PUBLIC HEALTH ASSESSMENT

CONROE CREOSOTING COMPANY
CONROE, MONTGOMERY COUNTY, TEXAS

November 23,2004

Prepared by:

The Texas Department of Health
Under a Cooperative Agreement with the
Agency for Toxic Substances and Disease Registry

Acronyms and Abbreviations
ATSDR	Agency for Toxic Substances and Disease Registry
CERCLA	Comprehensive Environmental Response, Compensation and Liability Act of 1980
CREG	Carcinogenic Risk Evaluation Guide
EMEG	Environmental Media Evaluation Guide
EPA	Environmental Protection Agency
HAC	Health Assessment Comparison Value
HOD	Health Outcome Data
MCL	Maximum Contaminant Level
mg/kg	milligrams per kilogram
MRL	Minimal Risk Level
NPL	National Priorities List
PCBs	Polychlorinated biphenyls
PHA	Public Health Assessment
ppb	parts per billion
QA/QC	Quality Assurance/Quality Control
RCRA	Resource Conservation Recovery Act
RfD	Reference Dose
RMEG	Reference Dose Media Evaluation Guide
SARA	Superfund Amendments and Reauthorization Act of 1986
SVOCs	Semi-Volatile Organic Compounds
TCEQ	Texas Commission on Environmental Quality
TDH	Texas Department of Health
µg/L	micrograms per liter
VOCs	Volatile Organic Compounds

Acronyms and Abbreviations

ATSDR

Agency for Toxic Substances and Disease Registry

CERCLA

Comprehensive Environmental Response, Compensation and Liability Act of 1980

CREG

Carcinogenic Risk Evaluation Guide

EMEG

Environmental Media Evaluation Guide

EPA

Environmental Protection Agency

HAC

Health Assessment Comparison Value

HOD

Health Outcome Data

MCL

Maximum Contaminant Level

mg/kg

milligrams per kilogram

MRL

Minimal Risk Level

NPL

National Priorities List

PCBs

Polychlorinated biphenyls

PHA

Public Health Assessment

ppb

parts per billion

QA/QC

Quality Assurance/Quality Control

RCRA

Resource Conservation Recovery Act

RfD

Reference Dose

RMEG

Reference Dose Media Evaluation Guide

SARA

Superfund Amendments and Reauthorization Act of 1986

SVOCs

Semi-Volatile Organic Compounds

TCEQ

Texas Commission on Environmental Quality

TDH

Texas Department of Health

µg/L

micrograms per liter

VOCs

Volatile Organic Compounds

Table 1. Evaluation of Potential Exposure Pathways for the Conroe Creosoting Company Site
PATHWAY NAME	PRIMARY CONTAMINANTS OF CONCERN	EXPOSURE PATHWAY ELEMENTS	TIME	CONCLUSIONS
Source	Transport Media	Point of Exposure	Route of Exposure	Exposed Population
Potential Exposure Pathways
Soil On-Site	Benzo(a)pyrene Arsenic Pentachlorophenol Naphthalene Chromium Dioxins	On-site activities, tanks, spills	Soil	On-site	Incidental ingestion, Dermal contact	Trespassers,Worker	Past Present Future	In the past, the site contaminants may have posed a public health hazard to on-site workers, trespassers and customers traversing the site. Contaminated soil was removed from the site in 2002-2003; therefore, exposure to soil on the site poses no health hazard.
Off-Site	No constituents at levels of health concern		Off-site Residential yards	Residents living along Stewart's Creek	Past Present Future	No apparent public health hazard
Sediment On-Site	Benzo(a)pyrene Arsenic	On-site activities, tanks, spills	Sediment	On-site drainage ditch and Stewart's Creek where it joins the drainage ditch	Incidental ingestion,Dermal contact	Workers,Trespassers on process areas	Past Present Future	In the past, site contaminants may have posed a public health hazard to on-site workers and trespassers. Contaminated sediment was removed from the site and a section of Stewart's Creek in 2002-2003; therefore, exposure to sediment on the site poses no health hazard.
Off-Site	No constituents at levels of health concern	Off-site Stewart's Creek below SH 105	Residents living along Stewart's Creek	Past Present Future	No apparent public health hazard
Surface Water On-Site	Arsenic Pentachlorophenol	Drainage ditch, Stewart's Creek	Surface Water	On-site drainage ditch	Incidental ingestion, Dermal contact	Workers,Trespassers	Past Present Future	In the past, surface water in the drainage ditch and entering Stewart's Creek may have posed a public health hazard. No public health hazard
Groundwater	Monitoring Wells	Pentachlorophenol	On-site activities, tanks, spills	Groundwater Monitoring wells	Incidental ingestion, Dermal contact	On-site workers	Present Future	No apparent public health hazard Water from the shallow aquifer is not used for drinking water or other household uses

