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PUBLIC HEALTH ASSESSMENT ADDENDUM

TEXARKANA WOOD PRESERVING COMPANY
TEXARKANA, BOWIE COUNTY, TEXAS


SUMMARY

The Texarkana Wood Preserving Company (TWPC) is a National Priorities List site located in northeastern Texas, at the southern extremity of the City of Texarkana in Bowie County. The TWPC site has been used for various lumber-related activities since the early 1900s and for creosoting operations since the early 1950s. The TWPC operated the site from 1961 to 1984 using a combination of creosote and pentachlorophenol to treat wood in large pressure cylinders. Contaminated soils, groundwater, surface water, and surface water sediments have been detected on and off of the TWPC site. The primary contaminants of concern are polycyclic aromatic hydrocarbons, pentachlorophenol, chlorinated dibenzodioxins and chlorinated dibenzofurans.

The population at greatest risk of exposure to these contaminants are on-site workers engaged in remedial activities. There are currently no residences or businesses located immediately adjacent to the site and no documentation that contaminated groundwater is being used for potable purposes. Should the current land use and/or groundwater use change, in the future, the general public could also be at an increased risk for adverse health effects from site contaminants. Based on the environmental data available for review, the TWPC site currently poses no apparent public health hazard; however, if the planned remedial action is not undertaken, the site could, in the future, pose a public health hazard for the general public residing in the vicinity of the site should the contamination spread to the residential wells.

The Texarkana Wood Preserving Company site has been evaluated by the Agency for Toxic Substances and Disease Registry (ATSDR) Health Activities Recommendation Panel (HARP) for appropriate follow-up with respect to health activities. Because there is no indication that human exposure to site contaminants at levels of public health concern is occurring or has occurred, this site is not being considered for follow-up health activities at this time. However, if data become available suggesting that human exposure to significant levels of hazardous substances is currently occurring or has occurred in the past, ATSDR and the Texas Department of Health (TDH) will reevaluate this site for any indicated follow-up.

To respond to community concerns and based on HARP recommendations, the ATSDR and TDH will continue to coordinate efforts with federal and state environmental agencies in evaluating the site's impact on public health and as new data becomes available they will provide recommendations to address public health issues.


BACKGROUND

A. SITE DESCRIPTION AND HISTORY

The Texarkana Wood Preserving Company (TWPC) is a National Priorities List (NPL) site located in northeastern Texas, at the southern extremity of the City of Texarkana in Bowie County. The Arkansas state line is approximately 3,000 feet due east of TWPC (see site location map - Appendix A). The site is bounded to the west by the Texas and Pacific Railroad right-of-way. Lubbock Street, a public roadway, intersects the site. Days Creek, an interstate tributary of the Sulphur River, is located less than 500 feet east of the site. The general direction of flow is to the south-southwest. Appendix B contains a site map.

The TWPC site has been used for various lumber-related activities since the early 1900s. Several lumber companies have owned or leased portions of the site, but information on the extent of early wood-treating activities was not available. However, aerial photos show some evidence of a wood-preserving operation in 1954.

In 1961, TWPC began their wood-preserving operations in the southwestern portion of the site. The small facility utilized pentachlorophenol and creosote to pressure treat wood. The early facility consisted of a process building, pressure-treatment cylinders, process waste and treatment ponds, and treated lumber drying areas on the southwest side of Lubbock Street. Two ponds on the southeast side of Lubbock Street were later added to serve as wastewater Exiting ATSDR Website evaporation ponds. In late 1971 or early 1972, TWPC moved its creosoting operations to improved facilities on the northwest part of the site. This new area had improved wastewater treatment facilities and was surrounded by a concrete dike designed to contain both spillage and runoff. Wastewater from both the creosote and pentachlorophenol processes was treated and eventually released into a series of three evaporation ponds on the east side of Lubbock Street. The facility closed in August 1984.

The present-day site looks much like it did in 1984, although most of the old equipment has been removed by salvagers and many areas are overgrown with vegetation. Of the pre-1972 facility, only three impoundments (#11, 12, and 13), some concrete slabs and supports, and the old office building remain in the southwest portion of the site. The two evaporation ponds on the southeast side of Lubbock Street are covered with trees and extremely dense groundcover. In the northwest part of the site where post-1972 operations took place, five impoundments (#6, 7, 8, 9, and 10), two large cylindrical tanks, and a dilapidated, rusty metal building still exist. The main process area (Impoundment #9), a large depressed area near the railroad tracks, is covered with a black, crusty pentachlorophenol/creosote residue. On the northeastern side of Lubbock Street, two of the three evaporation ponds (Impoundments #1 and 2) are surrounded by grass and brush, while the third pond (#3) is completely overgrown with vegetation.

Prompted by the report of effluent discharges into Days Creek, investigation of TWPC operations began in 1968 by state environmental agencies. One report noted that the bottom of Days Creek was coated with creosote. In the following 16 years, until operations ceased at the site in 1984, the TWPC was found to be either negligent or delinquent in its efforts to fulfill numerous permitting requirements. In late 1984, the Texas Department of Water Resources, a predecessor of the Texas Water Commission (TWC), first submitted TWPC as a candidate for clean-up under the Superfund program. Contaminated surface water runoff due to pond runoff and potential contamination of shallow groundwater were the major concerns at that time. In March, 1985, the TWPC site was included on the NPL by the Environmental Protection Agency (EPA).

Removal activities also began in 1984 with the pumping of process area rainwater into evaporation ponds. A fence was constructed around the site in 1987 and the Remedial Investigation and Feasibility Studies began in early 1988. Additional site activities have included periodic pumping of rainwater and the addition of more clay to the earthen berm located on the north and east sides of the post-1972 process area.

The Remedial Investigation/Feasibility Study was completed by the TWC in June 1990, and the Record of Decision (ROD) for the source was signed in September, 1990 (4). The selected remedy includes thermal destruction of contaminated soils, and pumping and treatment of the shallow groundwater contamination. A second RI/FS will be initiated by the TWC on the intermediate aquifer (4).

A preliminary health assessment for the TWPC site was performed by the Agency for Toxic Substances and Disease Registry (ATSDR) prior to the completion of the Remedial Investigation (RI) by the TWC (Appendix C). The report was released on April 20, 1989. The assessment, based on data available at the time, concluded that the site represented a potential public health concern to workers involved in remediating the site and to persons using off-site surface water for recreational purposes. The report also concluded that the site could pose a potential public health concern to area residents that ingest, or come into contact with, contaminated groundwater or through ingestion of livestock products. At the present time, no activities are currently taking place on the TWPC site.

B. SITE VISIT

Representatives from EPA Region 6 and ATSDR Region 6 conducted a site visit on January 22, 1987. Ponds, standing water, and sinks were visible on site. Surface runoff was observed to flow toward Days Creek and to the property located north and southwest of the site. A tank with unknown contents appeared to be buried in the southwest corner of the site. In addition, fence post holes in the same area show possible creosote seepage Exiting ATSDR Website. Both sides of the site, divided by a public roadway, Lubbock Street, were fenced.

A second site visit was conducted on November 8, 1989, by Texas Department of Health, TWC, and ATSDR Region 6 and Headquarters representatives. At the time of the visit, both sides of the site were fenced and secured with locked gates, although part of the east-side fence had been damaged.

The section of the site located east of Lubbock Street is wooded with heavy undergrowth. The east section was so overgrown that access was not attempted. Portions of the three evaporation ponds (Impoundments #1, 2, and 3) were visible from the road. The storm-water retention ponds, (Impoundments #4 and 5), were not apparent from the roadway.

The western section of the site was less wooded, but did have grasses and brush over most of this section. Portions of the main process area (post-1972) located on the northwest portion of the site, and the "old" process area (pre-1972), located on the southwest portion of the site, were not vegetated. The areas used as roadways were also barren. Piles of debris, including old furniture, oil cans, etc., were scattered across the western section. No evidence of recent trespasser activity was noted.

The only visible contamination was located in Waste Impoundment #9 in the main process area. Impoundment #9, which is surrounded by an earthen berm, was covered with a black creosote residue. The residue was crusty on top, but pliable underneath. A large metal tank was positioned in the middle of the impoundment. Portions of the concrete dike erected in the early 1970s were also visible. The TWC representative pointed out evidence that chains had been attached to the tank in an attempt to pull it over and remove it from the site. He speculated that the tank probably still contains creosote or creosote residue.

Also evident in the vicinity of the main process area were Impoundments #6, 7, 8, and 10. On the day of the site visit, only Impoundment #8 was not filled with water. Impoundments #6, 7, and 10 contained 2-3 feet of water. Waste material generated during the remedial investigation sampling program was placed into 266 55-gallon drums which are currently stacked in the drag out area.

The old process area was located on the southwestern portion of the site. The most noticeable features in this area included the remains of the old office building, several concrete pads, ponds, and an unpaved roadway. The property adjoining the southern perimeter of the site, by the old process area, is currently owned by the Tatum Excavation Company. The excavation company at one time had planned to mine gravel on the property, but elected not to once they were informed there could be drainage problems from the TWPC site. The property is maintained by the company, and there was no evidence of crop production or grazing activities.

