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PUBLIC HEALTH ASSESSMENT

CHEM-CENTRAL
GRAND RAPIDS, KENT COUNTY, MICHIGAN


APPENDIX A: FIGURES

Site Location
Figure 1. Site Location

EDI Sampling Locations (1980-1986)
Figure 2. EDI Sampling Locations (1980-1986) (Reference 1, Figure 5)

Phases I and II Boring and Well Locations
Figure 3. Phases I and II Boring and Well Locations (Reference 1, Figure 12)

Groundwater Interception, Purge, and Treatment System
Figure 4. Groundwater Interception, Purge, and Treatment System (Reference 1, Figure 9)


APPENDIX B: TABLES

Table 1. Contaminants of concern at the Chem Central site.

acetone
arsenic
benzene
benzo(a)anthracene
benzo(k)fluoranthene
bis(2-ethylhexyl)phthalate
bromodichloromethane
cadmium
chlordane
chloroethane
chloroform
chromium
di-n-butyl phthalate
dibenzo(a,h)anthracene
1,1-dichloroethane
1,2-dichloroethane
cis- and trans-1,2-dichloroethylene
1,1-dichloroethylene
1,3-dichloropropylene
ethylbenzene
indeno(1,2,3-cd)pyrene
isophorone
methylene chloride
naphthalene
polychlorinated biphenyls (PCBs)
1,1,2,2-tetrachloroethane
tetrachloroethylene
toluene
1,1,1-trichloroethane
1,1,2-trichloroethane
trichloroethylene
vinyl chloride
xylenes


Table 2. Contaminants of concern found in groundwater from on-site monitoring wells or a sampling trench at the Chem Central site.

Chemical Date

Maximum Concentration
(ppb)

