PUBLIC HEALTH ASSESSMENT ADDENDUM
TEXARKANA WOOD PRESERVING COMPANY
TEXARKANA, BOWIE COUNTY, TEXAS
The Texarkana Wood Preserving Company (TWPC) is a NationalPriorities List site located in northeastern Texas, at thesouthern extremity of the City of Texarkana in Bowie County. TheTWPC site has been used for various lumber-related activitiessince the early 1900s and for creosoting operations since theearly 1950s. The TWPC operated the site from 1961 to 1984 usinga combination of creosote and pentachlorophenol to treat wood inlarge pressure cylinders. Contaminated soils, groundwater,surface water, and surface water sediments have been detected onand off of the TWPC site. The primary contaminants of concernare polycyclic aromatic hydrocarbons, pentachlorophenol,chlorinated dibenzodioxins and chlorinated dibenzofurans.
The population at greatest risk of exposure to these contaminantsare on-site workers engaged in remedial activities. There arecurrently no residences or businesses located immediatelyadjacent to the site and no documentation that contaminatedgroundwater is being used for potable purposes. Should thecurrent land use and/or groundwater use change, in the future,the general public could also be at an increased risk for adversehealth effects from site contaminants. Based on theenvironmental data available for review, the TWPC site currentlyposes no apparent public health hazard; however, if the plannedremedial action is not undertaken, the site could, in the future,pose a public health hazard for the general public residing inthe vicinity of the site should the contamination spread to theresidential wells.
The Texarkana Wood Preserving Company site has been evaluated bythe Agency for Toxic Substances and Disease Registry (ATSDR)Health Activities Recommendation Panel (HARP) for appropriatefollow-up with respect to health activities. Because there is noindication that human exposure to site contaminants at levels ofpublic health concern is occurring or has occurred, this site isnot being considered for follow-up health activities at thistime. However, if data become available suggesting that humanexposure to significant levels of hazardous substances iscurrently occurring or has occurred in the past, ATSDR and theTexas Department of Health (TDH) will reevaluate this site forany indicated follow-up.
To respond to community concerns and based on HARPrecommendations, the ATSDR and TDH will continue to coordinateefforts with federal and state environmental agencies inevaluating the site's impact on public health and as new databecomes available they will provide recommendations to addresspublic health issues.
The Texarkana Wood Preserving Company (TWPC) is a NationalPriorities List (NPL) site located in northeastern Texas, at thesouthern extremity of the City of Texarkana in Bowie County. TheArkansas state line is approximately 3,000 feet due east of TWPC(see site location map - Appendix A). The site is bounded to thewest by the Texas and Pacific Railroad right-of-way. LubbockStreet, a public roadway, intersects the site. Days Creek, aninterstate tributary of the Sulphur River, is located less than500 feet east of the site. The general direction of flow is tothe south-southwest. Appendix B contains a site map.
The TWPC site has been used for various lumber-related activitiessince the early 1900s. Several lumber companies have owned orleased portions of the site, but information on the extent ofearly wood-treating activities was not available. However,aerial photos show some evidence of a wood-preserving operationin 1954.
In 1961, TWPC began their wood-preserving operations in thesouthwestern portion of the site. The small facility utilizedpentachlorophenol and creosote to pressure treat wood. The earlyfacility consisted of a process building, pressure-treatmentcylinders, process waste and treatment ponds, and treated lumberdrying areas on the southwest side of Lubbock Street. Two pondson the southeast side of Lubbock Street were later added to serveas wastewater evaporation ponds. In late 1971 or early 1972,TWPC moved its creosoting operations to improved facilities onthe northwest part of the site. This new area had improvedwastewater treatment facilities and was surrounded by a concretedike designed to contain both spillage and runoff. Wastewaterfrom both the creosote and pentachlorophenol processes wastreated and eventually released into a series of threeevaporation ponds on the east side of Lubbock Street. Thefacility closed in August 1984.
The present-day site looks much like it did in 1984, althoughmost of the old equipment has been removed by salvagers and manyareas are overgrown with vegetation. Of the pre-1972 facility,only three impoundments (#11, 12, and 13), some concrete slabsand supports, and the old office building remain in the southwestportion of the site. The two evaporation ponds on the southeastside of Lubbock Street are covered with trees and extremely densegroundcover. In the northwest part of the site where post-1972operations took place, five impoundments (#6, 7, 8, 9, and 10),two large cylindrical tanks, and a dilapidated, rusty metalbuilding still exist. The main process area (Impoundment #9), alarge depressed area near the railroad tracks, is covered with ablack, crusty pentachlorophenol/creosote residue. On thenortheastern side of Lubbock Street, two of the three evaporationponds (Impoundments #1 and 2) are surrounded by grass and brush,while the third pond (#3) is completely overgrown withvegetation.
Prompted by the report of effluent discharges into Days Creek,investigation of TWPC operations began in 1968 by stateenvironmental agencies. One report noted that the bottom of DaysCreek was coated with creosote. In the following 16 years, untiloperations ceased at the site in 1984, the TWPC was found to beeither negligent or delinquent in its efforts to fulfill numerouspermitting requirements. In late 1984, the Texas Department ofWater Resources, a predecessor of the Texas Water Commission(TWC), first submitted TWPC as a candidate for clean-up under theSuperfund program. Contaminated surface water runoff due to pondrunoff and potential contamination of shallow groundwater werethe major concerns at that time. In March, 1985, the TWPC sitewas included on the NPL by the Environmental Protection Agency(EPA).
Removal activities also began in 1984 with the pumping of processarea rainwater into evaporation ponds. A fence was constructedaround the site in 1987 and the Remedial Investigation andFeasibility Studies began in early 1988. Additional siteactivities have included periodic pumping of rainwater and theaddition of more clay to the earthen berm located on the northand east sides of the post-1972 process area.
The Remedial Investigation/Feasibility Study was completed by theTWC in June 1990, and the Record of Decision (ROD) for the sourcewas signed in September, 1990 (4). The selected remedy includesthermal destruction of contaminated soils, and pumping andtreatment of the shallow groundwater contamination. A secondRI/FS will be initiated by the TWC on the intermediate aquifer(4).
A preliminary health assessment for the TWPC site was performedby the Agency for Toxic Substances and Disease Registry (ATSDR)prior to the completion of the Remedial Investigation (RI) by theTWC (Appendix C). The report was released on April 20, 1989. The assessment, based on data available at the time, concludedthat the site represented a potential public health concern toworkers involved in remediating the site and to persons usingoff-site surface water for recreational purposes. The reportalso concluded that the site could pose a potential public healthconcern to area residents that ingest, or come into contact with,contaminated groundwater or through ingestion of livestockproducts. At the present time, no activities are currentlytaking place on the TWPC site.
Representatives from EPA Region 6 and ATSDR Region 6 conducted asite visit on January 22, 1987. Ponds, standing water, and sinkswere visible on site. Surface runoff was observed to flow towardDays Creek and to the property located north and southwest of thesite. A tank with unknown contents appeared to be buried in thesouthwest corner of the site. In addition, fence post holes inthe same area show possible creosote seepage. Both sides of thesite, divided by a public roadway, Lubbock Street, were fenced.