C. DEMOGRAPHICS, LAND USE, AND NATURAL RESOURCE USE

Demographics

Texarkana is located in Bowie County at the extreme northeast corner of Texas on the Texas/Arkansas state line. The total area of Bowie County covers approximately 891 square miles. The main industries in the area are livestock, crops, wood products, and gravel mining. The estimated 1988 population of Bowie County is 80,783 persons. The City of Texarkana is actually located in both Texas and Arkansas. The total population for Texarkana is estimated to be 78,813. According to the 1988 estimated population data, approximately 34,014 persons live in Texarkana, Texas (8, 9).

Precise population estimates for the area in the general vicinity of the site were not available. The site is contained within the boundaries of a single census tract, but several of the closest residences are allocated to a neighboring tract. According to the 1980 census, approximately 862 people lived within the two census tracts. The majority of the population in the two tracts is black with a wide distribution of ages. At the time of the 1980 census, 37% of the population in the two tracts was age 0-9 years (10, 11, 12). Health outcome data (mortality data, cancer incidence data, and reproductive outcome data) were not available by census tract for this area.

Land Use

The land directly adjacent to the site is currently unoccupied. The nearest residences are located approximately 300 yards west-northwest of the post-1972 facility's main process area, on the other side of the Texas and Pacific Railroad tracks. Several other single-family homes are located west of the site along with a stockyard and several small businesses. More extensive residential development occupies the land east of Days Creek along both sides of State Line Road. The nearest school is approximately one mile from the TWPC site, on the Arkansas side of Texarkana.

Natural Resource Use

The TWPC site is located approximately 3,000 feet south of the city limits, on the Texas side. Days Creek, an interstate tributary of the Sulphur River, flows in a south-southwesterly direction and is located less than 500 feet east of the site. It is a perennial stream which drains several major Texarkana industries and nearby urban areas. The average water level of Days Creek lies approximately 12 feet below its steeply cut banks, although a major rainstorm can cause the water level to rise as much as six feet.

D. STATE AND LOCAL HEALTH OUTCOME DATA

Based on evaluations performed as part of this health assessment, there is no indication that the public living around the site has been exposed to site-related contaminants. The only community health concern expressed has been the potential for an on-site fire. For those reasons, health outcome data were not evaluated during the conduct of this health assessment.


COMMUNITY HEALTH CONCERNS

In an initial effort to ascertain the current level of community awareness and concern about the TWPC site, EPA, the Texarkana- Bowie County Health Department and the City of Texarkana Office of Emergency Management were contacted in March 1990 (5, 6, 7). No citizen complaints had been recorded by the three agencies. Several city and county offices, however, did express concerns about the potential fire hazards associated with the site.

Bowie County Pollution Control and the local volunteer fire department had expressed their concerns that sparks from passing trains might ignite tall grasses along the railroad track right-of-way and that the fire could spread to the site. In response to these issues, the TWC contacted Union Pacific Railroad officials in September, 1989, to request a more aggressive maintenance schedule for the right-of-way.

The Texarkana Emergency Management Coordinator had also expressed similar concerns regarding the railroad and regarding "accidental" fires being started by passing motorists. He was specifically concerned about the potential toxicity of the smoke which would result from a fire on site, the effect of that smoke on the fire fighters and area residents, the potential for contamination of the water used to fight the fire, and the ultimate fate of that water. He noted that five grass fires had occurred in the general vicinity of the site since January 1, 1990. One fire had reached the boundaries of the site before it was extinguished. The Emergency Management Coordinator had been in contact with EPA and the TWC (6). In response to these concerns about on-site fires, in February 1991, the EPA with the consent of the TWC cleared the site of vegetation.

On March 30, 1992, TDH staff spoke with the Texarkana-Bowie County Health Department about any recent community health concerns related to this site. Mr. Cannon of the local health department indicated that they had not received any health concerns.


ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

A search of the 1987, 1988, and 1989 Toxic Chemical Release Inventory revealed releases from eight different companies located in the same zip code area as the site. None of the reported chemical releases are the same compounds as the contaminants of concern identified at the Texarkana site.

The environmental media sampling program at TWPC was divided into two phases. Phase I, conducted in June and July, 1988, was designed to characterize the nature of the on-site contamination and to plan the Phase II sampling. During Phase I, soil, wastewater, and waste material samples were collected from obviously contaminated areas. Groundwater samples were collected from four monitoring wells installed on site. Surface soil samples collected during Phase I were analyzed in the field. The remaining samples were analyzed in a laboratory.

Phase II samples, collected in October, November, and December 1988, were used to delineate the extent of contamination from the wood preserving activities at the site. Additional surface and subsurface soil samples were collected during the Phase II sampling program both on and off the TWPC site. Surface water and sediment samples were collected from on-site impoundments and along Days Creek. Additional monitoring wells were installed on site and off site in locations downgradient of potential sources of contamination, as delineated by the Phase I sampling. In addition, several residential and business wells were sampled. Ambient air monitoring and biological sampling (fish and rodents) were also conducted. Additional ambient air monitoring for pentachlorophenol was conducted in November 1989. Site maps depicting sample locations can be found in the TWPC Remedial Investigation (RI) Report, Volume I.

A. ON-SITE CONTAMINATION

Table I lists the contaminants of concern found on site and the range of concentrations detected in each environmental medium (References 1-4). During the Phase II sampling, twenty-nine surface soil samples (0-6" in depth) were collected at 27 locations across the TWPC site. All 29 samples were analyzed for semi-volatile organic compounds, six were analyzed for volatile organic compounds, seven for metals, and six were analyzed for chlorinated dibenzodioxins and chlorinated dibenzofurans (CDD/CDFs). Semi-volatile organic contaminants, particularly the polycyclic aromatic hydrocarbons (PAHs), were detected in significant concentrations across the site.

TABLE I. ON-SITE CONTAMINANTS OF CONCERN
CONTAMINANT
GROUNDWATER SHALLOW [LOWER] (g/l)
SURFACE SOIL (mg/kg)
SUBSURFACE SOIL (mg/kg)
WIPE SAMPLES (mg/kg)

VOLATILE ORGANIC COMPOUNDS
Benzene
BDL-310
N/D
BDL-0.013*
N/A
Styrene
BDL-88
N/D
BDL-0.17*
N/A
         
CDD/CDF
Chlorinated Dibenzodioxins
2,3,7,8-TCDD
N/D
N/D
N/D
BDL-0.0028*
Tetra-congener
N/D
N/D
N/D
BDL-0.0028*
Penta-congener
N/D
N/D
N/D
N/D
Hexa-congener
BDL-32
BDL-0.172
BDL-0.0029*
BDL-0.009*
Hepta-congener
BDL-810
BDL-10.461
BDL-0.19
0.105-0.531
Octa-congener
BDL-2900
BDL-16.682
BDL-1.1
0.604-8.797
Chlorinated Dibenzofurans
Tetra-congener
N/D
N/D
N/D
N/D
Penta-congener
N/D
N/D
N/D
N/D
Hexa-congener
BDL-49
BDL-0.052
BDL-0.0016
BDL-0.0029*
Hepta-congener
BDL-230
BDL-0.279
BDL-0.053
BDL-0.033
Octa-congener
BDL-320
BDL-0.27
BDL-0.12
BDL-0.313
         
SEMI-VOLATILE ORGANIC COMPOUNDS
Polycyclic Aromatic Hydrocarbons
Acenaphthene
BDL-5600[BDL-41]**
BDL-450
BDL-6000
N/D
Anthracene
BDL-2000
BDL-7200
BDL-4900
BDL-0.076
Benzo(a)anthracene
BDL-940*
BDL-1100
BDL-1200
BDL-0.075*
Benzo(b)fluoranthene
N/D
BDL-1400
BDL-490
N/D
Benzo(k)fluoranthene
N/D
BDL-690
BDL-450
N/D
Benzo(g,h,i)perylene
N/D
BDL-550
BDL-33
N/D
Benzo(a)pyrene
N/D
BDL-1200
BDL-390
N/D
2-chloronaphthalene
BDL-21*
N/D
N/D
N/D
Chrysene
BDL-910
BDL-1200
BDL-1300
BDL-0.017*
Dibenzo(a,h)anthracene
N/D
BDL-22
BDL-13
N/D
Fluoranthene
BDL-5000
BDL-4200
BDL-5600
BDL-0.140
Fluorene
BDL-3900[BDL-28]**
BDL-4400
BDL-5000
N/D
Indeno(1,2,3-cd)pyrene
N/D
BDL-770
BDL-18
N/D
2-methylnaphthalene
BDL-4500[BDL-88]**
BDL-49
BDL-3200
N/D
Naphthalene
BDL-8300[BDL-650]**
BDL-39
BDL-1700
N/D
Phenanthrene
BDL-13,000[BDL-38]**
BDL-10,000
BDL-8300
BDL-0.086
Pyrene
BDL-4700
BDL-2400
BDL-5100
BDL-0.180
Other Semi-Volatile Organic
Dibenzofuran
BDL-3300
BDL-25
BDL-3700
N/D
2,4-dimethylphenol
BDL-3300
N/D
N/D
N/D
2-methylphenol
BDL-2400
N/D
N/D
N/D
4-methylphenol
BDL-5900
N/D
N/D
N/D
Pentachlorophenol
BDL-4100
BDL-1300
BDL-4800
BDL-0.860*
Phenol
BDL-1700
N/D
N/D
N/D
2,4,5-trichlorophenol
BDL-90
N/D
N/D
N/D

From Roy F. Weston, Inc., 1988 (References 1-4)
BDL - Below Detectable Limit
N/A - Not Analyzed
N/D - Not Detected
* - Detected in one sample
** - Same well, but more than one sample with contaminant

Pentachlorophenol was detected at significant levels in only two surface soil samples, one taken near the cistern located at the northwest corner of the site and the other taken from the old process area. Chlorinated dibenzodioxins/chlorinated dibenzofurans were detected in all of the six samples analyzed. No 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) was detected in surface soil samples. No contamination from volatile organic compounds or the majority of metals was found in the surface soil samples. Mercury was detected at elevated concentrations in the old process area (82 mg/kg) and just east of the area used to store treated lumber (12 mg/kg).