Table 1. Evaluation of Potential Exposure Pathways for the Conroe Creosoting Company Site

PATHWAY NAME

PRIMARY CONTAMINANTS OF CONCERN

EXPOSURE PATHWAY ELEMENTS

TIME

CONCLUSIONS

Source

Transport Media

Point of Exposure

Route of Exposure

Exposed Population

Potential Exposure Pathways

Soil
On-Site

Benzo(a)pyrene
Arsenic
Pentachlorophenol
Naphthalene
Chromium
Dioxins

On-site activities, tanks, spills

Soil

On-site

Incidental ingestion, Dermal contact

Trespassers,Worker

Past

Present
Future

In the past, the site contaminants may have posed a public health hazard to on-site workers, trespassers and customers traversing the site.

Contaminated soil was removed from the site in 2002-2003; therefore, exposure to soil on the site poses no health hazard.

Off-Site

No constituents at levels of health concern

Off-site
Residential yards

Residents living along Stewart's Creek

Past
Present
Future

No apparent public health hazard

Sediment
On-Site

Benzo(a)pyrene
Arsenic

On-site activities, tanks, spills

Sediment

On-site drainage ditch and Stewart's Creek where it joins the drainage ditch

Incidental ingestion,Dermal contact

Workers,Trespassers on process areas

Past

Present
Future

In the past, site contaminants may have posed a public health hazard to on-site workers and trespassers.

Contaminated sediment was removed from the site and a section of Stewart's Creek in 2002-2003; therefore, exposure to sediment on the site poses no health hazard.

Off-Site

No constituents at levels of health concern

Off-site Stewart's Creek below SH 105

Residents living along Stewart's Creek

Past
Present
Future

No apparent public health hazard

Surface Water
On-Site

Arsenic
Pentachlorophenol

Drainage ditch, Stewart's Creek

Surface Water

On-site drainage ditch

Incidental ingestion,
Dermal contact

Workers,Trespassers

Past

Present
Future

In the past, surface water in the drainage ditch and entering Stewart's Creek may have posed a public health hazard.

No public health hazard

Groundwater

Monitoring Wells

Pentachlorophenol

On-site activities, tanks, spills

Groundwater Monitoring wells

Incidental ingestion, Dermal contact

On-site workers

Present

Future

No apparent public health hazard
Water from the shallow aquifer is not used for drinking water or other household uses

Table 2. On-site Soil Sample Locations (0-6"depth) November 2001 Conroe Creosoting Company Site Prior to Removal Action [4]
Sample ID	Sample Location
SO1	Background sample collected north of the fenced boundary
SO2	Background sample collected north of the fenced boundary
SO3	Background sample Lion's Park
SO4	Collected near the center of the site beside lumber piles
SO5	Duplicate of SO-4
SO6	Located next to the CCA building
SO7	Duplicate of SO-6
SO8	Collected next to a pressure vessel near the CCA area
SO9	Collected next to creosote tanks
SO10	Stained soil collected next to entry ramp of concrete surface impoundment
SO11	Collected next to the east tree line between the operations area and the lake
SO12	Collected near SO-11 behind an abandoned truck
SO13	Collected at the end of a concrete lined drainage ditch leading toward Stewart's Creek
SO14	Collected from natural drain pathway on west side of the site