Comparison Value
(ppb)
1,1-Dichloroethane 1982

<6,500.1

NAC
1983

3,400

1988

7,500

1,1-Dichloroethylene 1982

<6,500.1

90E, 0.058C
1983

880

1988

890

1,1,1-Trichloroethane 1979

7.T
NDW

200A
1982

7,300

1983

75,000

1988

150,000

1,1,2-Trichloroethane 1982

<6,500.1

3A, 0.61C
1983

420

1,1,2,2-Tetrachloroethane 1983

ND

0.18C
1988

2

1,2-Dichloroethane 1983

2,200

5M, 38C
1,2-Dichloroethylene (trans) 1982

<6,500.1

100A
1983

45,000

1988

53,000

1,3-Dichloropropylene 1983

300

3R, NAC
Acetone 1983

6,800

1,000R
1988

68

Arsenic 1983

20

3R
1988

24

Benzene 1982

<6,500.1

5M, 1.2C
1983

330

Benzo(a)anthracene 1983

2

0.1PM, NAC
Benzo(k)fluoranthene 1983

2

0.2PM, NAC
Bis(2-ethylhexyl)phthalate 1979

66,000.T
91.W

200A, 2.5C
1983

110

1988

430

Bromodichloromethane 1983

260

200E, 0.27C
Cadmium 1983

55

2E
Chloroform 1983

420

100E, 5.7C
Dibenzo(a,h)anthracene 1983

12

0.3PM, NAC
Di-n-butyl phthalate 1979

49,000.T
NDW

1,000R
1983

16

1988

43

Ethylbenzene 1982

<6,500.1

700A
1983

5,900

1988

6,000

Indeno(1,2,3-cd)pyrene 1983

16

0.4PM, NAC
1988

ND

Isophorone 1983

16

2,000E, 8.5C
1988

ND

Methylene chloride 1982

<6,500.1

600E, 4.7C
1983

5,100

1988

340

Naphthalene 1983

900

20A
1988

350

Polychlorinated biphenyls (PCBs) 1979

3,000.T
2.4W

0.05E, 0.0045C
1980

10

1983

ND

1988

ND

Tetrachloroethylene 1979

10.T
NQW

100R, NAC
1982

<6,500.1

1983

3,100

Tetrachloroethylene 1988

1,400

100R, NAC
Toluene 1979

30.T
NQW

1,000A
1982

23,400

1983

66,000

1988

70,000

Trichloroethylene 1979

10.T
NDW

5M, NAC
1982

6,500

1983

4,600

1988

12,000

Vinyl chloride 1983

8,400

0.2E, NAC
1988

2,000

Xylenes (total) 1979

12.T
NQW

10,000A
1982

6,500

1988

13,000

Reference: 1

Contaminants of concern that were never detected in this medium are not listed

ND -- Not Detected

1 -- "Lesser amounts" than 6.5 ppm of these chemicals were found in the 1982 sampling (Reference 1, p. 8).

T -- Concentration found in water from trench dug just north of Chem Central property
W -- Concentration found in Monitoring Wells
NQ.W -- Listed as detected in a monitoring well, but concentration not given in Reference 1, Table 1.

Comparison Value Bases

E -- ATSDR EMEGs for non-cancer endpoints, (child).
C -- Cancer Risk Evaluation Guide, based on adult intake and body weight, at 10-6 lifetime cancer risk.
R -- Concentration calculated from U.S. EPA Reference Dose for chronic exposure of a child.
A -- U.S. EPA Drinking Water Health Advisory.
M -- U.S. EPA Safe Drinking Water Act (SDWA) Maximum Contaminant Level.
PM -- U.S. EPA SDWA Proposed Maximum Contaminant Level.
NAC -- Possible Human Carcinogen (U.S. EPA Class C or higher). Slope Factor or other Comparison Value is Not Available
NA -- No Comparison Value available.


Table 3. Contaminants of concern found in groundwater in monitoring well SCH-2 at the Chem Central site.

Chemical Concentration
(ppb)
7/84 8/85 9/85 11/88
1,1-Dichloroethylene

550

55

580

720

1,1,1-Trichloroethane

ND

ND

ND

43

1,2-Dichloroethylene

1,100

290

4,300

3,500

Arsenic

NR

NR

NR

20

Benzene

1

ND

ND

ND

Ethylbenzene

3

29

130

190

Methylene chloride

ND

14

ND

ND

Tetrachloroethylene

9

ND

ND

ND

Toluene

59

14

43

39

Trichloroethylene

4,100

690

1,300

1,000

Vinyl chloride

2,300

12

1,700

1,100

Reference: 1

ND -- Not Detected
NR -- Not Reported


Table 4. Maximum concentrations of contaminants of concern found in surface and sub-surface soil on the Chem Central property.

Chemical Date

Maximum Concentration
(ppm)

Comparison Value
(ppm)
1,1-Dichloroethylene 1984

11

18E, 1.2C
1988

ND

1,1,1-Trichloroethane 1984

940

NA
1988

410

1,2-Dichloroethane 1984

6.5

7.7C
1988

ND

1,2-Dichloroethylene (trans) 1984

23

40R
1988

0.017

Arsenic 1988

4.3

0.6R
Bis(2-ethylhexyl)phthalate 1979

15.8

40R, 50C
1988

61

Cadmium 1988

9.4

0.4E
Chromium 1988

99

2,000 (III)
10E (VI)
Di-n-butyl phthalate 1979

4.25

200R
1988

6.1

Ethylbenzene 1984

320

200R
1988

120

Isophorone 1988

2.2

400E, 170C
Naphthalene 1979

18

NA
1988

13

Polychlorinated biphenyls (PCBs) 1979

1.1

0.01E, 0.09C
1988

0.54

Tetrachloroethylene 1984

1,800

20R, NAC
1988

1,100

Toluene 1984

2,500

400R
1988

370

Trichloroethylene 1984

340

NA
1988

1.9

Xylenes (total) 1988

160

4,000R

Reference: 1

Chemicals that were never detected in this medium are not listed

ND -- Not Detected

Comparison Value Bases

E -- ATSDR EMEGs for non-cancer endpoints (child, pica consumption of soil).
C -- Cancer Risk Evaluation Guide, based on adult intake and body weight, at 10-6 lifetime cancer risk.
R -- Concentration calculated from U.S. EPA Reference Dose for chronic exposure of a child (pica consumption rate of soil).
NAC -- Possible Human Carcinogen (U.S. EPA Class C or higher). Slope Factor or other Comparison Value is Not Available
NA -- No Comparison Value available.