Subsurface soil samples were collected from 43 locations across the site. The depth of the samples ranged from approximately one to four feet for samples collected in trenches, one to 25 feet for soil borings, and from seven feet to a depth of 117 feet for samples collected from monitoring well borings. Of the estimated 105 samples, 71 were collected between one and four feet, 21 were collected between six and 20 feet, and the remaining 13 were collected between 23 and 117 feet. The majority of the contamination was detected at depths of less than eight feet. Contamination with semi-volatile organic compounds, particularly PAHs, was detected across the site. Pentachlorophenol was detected in very few of the subsurface samples and only in areas associated with the two process areas. Chlorinated dibenzodioxins/chlorinated dibenzofurans were detected in 12 of the 24 subsurface samples for which the analysis was performed, but at much lower concentrations than those detected in surface soil samples. The results of the surface and subsurface soil samples indicate three primary areas of contamination - the main process area, the old process area, and the area to the east of Lubbock Street between evaporation ponds #1, 2, and 3 and storm-water retention ponds #4 and 5.

Seven wipe samples were taken from structures and tanks located on site during the Phase II sampling. The wipe samples were collected by wiping a 100 cm2 area with a hexane-soaked glass fiber filter supplied by the analytical laboratory. The protocol used in obtaining the wipe samples was taken from EPA Document 540-P-87-000, December 1987, entitled "A Compendium of Superfund Field Operations Methods." Each of the samples was analyzed for semi-volatile organic compounds. Only three of the samples were analyzed for CDD/CDFs. Several PAHs were identified in samples collected from a tank located at the center of Impoundment #9. Pentachlorophenol was detected on the surface of another tank which has since been removed from the site. Chlorinated dibenzodioxin/chlorinated dibenzofuran contamination was detected in each of the three samples which were analyzed for the compounds. Two of the CDD/CDF-contaminated wipe samples were collected from the tank in Impoundment #9 and one from the former office building associated with the old process area. The office building sample contained the highest levels of hepta-CDD, octa-CDD, and octa-CDF. The tank wipe sample showed contamination with seven CDD/CDFs including 2,3,7,8-TCDD.

Groundwater samples were collected from seven wells located on the TWPC site. Four wells placed in the shallow aquifer (Gravel Zone) were screened at a depth of less than 20 feet. The remaining three wells were placed in the intermediate aquifer (Silty Sand Zone) and were screened at depths of 43-105 feet. Fifteen samples were collected and analyzed for semi-volatile organic compounds and seven samples were analyzed for volatile organic compounds and CDD/CDFs. Samples collected from the shallow aquifer were contaminated with both volatile and semi-volatile organic compounds, including elevated levels of benzene, styrene, PAHs, phenols, and CDD/CDFs. Slight contamination was detected in the intermediate aquifer zone, primarily naphthalene and PAHs at concentrations less than 1 mg/l. Two plumes of contaminated groundwater were identified as the result of this limited sampling. One plume encompasses the majority of the site extending from the main process area to the east side of the site. The second plume, emanating from the old process area, is much smaller and extends south of the site boundaries. The contamination plumes appear to be moving in a southeasterly direction.

The contamination detected in the soils and groundwater are consistent with the types and degree of contamination found in the 13 waste impoundment areas at the TWPC site (References 1-4). Samples collected from the impoundment sludge and waste water contained elevated levels of CDD/CDFs, PAHs, pentachlorophenol, and other semi-volatile organic compounds. The most heavily contaminated impoundments were those associated with the main process area (Impoundments #6, 7, 8, 9) and the old process area (Impoundments #11, 12, 13). Although, volatile organic compounds and metals were detected in the impoundments, contamination did not appear to be significant or widespread. Table II lists the contaminants of concern detected in the impoundments and a range of concentrations.

Limited ambient air monitoring was conducted during the Phase II sampling program. Upwind and downwind samples were collected once from seven different locations at the TWPC site for approximately eight hours each. The sampling locations were selected based on wind direction and to correspond with specific site activities, such as well drilling. During the sample collection, wind speeds were typically below five mph and the direction was variable, although information from the Texarkana Regional Airport states that the wind predominantly blows from the southwest. The temperature ranged from 51-76 degrees Fahrenheit. Precipitation was frequent throughout the Phase II sampling. Each of the samples was analyzed for eight different PAHs and pentachlorophenol. Two of the samples were analyzed for volatile organic compounds. No significant concentrations of any of the contaminants attributable to the site were detected. During the original Phase II sampling in 1988, the analytical holding time limit for each of the pentachlorophenol samples was exceeded. Sampling for pentachlorophenol was repeated in November 1989. No pentachlorophenol was detected in these later samples (14).Organic Vapor Analyzer (OVA) readings collected from monitoring well installation, trenching, and soil boring activities, however, indicated that significant levels of organic vapors could be released during activities that disturb the ground. An OVA is a field screening device used to detect and measure the relative concentrations of organic vapors. The OVA cannot identify specific compounds. The risks associated with any emissions would depend on the nature of each specific compound released.

TABLE II. WASTE IMPOUNDMENT CONTAMINANTS OF CONCERN
CONTAMINANTS
IMPOUNDMENT WATER (g/l)
IMPOUNDMENT SLUDGE (mg/kg)

VOLATILE ORGANIC COMPOUNDS
Benzene
N/D
BDL-39*
Styrene
N/D
BDL-84
     
CDD/CDFS
Chlorinated Dibenzodioxins
2,3,7,8-TCDD
N/D
BDL-0.00044*
Tetra-congener
N/D
BDL-0.0062
Penta-congener
N/D
BDL-0.019
Hexa-congener
BDL-40
0.00038-1.49
Hepta-congener
16-1313
0.0042-18.503
Octa-congener
74-10,836
0.014-83.64
Chlorinated Dibenzofurans
Tetra-congener
N/D
BDL-0.028
Penta-congener
BDL-1.8*
BDL-0.141
Hexa-congener
BDL-19
0.0011-1.93
Hepta-congener
1.8-244
0.0039-6.59
Octa-congener
2.9-577
0.0018-9.59
     
SEMI-VOLATILE ORGANIC COMPOUNDS
Polycyclic Aromatic Hydrocarbons
Acenaphthene
BDL-1500*
BDL-77,000
Anthracene
BDL-1005*
BDL-29,000
Benzo(a)anthracene
BDL-740
BDL-7600
Benzo(b)fluoranthene
BDL-490
BDL-3300
Benzo(k)fluoranthene
BDL-6*
BDL-570
Benzo(g,h,i)perylene
N/D
BDL-7*
Benzo(a)pyrene
BDL-190*
BDL-440
Chrysene
BDL-910
BDL-8900
Fluoranthene
BDL-4600
BDL-60,000
Fluorene
BDL-1650
BDL-56,000
Indeno(1,2,3-cd)pyrene
N/D
BDL-8.5*
2-methylnaphthalene
BDL-330*
BDL-71,000
Naphthalene
BDL-370*
BDL-99,000
Phenanthrene
BDL-7100
BDL-130,000
Pyrene
BDL-3300
BDL-28,000
Other Semi-Volatile Organic
Dibenzofuran
BDL-905*
BDL-46,000
4-methylphenol
BDL-21*
N/D
Pentachlorophenol
BDL-1700
BDL-59,000

From Roy F. Weston, Inc., 1988 (References 1-4)
* - Detected in only one sample
BDL - Below Detection Limits
N/D - Not Detected

B. OFF-SITE CONTAMINATION

Table III lists the contaminants of concern detected during off-site sampling and the range of concentrations in each environmental medium.

Five surface soil samples were collected during Phase II sampling. All of the samples were analyzed for semi-volatile organic compounds. Two samples were analyzed for volatile organic compounds and CDD/CDFs. No significant surface soil contamination was detected.

Subsurface soil samples were collected from 21 off-site locations (References 1-4). A total of 35 subsurface samples, ranging in depth from 1-120 feet, were analyzed for semi-volatile organic compounds. Two of the samples were analyzed for volatile organic compounds and one for CDD/CDFs. Elevated levels of PAHs and pentachlorophenol were detected south of the old process area. Octa-CDD was detected in the one sample which was analyzed for CDD/CDFs. This sample was obtained from a monitoring well boring taken south of the old process area.