A second site visit was conducted on November 8, 1989, by TexasDepartment of Health, TWC, and ATSDR Region 6 and Headquartersrepresentatives. At the time of the visit, both sides of thesite were fenced and secured with locked gates, although part ofthe east-side fence had been damaged.
The section of the site located east of Lubbock Street is woodedwith heavy undergrowth. The east section was so overgrown thataccess was not attempted. Portions of the three evaporationponds (Impoundments #1, 2, and 3) were visible from the road. The storm-water retention ponds, (Impoundments #4 and 5), werenot apparent from the roadway.
The western section of the site was less wooded, but did havegrasses and brush over most of this section. Portions of themain process area (post-1972) located on the northwest portion ofthe site, and the "old" process area (pre-1972), located on thesouthwest portion of the site, were not vegetated. The areasused as roadways were also barren. Piles of debris, includingold furniture, oil cans, etc., were scattered across the westernsection. 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 surroundedby an earthen berm, was covered with a black creosote residue. The residue was crusty on top, but pliable underneath. A largemetal tank was positioned in the middle of the impoundment. Portions of the concrete dike erected in the early 1970s werealso visible. The TWC representative pointed out evidence thatchains had been attached to the tank in an attempt to pull itover and remove it from the site. He speculated that the tankprobably still contains creosote or creosote residue.
Also evident in the vicinity of the main process area wereImpoundments #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 generatedduring the remedial investigation sampling program was placedinto 266 55-gallon drums which are currently stacked in the dragout area.
The old process area was located on the southwestern portion ofthe site. The most noticeable features in this area included theremains of the old office building, several concrete pads, ponds,and an unpaved roadway. The property adjoining the southernperimeter of the site, by the old process area, is currentlyowned by the Tatum Excavation Company. The excavation company atone time had planned to mine gravel on the property, but electednot to once they were informed there could be drainage problemsfrom the TWPC site. The property is maintained by the company,and there was no evidence of crop production or grazingactivities.
Texarkana is located in Bowie County at the extreme northeastcorner of Texas on the Texas/Arkansas state line. The total areaof Bowie County covers approximately 891 square miles. The mainindustries in the area are livestock, crops, wood products, andgravel mining. The estimated 1988 population of Bowie County is80,783 persons. The City of Texarkana is actually located inboth Texas and Arkansas. The total population for Texarkana isestimated to be 78,813. According to the 1988 estimatedpopulation data, approximately 34,014 persons live in Texarkana,Texas (8, 9).
Precise population estimates for the area in the general vicinityof the site were not available. The site is contained within theboundaries of a single census tract, but several of the closestresidences are allocated to a neighboring tract. According tothe 1980 census, approximately 862 people lived within the twocensus tracts. The majority of the population in the two tractsis black with a wide distribution of ages. At the time of the1980 census, 37% of the population in the two tracts was age 0-9years (10, 11, 12). Health outcome data (mortality data, cancerincidence data, and reproductive outcome data) were not availableby census tract for this area.
The land directly adjacent to the site is currently unoccupied. The nearest residences are located approximately 300 yardswest-northwest of the post-1972 facility's main process area, onthe other side of the Texas and Pacific Railroad tracks. Severalother single-family homes are located west of the site along witha stockyard and several small businesses. More extensiveresidential development occupies the land east of Days Creekalong both sides of State Line Road. The nearest school isapproximately one mile from the TWPC site, on the Arkansas sideof Texarkana.
Natural Resource Use
The TWPC site is located approximately 3,000 feet south of thecity limits, on the Texas side. Days Creek, an interstatetributary of the Sulphur River, flows in a south-southwesterlydirection and is located less than 500 feet east of the site. Itis a perennial stream which drains several major Texarkanaindustries and nearby urban areas. The average water level ofDays Creek lies approximately 12 feet below its steeply cutbanks, although a major rainstorm can cause the water level torise as much as six feet.
Based on evaluations performed as part of this health assessment,there is no indication that the public living around the site hasbeen exposed to site-related contaminants. The only communityhealth concern expressed has been the potential for an on-sitefire. For those reasons, health outcome data were not evaluatedduring the conduct of this health assessment.
In an initial effort to ascertain the current level of communityawareness and concern about the TWPC site, EPA, the Texarkana-Bowie County Health Department and the City of Texarkana Officeof 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 concernsabout the potential fire hazards associated with the site.
Bowie County Pollution Control and the local volunteer firedepartment had expressed their concerns that sparks from passingtrains might ignite tall grasses along the railroad trackright-of-way and that the fire could spread to the site. Inresponse to these issues, the TWC contacted Union PacificRailroad officials in September, 1989, to request a moreaggressive 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-BowieCounty Health Department about any recent community healthconcerns related to this site. Mr. Cannon of the local healthdepartment indicated that they had not received any healthconcerns.
A search of the 1987, 1988, and 1989 Toxic Chemical ReleaseInventory revealed releases from eight different companieslocated in the same zip code area as the site. None of thereported chemical releases are the same compounds as thecontaminants of concern identified at the Texarkana site.
The environmental media sampling program at TWPC was divided intotwo phases. Phase I, conducted in June and July, 1988, wasdesigned to characterize the nature of the on-site contaminationand to plan the Phase II sampling. During Phase I, soil,wastewater, and waste material samples were collected fromobviously contaminated areas. Groundwater samples were collectedfrom four monitoring wells installed on site. Surface soilsamples collected during Phase I were analyzed in the field. Theremaining samples were analyzed in a laboratory.
Phase II samples, collected in October, November, and December1988, were used to delineate the extent of contamination from thewood preserving activities at the site. Additional surface andsubsurface soil samples were collected during the Phase IIsampling program both on and off the TWPC site. Surface waterand sediment samples were collected from on-site impoundments andalong Days Creek. Additional monitoring wells were installed onsite and off site in locations downgradient of potential sourcesof contamination, as delineated by the Phase I sampling. Inaddition, several residential and business wells were sampled. Ambient air monitoring and biological sampling (fish and rodents)were also conducted. Additional ambient air monitoring forpentachlorophenol was conducted in November 1989. Site mapsdepicting sample locations can be found in the TWPC RemedialInvestigation (RI) Report, Volume I.