Table 5. Contaminants of concern found in surface soil (0-2') on the Chem Central property during the RI (1988).

Chemical

Maximum Concentration
(ppm)

Comparison Value
(ppm)
1,1,1-Trichloroethane

0.085

NA
1,2-Dichloroethylene (trans)

0.01

40R
Arsenic

4.3

0.6R
Bis(2-ethylhexyl)phthalate

15.8

40R, 50C
Cadmium

9.4

0.4E
Chromium

15

2,000R (III)
10R (VI)
Di-n-butyl phthalate

0.15

200R
Ethylbenzene

4.6

200R
Isophorone

2.2

400E, 170C
Naphthalene

0.23

NA
Polychlorinated biphenyls (PCBs)

0.15

0.01E, 0.09C
Tetrachloroethylene

8.3

20R, NAC
Toluene

0.14

400R
Trichloroethylene

0.19

NA

Reference: 1

Chemicals that were not detected are not listed

Comparison Value Bases

E -- ATSDR EMEGs for non-cancer endpoints (child, pica consumption of soil).
C -- Cancer Risk Evaluation Guide, based on adult intake and body weight, at 10-6 lifetime cancer risk.
R -- Concentration calculated from U.S. EPA Reference Dose for chronic exposure of a child (pica consumption rate of soil).
NAC-- Possible Human Carcinogen (U.S. EPA Class C or higher). Slope Factor or other Comparison Value is Not Available
NA -- No Comparison Value available.


Table 6. Contaminants of concern found in soil between the Chem Central property and 28th Street.

Chemical Date

Maximum Concentration
(ppm)

Comparison Value
(ppm)
1,1,1-Trichloroethane 1988

2.8

NA
1989

0.059
ND (S)

Arsenic 1988

2.6

0.6E
1989

NR

Bis(2-ethylhexyl)phthalate 1979

24

40R, 50C
1988

0.73

1989

250
ND (S)

Chlordane 1988

0.63

1.2E, 0.54C
1989

ND

Chromium 1988

8.1

2,000R (III)

10R (VI)

1989

NR

Di-n-butyl phthalate 1979

5.2

200R
1988

ND

1989

4.6
ND (S)

Ethylbenzene 1988

2.6

200R
1989

ND

Naphthalene 1988

ND

NA
1989

4.2
ND (S)

Polychlorinated biphenyls (PCBs) 1979

2.65

0.01E, 0.09C
1988

0.24

1989

ND

Tetrachloroethylene 1988

31

20R, NAC
1989

290
0.15 (S)

Toluene 1988

7.1

400R
1989

ND

Trichloroethylene 1988

0.58

NA
1989

0.015(S)

Xylenes (total) 1988

34

4,000R
1989

ND

Reference: 1

Chemicals that were never detected in this medium are not listed

ND -- Not Detected
(S) -- Surface soil (0 to 2 feet deep)

Comparison Value Bases

E -- ATSDR EMEGs for non-cancer endpoints (child, pica consumption of soil).
C -- Cancer Risk Evaluation Guide, based on adult intake and body weight, at 10-6 lifetime cancer risk.
R -- Concentration calculated from U.S. EPA Reference Dose for chronic exposure of a child (pica consumption rate of soil).
NAC -- Possible Human Carcinogen (U.S. EPA Class C or higher). Slope Factor or other Comparison Value is Not Available
NA -- No Comparison Value available.


Table 7. Contaminants of concern found in soil or sediment from the 28th Street ditch area.