A total of 23 samples were taken from 11 off-site groundwater wells located in the shallow aquifer (Gravel Zone). All 23 samples were analyzed for semi-volatile organic compounds; three samples were also analyzed for volatile organic compounds and CDD/CDFs. The main contaminants detected in the shallow groundwater were PAHs and phenols, with most of the contamination detected along the south fence on both the west and east sides of the site. No CDD/CDFs were detected in the shallow wells. Two volatile organic compounds, chloroform and carbon tetrachloride, were detected at significant concentrations in a shallow well located north of the site. This well is located upgradient of the site and the concentration of chloroform and carbon tetrachloride are considered to be "background" values by Roy F. Weston, Inc., the contractor which conducted the Remedial Investigation. According to the Weston report, the exact source of chloroform and carbon tetrachloride could not be determined. A possible source of the chloroform was identified as the Texarkana city water which contained 84 g/l chloroform when sampled in 1985. A blank sample collected as part of the RI from the drilling water truck which contained Texarkana city water contained 66 g/l chloroform. No explanation was provided for the carbon tetrachloride found in the well (2).

TABLE III. OFF-SITE CONTAMINANTS OF CONCERN
CONTAMINANT
GROUNDWATER SHALLOW [LOWER] (g/l)
SURFACE WATER (g/l)
SURFACE WATER SEDIMENTS (mg/kg)
SUBSURFACE SOIL (mg/kg)

VOLATILE ORGANIC COMPOUNDS
Carbon tetrachloride
BDL-40**
N/D
N/D
N/D
Chloroform
BDL-400**
N/D
N/D
N/D
         
SEMI-VOLATILE ORGANIC COMPOUNDS
Chlorinated Dibenzodioxins
Hepta-congener
N/D
BDL-2.5
N/D
N/D
Octa-congener
N/D[BDL-17]
BDL-9.0
0.00051-0.0024
BDL-0.00019*
Chlorinated Dibenzofurans
Octa-congener
N/D[BDL-2.9]*
0.83*
0.00036*
N/D
Polycyclic Aromatic Hydrocarbons
Acenaphthene
BDL-430
N/D
BDL-25*
N/D
Acenaphthylene
BDL-16
N/D
BDL-18*
N/D
Anthracene
BDL-35*
BDL-43*
BDL-41
BDL-1.3
Benzo(a)anthracene
N/D
N/D
N/D
BDL-1.2*
Benzo(b)fluoranthene
N/D
N/D
BDL-E
BDL-3.2
Benzo(k)fluoranthene
N/D
N/D
BDL-52
BDL-2*
Benzo(g,h,i)perylene
N/D
N/D
BDL-31
BDL-1.2*
Benzo(a)pyrene
N/D
N/D
BDL-59
BDL-0.42*
Chrysene
N/D
N/D
BDL-E
BDL-2.4*
Dibenzo(a,h)anthracene
N/D
N/D
BDL-7.8
N/D
Fluoranthene
BDL-54
N/D
BDL-E
BDL-0.46*
Fluorene
BDL-150
N/D
BDL-9.4*
N/D
Indeno(1,2,3-cd)pyrene
N/D
N/D
BDL-27
BDL-1.2*
2-methylnaphthalene
BDL-710
N/D
BDL-17
N/D
Naphthalene
BDL-7100[BDL-14]*
N/D
N/D
BDL-0.51
Phenanthrene
BDL-360[BDL-17]**
N/D
BDL-13
BDL-0.78
Pyrene
BDL-55
N/D
BDL-E
BDL-0.4*
Other Semi-Volatile Organic Compounds
Dibenzofuran
BDL-190
N/D
N/D
N/D
2-methylphenol
BDL-750**
N/D
N/D
N/D
4-methylphenol
BDL-1500*
N/D
N/D
N/D
Pentachlorophenol
BDL-9300*
BDL-120*
BDL-E*
BDL-360

From Roy F. Weston, Inc., 1988 (References 1-4)
* - Only one sample with contaminant
** - Same well, but more than one sample with contaminant
BDL - Below Detectable Limit
N/D - Not Detected
E - Compound was detected beyond the upper calibration range
Surface Water - Contains samples from Days Creek, ditches, and run-off water
Surface Water Sediments - Contains samples from Days Creek, ditches, and run-off sediments

Six samples were obtained from three off-site wells installed in the intermediate aquifer (Silty Sand Zone) and two samples were collected from one well screened in the deep aquifer (Lignite Zone). All eight samples were analyzed for semi-volatile organic compounds and four of the samples were also analyzed for volatile organic compounds and CDD/CDFs. Contamination was detected in only one of the off-site intermediate wells. This well, located south of the old process area, contained low levels of phenanthrene, naphthalene, octa-CDD, and octa-CDF. No contamination was detected in the lower aquifer.

Twenty-six surface water samples were collected from 25 off-site locations. All 26 samples were analyzed for semi-volatile organic compounds: four of the samples were analyzed for volatile organic compounds and CDD/CDFs. Nine samples were taken from Days Creek and its tributaries: two were upstream of the site, four were downstream of the site, and three were from locations parallel to the site in areas potentially influenced by site drainage patterns. Hepta-CDD and octa-CDD were detected in one of the samples collected parallel to the site. Octa-CDD was also detected in one of the downstream samples.

Chlorinated dibenzodioxins/chlorinated dibenzofurans were also detected in two surface water samples collected from the railroad track ditch along the site's west side. Anthracene and pentachlorophenol were each detected in separate samples collected along Lubbock Street.

Twenty-one surface water sediment samples were collected from 20 off-site locations. All 21 were analyzed for semi-volatile organic compounds, four were analyzed for volatile organic compounds, and three were analyzed for CDD/CDFs. Five of the sediment samples were taken from Days Creek; two were collected upstream of the site, two were downstream, and the remaining sample was from a location parallel to the site. The sample collected from the area of the creek parallel to the site contained octa-CDD. One of the downstream sediment samples also contained octa-CDD and octa-CDF. Of the five sediment samples taken from Days Creek, these were the only two analyzed for CDD/CDFs.

Eight other sediment samples were found to contain elevated levels of semi-volatile organic compounds. In addition, one of the samples contained octa-CDD. The semi-volatile organic compound contamination was generally located along the southern portion of the site in two ditches which drain that area. The sediment sample contaminated with octa-CDD was collected along the railroad tracks on the site's west side in an area where surface water contamination was also found. The concentration of OCDD was below the 20 ppb TCDD equivalent action level specified in the ROD.

C. QUALITY ASSURANCE AND QUALITY CONTROL

Preliminary quality assurance and quality control information for the environmental sampling conducted at the TWPC site was provided to the Texas Department of Health. Analyses which did not meet accuracy and precision standards were flagged as unusable in the Remedial Investigation report and were not used in the preparation of this Health Assessment. The analyses and conclusions presented in this Health Assessment are based on the data contained in the Remedial Investigation report. The validity of the conclusions drawn for the Health Assessment are determined by the accuracy and reliability of the referenced information.

D. PHYSICAL AND OTHER HAZARDS

During the site visit conducted on November 28, 1989, an inspection was conducted on the west side of the site, including both process areas. A survey of the eastern portion of the site was not conducted due to the presence of heavy vegetation. Both portions of the site are fenced and have locked gates, although at the time of the site visit, a portion of the fence along Lubbock Street was damaged. The fence is also posted with "Warning - Hazardous Waste" signs. Several physical hazards were noted on the western portion of the site, including two cylindrical metal tanks (one on its side), several water-filled waste impoundments, a dilapidated, rusty tin building, an old office building, 266 55-gallon drums filled with waste generated by the remedial investigation, and scattered piles of trash and debris. The 266 drums of remedial investigation waste will eventually be disposed of on site, but while remaining uncovered on the site, may still pose risks.

The ponds may pose drowning hazards for trespassers. According to the RI report for TWPC, the depths of the waste impoundments vary from 0.5 to 5 feet. Of particular concern are the following ponds because of their depths: Pond #8 (2.5 feet), Ponds #6, 7, 10, and 11 (3 feet), and Pond #12 (5 feet). Pond #9 is the main process area and is at ground level; therefore, no depth below ground level was given.

The portion of the site east of Lubbock Street is covered with trees and dense groundcover. Five waste impoundments are located in this area and could also pose a drowning hazard. Although none were noted during the site visit, poisonous snakes (including cottonmouths and rattlesnakes) are indigenous to the area.


PATHWAYS ANALYSES

A. ENVIRONMENTAL PATHWAYS (FATE AND TRANSPORT)

Environmental sampling conducted during the Remedial Investigation at the TWPC site revealed contamination in soils, groundwater, surface water, and surface water sediments. The primary contaminants of concern found both on and off the site include PAHs, pentachlorophenol, and CDD/CDFs.

Analysis of surface and subsurface soil samples defined three primary areas of soil contamination: the main process area, the old process area, and an area on the east side of the site located between evaporation ponds #1-3 and storm-water retention ponds #4 and 5. With the exception of the soil contamination surrounding the old process area, the majority of contaminated soils were located within the site boundaries. Soil contamination around the old process area extended past the southern boundary of the site. A limited number of soil sample locations (five surface and 21 subsurface) were collected off site during Phase II sampling. Appendices D and E depict the extent of surface and subsurface soil contamination, respectively.

The majority of the contamination detected in the soils across the site was due to semi-volatile organic compounds, particularly the PAHs. Pentachlorophenol was detected in a limited number of soil samples collected on site and in even fewer samples collected off site. Most of the off-site samples in which pentachlorophenol was detected were located in an area directly south of the old process area. Chlorinated dibenzodioxins/ chlorinated dibenzofurans were found in all of the surface soil samples and in half of the subsurface samples which were collected on site and analyzed for the compounds. The CDD/CDF concentrations detected in the on-site subsurface soil samples were typically less than that found in the on-site surface samples. Chlorinated dibenzodioxins/chlorinated dibenzofurans were detected in only one off-site soil sample. This sample was collected just south of the old process area. Only five of the 40 off-site soil samples were analyzed for CDD/CDFs.