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.
|CONTAMINANT||GROUNDWATER SHALLOW [LOWER] (µg/l)||SURFACE SOIL (mg/kg)||SUBSURFACE SOIL (mg/kg)||WIPE SAMPLES (mg/kg)|
|VOLATILE ORGANIC COMPOUNDS|
|SEMI-VOLATILE ORGANIC COMPOUNDS|
|Polycyclic Aromatic Hydrocarbons|
|Other Semi-Volatile Organic|
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 twosurface soil samples, one taken near the cistern located at thenorthwest corner of the site and the other taken from the oldprocess area. Chlorinated dibenzodioxins/chlorinateddibenzofurans were detected in all of the six samples analyzed. No 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) wasdetected in surface soil samples. No contamination from volatileorganic compounds or the majority of metals was found in thesurface soil samples. Mercury was detected at elevatedconcentrations in the old process area (82 mg/kg) and just eastof 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 locatedon site during the Phase II sampling. The wipe samples werecollected by wiping a 100 cm2 area with a hexane-soaked glassfiber filter supplied by the analytical laboratory. The protocolused in obtaining the wipe samples was taken from EPA Document540-P-87-000, December 1987, entitled "A Compendium of SuperfundField Operations Methods." Each of the samples was analyzed forsemi-volatile organic compounds. Only three of the samples wereanalyzed for CDD/CDFs. Several PAHs were identified in samplescollected from a tank located at the center of Impoundment #9. Pentachlorophenol was detected on the surface of another tankwhich has since been removed from the site. Chlorinateddibenzodioxin/chlorinated dibenzofuran contamination was detectedin each of the three samples which were analyzed for thecompounds. Two of the CDD/CDF-contaminated wipe samples werecollected from the tank in Impoundment #9 and one from the formeroffice building associated with the old process area. The officebuilding sample contained the highest levels of hepta-CDD,octa-CDD, and octa-CDF. The tank wipe sample showedcontamination with seven CDD/CDFs including 2,3,7,8-TCDD.
Groundwater samples were collected from seven wells located onthe TWPC site. Four wells placed in the shallow aquifer (GravelZone) were screened at a depth of less than 20 feet. Theremaining 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-volatileorganic compounds and seven samples were analyzed for volatileorganic compounds and CDD/CDFs. Samples collected from theshallow aquifer were contaminated with both volatile andsemi-volatile organic compounds, including elevated levels ofbenzene, styrene, PAHs, phenols, and CDD/CDFs. Slightcontamination was detected in the intermediate aquifer zone,primarily naphthalene and PAHs at concentrations less than 1mg/l. Two plumes of contaminated groundwater were identified asthe result of this limited sampling. One plume encompasses themajority of the site extending from the main process area to theeast side of the site. The second plume, emanating from the oldprocess area, is much smaller and extends south of the siteboundaries. The contamination plumes appear to be moving in asoutheasterly direction.
The contamination detected in the soils and groundwater areconsistent with the types and degree of contamination found inthe 13 waste impoundment areas at the TWPC site (References 1-4). Samples collected from the impoundment sludge and waste watercontained elevated levels of CDD/CDFs, PAHs, pentachlorophenol,and other semi-volatile organic compounds. The most heavilycontaminated impoundments were those associated with the mainprocess area (Impoundments #6, 7, 8, 9) and the old process area(Impoundments #11, 12, 13). Although, volatile organic compoundsand metals were detected in the impoundments, contamination didnot appear to be significant or widespread. Table II lists thecontaminants of concern detected in the impoundments and a rangeof 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.
|CONTAMINANTS||IMPOUNDMENT WATER (µg/l)||IMPOUNDMENT SLUDGE (mg/kg)|
|VOLATILE ORGANIC COMPOUNDS|
|SEMI-VOLATILE ORGANIC COMPOUNDS|
|Polycyclic Aromatic Hydrocarbons|
|Other Semi-Volatile Organic|
From Roy F. Weston, Inc., 1988 (References 1-4)
* - Detected in only one sample
BDL - Below Detection Limits
N/D - Not Detected
Table III lists the contaminants of concern detected duringoff-site sampling and the range of concentrations in eachenvironmental medium.
Five surface soil samples were collected during Phase IIsampling. All of the samples were analyzed for semi-volatileorganic compounds. Two samples were analyzed for volatileorganic compounds and CDD/CDFs. No significant surface soilcontamination was detected.
Subsurface soil samples were collected from 21 off-site locations(References 1-4). A total of 35 subsurface samples, ranging indepth from 1-120 feet, were analyzed for semi-volatile organiccompounds. Two of the samples were analyzed for volatile organiccompounds and one for CDD/CDFs. Elevated levels of PAHs andpentachlorophenol were detected south of the old process area. Octa-CDD was detected in the one sample which was analyzed forCDD/CDFs. This sample was obtained from a monitoring well boringtaken 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 µg/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 µg/l chloroform. No explanation was provided for the carbon tetrachloride found in the well (2).
|CONTAMINANT||GROUNDWATER SHALLOW [LOWER] (µg/l)||SURFACE WATER (µg/l)||SURFACE WATER SEDIMENTS (mg/kg)||SUBSURFACE SOIL (mg/kg)|
|VOLATILE ORGANIC COMPOUNDS|
|SEMI-VOLATILE ORGANIC COMPOUNDS|
|Polycyclic Aromatic Hydrocarbons|
|Other Semi-Volatile Organic Compounds|
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 inthe intermediate aquifer (Silty Sand Zone) and two samples werecollected from one well screened in the deep aquifer (LigniteZone). All eight samples were analyzed for semi-volatile organiccompounds and four of the samples were also analyzed for volatileorganic compounds and CDD/CDFs. Contamination was detected inonly one of the off-site intermediate wells. This well, locatedsouth of the old process area, contained low levels ofphenanthrene, naphthalene, octa-CDD, and octa-CDF. Nocontamination was detected in the lower aquifer.
Twenty-six surface water samples were collected from 25 off-sitelocations. All 26 samples were analyzed for semi-volatileorganic compounds: four of the samples were analyzed for volatileorganic compounds and CDD/CDFs. Nine samples were taken fromDays Creek and its tributaries: two were upstream of the site, four were downstream of the site, and three were fromlocations parallel to the site in areas potentially influenced bysite drainage patterns. Hepta-CDD and octa-CDD were detected inone of the samples collected parallel to the site. Octa-CDD wasalso detected in one of the downstream samples.
Chlorinated dibenzodioxins/chlorinated dibenzofurans were alsodetected in two surface water samples collected from the railroadtrack ditch along the site's west side. Anthracene andpentachlorophenol were each detected in separate samplescollected along Lubbock Street.
Twenty-one surface water sediment samples were collected from 20off-site locations. All 21 were analyzed for semi-volatileorganic compounds, four were analyzed for volatile organiccompounds, and three were analyzed for CDD/CDFs. Five of thesediment samples were taken from Days Creek; two were collectedupstream of the site, two were downstream, and the remaining sample was from a location parallel to the site. The samplecollected from the area of the creek parallel to the sitecontained octa-CDD. One of the downstream sediment samples alsocontained octa-CDD and octa-CDF. Of the five sediment samplestaken from Days Creek, these were the only two analyzed forCDD/CDFs.
Eight other sediment samples were found to contain elevatedlevels of semi-volatile organic compounds. In addition, one ofthe samples contained octa-CDD. The semi-volatile organiccompound contamination was generally located along the southernportion of the site in two ditches which drain that area. Thesediment sample contaminated with octa-CDD was collected alongthe railroad tracks on the site's west side in an area wheresurface water contamination was also found. The concentration ofOCDD was below the 20 ppb TCDD equivalent action level specifiedin the ROD.