Table 2. On-site Soil Sample Locations (0-6"depth) November 2001
Conroe Creosoting Company Site Prior to Removal Action [4]

Sample ID

Sample Location

SO1

Background sample collected north of the fenced boundary

SO2

Background sample collected north of the fenced boundary

SO3

Background sample Lion's Park

SO4

Collected near the center of the site beside lumber piles

SO5

Duplicate of SO-4

SO6

Located next to the CCA building

SO7

Duplicate of SO-6

SO8

Collected next to a pressure vessel near the CCA area

SO9

Collected next to creosote tanks

SO10

Stained soil collected next to entry ramp of concrete surface impoundment

SO11

Collected next to the east tree line between the operations area and the lake

SO12

Collected near SO-11 behind an abandoned truck

SO13

Collected at the end of a concrete lined drainage ditch leading toward Stewart's Creek

SO14

Collected from natural drain pathway on west side of the site

Table 3. Sediment samples collected* on and in the vicinity of the Conroe Creosoting Company site November 2001
Sample ID	Sample Location
SE-1	Background sample collected in Stewart's Creek 0.67 miles upstream of CCC site
SE-2	Background sample collected in Stewart's Creek 0.6 miles upstream of CCC site
SE-15	Little Caney Creek 0.3 miles upstream of CCC site
SE-16	Little Caney Creek 0.4 miles upstream of CCC site
SE-4	Stewart's Creek along the west side of the CCC site
SE-5	Stewart's Creek 50 yards downstream of the SE-4
SE-9	Wetland along Stewart's Creek
SE-10	Stewart's Creek 0.1 mile downstream of SE-09
SE-17	The west bank of the on-site lake
SE-18	The west bank of the on-site lake south of SE-17
SE-19	Duplicate SE-18
SE-20	The beginning of Little Caney Creek after the spillway of the lake
* Prior to EPA removal action

Table 3. Sediment samples collected* on and in the vicinity of the Conroe Creosoting Company site November 2001

Sample ID

Sample Location

SE-1

Background sample collected in Stewart's Creek 0.67 miles upstream of CCC site

SE-2

Background sample collected in Stewart's Creek 0.6 miles upstream of CCC site

SE-15

Little Caney Creek 0.3 miles upstream of CCC site

SE-16

Little Caney Creek 0.4 miles upstream of CCC site

SE-4

Stewart's Creek along the west side of the CCC site

SE-5

Stewart's Creek 50 yards downstream of the SE-4

SE-9

Wetland along Stewart's Creek

SE-10

Stewart's Creek 0.1 mile downstream of SE-09

SE-17

The west bank of the on-site lake

SE-18

The west bank of the on-site lake south of SE-17

SE-19

Duplicate SE-18

SE-20

The beginning of Little Caney Creek after the spillway of the lake

* Prior to EPA removal action

Table 4. Constituents¹ Exceeding HAC Values in On-site Soil Samples Conroe Creosoting Company November 2001
Sample (mg/kg)	SO4	SO5	SO6	SO7	SO8	SO9	SO10	SO11	SO12	SO13	SO14	Health Assessment Comparison Value HAC (mg/kg)²
Semivolatile Organic Compounds
Pentachlorophenol	994	111	nd	nd	nd	nd	24	nd	150	nd	nd	50 child/700 adult chronic/int EMEG³ 2,000 child/20,000 RMEG⁴
Benzo(a)pyrene	71.6	73.3	nd	nd	3.3	28	nd	2.7	25	1.1	nd	0.1 CREG⁵
Naphthalene	1,860	3,120	nd⁶	nd	nd	nd	nd	nd	nd	nd	nd	1,000 child/10,000 adult RMEG/EMEG
Metals
Arsenic	nd	nd	187	162	1,790	8.4	nd	52.7	nd	23	7.2	20 child/200 adult EMEG/RMEG 0.5 CREG
Chromium	nd	nd	64	77	999	10.5	5	111	14	13	9	200 child / 2,000 adult RMEG
¹ mg/kg=milligrams per kilogram ² Health based comparison values are based on an assumed ingestion rate of 100 kg of soil for adults (body weight 70 kilograms) and an ingestion rate of 200 kg of soil for children (body weight 10 kg). ³ EMEG=Environmental Media Evaluation Guide and is based on ATSDR's MRL for chronic exposure ⁴ RMEG=Reference dose Media Evaluation Guide and is based on EPA's RfD for chronic exposure (unless otherwise specified) ⁵ CREG=Cancer Risk Evaluation Guide and is based on an excess cancer risk of one in one-million persons exposed over a lifetime ⁶ not detectable at quantitation limits