Volatile organic compounds were not detected in significant concentrations in either on-site or off-site samples. With the exception of mercury, metals were not detected in significantly elevated concentrations. Mercury was detected in nine of the ten soil samples that were analyzed for metals. Five of the samples contained amounts near or within the background range for mercury, which is 0.01-0.3 mg/kg (14). Of the remaining samples, the highest levels of mercury were detected in concentrations of 12 mg/kg (sample collected east of the treated lumber storage area) and 82 mg/kg (old process area). A duplicate soil sample was taken where the sample containing 82 mg/kg of mercury was collected. The concentration of mercury in the duplicate sample was 71.1 mg/kg. It should be noted that although the highest mercury concentrations appeared in the same general area (the old process area), only a limited number of samples were analyzed for metals (10 of 174).

Wipe samples taken from structures and tanks on-site did show contamination with CDD/CDFs, PAHs, and pentachlorophenol. The contaminated soil could serve as a reservoir for future groundwater contamination, surface water contamination through runoff, and ambient air contamination.

The majority of public and industrial water in the Texarkana area is provided by surface sources, however, groundwater is still utilized. Two aquifers furnish the groundwater which is used in the immediate vicinity of the site: the Quaternary Alluvium and the Wilcox Formation. The Quaternary Alluvium is composed of the Surficial Silty Sand unit and the shallowest water-bearing unit underlying the site, the Gravel Zone. The Gravel Zone is a confined system, typically encountered 6-8' below the ground surface, which unconformably lies on the eroded surface of the Wilcox Formation. The primary direction of flow in the Gravel Zone is southeast with discharge into Days Creek. The upper two units of the Wilcox Formation are the Clayey Sand Zone and the Silty Sand Zone. The Silty Sand Zone is encountered approximately 44-99' below the surface. The two deepest units of the Wilcox are the Lignite and the Deep Clay (References 1-4).

Hydraulic conductivity values for the Gravel Zone and the Clayey Sand and Silty Sand Zone were calculated using laboratory and in-situ tests. The hydraulic conductivity for the Gravel Zone was estimated to be between 0.12 and 5.31 ft./day, while the value for the Clayey Sand and Silty Sand Zone was estimated to be from 0.027 to 0.046 ft./day. Utilizing the estimated hydraulic conductivities, seepage velocities were then calculated, which are important in estimating the rate of groundwater movement within the water-bearing zones. In the Gravel Zone, the seepage velocity was calculated to be from 0.002 to 0.149 ft./day. The seepage velocity for the Clayey Sand and Silty Sand Zone was calculated to be in the range of 3.2 x 10-4 to 1.1 x 10-3 ft./day.

Groundwater samples collected from the shallow aquifer (Gravel Zone) defined two plumes of contamination underlying the TWPC site. The largest plume apparently originates at the main process area and encompasses the majority of the site including most of the site east of Lubbock Street. The second plume encompasses the old process area and extends past the southern boundary of the site. Semi-volatile organic compounds, including PAHs, pentachlorophenol, and CDD/CDFs are the primary contaminants of concern in the shallow aquifer. Four volatile organic compounds, however, were also detected in the shallow aquifer.

Limited contamination was also detected in the intermediate aquifer (Silty Sand Zone). CDD/CDFs, phenanthrene, and naphthalene were found in samples collected from one well located immediately south of the old process area. PAHs were also detected in an intermediate well located northwest of the main process area. Due to the limited amount of sampling conducted in the intermediate aquifer (six wells), it is not possible to establish the degree or extent of the contamination contained in the aquifer.

According to the TWPC RI report, the amount of time it would take for contaminated groundwater to move downward from the Gravel Zone to the Silty Sand Zone was estimated to be between 117 and 455 years. This time, however, could be shorter due to stratigraphic discontinuities and bias towards selection of low permeability soils that were used for permeability tests. The estimated groundwater velocity is 5.48 x 10-4 ft./day to 1.1 x 10-3 ft./day. These numbers roughly translate to approximately 4 to 5 inches of groundwater movement a year.

A well survey conducted as part of the Remedial Investigation identified 104 wells within a one mile radius of the TWPC site. Samples were collected from six of the wells (including five residential wells and one industrial well), an existing TWPC site well located at the southwest corner of the site, and a surface spring located near Lubbock Street approximately 200 yards from the Days Creek Bridge. These samples were analyzed for semi-volatile organic compounds. No contamination was detected.

The sampled industrial well is located northwest of the site and is screened at approximately 90 feet (in the intermediate aquifer). The five residential wells sampled are located approximately 0.5 miles southeast of the site. Although screening depths were not listed for these wells, the Remedial Investigation report noted they were screened in the Gravel Zone.

Surface water from the TWPC site drains into Days Creek (or into ditches which eventually reach Days Creek) due to the local topographic slope towards the southeast. Therefore, contaminants bound to soil particles could potentially migrate from the site towards Days Creek. Surface water and surface water sediment samples collected off site did show evidence of contaminant migration with the surface sediments showing greater levels of contamination than the surface water. The areas of heaviest contamination generally lie within drainage patterns of the site; however, no measurable impact on the water quality of Days Creek was found. Contamination detected along the railroad tracks could have originated on site or may have resulted from activities of the rail line. The contaminants of concern detected were CDD/CDFs, PAHs, and pentachlorophenol.

Ambient air monitoring conducted at seven different locations on the site and at the perimeter did not indicate any significant concentrations of contaminants attributable to the site. Sampling conditions, however, were less than ideal for full characterization of potential ambient air contamination. Temperatures were fairly cool (51-76F), wind speed was low (less than 5 mph), and there was sufficient precipitation during the Phase II sampling to keep the ground damp. It also rained during one of the sampling days. OVA readings collected during trenching and soil boring activities did indicate that organic vapors could be released during intrusive activities in some areas of the site.

The biological investigation conducted at the TWPC site was divided into three parts: a vegetation survey, small mammal sampling, and fish sampling. A qualitative vegetation survey designed to identify any visible evidence of vegetative stress was conducted in November 1988. The survey was compromised, however, because the fall die-back was in progress at the time of the survey. The frequency and distribution of various plant and tree species appeared to be similar for on-site and off-site areas.

Small mammals were trapped on and off of the site and tissues from two species (the house mouse and the white-footed mouse) were analyzed for semi-volatile organic compounds. The concentrations of semi-volatile organic compounds in both the on-site and off-site samples were below detection limits. The physical characteristics of mice collected on site and off site were also similar.

Two fish species were collected from Days Creek at locations purported to be upstream and downstream of the site; the samples were analyzed for physical differences and contaminants associated with the creosoting operation. No significant physical differences were noted between the two samples and no contaminants were detected. The "downstream" sample was collected along an area of Days Creek which historically (prior to 1974) received the majority of the site drainage via a ditch located along Lubbock Street. This area currently receives some overland drainage, but the majority of site runoff is collected and channeled into Days Creek by the South Ditch (located at the southwestern portion of the site). The South Ditch joins Wagner Creek prior to emptying into Days Creek. The Koppers-Texarkana NPL site is located upstream on Wagner Creek. The Koppers site was also a wood preserving facility. The decision was made not to collect samples below the confluence of the two streams and Days Creek due to the potential influence of the Koppers- Texarkana site and the possible interference of a sewage treatment plant. No conclusions can be reached concerning the potential impact of the TWPC site on downstream aquatic biota.

B. HUMAN EXPOSURE PATHWAYS

Inhalation, dermal contact, and ingestion of contaminated surface soils are the primary human exposure pathway of concern. On-site workers engaged in activities which could disturb the soil are the population at greatest risk from exposure. Limited off-site soil sampling detected an area of contamination directly south of the old process area. The extent of soil contamination south of the site, however, does not appear to be adequately characterized. This area is not currently in active use, although at one time a gravel company had planned to excavate the area. Should the status of this area change, workers engaged in gravel excavation could also be at risk. Access to the site is restricted by fences with locked gates. However, trespassers gaining access to the site may also be exposed to contaminated soils.

Ingestion, dermal contact, and the incidental inhalation (during showers, bathing, etc.) of contaminated groundwater are another possible human exposure pathway. There is no indication that the contaminant plume is presently impacting residential wells. Sampling in five residential wells located downgradient in the aquifer of concern (Gravel Zone) did not reveal any contamination. Limited contamination of the intermediate aquifer was also detected. The extent of contamination, however, was not well characterized. Contaminated groundwater could become a significant human exposure pathway if, in the future, the contaminated plumes extend to encompass residential wells and/or if additional wells are installed in the contaminated areas.

The potential air exposure pathway was not well characterized either for particulate or vapor-phase contaminants. The OVA readings did detect significant levels of organic vapors during trenching and soil boring activities indicating the potential for vapor releases during remediation activities. Although the majority of the site is vegetated, wind dispersion of particulates could also represent an additional pathway of concern. Workers engaged in remedial activities would be at greatest risk for exposure. There are currently no businesses or residences located adjacent to the site and no identifiable population at risk for off-site exposure by this pathway.