Chemical Date

Maximum Concentration
(ppm)

Comparison Value
(ppm)
1,1-Dichloroethane 1983

14

NAC
1988

ND

1,1-Dichloroethylene 1983

0.39

18E, 1.2C
1988

ND

1,1,1-Trichloroethane 1983

81

NA
1988

ND

1,2-Dichloroethane 1983

0.18

7.7C
1988

ND

1,2-Dichloroethylene (trans) 1983

26

40R
1988

0.045

Arsenic 1983

12

0.6E
1988

5.2

Benzene 1983

0.90

24C
1988

ND

Benzo(k)fluoranthene 1983

0.55

NAC
1988

ND

Bis(2-ethylhexyl)phthalate 1983

2,100

40R, 50C
1988

66

Cadmium 1983

0.8

0.4E
1988

ND

Chloroform 1983

0.50

20E, 110C
1988

ND

Chromium 1983

9.6

2,000R (III)
10R (VI)
1988

9

Dibenzo(a,h)anthracene 1983

0.36

NAC
1988

ND

Di-n-butyl phthalate 1983

4.7

200R
1988

0.83

Ethylbenzene 1983

140

200R
1988

0.65

Indeno(1,2,3-cd)pyrene 1983

0.40

NAC
1988

ND

Methylene chloride 1983

6.2

100E, 93C
1988

ND

Naphthalene 1983

8.5

NA
1988

2.2

Polychlorinated biphenyls (PCBs) 1978

2.65

0.01E, 0.09C
1981

2.0

1983

63.1

11/851

72

12/852

1.76

1988

0.54

Tetrachloroethylene 1983

180

20R, NAC
1988

ND

Toluene 1983

480

400R
1988

1

Trichloroethylene 1983

6.9

NA
1988

ND

Vinyl chloride 1983

1.2

0.04E, NAC
1988

ND

Xylenes (total) 1983

NR

4,000R
1988

2.2

Reference: 1

Contaminants of concern that were never detected in this medium are not listed.

ND -- Not Detected
NR -- Not Analyzed For

1 Before excavation
2 After excavation

Comparison Value Bases

E -- ATSDR EMEGs for non-cancer endpoints (child, pica consumption of soil).
C -- Cancer Risk Evaluation Guide, based on adult intake and body weight, at 10-6 lifetime cancer risk.
R -- Concentration calculated from U.S. EPA Reference Dose for chronic exposure of a child (pica consumption rate of soil).
NAC -- Possible Human Carcinogen (U.S. EPA Class C or higher). Slope Factor or other Comparison Value is Not Available
NA -- No Comparison Value available.

Table 8. Concentrations of contaminants of concern found in monitoring wells upgradient from the Chem Central site.

Chemical Maximum concentration (ppb) Comparison Value
(ppb)
1981 1982 1988
1,1,1-Trichloroethane

140

NR1

42

200A
1,1,2-Trichloroethane

1

NR1

ND

3A, 0.61C
1,1-Dichloroethylene

3

NR1

ND

90E, 0.058C
Trichloroethylene

3

NR1

6

5M
Chlordane

ND

6,400

ND

6E, 0.027C
Tetrachloroethylene

ND

NR1

110

100A, NAC
1,1-Dichloroethane

ND

NR1

2

NAC
Chloroform

ND

ND

2

100E, 5.7C
Bis(2-ethylhexyl)phthalate

ND

ND

43

200R, 2.5C
Di-n-butyl phthalate

ND

ND

1

1,000R
Semi-volatile hydrocarbons

ND

ND

510

NA
Oil and grease

ND

ND

2,600

NA

Reference: 1

ND -- Not Detected
NR1-- Listed in Reference 1, page 8, as potentially present, but concentration not reported.

Comparison Value Bases

E -- ATSDR EMEGs for non-cancer endpoints, (child).
C -- Cancer Risk Evaluation Guide, based on adult intake and body weight, at 10-6 lifetime cancer risk.
R -- Concentration calculated from U.S. EPA Reference Dose for chronic exposure of a child.
A -- U.S. EPA Drinking Water Health Advisory.
M -- U.S. EPA Safe Drinking Water Act (SDWA) Maximum Contaminant Level.
NAC-- Possible Human Carcinogen (U.S. EPA Class C or higher). Slope Factor or other Comparison Value is Not Available
NA -- No Comparison Value available.


