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HEALTH CONSULTATION

Evaluation of Removal Site Evaluation Data

MOUNTAIN PINE PRESSURE TREATING, INCORPORATED
PLAINVIEW, YELL COUNTY, ARKANSAS


BACKGROUND AND STATEMENT OF ISSUES

The Mountain Pine Pressure Treating, Inc. (MPPT) site is a former wood treating facility situatedon 95 acres located on the western border of Plainview, Yell County, Arkansas. Sampling wasconducted in October 2002 as part of an US Environmental Protection Agency (EPA) removalsite evaluation report. The sampling was conducted to evaluate the levels of pentachlorophenoland arsenic inside and around two buildings located on an 8.57 acre portion of the site that hasbeen proposed for reutilization. The sampling plan consisted of air sampling inside the building,soil sampling around the buildings, and surface wipe samples inside the buildings. ArkansasDepartment of Health (ADH) evaluated the results of the environmental samples to determine ifthe constituent levels in and around the buildings posed a public health threat.

Under the proposed plan, the portion of the site that will be reutilized will remain industrial. Aperimeter fence will be constructed around the portion of the site under consideration. The twobuildings on the site will only be used temporarily until two new metal buildings are constructedto replace the old buildings. Once the new buildings are in place, the old structures will bedemolished. The goal is to replace the old buildings within the first year of the reutilization. Onebuilding consists of a roof supported by wooden pillars with one small divider wall in thebuilding and a partial wall on the north side. This building will be used for storage of metalmaterials. The other building will be used as office space for a roof decking company until thenew building is constructed.

When the MPPT site was operational, it consisted of three related contiguous facilities. The threefacilities were MPPT, Plainview Lumber, and the Chromated Copper Arsenate (CCA) TreatmentPlant. MPPT, a subsidiary of Plainview Lumber Company, treated lumber with solutions ofpentachlorophenol (PCP) and CCA from 1965 to 1981. The CCA Treatment Plant used a closedloop system to treat lumber with CCA solutions.

Two distinct treatment processes–the PCP process and the CCA process–occurred during site operations. The Mountain Pine Pressure Treating waste management system consisted of separate PCP and CCA drip tracks, a recovery holding pond, separate PCP and CCA treatment cylinders, a spray evaporation pond, and an oil separator. During both operations, the treated lumber was placed on the drip tracks and the excess solution was allowed to drain onto the tracks. It operated from 1980 to 1986 and reopened briefly in the summer of 1989. Contaminants of concern include PCP, arsenic, copper, lead, chromium, and chlorinated dibenzo-p-dioxins.

In 1987, EPA began a Removal Action to alleviate liquid and sludge releases from a recoveryholding pond. Approximately 2,500 cubic yards of sludge mixed with solidification additiveswere placed beneath a two-foot cap constructed by the EPA in February 1988. A site RemedialInvestigation/Feasibility Study was conducted in December 1998. Soil samples collected andanalyzed through October 2002 indicate that on-site soils contain elevated concentrations of thefollowing metals: arsenic, copper, lead, cadmium, and chromium.

EPA conducted a Preliminary Assessment in October of 1987, and a Site Investigation in May of1988. The MPPT site was proposed to the National Priorities List on April 23, 1999 and wasfinalized to the list July 22, 1999. ADH under a cooperative agreement with the Agency forToxic Substances and Disease Registry (ATSDR) finalized a Public Health Assessment of theentire site in September 2002.

The site is bordered on the north by State Highway 28. The land west of the property is a wildlifemanagement wetland. The property south of the site boundary is owned by the U.S. Army Corpsof Engineers and is covered with native grasses and other plants. The east boundary of the site isTippy Lane in the city of Plainview, which had a population of 685 residents in 1990 and ispresently estimated to have a population of 718 residents. Residences are located directly northand east of the site boundary. There are no residences south and west of the site. The nearestresidences on the north and east sides of the site are approximately 240 feet from the site. Thereis a school (grades K through 12) located approximately 1500 feet from the northeast edge of thesite. A day care center and the city park are less than one mile from the site.

This Health Consultation restricts its evaluation to the proposed reutilization of the 8.57 acresand the two buildings that are located on the 8.57 acres. The public health implicationsassociated with the entire site are discussed in the September 2002 Public Health Assessment for Mountain Pine Pressure Treating [1].


