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HEALTH CONSULTATION

DUXBURY WATER DISTRIBUTION
DUXBURY, PLYMOUTH COUNTY, MASSACHUSETTS


APPENDIX A

Health assessors use a variety of health comparison values to help decide whether compounds may need further evaluation: Environmental Media Evaluation Guide (EMEG), Reference Dose Media Evaluation Guide (RMEG), and Cancer Risk Evaluation Guide (CREG). These comparison values have been scientifically peer-reviewed and published by the U.S. Agency for Toxic Substances and Disease Registry (ATSDR) and/or the U.S. Environmental Protection Agency (USEPA). EMEG and RMEG values are used to evaluate the potential for non-cancer health effects. CREG values provide information on the potential for carcinogenic effects. If the concentration of a chemical exceeds a health comparison value, adverse health effects are not necessarily expected. Rather, these comparison values help in selecting compounds for further consideration. For example, if the concentration of a chemical in a medium (i.e., air, water, or soil) is greater than the EMEG for that medium, the potential for exposure to the compound should be further evaluated for the specific situation to determine whether non-cancer health effects may be possible. Conversely, if the concentration is less than the EMEG, it is unlikely that exposure would result in non-cancer health effects. EMEG values are derived for different durations of exposure. Acute EMEGs correspond to exposures lasting less than 14 days. Intermediate EMEGs correspond to exposures lasting between 14 days and 1 year. Chronic EMEGs correspond to exposures lasting longer than 1 year. CREG and RMEG values are derived assuming a lifetime duration of exposure. All the comparison values (i.e., CREG, EMEG, RMEG) are derived assuming opportunities for exposure in a residential setting.


APPENDIX B

Documents reviewed to generate a database of PCE testing results for the Duxbury water distribution system.


Table 1: PCE concentrations in samples taken from the Duxbury water distribution system between 1980 and 1997

Period Detects/Samples Mean PCE concentration in
all samples1
(ug/L)		 Mean of
detected PCE concentrations2
(ug/L)		 Maximum
PCE concentration
(ug/L)		 ATSDR
Comparison Values or MMCL
(ug/L)
1980-1996 69/96 12.56 17.47 180 CREG = 0.7
MMCL = 5  
19973 191/337 1.26 2.22 16.8
All Samples3 260/433 3.76 6.26 180

Notes:
1. Mean concentrations calculated using a concentration of 0 for samples in which PCE was not detected.
2. Mean concentrations calculated by excluding samples in which PCE was not detected.
3. The most recent testing data available to MDPH are through 1-Jun-97.
CREG = Cancer Risk Evaluation Guide from the Agency for Toxic Substances and Disease Registry (see Appendix A).
MMCL = Massachusetts Maximum Contaminant Level established by the Massachusetts Department of Environmental Protection.


Table 2: PCE concentrations in the Duxbury water distribution system grouped by the season of the test

Season Detects/Samples Mean PCE concentration in
all samples1
(ug/L)		 Mean of
detected PCE concentrations2
(ug/L)		 Maximum
PCE concentration
(ug/L)		 ATSDR
Comparison
Values or MMCL
(ug/L)
Summer
(March 21 to
September 21)3		 132/244 3.61 6.68 180 CREG = 0.7
MMCL = 5
Winter
(September 22 to
March 20)3		 128/189 3.95 5.84 120

Note:
1. Mean concentrations calculated using a concentration of 0 for samples in which PCE was not detected.
2. Mean concentrations calculated by excluding samples in which PCE was not detected.
3. The most recent testing data available to MDPH are through 1-Jun-97.
CREG = Cancer Risk Evaluation Guide from the Agency for Toxic Substances and Disease Registry (see Appendix A).
MMCL = Massachusetts Maximum Contaminant Level established by the Massachusetts Department of Environmental Protection.


Table 3: PCE concentrations in the Duxbury water distribution system grouped by the configuration of the VLAC pipe at the testing location.

Type Detects/Samples Mean PCE concentration in
all samples1
(ug/L)		 Mean of
detected PCE concentrations2
(ug/L)		 Maximum
PCE concentration
(ug/L)		 ATSDR Comparison
Values or MMCL
(ug/L)
Dead end street with VLAC pipe without bleeder 182/269 5.35 7.91 180 CREG = 0.7
MMCL = 5
Dead end street with VLAC pipe with bleeder 72/117 1.53 2.48 16.8
Looped VLAC pipe 6/36 0.31 1.83 3.20
Location with A-C pipe but not vinyl lining or without A-C pipe 0/11 0 0 0

Notes:
1. Mean concentrations calculated using a concentration of 0 for samples in which PCE was not detected.
2. Mean concentrations calculated by excluding samples in which PCE was not detected.
3. The most recent testing data available to MDPH are through 1-Jun-97.
CREG = Cancer Risk Evaluation Guide from the Agency for Toxic Substances and Disease Registry (see Appendix A).
MMCL = Massachusetts Maximum Contaminant Level established by the Massachusetts Department of Environmental Protection.