Table 9. Contaminants of concern found in groundwater from monitoring wells north of 28th Street in the vicinity of the Chem Central site.

Chemical Date

Maximum Concentration
(ppb)

Comparison Value
(ppb)
1,1-Dichloroethane 1984

120

NAC
1985

180

1988

140

1,1-Dichloroethylene 1984

31

90E, 0.058C
1985

12

1,1,1-Trichloroethane 1984

960

200A
1985

320

1988

17

1,2-Dichloroethane 1988

3

5M, 38C
1,2-Dichloroethylene (trans) 1984

280

100A
1985

37

1988

7

Benzene 1984

4

5M, 1.2C
1985

2

1988

2

Bis(2-ethylhexyl)phthalate 1988

13

200A, 2.5C
Chloroethane 1984

200

NA
1985

340

1988

640

Chloroform 1984

1

100E, 5.7C
1985

1

Di-n-butyl phthalate 1988

6

1,000R
Methylene chloride 1984

2

600E, 4.7C
Tetrachloroethylene 1984

440

100R, NAC
1985

280

1988

27

Trichloroethylene 1984

56

5M, NAC
1985

70

1988

12

Reference: 1

Contaminants of concern that were never detected in this medium are not listed

ND -- Not Detected

Comparison Value Bases

E -- ATSDR EMEGs for non-cancer endpoints, (child).
C -- Cancer Risk Evaluation Guide, based on adult intake and body weight, at 10-6 lifetime cancer risk.
R -- Concentration calculated from U.S. EPA Reference Dose for chronic exposure of a child.
A -- U.S. EPA Drinking Water Health Advisory.
M -- U.S. EPA Safe Drinking Water Act (SDWA) Maximum Contaminant Level.
PM -- U.S. EPA SDWA Proposed Maximum Contaminant Level.
NAC -- Possible Human Carcinogen (U.S. EPA Class C or higher). Slope Factor or other Comparison Value is Not Available
NA -- No Comparison Value available.


Table 10. Contaminants of concern found in sediment samples from the Cole Drain near the Chem Central site.

Chemical Date

Maximum Concentration
(ppm)

Comparison Value
(ppm)
Arsenic 1988

3.1

0.6R
Benzo(a)anthracene 1988

1.7

NAC
Benzo(k)fluoranthene 1988

1.1

NAC
Chromium 1988

14

2,000R (III)
10R (VI)
Bis(2-ethylhexyl)phthalate 1979

0.09

40R, 50C
1988

ND

Di-n-butyl phthalate 1979

0.08

200R
1988

1.1

Polychlorinated biphenyls (PCBs) 1979

0.23

0.01E, 0.09C
1988

ND

Reference: 1

Contaminants of concern never detected in this medium are not listed.

Comparison Value Bases

E -- ATSDR EMEGs for non-cancer endpoints, lowest value given (child, pica consumption of soil).
C -- Cancer Risk Evaluation Guide, based on adult intake and body weight, at 10-6 lifetime cancer risk.
R -- Concentration calculated from U.S. EPA Reference Dose for chronic exposure of a child (pica consumption rate of soil).
NAC-- Possible Human Carcinogen (U.S. EPA Class C or higher). Slope Factor or other Comparison Value is Not Available


Table 11. Concentrations of contaminants of concern in individual sediment samples collected during the RI (1988).

Chemical Location (see Figure 3)
1 2 3 4 5 5D 6 7 8
As

2.6

1.1

1.7

1.5

2.2

3.1

1.9

1.5

2.5

B(a)A

0.74

ND

1.7

ND

ND

ND

ND

ND

ND

B(k)F

0.71

ND

1.1

ND

ND

ND

ND

ND

ND

Cr

14

8.9

9

9.3

6.6

11

11

6.8

6.1

DnBP

ND

ND

0.39

ND

0.59

0.48

0.62

0.65

1.1

Reference: 1

As -- Arsenic
B(a)A -- Benzo(a)anthracene
B(k)F -- Benzo(k)fluoranthene
Cr -- Chromium
DnBP -- Di-n-butyl phthalate