DISCUSSION

Air Samples

Two air samples were collected for PCP and arsenic analysis using high volume samplers fromthe building that will be used for office space. Two polyurethane foam (PUF) samples werecollected from the interior of the building for the PCP analysis. One sampling unit was located inthe middle of the main part of the building, and the second unit was located approximately 20feet from double roll-up garage type doors. For the arsenic analysis, one total suspendedparticulate (TSP) filter was collected from a sampling unit located in the center of the main partof the building. Since the building contained several openings to the exterior and is more than 20feet tall, no attempts to isolate the building from exterior influences were made. A second TSPsample was collected from a unit that was set up outside the building on the east side. Nosamples were collected from the building slated for storage use given its open structure.

PCP was detected in both of the air samples at concentrations of 1 microgram per cubic meter ofair (µg/m3). Doses were estimated for an adult male (whose greater daily inhalation rate exposeshim to the largest dose) and a 10-year-old child. Limited data are available on the inhalationtoxicity of pentachlorophenol in humans. Most information available comes from occupationalexposures involving both inhalation and dermal exposure to PCP [2]. There were no studiesfound which supported adverse health effects associated with inhalation exposures to aircontaining PCP at the detected concentrations.

No arsenic was detected in either of the samples. The detection limit of the arsenic analyticalmethod was 0.01 milligrams per cubic meter of air (mg/m3.) This method is useful foroccupational exposures since the Occupational Safety and Health Administration (OSHA)permissible exposure limit is a time weighted average exposure concentration for 40 hour workweek is 0.01 mg/m3. These samples confirmed that the arsenic concentration in the air meets theOSHA workers' standard.

Since observations made during site visits by ADH personnel during the preparation of thePublic Health Assessment found evidence that trespassers had entered the MPPT site in the past[1], exposure potentials for trespassers were also considered in the evaluation. The method usedfor sampling confirmed that the air met the workers' standard, but the detection limit of themethod could not confirm that the concentrations were below the EPA screening value of0.00045 micrograms per cubic meter of air (µg/m3) or the ATSDR comparison value of 0.002µg/m3. An adult male who has a daily exposure to air containing 0.01 mg/m3 (the detection limitof the reported analytical method) would be exposed to an estimated dose of 0.0033 mg/kg/dayof arsenic. This dose is below the dose anticipated to create a risk of adverse health effectsassociated with exposure. A 10-year-old child exposed to the same air would receive anestimated dose of 0.01 mg/kg/day. The lowest cancer effect level reported is 0.05 mg/kg/day [3].The estimated child dose is below the reported cancer effect level, but there are uncertaintyfactors entailed in the estimation of doses. The weight of evidence indicates that potentiallyexposed children would not be exposed to concentrations that would be of health concern.Confirmation sampling using a method with a lower detection limit would provide the necessaryinformation for ADH to make a data supported health conclusion. Under the proposed reuse, theparcel of land will be fenced. The doses were estimated based on daily exposures to the air. Thepotential for children from the school to trespass on the site and be exposed to site relatedcontaminants will be minimized by the construction of the fence. This physical barrier will alsoeliminate the potential for chronic exposures by children thus eliminating the potential forexposures resulting in doses that would be of health concern.

Soil Samples

Fifteen soil samples were collected around the two buildings. There was no PCP detected in anyof the soil samples. Arsenic was found in all the samples. The concentrations ranged from 7.2milligrams arsenic per kilogram of soil (mg/kg) to 60 mg/kg. One of the samples was collectedoff site near the entrance gate to the former facility and was used as a background sample. Thebackground sample contained 19.4 mg/kg arsenic. The dose estimates were calculated using thesample with the greatest concentration of arsenic. The estimated incidental ingestion dose for anadult was 0.00004 mg/kg/day and for a child was 0.0006 mg/kg/day. The ATSDR minimum risklevel for oral exposure to arsenic is 0.005 mg/kg/day [3]. The estimated doses are below theexposure to arsenic that is likely to have an appreciable risk of deleterious effects.

Wipe Samples

Fourteen wipe samples were taken in the buildings. No PCP was detected in any of the wipesamples. Arsenic was detected in all but one of the samples. Surface wipe samples are used toconfirm the lack of contamination using the null hypothesis approach. In this approach a negativesample indicates that the contaminant is not present and a positive sample verifies the presenceof a contaminant. These samples are typically used to measure the adequacy of industrialhousekeeping or to validate a decontamination effort (such as the Massachusetts Institute forTechnology (MIT) toxic metal decontamination procedure) [4] and cannot be used to estimate exposures. Since this type of sampling is qualitative, an assessment of potential health effectsassociated with exposures cannot be made.