Table 4: PCE concentrations in the Duxbury water distribution system grouped by individual streets or subdivisions. Concentrations greater than the Massachusetts Maximum Contaminant Level (5 ppb) are shown in bold.

Street or Subdivision Water main type Detects/
Samples		 Mean PCE concentration in all samples1

(ug/L)

 Mean of
detected PCE concentrations2

(ug/L)

 Maximum
PCE concentration

(ug/L)

 Date of
First
Test		 Date of
Most Recent
Test7
Bassett Brook Ln. looped3 3/3 3.03 3.03 3.2 2/28/97 5/18/97
Bayberry Ln. dead end 3/4 1.05 1.4 1.7 2/28/97 4/14/97
Bianca Rd. looped 0/4 0 0 0 2/28/97 4/21/97
Birch St. Tank dead end4 1/5 4 20 20 4/23/80 5/10/97
Bolas Rd. looped 1/4 0.13 0.5 0.5 4/23/80 4/21/97
Bowsprit Ln. dead end 0/4 0 0 0 1/13/81 4/23/97
Boxwood Ln. dead end 3/8 1.38 3.67 5.7 1/13/81 5/10/97
Bravender Rd. dead end 0/4 0 0 0 3/1/97 5/1/97
Brewster St. dead end 1/3 0.63 1.9 1.9 3/6/97 5/18/97
Brick Hill Ln. dead end 4/5 0.52 0.65 0.7 4/23/80 5/1/97
Bristol Dr. dead end 0/4 0 0 0 3/1/97 5/1/97
Buckboard Rd. looped 0/3 0 0 0 2/28/97 4/14/97
Candlewick Close dead end 0/3 0 0 0 3/7/97 5/22/97
Chandler School dead end 0/3 0 0 0 2/28/97 5/10/97
Christina Ct. dead end 4/4 0.8 0.8 1.2 3/1/97 4/26/97
Clearwater Dr. dead end 1/5 10 50 50 4/23/80 6/1/97
Clover Circle dead end 0/4 0 0 0 3/1/97 5/1/97
Colonial Dr. dead end 4/5 0.74 0.93 1.5 1/13/81 4/21/97
Conservation Ln. dead end 1/3 0.2 0.6 0.6 3/1/97 4/24/97
Cordwood Path dead end 1/4 0.15 0.6 0.6 4/23/80 5/18/97
Cottontail Dr. dead end 7/10 1.85 2.64 5.2 3/7/97 5/10/97
Cranberry Dr. dead end 0/7 0 0 0 1/16/90 6/1/97
Deer Path Trail North dead end 4/4 3.08 3.08 5.1 3/1/97 5/10/97
Deer Path Trail South dead end 3/4 0.6 0.8 1 4/23/80 5/18/97
Duxborough Trail dead end 3/3 1.53 1.53 1.9 3/1/97 5/18/97
Ellison High dead end 0/3 0 0 0 2/28/97 5/10/97
Fordville Rd. dead end 4/4 1.25 1.25 1.6 3/1/97 5/1/97
Grandview Ave. dead end 2/3 1.13 1.7 1.8 3/1/97 5/10/97
Greenleaf Dr. dead end 4/4 0.75 0.75 1 3/1/97 5/1/97
Harrison St. looped 0/3 0 0 0 3/7/97 5/18/97
Harvest Dr. looped 0/3 0 0 0 3/11/97 5/10/97
Heritage Ln. looped 0/4 0 0 0 4/23/80 4/23/97
Hidden Acres Dr. dead end 10/10 6.43 6.43 23 1/13/81 5/10/97
Highland Trail dead end 4/4 1.15 1.15 1.2 2/28/96 5/1/97
Hitty Tom Rd. dead end 5/5 2.12 2.12 3.6 2/28/97 5/1/97
Jeremiah Dr. dead end 3/3 0.93 0.93 1.1 3/1/97 5/18/97
Laurel St. dead end 1/3 0.17 0.5 0.5 2/28/97 5/18/97
Ledgewood Dr. dead end 5/5 7.12 7.12 23.4 1/13/81 4/21/97
Meadow Ln. dead end 0/3 0 0 0 2/28/97 4/12/97
Millbrook Way dead end 1/6 4.67 28 28 4/23/80 4/23/97
Old Barn Rd. dead end 7/7 20.1 20.1 43 1/13/81 5/18/97
Old Farm Rd. dead end 3/3 2.4 2.4 4.8 2/28/97 5/1/97
Old Pasture Rd. dead end 1/3 0.2 0.6 0.6 3/7/97 6/1/97
Parks St. (off) dead end 2/6 0.22 0.65 0.7 2/28/97 6/1/97
Parting Rock Rd. dead end 3/4 0.88 1.17 1.4 2/28/97 5/18/97
Pettibush Ln. looped 0/3 0 0 0 3/1/97 4/28/97
Pioneer Dr. dead end 2/3 0.4 0.6 0.6 3/1/97 4/21/97
Plantation Dr. dead end 13/29 9.52 21.23 180 1/13/81 5/10/97
Puritan Way dead end 3/3 0.87 0.87 1 2/28/97 4/23/97
Reynolds Way dead end 3/4 2.3 3.07 3.9 2/26/97 4/23/97
Roundtree Dr. dead end 3/3 0.77 0.77 1.1 3/1/97 5/1/97
Sarahs Circle dead end 1/1 1.1 1.1 1.1 6/1/97 6/1/97
Seabury Point Rd. dead end 17/20 5.19 6.11 16.8 2/26/97 5/17/97
Settlers Path dead end 2/3 0.63 0.95 1 3/15/97 5/18/97
South River Ln. East dead end 15/16 2.44 2.6 12 8/21/86 5/10/97
South River Ln. West dead end 14/15 2.08 2.23 14 1/23/97 5/10/97
South River Trail dead end 12/12 3.42 3.42 8.2 2/28/96 3/7/97
Stockade Path dead end 8/12 1.4 2.1 5 2/28/97 5/10/97
Stone Gate Ln. dead end 3/10 1.18 3.93 6.5 3/1/97 5/10/97
Tanglewood Trail dead end 15/16 3.69 3.93 13 1/13/81 5/10/97
Temple St. dead end 3/3 1.47 1.47 1.7 3/1/97 5/18/97
Templewood Dr. dead end 3/3 1.37 1.37 1.7 3/7/97 5/18/97
The Marshes dead end 4/15 0.73 2.73 4.9 6/29/82 4/21/97
Tinkertown Ln. dead end 4/4 2.43 2.43 3.7 2/18/85 5/1/97
Tinkertown Ponds6 dead end 21/25 19.44 23.14 125 9/18/81 6/1/97
Torrey Ln. dead end 5/6 4 4.8 15 6/2/82 4/14/97
Treetop Ln. dead end 5/5 5.6 5.6 20 4/23/80 5/1/97
Trout Farm Ln. looped 1/3 0.27 0.8 0.8 2/28/97 4/12/97
Trout Farm Rd. dead end 0/3 0 0 0 3/1/97 5/10/97
Turkey Ridge Ln. looped 0/3 0 0 0 2/28/97 5/10/97
Wildflower Path looped 1/3 0.2 0.6 0.6 2/28/97 4/12/97
Woodland Way dead end 3/3 2.23 2.23 2.3 3/1/97 5/10/97
Chandler Mill Dr. no VLACP5 0/1 0 0 0 4/9/97 4/9/97
Enterprise St. no VLACP 0/3 0 0 0 4/24/97 6/1/97
King Caesar Rd. no VLACP 0/3 0 0 0 4/24/97 6/1/97
Powder Point Rd. no VLACP 0/1 0 0 0 6/1/97 6/1/97
Spruce Ln. no VLACP 0/1 0 0 0 4/12/97 4/12/97
Strawberry Ln. no VLACP 0/1 0 0 0 1/13/81 1/13/81
West St. no VLACP 0/1 0 0 0 1/23/97 1/23/97