Surface water and surface water sediments sampled did indicate contamination, the sediments more so than the surface water. Dermal contact, ingestion, and incidental ingestion of surface water are possible human exposure pathways. With the exception of the CDD/CDFs, given that only two additional contaminants were found in relatively low concentrations, these pathways would not appear to predict significant exposure. Exposure to the surface water would be intermittent, further reducing the likelihood of significant exposure. The primary population of concern would be children playing in Days Creek or in other areas of off-site ponded water.

Ingestion of contaminated biota would not appear to be an exposure pathway of concern. No food or forage crops are grown in the immediate vicinity of the site. The small mammals collected on site and analyzed did not reveal any site-related contamination. The attempt to characterize possible site impact on downstream fish was hampered by the possible contribution of another NPL site which was once a wood preserving facility. Additional sampling of fish downstream of the site would help characterize the risk associated with consumption of fish from Days Creek. Days Creek in the area of the site is a relatively small creek and is not considered a major recreational/sporting area.


PUBLIC HEALTH IMPLICATIONS

The primary contaminants of concern detected at the TWPC site are PAHs, pentachlorophenol, and CDD/CDFs. These contaminants were detected in all environmental media. There is, however, no indication of a completed pathway for human exposure at this time. On-site workers engaged in remedial activities would be at greatest risk of exposure to site contaminants, if not properly protected. Dibenzofurans were also detected in soil and groundwater. Volatile organic compounds, including benzene, styrene, chloroform, and carbon tetrachloride, were detected at significant concentrations only in isolated groundwater wells.

Polycyclic aromatic hydrocarbons (PAHs) are a class of structurally-related compounds which were detected in the soils, groundwater, wipe samples, surface water, and surface water sediments at the TWPC site. Within the PAH class of compounds there are hundreds of specific compounds which may vary widely in their toxicities. At the TWPC site, 18 PAHs were identified. Two primary types of adverse health effects have been associated with PAH exposure: dermal effects and cancer.

PAHs may be absorbed through intact human skin. Dermal exposure to certain PAHs, such as anthracene and phenanthrene, followed by exposure to sunlight may result in phototoxic effects such as erythema (redness of the skin), urticaria (elevated patches of skin), and burning and itching (18, 19). Other PAHs, particularly benzo(a)pyrene and benzo(a)anthracene, and mixtures of PAHs have been shown to be carcinogenic in experimental animal studies. Epidemiologic studies of workers occupationally exposed to PAHs have provided limited evidence that PAH exposure may contribute to increased incidence of skin, lung, and urinary tract cancers. The evidence, however, is not considered conclusive. EPA has designated benzo(a)pyrene as a Group B2 - Probable Human Carcinogen (18, 19). Benzo(a)pyrene has also been associated with developmental toxicity and adverse reproductive effects. No studies on the reproductive effects of benzo(a)pyrene or mixtures of PAHs were available for human populations.

Exposure to the maximum concentrations of PAHs found at the site would be of public health concern, particularly exposure to the maximum detected concentration of the carcinogenic PAHs. Off-site contamination with PAHs was limited primarily to low levels in the subsurface soil and surface water sediments. Frequent exposure to these environmental media would not be expected and should pose a minimal health risk.

Pentachlorophenol was detected on site in both surface and subsurface soils, several of the waste impoundments, in wipe samples, and in the groundwater wells. Other phenolic compounds detected at the site included 2,4,5-trichlorophenol, phenol, 2,4-dimethylphenol, 2-methylphenol, and 4-methylphenol. All were detected in the groundwater, generally in smaller concentrations. Off-site, pentachlorophenol was detected in a limited number of samples including one sample collected from a groundwater well located immediately south of the old process area. Both 2- methylphenol and 4-methylphenol were also detected off site in the same groundwater well in which pentachlorophenol was detected.

Pentachlorophenol has been demonstrated to be a highly toxic compound in both humans (primarily through occupational health studies) and experimental animals. The major organs and body systems affected by pentachlorophenol in both humans and animals are the liver, kidney, and central nervous system. There is also evidence in humans that high serum levels of pentachlorophenol may be associated with two skin diseases - pemphigus vulgaris (which produces erosive lesions) and chronic urticaria (a vascular allergic reaction which is characterized by weals) (19, 20, 21). In animal studies, pentachlorophenol has been shown to be toxic to developing embryos and fetuses, but only at doses which also cause maternal toxicity. It has not, however, been shown to be a teratogen. Adverse effects on the immune system have also been documented in experimental animal studies (21).

EPA has designated pentachlorophenol as a Group B2 - Probable Human Carcinogen. This is based on a number of animal studies which have shown pentachlorophenol to be a carcinogen. Evidence for human carcinogenicity is less clear. No convincing evidence has been gathered from human epidemiologic studies, but case reports have suggested an association between certain cancers (Hodgkin's, soft tissue sarcoma, and acute leukemia) and occupational exposure to pentachlorophenol. As was the case with CDD/CDFs, in the human studies, concurrent exposure to other chemicals could not be ruled out (21). The potential exposures at the TWPC site, however, are potentially mixed exposures to a number of chemicals which may affect the same organ systems.

Acute effects from exposure to pentachlorophenol in humans are generally expected only in occupational settings in which extremely high concentrations of pentachlorophenol may be inhaled or in accidental or intentional ingestion cases where pentachlorophenol is ingested in an herbicide mixture. The concentration of pentachlorophenol detected at the TWPC site would not be expected to produce acute effects under reasonable exposure conditions. There are several population groups, however, which may be at a higher risk from exposure to pentachlorophenol. These groups include people with impaired liver or kidney function, malnourished people, pregnant women, the very young, and the very old. There is evidence to suggest that children, in particular, may be more susceptible to the effects of pentachlorophenol.

Long-term or chronic effects from exposure to pentachlorophenol at the site are the primary concern. EPA has proposed a maximum contaminant level goal of 0.22 mg/l for pentachlorophenol in drinking water. The concentrations of pentachlorophenol in the groundwater detected both on and off of the TWPC site greatly exceed this level. If the contaminated groundwater were to be used as a drinking water source, the population could be at a greatly increased risk for both cancer and non-cancer chronic effects. Ingestion and/or inhalation of contaminated soils along with dermal absorption would enhance that risk.

Chlorinated dibenzodioxins and chlorinated dibenzofurans were detected in the surface soil, subsurface soil, groundwater, waste impoundments, and wipe samples on the TWPC site. The CDDs/CDFs are structurally-related classes of chemical compounds which may produce similar toxic effects. Within the general classes of CDDs/CDFs, however, there are a number of different specific CDD/CDF compounds (called congeners), each of which may have a different toxic potency. The most widely studied CDD/CDF congener and the one which is considered to be the most toxic is 2,3,7,8-TCDD.

The CDD congener 2,3,7,8-TCDD was detected only in the wipe samples and in samples collected in the waste impoundments on the TWPC site. Several other congeners, however, were detected in the soil samples, groundwater samples, and in waste impoundments at significantly elevated concentrations. The compounds detected were the penta through octa congeners of CDDs/CDFs. Although these congeners are generally considered to be less toxic than 2,3,7,8-TCDD, the overall toxic potential of a mixture of CDDs/CDFs may be substantial when the concentration of the individual compounds are considered and when the potencies of the congeners are summed.

EPA has developed a procedure for expressing the relative potency of CDD/CDF mixtures compared to the potency of 2,3,7,8-TCDD by assigning each congener a potency factor. The individual estimated potencies of the congeners are then summed and the CDD/CDF mixture's potency is expressed as toxic equivalents of 2,3,7,8-TCDD. The existing toxicological information for 2,3,7,8-TCDD may then be applied to CDD/CDF mixtures (15).

Both EPA and the International Agency for Research on Cancer (IARC) have classified 2,3,7,8-TCDD as a probable human carcinogen. This classification was chosen based on the clear evidence of 2,3,7,8-TCDD carcinogenicity in animal studies, but limited and sometimes conflicting evidence of carcinogenicity in human studies. Several epidemiological studies of human populations exposed to herbicides contaminated with 2,3,7,8-TCDD have demonstrated an association with an increased incidence of stomach cancer, soft tissue sarcomas (at various sites), and lymphomas. These studies have been criticized, however, due to their inability to accurately assess the actual exposure to 2,3,7,8-TCDD (both the concentration and duration of exposure) and their failure to control concurrent exposure to other toxic compounds. A number of additional epidemiological studies have been unable to substantiate an increase in stomach cancer, soft tissue sarcoma, or lymphomas (15).

After a comprehensive review of the available epidemiological studies on 2,3,7,8-TCDD, EPA determined that the data indicated exposure to phenoxy acid herbicides and/or chlorophenols (including pentachlorophenol) is related to an increased risk for soft tissue sarcoma, but that the data were not sufficient to implicate 2,3,7,8-TCDD alone (15).

Animal studies have indicated 2,3,7,8-TCDD is teratogenic and fetotoxic. Exposure during pregnancy may result in a number of adverse reproductive outcomes ranging from spontaneous abortion to developmental abnormalities in the offspring. Animal studies have also demonstrated adverse effects on the immune system, liver, and kidney. In addition, a condition known as the "wasting syndrome" has been reported in many of the animal studies. This syndrome is characterized by loss of appetite, weight loss, and digestive disorders. The type of adverse effects and the severity of the effects of exposure to 2,3,7,8-TCDD in animal studies, however, varies widely depending on the species tested (15).