The American Wood Preservers Institute has developed an arsenic wood surface target quantityfor decks or playground equipment constructed of treated wood. That target is 423 microgramsper 100 square centimeters (µg/cm2) [5]. All of the wipe samples except one exceeded that targetquantity. The arsenic wood surface target quantity is based on long term usage (5 years) andfrequent (150 days per year) contact with surfaces. The calculations for the target quantity arebased on a child's body weight (18 kilograms.) If an adult body weight of 70 kilograms issubstituted, the target quantity is 1660 µg/cm2 (or 1.6 mg/cm2.) The wipe samples analyzed alsoexceeded the calculated adult target quantity. The presence of arsenic in the buildings is anindicator that quantitative sampling is needed to verify that the surfaces do not pose a health hazard.


CHILD HEALTH INITIATIVE

ATSDR's Child Health Initiative recognizes that the unique vulnerabilities of infants andchildren demand special emphasis in communities faced with contamination of their water, soil,air, or food. Children are at greater risk than adults from certain kinds of exposures to hazardoussubstances emitted from waste sites and emergency events. They are more likely to be exposedbecause they play outdoors and they often bring food into contaminated areas. They are shorterthan adults, which means they breathe dust, soil, and heavy vapors close to the ground. Childrenare also smaller, resulting in higher doses of chemical exposure per body weight. Thedeveloping body systems of children can sustain permanent damage if toxic exposures occurduring critical growth stages. Most important, children depend completely on adults for riskidentification and management decisions, housing decision, and access to medical care.

In the evaluation of the parcel sample results, ADH estimated child doses for potential exposuresto site related contaminants. ADH also evaluated the likelihood for children living in the vicinityof the proposed reutilization parcel of the MPPT site to be exposed to site contaminants at levelsof health concern. There is a public school located less than one mile from the site and childrenpass by the site in route to school. The proximity of the school and a day care center to the MPPTsite create a potential for children to access areas within the boundaries of the site. Under theproposed plan, a perimeter fence and a locking gate will be constructed around the parcel of thesite that will be reutilized. The physical barrier around the site should provide a sufficientdeterrent to potential trespassers. ADH concluded that the potential for trespassing children to beexposed to site contaminants is very low. Potential exposures that could result from trespassingchildren would be of such short duration that it they would not be at levels of health concern.


CONCLUSIONS

A. Present Site Conditions

  1. Under present site conditions, exposure to surfaces inside the buildings is anindeterminate public health hazard. Wipe samples confirmed that arsenic is present in thebuildings. Since the wipe samples are confirmation samples that cannot be used toestimate exposure doses, ADH could not determine if the levels of arsenic in the buildingposed a public health threat.

  2. The air sample inside the building has small concentrations of pentachlorophenol, but theconcentrations are lower than adverse effect levels and do not pose a public health hazard.The methodology used to sample the arsenic in the air confirmed that there was noarsenic in the air at concentrations greater than the OSHA workers' standard, but thedetection limit of the method could not confirm that arsenic was not present at the EPAscreening concentration. The lowest detection limit of the method restricts the doseestimation to a dose that is very near the health effect level for children. Although theestimated dose is below health effect levels, a greater degree of certainty would beattained with a method that has a lower detection limit. Based on the data available, underpresent site conditions and proposed future use, the air pathway poses no apparent publichealth hazard.

  3. The concentrations of arsenic in the sampled soils do not pose a public health threat basedon incidental soil ingestion. Under present site conditions, the soil pathway poses nopublic health hazard.

B. Future Use

When the proposals for the reutilization are completed, the site will pose no public health hazard.The construction of new buildings in conjunction with the destruction of the old buildings willeliminate potential for exposure to contaminated surfaces in the old buildings. The constructionof a perimeter fence with a locking gate will create an impediment to trespassing by children.


RECOMMENDATIONS

  1. Conduct additional air sampling for arsenic using a method with a lower detection limitbefore existing structures are put back in use.

  2. If resampling is not conducted prior to reoccupancy, develop and implement measures toreduce or eliminate the potential for exposure to surfaces within the old structures whilethe new buildings are being constructed.

  3. Construct the perimeter fence and locking gate before the site is reutilized.

REFERENCES

  1. Agency for Toxic Substances and Disease Registry. Health assessment for Mountain PinePressure Treating, Plainview, Yell County, Arkansas. Atlanta: US Department of Healthand Human Services; 2002.

  2. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Pentachlorophenol. Atlanta: US Department of Health and Human Services; 2001.

  3. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Arsenic.Atlanta: US Department of Health and Human Services; 2001.

  4. Massachusetts Institute of Technology, Environmental Health and Safety Program,Decontamination Procedures for Toxic Metals and Final Acceptance Criteria. Availableat http://web.mit.edu/environment/programs/decontamination.html .

