed that netfishing occurs on the river as many as 119 times per year based on comments provided by the Muckleshoot Tribe on the LDWG scoping document (Muckleshoot). The 95th UCL concentrations of combined intertidal and subtidal sediments from the entire LDW were considered when calculating netfisher's exposures to each of the contaminants of concern. An exposure dose was also calculated accounting for children that accompany adult fisher people considering comments from the Suquamish Tribe. In this scenario, it was assumed that children were fishing 30 days per year for 10 years. The resulting exposure doses were summed with those of the adult scenario to provide a worst-case dose estimate.

The surface area of skin (SA) exposed was based on the assumption that fisher people had exposed face, neck, hands, forearms, and lower legs in the warmer months (~ 5700 cm2), and face and hands in the cooler months (~2000 cm). It was assumed that half of the fishing season was conducted during the warmer months and half in the cooler months for an average surface area of 3850 cm2. This is likely an overestimate of exposed skin because the Suquamish Tribe fishers claim that they wear full impermeable pants and jackets as well as work gloves year- round.

The adherence factor (AF) for fisher people was weighted by body part based on the reed gatherer population presented in Exposure Factors Handbook (EFH). There was no reported AF for the face or neck in the study, so a gardening scenario was chosen to approximate AF for those portions of the body.

It should be noted that RfDs and oral cancer potency factors are not available for the dermal route of exposure. While a dermal dose represents the amount that is absorbed into the body, an oral dose is the amount that is ingested. In most cases, only a fraction of the ingested dose is absorbed through the gastro-intestinal tract. The fraction that is absorbed in the gut depends largely on the chemical and the medium in which it is ingested (e.g., food, water, soil, etc.) RfDs and oral cancer potency factors are often based on the amount that an animal/human ingests orally, not the amount that is absorbed in the gut. Dermal doses are based on the amount absorbed through the skin. Therefore, using the oral RfD in conjunction with a dermal dose may underestimate the potential for adverse health effect to result from dermal exposure. Adjustment factors can be applied to account for the difference in exposure routes, but in the case of the LDW sediment contaminants of concern, Risk Assessment Guidance for Superfund part E does not recommend an adjustment for these chemicals.

Table C11.

Noncancer hazard calculations for exposure to Lower Duwamish Waterway sediment
Receptor Population Media Contaminant 95 UCL Concentration
(ppm)
Exposure Route Estimated Dose
(mg/kg-day)
MRL/RfD
(mg/kg-day)
Hazard Quotient
Tribal netfisher Intertidal and Subtidal Sediment Arsenic 16 Ingestion/Dermal Contact 6e-06 3e-04 2e-02
Cadmium 1.6 4e-07 1e-03 4e-04
Chlordane 0.014 4e-09 5e-04 8e-06
PCBs 2.2 2e-06 2e-05 9e-02
Mercury 0.29 8e-08 1e-04 8e-04

Hazard Index

1e-01
Tribal netfisher
(child to adult)
Intertidal and Subtidal Sediment Arsenic 16 Ingestion/Dermal Contact 8e-06 3e-04 3e-02
Cadmium 1.6 1e-06 1e-03 1e-03
Chlordane 0.014 1e-08 5e-04 2e-05
PCBs 2.2 4e-06 2e-05 2e-01
Mercury 0.29 2e-07 1e-04 2e-03

Hazard Index

3e-01
Children playing at Duwamish River Park Intertidal Sediment Arsenic 11 Ingestion/Dermal Contact 2e-05 3e-04 6e-02
Cadmium 0.4 6e-07 1e-03 6e-04
Chlordane NA NA 5e-04 NA
PCBs 0.7 1e-06 2e-05 7e-02
Mercury 0.3 5e-07 1e-04b 5e-03