Preliminary quality assurance and quality control information forthe environmental sampling conducted at the TWPC site wasprovided to the Texas Department of Health. Analyses which didnot meet accuracy and precision standards were flagged asunusable in the Remedial Investigation report and were not usedin the preparation of this Health Assessment. The analyses andconclusions presented in this Health Assessment are based on thedata contained in the Remedial Investigation report. Thevalidity of the conclusions drawn for the Health Assessment aredetermined by the accuracy and reliability of the referencedinformation.
During the site visit conducted on November 28, 1989, aninspection was conducted on the west side of the site, includingboth process areas. A survey of the eastern portion of the sitewas not conducted due to the presence of heavy vegetation. Bothportions of the site are fenced and have locked gates, althoughat the time of the site visit, a portion of the fence alongLubbock Street was damaged. The fence is also posted with"Warning - Hazardous Waste" signs. Several physical hazards werenoted on the western portion of the site, including twocylindrical metal tanks (one on its side), several water-filledwaste impoundments, a dilapidated, rusty tin building, an oldoffice building, 266 55-gallon drums filled with waste generatedby the remedial investigation, and scattered piles of trash anddebris. The 266 drums of remedial investigation waste willeventually be disposed of on site, but while remaining uncoveredon the site, may still pose risks.
The ponds may pose drowning hazards for trespassers. Accordingto the RI report for TWPC, the depths of the waste impoundments vary from 0.5 to 5 feet. Of particular concern are the followingponds 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 mainprocess area and is at ground level; therefore, no depth belowground level was given.
The portion of the site east of Lubbock Street is covered withtrees and dense groundcover. Five waste impoundments are locatedin this area and could also pose a drowning hazard. Althoughnone were noted during the site visit, poisonous snakes(including cottonmouths and rattlesnakes) are indigenous to thearea.
Environmental sampling conducted during the RemedialInvestigation at the TWPC site revealed contamination in soils,groundwater, surface water, and surface water sediments. Theprimary contaminants of concern found both on and off the siteinclude PAHs, pentachlorophenol, and CDD/CDFs.
Analysis of surface and subsurface soil samples defined threeprimary areas of soil contamination: the main process area, theold process area, and an area on the east side of the sitelocated between evaporation ponds #1-3 and storm-water retentionponds #4 and 5. With the exception of the soil contaminationsurrounding the old process area, the majority of contaminatedsoils were located within the site boundaries. Soilcontamination around the old process area extended past thesouthern boundary of the site. A limited number of soil samplelocations (five surface and 21 subsurface) were collected offsite during Phase II sampling. Appendices D and E depict theextent of surface and subsurface soil contamination,respectively.
The majority of the contamination detected in the soils acrossthe site was due to semi-volatile organic compounds, particularlythe PAHs. Pentachlorophenol was detected in a limited number ofsoil samples collected on site and in even fewer samplescollected off site. Most of the off-site samples in whichpentachlorophenol was detected were located in an area directlysouth of the old process area. Chlorinated dibenzodioxins/chlorinated dibenzofurans were found in all of the surface soilsamples and in half of the subsurface samples which werecollected on site and analyzed for the compounds. The CDD/CDFconcentrations detected in the on-site subsurface soil sampleswere typically less than that found in the on-site surfacesamples. Chlorinated dibenzodioxins/chlorinated dibenzofuranswere detected in only one off-site soil sample. This sample wascollected just south of the old process area. Only five of the40 off-site soil samples were analyzed for CDD/CDFs.
Volatile organic compounds were not detected in significantconcentrations in either on-site or off-site samples. With theexception of mercury, metals were not detected in significantlyelevated concentrations. Mercury was detected in nine of the tensoil samples that were analyzed for metals. Five of the samplescontained amounts near or within the background range formercury, which is 0.01-0.3 mg/kg (14). Of the remaining samples,the highest levels of mercury were detected in concentrations of12 mg/kg (sample collected east of the treated lumber storagearea) and 82 mg/kg (old process area). A duplicate soil samplewas taken where the sample containing 82 mg/kg of mercury wascollected. The concentration of mercury in the duplicate samplewas 71.1 mg/kg. It should be noted that although the highestmercury concentrations appeared in the same general area (the oldprocess area), only a limited number of samples were analyzed formetals (10 of 174).
Wipe samples taken from structures and tanks on-site did showcontamination with CDD/CDFs, PAHs, and pentachlorophenol. Thecontaminated soil could serve as a reservoir for futuregroundwater contamination, surface water contamination throughrunoff, and ambient air contamination.
The majority of public and industrial water in the Texarkana areais provided by surface sources, however, groundwater is stillutilized. Two aquifers furnish the groundwater which is used inthe immediate vicinity of the site: the Quaternary Alluvium andthe Wilcox Formation. The Quaternary Alluvium is composed of theSurficial Silty Sand unit and the shallowest water-bearing unitunderlying the site, the Gravel Zone. The Gravel Zone is aconfined system, typically encountered 6-8' below the groundsurface, which unconformably lies on the eroded surface of theWilcox Formation. The primary direction of flow in the GravelZone is southeast with discharge into Days Creek. The upper twounits of the Wilcox Formation are the Clayey Sand Zone and theSilty Sand Zone. The Silty Sand Zone is encounteredapproximately 44-99' below the surface. The two deepest units ofthe Wilcox are the Lignite and the Deep Clay (References 1-4).
Hydraulic conductivity values for the Gravel Zone and the ClayeySand and Silty Sand Zone were calculated using laboratory andin-situ tests. The hydraulic conductivity for the Gravel Zonewas estimated to be between 0.12 and 5.31 ft./day, while thevalue for the Clayey Sand and Silty Sand Zone was estimated to befrom 0.027 to 0.046 ft./day. Utilizing the estimated hydraulicconductivities, seepage velocities were then calculated, whichare important in estimating the rate of groundwater movementwithin the water-bearing zones. In the Gravel Zone, the seepagevelocity was calculated to be from 0.002 to 0.149 ft./day. Theseepage velocity for the Clayey Sand and Silty Sand Zone wascalculated 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 (GravelZone) defined two plumes of contamination underlying the TWPCsite. The largest plume apparently originates at the mainprocess area and encompasses the majority of the site includingmost of the site east of Lubbock Street. The second plumeencompasses the old process area and extends past the southernboundary of the site. Semi-volatile organic compounds, includingPAHs, pentachlorophenol, and CDD/CDFs are the primarycontaminants of concern in the shallow aquifer. Four volatileorganic compounds, however, were also detected in the shallowaquifer.
Limited contamination was also detected in the intermediateaquifer (Silty Sand Zone). CDD/CDFs, phenanthrene, andnaphthalene were found in samples collected from one well locatedimmediately south of the old process area. PAHs were alsodetected in an intermediate well located northwest of the mainprocess area. Due to the limited amount of sampling conducted inthe intermediate aquifer (six wells), it is not possible toestablish the degree or extent of the contamination contained inthe aquifer.