Table 4. Constituents¹ Exceeding HAC Values in On-site Soil Samples Conroe Creosoting Company November 2001

Sample (mg/kg)

SO4

SO5

SO6

SO7

SO8

SO9

SO10

SO11

SO12

SO13

SO14

Health Assessment Comparison Value HAC (mg/kg)²

Semivolatile Organic Compounds

Pentachlorophenol

994

111

150

50 child/700 adult chronic/int EMEG³

2,000 child/20,000 RMEG⁴

Benzo(a)pyrene

71.6

73.3

3.3

2.7

1.1

0.1 CREG⁵

Naphthalene

1,860

3,120

nd⁶

1,000 child/10,000 adult RMEG/EMEG

Metals

Arsenic

187

162

1,790

8.4

52.7

7.2

20 child/200 adult EMEG/RMEG
0.5 CREG

Chromium

999

10.5

111

200 child / 2,000 adult RMEG

¹  mg/kg=milligrams per kilogram
²  Health based comparison values are based on an assumed ingestion rate of 100 kg of soil for adults (body weight 70 kilograms) and an ingestion rate of 200 kg of soil for children (body weight 10 kg).
³  EMEG=Environmental Media Evaluation Guide and is based on ATSDR's MRL for chronic exposure
⁴  RMEG=Reference dose Media Evaluation Guide and is based on EPA's RfD for chronic exposure (unless otherwise specified)
⁵  CREG=Cancer Risk Evaluation Guide and is based on an excess cancer risk of one in one-million persons exposed over a lifetime
⁶  not detectable at quantitation limits

Table 5. Constituents Exceeding HAC Values (mg/kg)¹ in On-site Sediment Samples Conroe Creosoting Company
Sample	SE-4	SE-5	SE-9	SE-10	SE-20	Health Assessment Comparison Value (mg/kg)²
Arsenic	6	6.3	14.2	10.3	6.6	20 child/200 adult EMEG³ /RMEG⁴ 0.5 CREG⁵
¹ mg/kg=milligrams per kilogram ² Health based comparison values are based on an assumed daily ingestion rate of 100 mg of soil for a 70 kilogram (kg) body weight adult and an ingestion rate of 200 mg of soil for a 10 kg child. ³ EMEG=Environmental Media Evaluation Guide and is based on ATSDR's MRL for chronic exposure ⁴ RMEG=Reference Dose Media Evaluation guide and is based on EPA's RfD for chronic exposure ⁵ CREG=Cancer Risk Evaluation Guide and is based on an excess cancer risk of one in one-million persons exposed over a lifetime

Table 5. Constituents Exceeding HAC Values (mg/kg)¹ in On-site Sediment Samples
Conroe Creosoting Company

Sample

SE-4

SE-5

SE-9

SE-10

SE-20

Health Assessment Comparison Value (mg/kg)²

Arsenic

6.3

14.2

10.3

6.6

20 child/200 adult EMEG³ /RMEG⁴
0.5 CREG⁵

¹  mg/kg=milligrams per kilogram
²  Health based comparison values are based on an assumed daily ingestion rate of 100 mg of soil for a 70 kilogram (kg) body weight adult and an ingestion rate of 200 mg of soil for a 10 kg child.
³  EMEG=Environmental Media Evaluation Guide and is based on ATSDR's MRL for chronic exposure
⁴  RMEG=Reference Dose Media Evaluation guide and is based on EPA's RfD for chronic exposure
⁵  CREG=Cancer Risk Evaluation Guide and is based on an excess cancer risk of one in one-million persons exposed over a lifetime