Hazard Index

1e-01
Children playing at Gateway Park - South Intertidal Sediment Arsenic 16 Ingestion/Dermal Contact 3e-05 3e-04 9e-02
Cadmium 0.3 5e-07 1e-03 5e-04
Chlordane NA NA 5e-04 NA
PCBs 0.4 8e-07 2e-05 4e-02
Mercury 0.2 3e-07 1e-04b 3e-03
Hazard Index 1e-01
Children playing at Gateway Park - North Intertidal Sediment Arsenic 12 Ingestion/Dermal Contact 2e-05 3e-04 7e-02
Cadmium 0.7 1e-06 1e-03 1e-03
Chlordane NA NA 5e-04 NA
PCBs 0.5 1e-06 2e-05 5e-02
Mercury 0.2 3e-07 1e-04b 3e-03
Hazard Index 1e-01
Children playing along Boeing View Trail Intertidal Sediment Arsenic 14 Ingestion/Dermal Contact 2e-05 3e-04 8e-02
Cadmium 2 3e-06 1e-03 3e-03
Chlordane NA NA 5e-04 NA
PCBs 2.6 5e-06 2e-05 3e-01
Mercury 0.935 1e-06 1e-04b 1e-02

Hazard Index

4e-01
Crabfishers near Terminal 105 Intertidal and Subtidal Sediment Arsenic 17 Ingestion/Dermal Contact 7e-06 3e-04 2e-02
Cadmium 8 3e-06 1e-03 3e-03
Chlordane NA NA 5e-04 NA
PCBs 0.5 5e-07 2e-05 3e-02
Mercury 0.5 2e-07 1e-04b 2e-03

Hazard Index

5e-02
Children playing along Herring's House Park Intertidal Sediment Arsenic 18 Ingestion/Dermal Contact 3e-05 3e-04 1e-01
Cadmium 0.7 1e-06 1e-03 1e-03
Chlordane NA NA 5e-04 NA
PCBs 0.8 2e-06 2e-05 8e-02
Mercury 0.2 3e-07 1e-04b 3e-03

Hazard Index

2e-01
Shellfishers at Kellogg Island Intertidal Sediment Arsenic 18 Ingestion/Dermal Contact 8e-06 3e-04 3e-02
Cadmium 0.8 2e-07 1e-03 2e-04
Chlordane NA NA 5e-04 NA
PCBs 0.8 8e-07 2e-05 4e-02
Mercury 0.3 1e-07 1e-04b 1e-03

Hazard Index

7e-02

95 UCL = 95th upper confidence limit on the mean assuming a normal distribution. Public access scenarios used 95th percentile of intertidal sediment samples located within 1000 ft of access area
Note - Doses are reported in scientific notation format. For example, 1e-02 is the same as 1 x 10-2 or 0.01.


Table C12.

Cancer risk calculations for exposure to Duwamish River sediment
Receptor Population Media Contaminant 95 UCL Concentration
(ppm)
Exposure Route Estimated Dose
(mg/kg-day)
Cancer Potency Factor) Cancer Risk EPA Cancer Group
Tribal Netfishers Intertidal and Subtidal Sediment Arsenic 16 Ingestion/Dermal Contact 3e-06 1.5 5e-06 A
Chlordane 0.014 2e-09 0.35 1e-09 B2
cPAHs 0.61 3e-07 7.3 2e-06 B2
DDE 0.009 3e-08 0.34 1e-08 B2
PCBs 2.2 1e-06 2 2e-06 B2

Sum of Cancer Risks

9e-06
Tribal Netfishers (child to adult) Intertidal and Subtidal Sediment Arsenic 16 Ingestion/Dermal Contact 5e-06 1.5 7e-06 A
Chlordane 0.014 3e-09 0.35 2e-09 B2
cPAHs 0.61 3e-07 7.3 2e-06 B2
DDE 0.009 5e-08 0.34 2e-08 B2
PCBs 2.2 1e-06 2 3e-06 B2
1e-05

95 UCL = 95th upper confidence limit on the mean assuming a normal distribution.
Note - Cancer risks are reported in scientific notation format. For example, 1e-02 is the same as 1 x 10-2 or 0.01.


Table C12 Continued.