According to the TWPC RI report, the amount of time it would takefor contaminated groundwater to move downward from the GravelZone to the Silty Sand Zone was estimated to be between 117 and455 years. This time, however, could be shorter due tostratigraphic discontinuities and bias towards selection of lowpermeability soils that were used for permeability tests. Theestimated groundwater velocity is 5.48 x 10-4 ft./day to 1.1 x10-3 ft./day. These numbers roughly translate to approximately 4to 5 inches of groundwater movement a year.
A well survey conducted as part of the Remedial Investigationidentified 104 wells within a one mile radius of the TWPC site. Samples were collected from six of the wells (including fiveresidential wells and one industrial well), an existing TWPC sitewell located at the southwest corner of the site, and a surfacespring located near Lubbock Street approximately 200 yards fromthe Days Creek Bridge. These samples were analyzed forsemi-volatile organic compounds. No contamination was detected.
The sampled industrial well is located northwest of the site andis screened at approximately 90 feet (in the intermediateaquifer). The five residential wells sampled are locatedapproximately 0.5 miles southeast of the site. Althoughscreening depths were not listed for these wells, the RemedialInvestigation report noted they were screened in the Gravel Zone.
Surface water from the TWPC site drains into Days Creek (or intoditches which eventually reach Days Creek) due to the localtopographic slope towards the southeast. Therefore, contaminantsbound to soil particles could potentially migrate from the sitetowards Days Creek. Surface water and surface water sedimentsamples collected off site did show evidence of contaminantmigration with the surface sediments showing greater levels ofcontamination than the surface water. The areas of heaviestcontamination generally lie within drainage patterns of the site;however, no measurable impact on the water quality of Days Creekwas found. Contamination detected along the railroad trackscould have originated on site or may have resulted fromactivities of the rail line. The contaminants of concerndetected were CDD/CDFs, PAHs, and pentachlorophenol.
Ambient air monitoring conducted at seven different locations onthe site and at the perimeter did not indicate any significantconcentrations of contaminants attributable to the site. Sampling conditions, however, were less than ideal for fullcharacterization of potential ambient air contamination. Temperatures were fairly cool (51-76F), wind speed was low (lessthan 5 mph), and there was sufficient precipitation during thePhase II sampling to keep the ground damp. It also rained duringone of the sampling days. OVA readings collected duringtrenching and soil boring activities did indicate that organicvapors could be released during intrusive activities in someareas of the site.
The biological investigation conducted at the TWPC site wasdivided into three parts: a vegetation survey, small mammalsampling, and fish sampling. A qualitative vegetation surveydesigned to identify any visible evidence of vegetative stresswas conducted in November 1988. The survey was compromised,however, because the fall die-back was in progress at the time ofthe survey. The frequency and distribution of various plant andtree species appeared to be similar for on-site and off-siteareas.
Small mammals were trapped on and off of the site and tissuesfrom two species (the house mouse and the white-footed mouse)were analyzed for semi-volatile organic compounds. Theconcentrations of semi-volatile organic compounds in both theon-site and off-site samples were below detection limits. Thephysical characteristics of mice collected on site and off sitewere also similar.
Two fish species were collected from Days Creek at locationspurported to be upstream and downstream of the site; the sampleswere analyzed for physical differences and contaminantsassociated with the creosoting operation. No significantphysical differences were noted between the two samples and nocontaminants were detected. The "downstream" sample wascollected along an area of Days Creek which historically (priorto 1974) received the majority of the site drainage via a ditchlocated along Lubbock Street. This area currently receives someoverland drainage, but the majority of site runoff is collectedand channeled into Days Creek by the South Ditch (located at thesouthwestern portion of the site). The South Ditch joins WagnerCreek prior to emptying into Days Creek. The Koppers-TexarkanaNPL site is located upstream on Wagner Creek. The Koppers sitewas also a wood preserving facility. The decision was made notto collect samples below the confluence of the two streams andDays Creek due to the potential influence of the Koppers-Texarkana site and the possible interference of a sewagetreatment plant. No conclusions can be reached concerning thepotential impact of the TWPC site on downstream aquatic biota.
Inhalation, dermal contact, and ingestion of contaminated surfacesoils are the primary human exposure pathway of concern. On-siteworkers engaged in activities which could disturb the soil arethe population at greatest risk from exposure. Limited off-sitesoil sampling detected an area of contamination directly south ofthe old process area. The extent of soil contamination south ofthe site, however, does not appear to be adequatelycharacterized. This area is not currently in active use,although at one time a gravel company had planned to excavate thearea. Should the status of this area change, workers engaged ingravel excavation could also be at risk. Access to the site isrestricted by fences with locked gates. However, trespassersgaining access to the site may also be exposed to contaminatedsoils.
Ingestion, dermal contact, and the incidental inhalation (duringshowers, bathing, etc.) of contaminated groundwater are anotherpossible human exposure pathway. There is no indication that thecontaminant plume is presently impacting residential wells. Sampling in five residential wells located downgradient in theaquifer of concern (Gravel Zone) did not reveal anycontamination. Limited contamination of the intermediate aquiferwas also detected. The extent of contamination, however, was notwell characterized. Contaminated groundwater could become asignificant human exposure pathway if, in the future, thecontaminated plumes extend to encompass residential wells and/orif additional wells are installed in the contaminated areas.
The potential air exposure pathway was not well characterizedeither for particulate or vapor-phase contaminants. The OVAreadings did detect significant levels of organic vapors duringtrenching and soil boring activities indicating the potential forvapor releases during remediation activities. Although themajority of the site is vegetated, wind dispersion ofparticulates could also represent an additional pathway ofconcern. Workers engaged in remedial activities would be atgreatest risk for exposure. There are currently no businesses orresidences located adjacent to the site and no identifiablepopulation at risk for off-site exposure by this pathway.
Surface water and surface water sediments sampled did indicatecontamination, the sediments more so than the surface water. Dermal contact, ingestion, and incidental ingestion of surfacewater are possible human exposure pathways. With the exceptionof the CDD/CDFs, given that only two additional contaminants werefound in relatively low concentrations, these pathways would notappear to predict significant exposure. Exposure to the surfacewater would be intermittent, further reducing the likelihood ofsignificant exposure. The primary population of concern would bechildren playing in Days Creek or in other areas of off-siteponded water.
Ingestion of contaminated biota would not appear to be anexposure pathway of concern. No food or forage crops are grownin the immediate vicinity of the site. The small mammalscollected on site and analyzed did not reveal any site-relatedcontamination. The attempt to characterize possible site impacton downstream fish was hampered by the possible contribution ofanother NPL site which was once a wood preserving facility. Additional sampling of fish downstream of the site would helpcharacterize the risk associated with consumption of fish fromDays Creek. Days Creek in the area of the site is a relativelysmall creek and is not considered a major recreational/sportingarea.