In humans, the only clearly demonstrated adverse health effect from exposure to CDD/CDFs is a severe acne-like skin condition known as chloracne. The occurrence of chloracne has been documented both in occupational settings and in the general population after accidental releases. A recent occupational study of workers exposed to chlorinated dioxins found that the risk of developing chloracne was associated with the age at which exposure first occurred (younger employees were at higher risk), the intensity of exposure to tetra-, hepta-, and octa-congeners of CDD, the cumulative exposure to tetra-, hepta-, and octa-congeners, and the duration of exposure (16). Although no threshold for chloracne has been determined for CDD/CDF exposure, there are indications that soil concentrations with 100 ppm of 2,3,7,8-TCDD or greater are likely to produce chloracne.

Dibenzofuran (diphenylene oxide) was detected on site in small concentrations in surface soil, in much greater concentrations in subsurface soil, in the groundwater, and in the waste impoundments. It was detected off site in one well located just south of the old process area and in one well located southeast of Impoundments #4 and 5. Insufficient human and/or animal data exists to allow an evaluation of the potential toxicity of the dibenzofuran concentration found at the TWPC site.

Volatile organic compounds were not a widespread problem either on site or off site. Benzene and styrene were found in significant concentrations in one well located on site, southeast of the main process area. The highest levels of benzene and styrene detected were 310 g/l and 88 g/l, respectively. The concentrations of benzene detected in the samples collected from the well significantly exceeded the Safe Drinking Water Act maximum contaminant level (MCL) of 5 g/l. Benzene is classified by EPA as a Group A - Known Human Carcinogen. The carcinogenic classification of styrene is still under review by EPA. Should EPA determine styrene to be carcinogenic, the Proposed Maximum Contaminant Level (PMCL) will be 5 g/l. If it is not determined to be a carcinogen, the PMCL will be 100 g/l.

Chloroform and carbon tetrachloride were detected off site in one well located north of the site. The maximum concentrations of each contaminant also significantly exceed the MCL of 100 g/l for chloroform and 5 g/l for carbon tetrachloride. Both contaminants have been classified as B2 - Probable Human Carcinogens by EPA.

In general, contamination with volatile organic compounds was not a significant problem either on or off the TWPC site and was confined to two wells. Should people use the contaminated water supply, no acute effects would be expected to result. However, the people could be at an increased risk of developing cancer from ingesting the contaminated drinking water.

Mercury was the only metal detected in significant concentrations on site. Based on the limited soil sampling data on metals available for review, the extent of the mercury contamination cannot be determined, although it appears to be limited to one area. Groundwater and surface water samples were not analyzed for metal content. Inhalation, ingestion, and dermal absorption of mercury compounds have been associated with systemic toxicity in humans. The primary target organs or systems affected by mercury are the kidney and central nervous system. Adverse developmental and reproductive effects have also been reported. Mercury has not at this time been determined to be a carcinogen. On-site workers exposed to areas of high mercury contamination would be the population at greatest risk from exposure (22).


CONCLUSIONS

On the basis of the information reviewed, the Texas Department of Health has concluded that this site currently poses no apparent public health hazard because there is no indication that human exposure to site contaminants at levels of public health concern is occurring or has occurred. In the future, this site could pose a public health hazard if it is not remediated and if the contaminants are allowed to migrate into the drinking water supply. As noted in the Environmental Pathways and Human Exposure Pathways Sections above, human exposure may have occurred in the past by inhalation, ingestion, or dermal absorption of contaminated soils. Improperly protected on-site workers and potential trespassers could be exposed to hazardous substances at concentrations that could result in adverse health effects.

Groundwater at the site is heavily contaminated with CDD/CDFs, PAHs, and pentachlorophenol. The contamination is heaviest in the shallow aquifer (Gravel Zone), but has also been detected in the intermediate aquifer (Silty Sand Zone). The extent of the contamination in the intermediate aquifer has not been adequately characterized. Two wells also appear to be contaminated with volatile organic compounds. Volatile organic compound contamination does not appear to be widespread. According to the information provided, groundwater contamination from the TWPC site has not impacted nearby residential wells to date. Nevertheless, five of the wells which were sampled are located southeast and downgradient of the site, and the plume appears to be traveling in a southeasterly direction. In the future, groundwater could provide a significant route of exposure should the contaminant plumes migrate to existing residential wells located downgradient of the site or should additional residential or industrial wells be placed in the shallow aquifer in an area of contamination. At this time, though, the primary population of concern would be on-site workers engaged in any additional sampling or remedial activities.

Surface water located off of the site, including Days Creek and pond water, does not appear to be significantly contaminated. Higher levels of contamination have been detected in surface water sediments perhaps representing much more significant historical contamination of the surface water. The presence of contaminants in the surface water, however, indicate continued off-site migration of contaminants. Heavy rains or flooding may result in greater amounts of off-site contamination. Fish downstream of the site in Days Creek were not adequately characterized for potential site-contributed contamination due to the possible contribution of similar contaminants from another NPL site. According to local officials, Days Creek is not used frequently for fishing.

The potential for the release of either particulate matter or organic vapors from the site was not adequately characterized by the ambient air monitoring conducted during the Remedial Investigation. OVA readings taken during drilling and trenching indicate that significant releases of organic compounds are possible; however, the risks associated with these releases would depend upon compounds being released. The primary population of concern would be workers engaged in on-site activities. There are no residences or businesses immediately adjacent to the site which would likely be impacted by off-site releases of fugitive dust or volatile organic compounds. Additionally, the EPA has indicated that a detailed engineering plan will be in place to control the emissions resulting from the excavation activities.

Access to the site is currently restricted by a fence with locked gates. One area of the fence along Lubbock Street was damaged at the time of the site visit. The damaged fence may not adequately restrict unauthorized entry onto the site.


RECOMMENDATIONS

Cease/Reduce Exposure Recommendations

  1. Worker contact with contaminated environmental media on site should be minimized. Workers should be provided with the appropriate personal protection equipment and training in accordance with applicable Occupational Safety and Health Administration (OSHA) regulations and OSHA and National Institute of Occupational Safety and Health guidelines and advisories.


  2. The fence around the site should be repaired and maintained.

Site Characterization Recommendations

  1. Periodic sampling of nearby residential wells located downgradient of the site and within one-half mile of the site should be conducted to monitor future encroachment of the contaminated groundwater plume in the shallow aquifer (Gravel Zone). In addition, samples should be analyzed for metals, particularly mercury.


  2. Additional groundwater monitoring of the intermediate aquifer (Silty Sand Zone) should be conducted to fully characterize the extent of the contamination.


  3. Additional on-site sampling of aquatic animals (i.e. fish and crawfish) along Days Creek may be undertaken to confirm the presence or absence of contamination in the biota as sufficient funds become available.


  4. Additional soil sampling should be conducted to more adequately characterize possible metals contamination, particularly mercury.


  5. Additional measures should be implemented at the site to contain surface water run-off and prevent migration of contaminants off-site via this route.


  6. Additional air monitoring should be conducted at the site to fully characterize the potential for contaminant migration off-site via ambient air. Sampling should be conducted under conditions which would optimize the opportunity to detect air-borne contaminants (hot, dry conditions).

HEALTH ACTIVITIES RECOMMENDATION PANEL (HARP) RECOMMENDATIONS

In accordance with the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980, as amended, the Texarkana Wood Preserving Company site has been evaluated for appropriate follow-up with respect to health activities. Because there is no indication that human exposure to site contaminants at levels of public health concern is occurring or has occurred, this site is not being considered for follow-up health activities at this time. However, if data become available suggesting that human exposure to significant levels of hazardous substances is currently occurring or has occurred in the past, ATSDR and TDH will reevaluate this site for any indicated follow-up.

If future TDH/ATSDR evaluations indicate that a substantive completed exposure pathway exists, or that the community has expressed specific health concerns, then health outcome databases should be evaluated when future assessments or addenda are prepared for this site.


PUBLIC HEALTH ACTION

To respond to community concerns and based on HARP recommendations, the following actions have been or will be performed to meet the needs expressed by the recommendations of this Health Assessment Addendum.

  1. ATSDR and TDH will continue to coordinate efforts with federal and state environmental agencies in evaluating the site's impact on public health and as new data becomes available they will provide recommendations to address public health issues.

PREPARERS OF THE REPORT

Texas Department of Health

Reviewers:

Judy Henry, M.S.
Staff Epidemiologist

Michelle Kelly, M.M.Sc.
Environmental Quality Specialist

John F. Villanacci, Ph.D., FACSM
Health Assessment Coordinator
Environmental Epidemiology Program

Typist and Graphics:

Mandy Holt
Administrative Technician

Nancy B. Ingram
Administrative Technician


ATSDR REGIONAL REPRESENTATIVES

Carl Hickam, R.S.
Senior Regional Consultant
ATSDR Region 6

George Pettigrew, P.E.
Regional Representative
ATSDR, Region 6


ATSDR TECHNICAL PROJECT OFFICER

William Greim, M.S., M.P.H.
Remedial Programs Branch
Division of Health Assessment and Consultation


CERTIFICATION

This Public Health Assessment Addendum was prepared by the Texas Department of Health under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the Public Health Assessment Addendum was initiated.