Table 6. Description of Monitoring Wells on the Conroe Creosoting Company Site
Well Identifier	Well Location	Unit Screened	Screened Interval (depth below ground surface in feet)
MW1A	300' northeast of rework area	Shallow	59.5-74.8
MW1B	94.2-104.2
MW2A	300' northeast of Plane Fast Trucking Company	Shallow	60-75
MW2B	98.7-108.7
MW3A	150' southeast of re-work area	Shallow	53.9-68.9
MW3B	100.5-110.5
MW4A	Southeast corner of site between Big Tin Barn lumber yard and nearest residence	Shallow	55-70
MW4B	99-109
MW5A	Southeast corner of site near Big Tin Barn lumber yard and SH 105*	Shallow	59.7-74.7
MW5B	94.2-104.2
MW6A	Southwest corner of Big Tin Barn lumber yard and SH 105	Shallow	65-80
MW6B	98.5-108.5
MW7A	Adjacent to Conroe Truck and Trailer Company and SH 105	Shallow	64.4-79.4
MW7B	108.3-118.3
MW8A	Between creosote process area and SH 105	Shallow	59.4-74.4
MW8B	100-110.9
MW9A**	Center of site adjacent to miscellaneous sheds area	Shallow	62-77
MW9B	93-103
MW10A	Center of site	Shallow	60-75
MW10B	108.4-118.4
MW11A	Southeast corner of site near Big Tin Barn lumber yard	Shallow	61-76
MW12	Southeast corner of site near Big Tin Barn lumber yard and SH 105	Deep	129-139
MW13	Southeast corner of site near Big Tin Barn lumber yard and SH 105	Deep	132-142
MW14	South of the former creosote/PCP area	Deep	129-139
* SH 105 - State Highway 105 **A private water supply well is located adjacent to MW9A/9B; it is screened between 150 and 165 feet below ground surface (deep)

Table 6. Description of Monitoring Wells on the Conroe Creosoting Company Site

Well Identifier

Well Location

Unit Screened

Screened Interval (depth below ground surface in feet)

MW1A

300' northeast of rework area

Shallow

59.5-74.8

MW1B

94.2-104.2

MW2A

300' northeast of Plane Fast Trucking Company

Shallow

60-75

MW2B

98.7-108.7

MW3A

150' southeast of re-work area

Shallow

53.9-68.9

MW3B

100.5-110.5

MW4A

Southeast corner of site between Big Tin Barn lumber yard and nearest residence

Shallow

55-70

MW4B

99-109

MW5A

Southeast corner of site near Big Tin Barn lumber yard and SH 105*

Shallow

59.7-74.7

MW5B

94.2-104.2

MW6A

Southwest corner of Big Tin Barn lumber yard and SH 105

Shallow

65-80

MW6B

98.5-108.5

MW7A

Adjacent to Conroe Truck and Trailer Company and SH 105

Shallow

64.4-79.4

MW7B

108.3-118.3

MW8A

Between creosote process area and SH 105

Shallow

59.4-74.4

MW8B

100-110.9

MW9A**

Center of site adjacent to miscellaneous sheds area

Shallow

62-77

MW9B

93-103

MW10A

Center of site

Shallow

60-75

MW10B

108.4-118.4

MW11A

Southeast corner of site near Big Tin Barn lumber yard

Shallow

61-76

MW12

Southeast corner of site near Big Tin Barn lumber yard and SH 105

Deep

129-139

MW13

Southeast corner of site near Big Tin Barn lumber yard and SH 105

Deep

132-142

MW14

South of the former creosote/PCP area

Deep

129-139

* SH 105 - State Highway 105
**A private water supply well is located adjacent to MW9A/9B; it is screened between 150 and 165 feet below ground surface (deep)