The primary contaminants of concern detected at the TWPC site arePAHs, pentachlorophenol, and CDD/CDFs. These contaminants weredetected in all environmental media. There is, however, noindication of a completed pathway for human exposure at thistime. On-site workers engaged in remedial activities would beat greatest risk of exposure to site contaminants, if notproperly protected. Dibenzofurans were also detected in soil andgroundwater. Volatile organic compounds, including benzene,styrene, chloroform, and carbon tetrachloride, were detected atsignificant concentrations only in isolated groundwater wells.
Polycyclic aromatic hydrocarbons (PAHs) are a class ofstructurally-related compounds which were detected in the soils,groundwater, wipe samples, surface water, and surface watersediments at the TWPC site. Within the PAH class of compoundsthere are hundreds of specific compounds which may vary widely intheir toxicities. At the TWPC site, 18 PAHs were identified. Two primary types of adverse health effects have been associatedwith PAH exposure: dermal effects and cancer.
PAHs may be absorbed through intact human skin. Dermal exposureto certain PAHs, such as anthracene and phenanthrene, followed byexposure to sunlight may result in phototoxic effects such aserythema (redness of the skin), urticaria (elevated patches ofskin), and burning and itching (18, 19). Other PAHs,particularly benzo(a)pyrene and benzo(a)anthracene, and mixturesof PAHs have been shown to be carcinogenic in experimental animalstudies. Epidemiologic studies of workers occupationally exposedto PAHs have provided limited evidence that PAH exposure maycontribute to increased incidence of skin, lung, and urinarytract cancers. The evidence, however, is not consideredconclusive. EPA has designated benzo(a)pyrene as a Group B2 -Probable Human Carcinogen (18, 19). Benzo(a)pyrene has also beenassociated with developmental toxicity and adverse reproductiveeffects. No studies on the reproductive effects ofbenzo(a)pyrene or mixtures of PAHs were available for humanpopulations.
Exposure to the maximum concentrations of PAHs found at the sitewould be of public health concern, particularly exposure to themaximum detected concentration of the carcinogenic PAHs. Off-site contamination with PAHs was limited primarily to lowlevels in the subsurface soil and surface water sediments. Frequent exposure to these environmental media would not beexpected and should pose a minimal health risk.
Pentachlorophenol was detected on site in both surface andsubsurface soils, several of the waste impoundments, in wipesamples, and in the groundwater wells. Other phenolic compoundsdetected at the site included 2,4,5-trichlorophenol, phenol,2,4-dimethylphenol, 2-methylphenol, and 4-methylphenol. All weredetected in the groundwater, generally in smaller concentrations. Off-site, pentachlorophenol was detected in a limited number ofsamples including one sample collected from a groundwater welllocated immediately south of the old process area. Both 2-methylphenol and 4-methylphenol were also detected off site inthe same groundwater well in which pentachlorophenol wasdetected.
Pentachlorophenol has been demonstrated to be a highly toxiccompound in both humans (primarily through occupational healthstudies) and experimental animals. The major organs and bodysystems affected by pentachlorophenol in both humans and animalsare the liver, kidney, and central nervous system. There is alsoevidence in humans that high serum levels of pentachlorophenolmay be associated with two skin diseases - pemphigus vulgaris(which produces erosive lesions) and chronic urticaria (avascular allergic reaction which is characterized by weals) (19,20, 21). In animal studies, pentachlorophenol has been shown tobe toxic to developing embryos and fetuses, but only at doseswhich also cause maternal toxicity. It has not, however, beenshown to be a teratogen. Adverse effects on the immune systemhave also been documented in experimental animal studies (21).
EPA has designated pentachlorophenol as a Group B2 - ProbableHuman Carcinogen. This is based on a number of animal studieswhich have shown pentachlorophenol to be a carcinogen. Evidencefor human carcinogenicity is less clear. No convincing evidencehas been gathered from human epidemiologic studies, but casereports have suggested an association between certain cancers(Hodgkin's, soft tissue sarcoma, and acute leukemia) andoccupational exposure to pentachlorophenol. As was the case withCDD/CDFs, in the human studies, concurrent exposure to otherchemicals could not be ruled out (21). The potential exposuresat the TWPC site, however, are potentially mixed exposures to anumber of chemicals which may affect the same organ systems.
Acute effects from exposure to pentachlorophenol in humans aregenerally expected only in occupational settings in whichextremely high concentrations of pentachlorophenol may be inhaledor in accidental or intentional ingestion cases wherepentachlorophenol is ingested in an herbicide mixture. Theconcentration of pentachlorophenol detected at the TWPC sitewould not be expected to produce acute effects under reasonableexposure conditions. There are several population groups,however, which may be at a higher risk from exposure topentachlorophenol. These groups include people with impairedliver or kidney function, malnourished people, pregnant women,the very young, and the very old. There is evidence to suggestthat children, in particular, may be more susceptible to theeffects of pentachlorophenol.
Long-term or chronic effects from exposure to pentachlorophenolat the site are the primary concern. EPA has proposed a maximumcontaminant level goal of 0.22 mg/l for pentachlorophenol indrinking water. The concentrations of pentachlorophenol in thegroundwater detected both on and off of the TWPC site greatlyexceed this level. If the contaminated groundwater were to beused as a drinking water source, the population could be at agreatly increased risk for both cancer and non-cancer chroniceffects. Ingestion and/or inhalation of contaminated soils alongwith dermal absorption would enhance that risk.
Chlorinated dibenzodioxins and chlorinated dibenzofurans weredetected in the surface soil, subsurface soil, groundwater, wasteimpoundments, and wipe samples on the TWPC site. The CDDs/CDFsare structurally-related classes of chemical compounds which mayproduce similar toxic effects. Within the general classes ofCDDs/CDFs, however, there are a number of different specificCDD/CDF compounds (called congeners), each of which may have adifferent toxic potency. The most widely studied CDD/CDFcongener and the one which is considered to be the most toxic is2,3,7,8-TCDD.
The CDD congener 2,3,7,8-TCDD was detected only in the wipesamples and in samples collected in the waste impoundments on theTWPC site. Several other congeners, however, were detected inthe soil samples, groundwater samples, and in waste impoundmentsat significantly elevated concentrations. The compounds detectedwere the penta through octa congeners of CDDs/CDFs. Althoughthese congeners are generally considered to be less toxic than2,3,7,8-TCDD, the overall toxic potential of a mixture ofCDDs/CDFs may be substantial when the concentration of theindividual compounds are considered and when the potencies of thecongeners are summed.