William Greim
Technical Project Officer, SPS, RPB, DHAC


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

Director, DHAC, ATSDR


REFERENCES

  1. Texarkana Wood Preserving Company Superfund Site, May 1989, Volume 1 (draft), prepared by: Roy F. Weston, Inc.


  2. Texarkana Wood Preserving Company Superfund Site, June 1989, Volume 1, Prepared by: Roy F. Weston, Inc.


  3. Texarkana Wood Preserving Company Superfund Site, May 1989, Volume 2 (draft), prepared by: Roy F. Weston, Inc.


  4. Texarkana Wood Preserving Company Superfund Site, May 1989, Volume 3 (draft), prepared by: Roy F. Weston, Inc.


  5. USEPA (United States Environmental Protection Agency), Region 6, February, 1991. Quarterly Status Report of Superfund Sites.


  6. Personal communication between Judy Henry, Texas Department of Health (TDH) and Delna Orr, Texarkana-Bowie County Health Department, March 12, 1990.


  7. Personal communication between Judy Henry, TDH and Dave Hall, Emergency Management Coordinator, City of Texarkana, March 12, 1990.


  8. Personal communication between Judy Henry, TDH and Sherry Fuerst, EPA, March 16, 1990.


  9. 1990-1991 Texas Almanac, copyright 1989, published by the Dallas Morning News, Mike Kingston, editor.


  10. 1988-89 Texas Almanac, copyright 1987, published by the Dallas Morning News, Mike Kingston, editor.


  11. 1980 Census Data, Texas Natural Resources Information System, Census of Population and Housing, 1980 Summary Tape File 3A.


  12. U.S. Department of Commerce, Bureau of the Census, Local Population Estimates, SOUTH 1986 Population and 1985 per Capita Income Estimates for Counties and Incorporated Places, Series p-26, No. 86-S-SC.


  13. "Estimates of the Total Populations of Counties and Places in Texas for July 1, 1988", The Texas State Data Center, The Texas State Population Estimates and Projections Program, Texas Department of Commerce, November, 1989.


  14. Pentachlorophenol Ambient Air Sampling Results. Personal communication between Joe H. Brown, TWC, and Donald Ripley, Weston, February 23, 1990.


  15. "Hazardous Waste Land Treatment", U.S. EPA, Office of Solid Waste and Emergency Response, Washington, D.C., April 1983.


  16. Toxicological Profile for 2,3,7,8-Tetrachlorodibenzo-p- dioxin, Agency for Toxic Substances and Disease Registry (ATSDR), U.S. Public Health Service, June, 1989.


  17. "Incidence of Chloracne Among Chemical Workers Potentially Exposed to Chlorinated Dioxins", Gregory Bond, et. al. Journal of Occupational Medicine, Volume 31, No. 9, pp. 771-774, September, 1989.


  18. National Library of Medicine, Hazardous Substances Data Base, Accessed March, 1990.


  19. Toxicological Profile for Benzo(a)pyrene, Draft for Public Comment; ATSDR, U.S. Public Health Service, October, 1987.


  20. Matthew Ellenhorn and Donald Barceloux. Medical Toxicology: Diagnosis and Treatment of Human Poisoning, Elsevier Science Publishing Company, 1988.


  21. Klaassen, C., Amdur, M., Doull, J. Casarett and Doull's Toxicology The Basic Science of Poisons. Third Edition. New York : Macmillan Publishing Company, 1986.


  22. Toxicological Profile for Pentachlorophenol, Draft for Public Comment; ATSDR, U.S. Public Health Service, December, 1988.


  23. Toxicological Profile for Mercury, Agency for Toxic Substances and Disease Registry (ATSDR), U.S. Public Health Service, December 1988.

APPENDICES

Site Location Map
Appendix A. Site Location Map


Site Layout
Appendix B. Site Layout


APPENDIX C: PRELIMINARY HEALTH ASSESSMENT FOR TEXARKANA WOOD PRESERVING SITE


PRELIMINARY HEALTH ASSESSMENT

TEXARKANA WOOD PRESERVING SITE
TEXARKANA, BOWIE COUNTY, TEXAS

EPA FACILITY ID: TX008056152 Exiting ATSDR Website

Prepared by:

Office of Health Assessment
Agency for Toxic Substance and Disease Registry (ATSDR)


HEALTH ASSESSMENT: A NOTE OF EXPLANATION

Section 104(i) (7) (A) of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), as amended, states "...the term 'health assessment' shall include preliminary assessments of potential risks to human health posed by individual sites and facilities, based on such factors as the nature and extent of contamination, the existence of potential pathways of human exposure (including ground or surface water contamination, air emissions, and food chain contamination), the size and potential susceptibility of the community within the likely pathways of exposure, the comparison of expected human exposure levels to the short-term and long-term health effects associated with identified hazardous substances and any available recommended exposure or tolerance limits for such hazardous substances, and the comparison of existing morbidity and mortality data on diseases that may be associated with the observed levels of exposure. The Administrator of ATSDR shall use appropriate data, risk assessments, risk evaluations and studies available from the Administrator of EPA."

In accordance with the CERCLA section cited, ATSDR has conducted this preliminary health assessment on the data in the site summary form. Additional health assessments may be conducted for this site as more information becomes available to ATSDR.


BACKGROUND

The Texarkana Wood Preserving Site (TWP) is listed by the U.S. Environmental Protection Agency on the National Priorities List. The 25 acre site is located in Texarkana (Bowie County), in northeastern Texas. TWP in an inactive wood preserving plant which utilized both creosote and pentachlorophenol in a steam/vacuum pressure treatment process. A public road crosses the site in a north/south direction. TWP is bordered to the east and south by pasture and to the west and north by light industrial facilities. Remedial actions have consisted of pumping the contaminated water from the main process area to evaporation ponds to reduce the potential for overflowing during periods of heavy rainfall. Access to the site is restricted and controlled through the fencing of the site on both sides of the road.


ENVIRONMENTAL CONTAMINATION AND PHYSICAL HAZARDS

Preliminary sampling results of on-site contaminants have demonstrated furans, dioxins, polyaromatic hydrocarbons (PAH's), and pentachlorophenols (PCP's) in soil. In addition, PHA's and PCP were detected in sludge, water and solid waste on-site. Off-site sampling results demonstrated PCP's in surface water.


POTENTIAL ENVIRONMENTAL AND HUMAN EXPOSURE PATHWAYS

Potential environmental pathways include those contaminated groundwater, surface water, on-site soils, and volatilization of contaminants in ambient air. Potential human exposure to contaminants include ingestion and direct contact with groundwater both on and off-site. In addition, direct contact with on-site soils and inhalation of volatilized contaminants during remedial operations may be a potential source for human exposure.


DEMOGRAPHICS

TWP is located in a rural area. There are about 3,010 people living within a mile radius of the site. The distance from TWP to the nearest residence is 0.36 of a mile.


EVALUATION AND DISCUSSION

On-site soils represent a potential public health concern to workers involved in remediation efforts. On-site soils contain dibenzofurans (ND to 10 ppb) and dibenzodioxins (ND to 15 ppb). Tetrachlorodibenzodioxin was not identified from the soil sampling analysis. In addition, PAH's (23,800 ppm in sludge, and 43,000 ppm in solid waste) and PCP (9,800 ppm in sludge, and 7,700 PPM in solid waste) were detected on-site. Soil sampling results did not demonstrate the presence of site-related contaminants off-site.

On-site ponds are subject to overflow and contaminant runoff and may also pose a potential public health concern to remediation workers. Surface water concentrations of PAH's and PCP were reported to be 64 ppb and 1,600 ppb respectively. Moreover, PCP was detected in an off-site surface water sample at a concentration of 56 ppm. The possibility exists for contaminants to migrate off-site into roadside ditches that empty into Days Creek (approximately 2,500 feet to the south and east). A potential public health concern may result from direct contact with contaminated surface water and sediment as well as ingestion of aquatic organisms including fish. However, it has been reported that surface water is not used for potable or recreational purposes.

The municipal water supply is obtained from Lake Texarkana which is southwest and upstream of TWP. However, approximately 1,200 people obtain their water supply from the aquifer of concern. It is unknown as to whether off-site wells both public and private have been sampled for sited-related contaminants. Moreover, the number of irrigation wells using water from this aquifer was not given.


CONCLUSIONS AND RECOMMENDATIONS

TWP represents a potential public health concern to workers involved in remediating the site and to persons using off-site surface water for recreational purposes. Information regarding groundwater and ambient air pathways is not adequate for ATSDR to determine if a public health problem exists requiring mitigative action. TWP may pose potential public health concern to area residents that ingest, or come in direct contact with, contaminated groundwater or through ingestion of livestock products.

To determine the public health implications of this site, ATSDR would require additional information on contaminants released, populations potentially exposed, and environmental pathways through which the contaminants can reach these populations. At a minimum, future investigations of this site should include a survey of municipal and private wells used in the area, characterization of the site and site contaminants, and a characterization of the hydrogeology of the area.

Further environmental characterization and sampling of the site and impacted off-site areas during the Remedial Investigation and Feasibility Study (RI/FS) should be designed to address the environmental and human exposure pathways discussed above. When additional information and data become available, e.g., the completed RI/FS, such material will form the basis for further assessment by ATSDR.



Estimated Surface Soil Contamination
Appendix D. Estimated Surface Soil Contamination


Extent of Subsurface Soil Contamination
Appendix E. Extent of Subsurface Soil Contamination

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