D -- Duplicate Sample

ND -- Not Detected


RESPONSIVENESS SUMMARY

The MDPH released this public health assessment for public comment on April 20, 1993. The open comment period lasted until May 20, 1993. MDPH received an extensive critique of the assessment from WW Engineering and Science (WWES), a contractor for the Potentially Responsible Parties at the site. WWES's comments and MDNR's and ATSDR's responses to them are given below. Page and paragraph references are from the WWES comments, referring to the draft they reviewed, and may not agree with the current text.

GENERAL COMMENTS

  1. A quantitative Baseline Risk Assessment was prepared and approved by the U.S. EPA and MDNR for this site over two years ago, but the Public Health Assessment does not refer to the risk assessment. This first paragraph of the Public Health Assessment indicates that "the administrator of ATSDR shall use appropriate data, risk assessments, risk evaluations, and studies available from the Administrator of EPA." The Baseline Risk Assessment was not used and some of the data that were used are out of date and are no longer appropriate.

Response: In response to Comment 10, page RS - 4, we have added a reference to the Baseline Risk Assessment. ATSDR Public Health Assessments are separate from and independent of U.S. EPA Baseline Risk Assessments, with different goals and methods. There was no reason to cite the Baseline Risk Assessment's conclusions, since we drew our own using ATSDR methodologies. All available data, regardless of age, was cited, at least for informational purposes.

  1. Some of the chemicals identified as "contaminants of concern" in Table 1 either occur at similar concentrations in background samples or occur only in background samples. For example:

    Arsenic, chromium, copper, and barium in soil in the potentially impacted area were not significantly different from concentrations of these chemical in background soils.

    Chromium concentrations in surface soils, soils between the site and 28th Street, and soils in the 28th Street ditch are not significantly different from background concentrations.

    Chloroform was only detected in wells upgradient of the site. Chloroform was detected in 1983 in the 28th Street ditch, but this ditch no longer exists.

Response: ATSDR policy is to evaluate the health effects of all chemicals found at or near the sites assessed, including those in background samples, if they are present in concentrations that could possibly affect public health.

  1. Much of the data used is quite old and has been superseded by newer data during the remedial investigation. Some of the data cited are for the 28th Street ditch before it was remediated.

Response: All available data, regardless of age, was cited, at least for informational purposes. It is within the scope of a public health assessment to evaluate public health threats that existed in the past, currently exist, or could exist in the future.

SPECIFIC COMMENTS

  1. Preface Note: The first sentence indicated that "available" data were used. The last sentence of the first paragraph cites CERCLA and the requirement that "appropriate" data be used. Not all of the available data are appropriate (see General Comment 3).

Response: MDPH does not see these as conflicting. MDPH and ATSDR use their best professional judgment to decide what available data is approprate.

  1. Page 6, paragraph 3. The term "deep aquifer" used in this paragraph is a misnomer. This term was originally used by the regulatory agencies and subsequently has been carried through to the documents generated as a result of the Remedial Investigation (RI) for purposes of clarity and continuity. The RI has established the hydraulic characteristics of the deeper saturated lenses. The investigation has demonstrated that the deeper saturated lenses will not yield ground water to a well in usable quantities. The maximum sustained yield from SCH-2 has been demonstrated to be less than or equal to 0.8 gallons per minute. The deeper saturated lenses, therefore, do not fit the definition of a usable "aquifer", subsequently potential exposure from this source is very low.

Response: Usability as a water supply is not one of the criteria necessary to designate a water-bearing geological formation an "aquifer". In response to this comment, the Potential Exposure Pathways section of the assessment has been rewritten to include the unsuitability of the "deep aquifer" as a water supply.

  1. Page 10, paragraph 2. The RI data were collected in accordance with work plans approved by the MDNR and U.S. EPA, and in accordance with a strict quality control requirements. Many of the earlier data were not collected using such strict protocols, and in one case, locations of the samples were not recorded. The RI data should be given greater weight than earlier data because they were collected and reported using documented quality assurance procedures and because these are the most recent data. The Public Health Assessment gives all of the data equal weight.