EPA has developed a procedure for expressing the relative potencyof CDD/CDF mixtures compared to the potency of 2,3,7,8-TCDD byassigning each congener a potency factor. The individualestimated potencies of the congeners are then summed and theCDD/CDF mixture's potency is expressed as toxic equivalents of2,3,7,8-TCDD. The existing toxicological information for2,3,7,8-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 humancarcinogen. This classification was chosen based on the clearevidence of 2,3,7,8-TCDD carcinogenicity in animal studies, butlimited and sometimes conflicting evidence of carcinogenicity inhuman studies. Several epidemiological studies of humanpopulations exposed to herbicides contaminated with 2,3,7,8-TCDDhave demonstrated an association with an increased incidence ofstomach cancer, soft tissue sarcomas (at various sites), andlymphomas. These studies have been criticized, however, due totheir inability to accurately assess the actual exposure to2,3,7,8-TCDD (both the concentration and duration of exposure)and their failure to control concurrent exposure to other toxiccompounds. A number of additional epidemiological studies havebeen unable to substantiate an increase in stomach cancer, softtissue sarcoma, or lymphomas (15).
After a comprehensive review of the available epidemiologicalstudies on 2,3,7,8-TCDD, EPA determined that the data indicatedexposure to phenoxy acid herbicides and/or chlorophenols(including pentachlorophenol) is related to an increased risk forsoft tissue sarcoma, but that the data were not sufficient toimplicate 2,3,7,8-TCDD alone (15).
Animal studies have indicated 2,3,7,8-TCDD is teratogenic andfetotoxic. Exposure during pregnancy may result in a number ofadverse reproductive outcomes ranging from spontaneous abortionto developmental abnormalities in the offspring. Animal studieshave 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 animalstudies. This syndrome is characterized by loss of appetite,weight loss, and digestive disorders. The type of adverseeffects and the severity of the effects of exposure to2,3,7,8-TCDD in animal studies, however, varies widely dependingon the species tested (15).
In humans, the only clearly demonstrated adverse health effectfrom exposure to CDD/CDFs is a severe acne-like skin conditionknown as chloracne. The occurrence of chloracne has beendocumented both in occupational settings and in the generalpopulation after accidental releases. A recent occupationalstudy of workers exposed to chlorinated dioxins found that therisk of developing chloracne was associated with the age at whichexposure first occurred (younger employees were at higher risk),the intensity of exposure to tetra-, hepta-, and octa-congenersof CDD, the cumulative exposure to tetra-, hepta-, andocta-congeners, and the duration of exposure (16). Although nothreshold for chloracne has been determined for CDD/CDF exposure,there are indications that soil concentrations with 100 ppm of2,3,7,8-TCDD or greater are likely to produce chloracne.
Dibenzofuran (diphenylene oxide) was detected on site in smallconcentrations in surface soil, in much greater concentrations insubsurface soil, in the groundwater, and in the wasteimpoundments. It was detected off site in one well located justsouth of the old process area and in one well located southeastof Impoundments #4 and 5. Insufficient human and/or animal dataexists to allow an evaluation of the potential toxicity of thedibenzofuran concentration found at the TWPC site.
Volatile organic compounds were not a widespread problem eitheron site or off site. Benzene and styrene were found insignificant concentrations in one well located on site, southeastof the main process area. The highest levels of benzene andstyrene detected were 310 µg/l and 88 µg/l, respectively. Theconcentrations of benzene detected in the samples collected fromthe well significantly exceeded the Safe Drinking Water Actmaximum contaminant level (MCL) of 5 µg/l. Benzene is classifiedby EPA as a Group A - Known Human Carcinogen. The carcinogenicclassification of styrene is still under review by EPA. ShouldEPA determine styrene to be carcinogenic, the Proposed MaximumContaminant Level (PMCL) will be 5 µg/l. If it is not determinedto be a carcinogen, the PMCL will be 100 µg/l.
Chloroform and carbon tetrachloride were detected off site in onewell located north of the site. The maximum concentrations ofeach contaminant also significantly exceed the MCL of 100 µg/lfor chloroform and 5 µg/l for carbon tetrachloride. Bothcontaminants have been classified as B2 - Probable HumanCarcinogens by EPA.
In general, contamination with volatile organic compounds was nota significant problem either on or off the TWPC site and wasconfined to two wells. Should people use the contaminated watersupply, no acute effects would be expected to result. However,the people could be at an increased risk of developing cancerfrom ingesting the contaminated drinking water.
Mercury was the only metal detected in significant concentrationson site. Based on the limited soil sampling data on metalsavailable for review, the extent of the mercury contaminationcannot be determined, although it appears to be limited to onearea. Groundwater and surface water samples were not analyzedfor metal content. Inhalation, ingestion, and dermal absorptionof mercury compounds have been associated with systemic toxicityin humans. The primary target organs or systems affected bymercury are the kidney and central nervous system. Adversedevelopmental 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 contaminationwould be the population at greatest risk from exposure (22).
On the basis of the information reviewed, the Texas Department ofHealth has concluded that this site currently poses no apparentpublic health hazard because there is no indication that humanexposure to site contaminants at levels of public health concernis occurring or has occurred. In the future, this site couldpose a public health hazard if it is not remediated and if thecontaminants are allowed to migrate into the drinking watersupply. As noted in the Environmental Pathways and HumanExposure Pathways Sections above, human exposure may haveoccurred in the past by inhalation, ingestion, or dermalabsorption of contaminated soils. Improperly protected on-siteworkers and potential trespassers could be exposed to hazardoussubstances at concentrations that could result in adverse healtheffects.
Groundwater at the site is heavily contaminated with CDD/CDFs,PAHs, and pentachlorophenol. The contamination is heaviest inthe shallow aquifer (Gravel Zone), but has also been detected inthe intermediate aquifer (Silty Sand Zone). The extent of thecontamination in the intermediate aquifer has not been adequatelycharacterized. Two wells also appear to be contaminated withvolatile organic compounds. Volatile organic compoundcontamination does not appear to be widespread. According to theinformation provided, groundwater contamination from the TWPCsite has not impacted nearby residential wells to date. Nevertheless, five of the wells which were sampled are locatedsoutheast and downgradient of the site, and the plume appears tobe traveling in a southeasterly direction. In the future,groundwater could provide a significant route of exposure shouldthe contaminant plumes migrate to existing residential wellslocated downgradient of the site or should additional residentialor industrial wells be placed in the shallow aquifer in an areaof contamination. At this time, though, the primary populationof concern would be on-site workers engaged in any additionalsampling or remedial activities.
Surface water located off of the site, including Days Creek andpond water, does not appear to be significantly contaminated. Higher levels of contamination have been detected in surfacewater sediments perhaps representing much more significanthistorical contamination of the surface water. The presence ofcontaminants in the surface water, however, indicate continuedoff-site migration of contaminants. Heavy rains or flooding mayresult in greater amounts of off-site contamination. Fishdownstream of the site in Days Creek were not adequatelycharacterized for potential site-contributed contamination due tothe possible contribution of similar contaminants from anotherNPL site. According to local officials, Days Creek is not usedfrequently for fishing.
The potential for the release of either particulate matter ororganic vapors from the site was not adequately characterized bythe ambient air monitoring conducted during the RemedialInvestigation. OVA readings taken during drilling and trenchingindicate that significant releases of organic compounds arepossible; however, the risks associated with these releases woulddepend upon compounds being released. The primary population ofconcern would be workers engaged in on-site activities. Thereare no residences or businesses immediately adjacent to the sitewhich would likely be impacted by off-site releases of fugitivedust or volatile organic compounds. Additionally, the EPA hasindicated that a detailed engineering plan will be in place tocontrol the emissions resulting from the excavation activities.