  5. American Wood Preservers Institute. Development of Wood Surface Target Quantity forArsenic Based Exposure to Decks or Playground Equipment Constructed of CCA -Treated Wood. Fairfax, VA. Prepared by Hazardous Substance and Waste ManagementResearch, Inc. Tallahassee, Florida. April, 2001.

PREPARER OF HEALTH CONSULTATION

Health Assessor:

Michael Watts
Arkansas Department of Health


ATSDR Regional Representative:

George Pettigrew
ATSDR Region VI


ATSDR Technical Project Officer:

Tammie McRae
Division of Health Assessment and Consultation
Agency for Toxic Substances and Disease Registry


CERTIFICATION

This Health Consultation for the Mountain Pine Pressure Treating site in Plainview, Arkansas,was prepared by the Arkansas Department of Health under a cooperative agreement with theAgency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approvedmethodology and procedures existing at the time the health consultation was begun.

Roberta Erlwein
Technical Project Officer
Superfund Site Assessment Branch (SSAB)
Division of Health Assessment and Consultation (DHAC)
ATSDR


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

Richard Gillig
Chief, SSAB, DHAC, ATSDR


ATTACHMENTS

Table 1.

Summary of Analytical Results for Soil Samples
Sampling Location Arsenic
(mg/kg)
PCP
(mg/kg)
Near east doorway, Building 1 60 ND
South-east corner of Building 1 34.4 ND
South of Building 1, lowest ground level 27.1 ND
Along east wall, Building 1 18.7 ND
North side, near east corner, Building 1 32.7 ND
North-west corner of Building 1 15.2 ND
Along west wall, middle of storage area,
Building 1
13.8 ND
Along west wall, middle of storage area,
Building 1, lab matrix spike
11.6 ND
Along west wall, middle of storage area,
Building 1, lab matrix spike duplicate
15.4 ND
North-west of drain, Building 2 17.4 ND
North-west of drain, Building 2,
duplicate of S08-0-6-G-N
11.4 ND
Shelf surface, storage area 18.7 ND
West side of Building 2, near second
pillar from north
7.2 ND
North-east-comer, near drain pipe 10.2 ND
Background, near entrance gate 19.4 ND

ND = non detect, detection limit for PCP was approximately 25 micrograms per kilogram mg/kg

Table 2.

Summary of Analytical Results for Wipe Samples
Building Sampling Location Arsenic
(mg/wipe)
PCP
(mg/wipe)
1 South wall, main area 75.5 ND
1 Table surface, main area 3.1 ND
1 [West wall, main area 1.8 ND
1 East wall, main area 2.9 ND
1 Shelf surface, main area 7.3 ND
1 Floor, main area 4.2 ND
1 Shelf surface, storage area 3.6 ND
1 Surface of door to storage 10.9 ND
1 Shelf surface, storage area 13.1 ND
1 Floor, main area 3.7 ND
2 Metal wall, center 9.9 ND
2 North wall (wood) 227 ND
2 Wooden pillar, center east ND ND
2 Wooden pillar, southeast corner 9.5 ND

Table 3.

Summary of Analytical Results for Air Samples
Sampling Location PCP
Micrograms per cubic meter air
Center of Building 1 1
Near Garage Door in Building 1 1
  Arsenic
Milligrams per cubic meter air
Center of Building 1 <0.01
East Side Building 1 <0.01


Sampling Map
Figure 1. Sampling Map

Figure 2. Dose Calculations

Air

Dose equals Contaminant concentration (mg/m cubed) times Inhalation Rate (m cubed/day) times Exposure Factor divided by Body Weight

Standard Inhalation Rates:
Adult male - 23 mg/m3
10 year old child - 15 mg/m3

Standard Inhalation Rates:
Age Arsenic Concentration
mg/m3
Dose
mg/kg/day
Adult 0.01 0.003286
Child
(10 Year Old)
0.01 0.009375

Age PCP Concentration
mg/m3
Dose
mg/kg/day
Adult 0.001 0.000329
Child
(10 Year Old)
0.001 0.000938

Soil Ingestion

Dose equals Contaminant concentration (mg/kg) times Inhalation Rate (mg/day) times Exposure Factor times 10 sup -6 divided by Body Weight

Standard Soil Ingestion Rates:
Adult - 50 mg/day
Child - 50-100 mg/day

Standard Soil Ingestion Rates:
Age Arsenic Concentration
mg/kg
Dose
mg/kg/day
Adult 60 0.0000429
Child
(Infant)
60 0.0006000


Table of Contents

  
 
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