Response: The only environmental data used in the Toxicological Evaluation section was taken from the RI. Other data was cited for information purposes, and to give an indication of former conditions at the site.

  1. Page 10, paragraph 4. Cole Drain is not owned by CHEMCENTRAL, nor is CHEMCENTRAL responsible for maintaining the drain. Any physical hazards related to the drain are not related to the site in any way.

Response: ATSDR attempts to identify all potential health hazards associated with the site being assessed and its vicinity, regardless of whether the hazard is directly associated with the site and regardless of who owns the location of the hazard.

  1. Page 11, paragraph 1. In December 1992 the MDNR approved an engineering modification to the ground water treatment system whereby recovery of ground water continues during periods when the system is inoperable, whether due to breakdown or maintenance. The ground water recovered during inoperational periods is routed to the sanitary sewer servicing the facility. This modification eliminates potential increases of ground water discharge from the site to Cole Drain during inoperational periods.

Response: Thank you for this information. The text has been modified in appropriate places to reflect this operational modification.

  1. Page 11, paragraph 2. On site concentrations of arsenic in soil were not significantly different from background concentrations.

Response: ATSDR policy is to evaluate the health effects of all chemicals found at or near the sites assessed, including those in background samples.

  1. Page 12, paragraph 1. Wading and fishing in Plaster Creek probably occurs upstream of the confluence of Plaster Creek and Cole Drain, where residential and recreational areas predominate. The downstream part of the creek is mostly industrial.

Response: Grand Rapids city maps show two parks along Plaster Creek downstream of the confluence with the Cole Drain. Though recreational use may not predominate along this section of the creek, the opportunity is there. The text has been changed to mention the land use along the creek.

  1. Page 12, paragraph 4. Cole Drain is too small to support an indigenous population of edible-sized fish and is too small to encourage swimming. The sediments were sampled and analyzed from eight locations upstream and downstream of the site during the RI. There is no evidence that chemicals in the sediments are related to the site because they occurred in similar concentrations upstream and downstream of the site and/or because they occurred in similar concentrations in other parts of Plaster Creek.

Response: Experienced anglers on the MDPH staff who have visited the site are of the opinion that the drain is of adequate size to support edible-size fish. ATSDR policy is to investigate and consider all potential human exposures to potentially hazardous chemicals in the vicinity of NPL sites, whether the chemicals can be shown to be related to the sites or not.

  1. Page 12, paragraph 5. The location of the sample collected from Cole Drain sediments that had PCBs is not known. PCBs were not detected in more recent and more extensive sampling of drain sediments conducted during the RI. The 28th Street ditch was eliminated eight years ago, and so is no longer a source of any chemicals. Edible-sized fish cannot live in Cole Drain for most of their lives, so the potential for contaminated fish to migrate to Plaster Creek is not significant. For these reasons any exposure to site-related chemicals via Cole Drain will be very low.

Response: The results of recent sampling were cited in the paragraph. A statement describing the status of the ditch has been added. See the response to Specific Comment 8 on the possibility of edible-size fish in the drain.

  1. Page 15, paragraph 1. See above comment. The risk assessment evaluated potential exposure to PCBs through ingestion of fish from Cole Drain.

Response: The risk assessment analysis may be flawed. They concluded that there was no potential for human exposure because there were no PCBs detected in the water or sediment and, from a calculation using bioconcentration factors (BCFs), none would be found in fish from the Drain (Reference 15, Tables 8 and 19). The risk assessment used a BCF for PCBs from water to fish of 100,000 (Op. cit., Table 2). According to the RI Work Plan, the detection limit for the analytical technique used for PCBs in water was 1 ppb (16). Using the BCF cited in the risk assessment, fish living in water containing a concentration of PCBs at the detection limit could contain 100 ppm of PCBs, far in excess of the FDA Action Level for PCBs (2 ppm). The lowest detection limit for any analytical technique for PCBs in water listed in the Toxicological Profile for PCBs is 0.6 ppb, dependent on the PCB mixture assumed to be present (Reference 8, Table 6-2).