Notes:
1. Mean concentrations calculated using a concentration of 0 for samples in which PCE was not detected.
2. Mean concentrations calculated by excluding samples in which PCE was not detected.
3. The street or subdivision has VLAC pipe that is looped back to the water main to promote water movement.
4. The street or subdivision is a cul-de-sac with VLAC pipe
5. The street or subdivision does not have VLAC pipe.
6. The Tinkertown Ponds Subdivision includes Tinkers Ledge Rd., Pine Lake Rd., and Village Way.
7. The most recent testing data available to MDPH are through 1-Jun-97.


CERTIFICATION

The Health Consultation for Duxbury, Massachusetts was prepared by the Massachusetts Department of Public Health under a cooperative agreement with the Agency for Toxic Substances and Disease Registy (ATSDR). It is in accordance with approved methodology and procedures existing at the time the Health Consultation was initiated.

Tina Forrester
Technical Project Officer, SPS, SSAB, DHAC

The Division of Health Assessment and Consultation, ATSDR, has reviewed this Health Consultation and concurs with its findings.

Richard Gillig
Chief, SPS, SSAB, DHAC, ATSDR


1 The average household size in Duxbury is 2.97 persons per household according to the 1990 Census (Duxbury Town Clerk, personal communication).

2 When calculating mean concentrations, it is common to include the samples in which the compound was not detected with a value equal to one-half the method detection limit. It was not possible to do this with the data on PCE concentrations in the Duxbury water distribution system because the method detection limits were often not reported. Excluding samples in which PCE was not detected from the calculation of the mean value is a conservative approach that will tend to overestimate the actual mean value.

3 Bladder cancer, OR = 6.04, 95% CI = 1.32-21.84.

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