Cancer risk calculations for exposure to Duwamish River sediment
Receptor Population Media Contaminant Maximum Concentration
(ppm)
Exposure Route Estimated Dose
(mg/kg-day)
Cancer Potency Factor) Cancer Risk EPA Cancer Group
People recreating at Duwamish River Park Intertidal Sediment Arsenic 11 Ingestion/Dermal Contact 1e-06 1.5 2e-06 A
Chlordane NA NA 0.35 NA B2
cPAHs
0.2
4e-09 7.3 3e-08 B2
DDE NA NA 0.34 NA B2
PCBs 0.7 5e-08 2 1e-07 B2

Sum of Risks

2e-06
People Recreating at Gateway Park - South Intertidal Sediment Arsenic 16 Ingestion/Dermal Contact 2e-06 1.5 3e-06 A
Chlordane NA NA 0.35 NA B2
cPAHs 1.21 2e-08 7.3 2e-07 B2
DDE NA NA 0.34 NA B2
PCBs 0.4 3e-08 2 6e-08 B2

Sum of Cancer Risks

3e-06
Gateway Park-North Intertidal Sediment Arsenic 12 Ingestion/Dermal Contact 1e-06 1.5 2e-06 A
Chlordane NA NA 0.35 NA B2
cPAHs
1.8
2e-07 7.3 1e-06 B2
DDE NA NA 0.34 NA B2
PCBs 0.5 6e-08 2 1e-07 B2

Sum of Cancer Risks

2e-06
Boeing View Trail Intertidal Sediment Arsenic 15 Ingestion/Dermal Contact 1e-06 1.5 2e-06 A
Chlordane NA NA 0.35 NA B2
cPAHs
2.3
2e-07 7.3 2e-06 B2
DDE NA NA 0.34 NA B2
PCBs 2.6 3e-07 2 6e-07 B2

Sum of Cancer Risks

5e-06
Crab fishing near Terminal 105 Intertidal and Subtidal Sediment Arsenic 17 Ingestion/Dermal Contact 1e-06 1.5 2e-06 A
Chlordane NA NA 0.35 NA B2
cPAHs
1.57
3e-07 7.3 2e-06 B2
DDE 0.004 NA 0.34 NA B2
PCBs 0.5 8e-08 2 2e-07 B2

Sum of Cancer Risks

4e-06
Children playing near Herring's House Park Intertidal Sediment Arsenic 18 Ingestion/Dermal Contact 2e-06 1.5 3e-06 A
Chlordane NA NA 0.35 NA B2
cPAHs
0.27
5e-09 7.3 4e-08 B2
DDE NA NA 0.34 NA B2
PCBs 0.8 6e-08 2 1e-07 B2

Sum of Cancer Risks

3e-06

Shellfishers near Kellogg Island Intertidal Sediment Arsenic 18 Ingestion/Dermal Contact 1e-06 1.5 2e-06 A
Chlordane NA NA 0.35 NA B2
cPAHs
0.64
1e-07 7.3 7e-07 B2
DDE NA NA 0.34 NA B2
PCBs 0.8 1e-07 2 3e-07 B2

Sum of Cancer Risks

3e-06

95th percentile of intertidal sediment samples located within 1000 ft of access area
Note - Doses are reported in scientific notation format. For example, 1e-02 is the same as 1 x 10-2 or 0.01.


APPENDIX D: COMMUNITY INTERVIEW QUESTIONS

1. Do you know people who fish in the river?

2. Have you heard about people eating fish, shellfish or crab from the Duwamish River?

3. How often do they eat fish from the river? Daily? 2 times a week? Weekly?

4. Do people eat the organs of the fish? The liver? The head?

5. Do you know anyone who has become sick from eating the seafood?

6. Have you heard any stories about fish that look different or unusual from the river?

7. Do you or does anyone in your family have health concerns regarding the Duwamish River?


APPENDIX E:

PUBLIC HEALTH HAZARD CONCLUSION CATEGORIES
Category Definition
1. Urgent Public Health Hazard This category is used for sites where short-term exposures (<1 yr) to hazardous substances or conditions could result in adverse health effects that require rapid intervention.
2. Public Health Hazard This category is used for sites that pose a public health hazard due to the existence of long-term exposures (>1 yr) to hazardous substances or conditions that could result in adverse health effects.
3. Indeterminate Public Health Hazard This category is used to sites in which "critical" data are insufficient with regard to extent of exposure and/or toxicologic properties at estimated exposure levels.
4. No Apparent Public Health Hazard The category is used for sites where human exposure to contaminated media may be occurring, may have occurred in the past, and/or may occur in the future, but the exposure is not expected to cause any adverse health effects.
5. No Public Health Hazard This category is used for sites that, because of the absence of exposure, do NOT pose a public health hazard.


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