Access to the site is currently restricted by a fence with lockedgates. One area of the fence along Lubbock Street was damaged atthe time of the site visit. The damaged fence may not adequatelyrestrict unauthorized entry onto the site.
Cease/Reduce Exposure Recommendations
- Worker contact with contaminated environmental media on siteshould be minimized. Workers should be provided with theappropriate personal protection equipment and training inaccordance with applicable Occupational Safety and HealthAdministration (OSHA) regulations and OSHA and NationalInstitute of Occupational Safety and Health guidelines andadvisories.
- The fence around the site should be repaired and maintained.
Site Characterization Recommendations
- Periodic sampling of nearby residential wells locateddowngradient of the site and within one-half mile of thesite should be conducted to monitor future encroachment ofthe contaminated groundwater plume in the shallow aquifer(Gravel Zone). In addition, samples should be analyzed formetals, particularly mercury.
- Additional groundwater monitoring of the intermediateaquifer (Silty Sand Zone) should be conducted to fullycharacterize the extent of the contamination.
- Additional on-site sampling of aquatic animals (i.e. fishand crawfish) along Days Creek may be undertaken to confirmthe presence or absence of contamination in the biota assufficient funds become available.
- Additional soil sampling should be conducted to moreadequately characterize possible metals contamination,particularly mercury.
- Additional measures should be implemented at the site tocontain surface water run-off and prevent migration ofcontaminants off-site via this route.
- Additional air monitoring should be conducted at the site tofully characterize the potential for contaminant migrationoff-site via ambient air. Sampling should be conductedunder conditions which would optimize the opportunity todetect air-borne contaminants (hot, dry conditions).
In accordance with the Comprehensive Environmental Response,Compensation, and Liability Act (CERCLA) of 1980, as amended, theTexarkana Wood Preserving Company site has been evaluated forappropriate follow-up with respect to health activities. Becausethere is no indication that human exposure to site contaminantsat levels of public health concern is occurring or has occurred,this site is not being considered for follow-up health activitiesat this time. However, if data become available suggesting thathuman exposure to significant levels of hazardous substances iscurrently occurring or has occurred in the past, ATSDR and TDHwill reevaluate this site for any indicated follow-up.
If future TDH/ATSDR evaluations indicate that a substantivecompleted exposure pathway exists, or that the community hasexpressed specific health concerns, then health outcome databasesshould be evaluated when future assessments or addenda areprepared for this site.
To respond to community concerns and based on HARPrecommendations, the following actions have been or will beperformed to meet the needs expressed by the recommendations ofthis Health Assessment Addendum.
- ATSDR and TDH will continue to coordinate efforts withfederal and state environmental agencies in evaluating thesite's impact on public health and as new data becomesavailable they will provide recommendations to addresspublic health issues.
Texas Department of Health
Judy Henry, M.S.
Michelle Kelly, M.M.Sc.
Environmental Quality Specialist
John F. Villanacci, Ph.D., FACSM
Health Assessment Coordinator
Environmental Epidemiology Program
Typist and Graphics:
Nancy B. Ingram
ATSDR REGIONAL REPRESENTATIVES
Carl Hickam, R.S.
Senior Regional Consultant
ATSDR Region 6
George Pettigrew, P.E.
ATSDR, Region 6
ATSDR TECHNICAL PROJECT OFFICER
William Greim, M.S., M.P.H.
Remedial Programs Branch
Division of Health Assessment and Consultation
This Public Health Assessment Addendum was prepared by the TexasDepartment of Health under a cooperative agreement with theAgency for Toxic Substances and Disease Registry (ATSDR). It isin accordance with approved methodology and procedures existingat the time the Public Health Assessment Addendum was initiated.
Technical Project Officer, SPS, RPB, DHAC
The Division of Health Assessment and Consultation, ATSDR, hasreviewed this Public Health Assessment Addendum and concurs withits findings.
Director, DHAC, ATSDR
- Texarkana Wood Preserving Company Superfund Site, May 1989,Volume 1 (draft), prepared by: Roy F. Weston, Inc.
- Texarkana Wood Preserving Company Superfund Site, June 1989,Volume 1, Prepared by: Roy F. Weston, Inc.
- Texarkana Wood Preserving Company Superfund Site, May 1989,Volume 2 (draft), prepared by: Roy F. Weston, Inc.
- Texarkana Wood Preserving Company Superfund Site, May 1989,Volume 3 (draft), prepared by: Roy F. Weston, Inc.
- USEPA (United States Environmental Protection Agency),Region 6, February, 1991. Quarterly Status Report ofSuperfund Sites.
- Personal communication between Judy Henry, Texas Departmentof Health (TDH) and Delna Orr, Texarkana-Bowie County HealthDepartment, March 12, 1990.
- Personal communication between Judy Henry, TDH and DaveHall, Emergency Management Coordinator, City of Texarkana,March 12, 1990.
- Personal communication between Judy Henry, TDH and SherryFuerst, EPA, March 16, 1990.
- 1990-1991 Texas Almanac, copyright 1989, published by theDallas Morning News, Mike Kingston, editor.
- 1988-89 Texas Almanac, copyright 1987, published by theDallas Morning News, Mike Kingston, editor.
- 1980 Census Data, Texas Natural Resources InformationSystem, Census of Population and Housing, 1980 Summary TapeFile 3A.
- U.S. Department of Commerce, Bureau of the Census, LocalPopulation Estimates, SOUTH 1986 Population and 1985 perCapita Income Estimates for Counties and IncorporatedPlaces, Series p-26, No. 86-S-SC.
- "Estimates of the Total Populations of Counties and Placesin Texas for July 1, 1988", The Texas State Data Center, TheTexas State Population Estimates and Projections Program,Texas Department of Commerce, November, 1989.
- Pentachlorophenol Ambient Air Sampling Results. Personalcommunication between Joe H. Brown, TWC, and Donald Ripley,Weston, February 23, 1990.
- "Hazardous Waste Land Treatment", U.S. EPA, Office of SolidWaste and Emergency Response, Washington, D.C., April 1983.
- 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.
- "Incidence of Chloracne Among Chemical Workers PotentiallyExposed to Chlorinated Dioxins", Gregory Bond, et. al. Journal of Occupational Medicine, Volume 31, No. 9, pp.771-774, September, 1989.
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- Toxicological Profile for Benzo(a)pyrene, Draft for PublicComment; ATSDR, U.S. Public Health Service, October, 1987.
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PRELIMINARY HEALTH ASSESSMENT
TEXARKANA WOOD PRESERVING SITE
TEXARKANA, BOWIE COUNTY, TEXAS
EPA FACILITY ID: TX008056152
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.
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.
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 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.
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.
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.
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.