The biota-sediment accumulation factor (BSAF) for PCBs in carp has been found to be on the order of 10, though values derived from field data have a large amount of scatter (17). A 1977 MDNR study on the Shiawassee River found a BSAF for PCBs in carp on the order of 100 (cited in Reference 18, Table 5-4). The detection limit for PCBs in soil or sediment cited in the Chem Central RI Work Plan was 0.1 ppm (16). Fish living in waters with no detectable PCBs in the sediment could contain as much as 1 ppm PCBs, or even more. It may not be reliable to assume that the fish from a stream contain no PCBs because the analysis cannot detect any in the water or sediment.

  1. Page 15, paragraph 2. Restrictive covenants to the deed for the facility are in place, limiting the ability for changes in site use that would result in a completed exposure pathway.

Response: Thank you for the information. A statement describing these restrictions has been included in the Pathways Analysis section. However, such institutional controls may be altered, removed, evaded, or ignored.

  1. Page 16, recommendation 1. The collection system is shut down for regular and special maintenance as needed. Most recently CHEMCENTRAL arranged with city to received untreated water during maintenance, subject to the city's total toxic organic limits (see comment 5). The system was down for 20 minutes for the bypass to be installed, and the city's limit was not exceeded. Components of the system are being upgraded as they are replaced. This recommendation is unwarranted because CHEMCENTRAL has developed procedures to minimize the time the system is not in operation, and because mandating continuous operation will not remove the need to shut down the system for needed maintenance.

Response: The recommendation has been modified to allow for regular maintenance. We have also added a reference to Chem Central's arrangement with the City for limited disposal of untreated purged groundwater when the on-site treatment plant is off-line.

  1. Page 16, recommendation 2. It is unlikely that significant numbers of edible fish could be collected from Cole Drain to be analyzed for potential chemical affects. Even if enough fish could be collected, there would be no way to attribute any chemicals found in the fish to CHEMCENTRAL because the fish will not reside in one place for their entire lives and because there are many sources of chemicals to Cole Drain and Plaster Creek. The Baseline Risk Assessment estimated potential risks that could occur due to exposure to water and consumption of fish from Cole Drain. The carcinogenic and noncarcinogenic risks were insignificant, whether or not the collection system was in operation. This evaluation was based on a number of very conservative assumptions. This recommendation for further investigation is unwarranted because it seems to be based on old data collected from an unknown location, it does not consider more recent data and evaluations, it would not provide results that could be attributed to the site, and would be redundant of efforts previously performed during the Baseline Risk Assessment.

Response: ATSDR policy is to investigate all potential human exposures to potentially hazardous chemicals in the vicinity of NPL sites, whether the chemicals can be shown to be related to the sites or not. As mentioned above in our response to Specific Comment 10, the analysis in the Baseline Risk Assessment may be flawed.

  1. Page 16, recommendation 3. There already is an institutional control to prevent future use of contaminated shallow ground water near the site. Michigan Public Health codes prohibit installation of drinking water wells that are screened at less than 25 feet deep. Almost all of the ground water impact in the area is at depths less that 25 feet. Deeper saturated lenses (e.g. SCH-2) will not yield ground water in usable quantities as demonstrated during the RI (see comment 2).

Response: That institutional control may not be adequate. The bottom of the shallow aquifer is 30 feet below ground surface at well cluster 16 and 40 feet below ground surface at well cluster 24.(2) Water sampled during the RI from the deepest wells in these clusters, screened just above the lower confining layer, contained measurable concentrations of contaminants. They were not as contaminated as the shallower wells in the same clusters, but the contamination was present.


2. The ground surface at monitoring well cluster 24 is approximately 10 feet higher than at cluster 16, because cluster 24 is located on the embankment for the approach ramp for the overpass carrying 28th Street over Cole Drain, the railroad tracks, and U.S. 131.


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