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HEALTH CONSULTATION

SOCIAL CIRCLE COTTON MILL
SOCIAL CIRCLE, WALTON COUNTY, GEORGIA


BACKGROUND AND STATEMENT OF ISSUES

Under a regional brownfield program, the U.S. Environmental Protection Agency (EPA), Region IV, selected the former Social Circle Cotton Mill for a site assessment. A brownfield is a site or portion of a site that has actual or perceived contamination and an active potential for redevelopment or reuse. Currently, the property is privately owned by Jackson Carter, Incorporated. The city of Social Circle, Georgia, is negotiating with the current owners for an option to purchase the property for public use. The possible sale and development of the cotton mill for commercial or high-density residential use have raised concerns over whether contamination of the surface soil poses an unacceptable risk to human health.

EPA Region IV requested that the Agency for Toxic Substances and Disease Registry (ATSDR) review the assessment data to determine if surface soil and groundwater contamination would pose a threat to human health. The site was referred to the Georgia Division of Public Health (GDPH) under a cooperative agreement with ATSDR. In assessing potential exposure at the site brought about by redevelopment or reuse, GDPH conservatively assumes children and adults would be exposed to the highest contaminant concentrations on a daily basis.

Site Description

The former Social Circle Cotton Mill is located in the city of Social Circle in Walton County, Georgia. The site is on Cannon Road near its intersection with South Cherokee Streetand is bordered on the north by a railroad and on the east by an overgrown field. Many of the old mill houses along the western and southern sides of the site are still occupied.

The Social Circle Cotton Mill operated at the site from 1901 until 1982. The mill manufactured bed sheeting made from 35% cotton and 65% polyester. During its peak the mill employed 225 workers. In April 1994, the mill's main structure was severely damaged by fire. Less than half of the 3-story brick structure remains standing today. There are also several support buildings for the mill in varying stages of decay on the 3.84-acre site.

In 1990, a spill of 585 gallons of polychlorinated biphenyl (PCB)-contaminated oil occurred onsite at the power substation. During the cleanup, soil was removed to a depth where no visibly oil-stained soil was evident. As a precautionary measure, a 1 foot buffer of soil from around the perimeter of the spill area was removed. The total volume of soil removed is not known [1].


DISCUSSION

In the brownfield assessment conducted under contract with EPA, Region IV, the U.S. Army Corps of Engineers collected 19 soil samples, 0 -1 foot in depth, from across the site (Figure 1) [1]. In a soil exposure pathway analysis, ATSDR defines surface soil as 0-3 inches, but for purposes of this health consultation we are assuming that levels found at lower depths are equal to those found in the top 3 inches. All soil samples were analyzed for semivolatile organic compounds (SVOCs), metals, and pesticides. Additionally, soil samples were collected for PCB and VOC analyses. The soil samples collected for VOC analysis were not mixed to prevent loss of the volatile constituents.

In addition to the above soil sampling, groundwater was analyzed to determine if the activities at the former cotton mill site contaminated the aquifer. Four groundwater monitoring wells were installed across the site and sampled for the identical analytes, except PCBs, as in soil.

Determining exposure to environmental contamination is done by examining exposure pathways. Exposure pathways are generally classified by media (e.g., groundwater, soil, or air). A completed exposure pathway is one in which people are actually exposed through drinking, inhaling, or coming in contact with a contaminated media. Currently, the cotton mill site is fenced and unused but a potential exposure pathway might occur if it is developed.

Onsite soil and groundwater data collected during the assessment are used to determine which contaminants exceed their respective comparison value (CV), which are used only as screening values and do not represent a toxicity threshold. Levels of exposure above these values do not indicate that adverse health effects are expected. For this consultation, each contaminant that exceeds the ATSDR soil or groundwater CV or the EPA, Region III, residential preliminary remediation goal (PRG) [1], if no ATSDR CV exists, is selected as a contaminant of concern. Tables 1- 4 summarize the contaminants of concern, their respective CV or PRG, and the highest concentration found in soil. Table 5 summarizes the groundwater contaminants of concern.

An exposure dose is derived for contaminants of concern and compared to a chemical-specific ATSDR minimal risk level (MRL) or other health guideline value. An MRL is defined as a dose, a milligram of substance per kilogram of body weight per day, below which noncancerous adverse health effects are not likely to occur in people [2]. If the exposure dose exceeds the MRL, then we review scientific literature for possible adverse health effects associated with the contaminant at the estimated exposure dose. Exceeding an MRL does not necessarily mean exposure will be harmful. MRLs have conservative safety factors built in. The results of our review of the contaminants of concern are presented in this section.

Arsenic: The lowest observable adverse health effects dose is 0.01 mg/kg/day. The estimated exposure dose for children at the site is at the threshold dose, 0.01mg/kg/day, known to cause less serious noncancerous health effects. The adult estimated exposure dose of 0.00075 mg/kg/day is below levels known to cause less serious noncancerous health effects. Skin lesions, or a darkening of the skin known as hyperkeratosis, appear to be the earliest observable sign of chronic oral exposure. The exposure dose is derived using conservative assumptions. The assumptions are a child weighing 10 kilograms (22 pounds) and daily consuming 200 milligrams of contaminated soil over a 1-year period of time.

Relatively little information is available on the effects due to direct dermal contact in soil, but several studies in workers have shown that direct dermal contact to inorganic arsenic can cause contact dermatitis or local irritation, with little risk of long-term health effects. Arsenic might also come from naturally occurring sources, and, in U.S. soil, naturally occurring arsenic levels range from 0.10 to 97 mg/kg [4]. All 21 soil samples collected on the cotton mill site contained arsenic.

The Department of Health and Human Services (DHHS) has determined arsenic to be a human carcinogen. Studies have shown an increased risk of skin cancer associated with ingestion of arsenic.An increased lifetime risk of cancer might be associated with long-term ingestion of soil at the site. However, the risk is likely lower because actual ingestion rates might not be as high, and daily contact with the highest levels of arsenic in soil is not likely. As a note, cancer risk estimates do not predict or determine if an individual will develop cancer. They are population based and only help determine if you might be at a higher risk.

Thallium: ATSDR has no MRL for thallium. However, an EPA oral reference dose (RfD) exists for thallium sulfate, a common thallium compound. The thallium estimated exposure dose for children was above the RfD for thallium sulfate. To be the more protective of human health, the thallium detected is assumed to be the thallium sulfate compound.

No information was available on adverse health effects in humans after exposure to smaller, chronic doses of thallium. An acute lethal dose for the average adult for thallium is estimated to be approximately 14-15 mg/kg. The lowest observable adverse health effects dose in animals was 0.08 mg/kg/day. The highest estimated exposure dose of 0.0012 mg/kg for children is below the level known to cause less serious adverse health effects in animals. A study of mothers presumed exposed to thallium from eating vegetables from gardens planted in contaminated soil revealed no firm conclusions on exposure and the possibility of adverse developmental effects in children. The study lacked adequate data. The concentrations of thallium found in soil are below levels that would result in a dose shown to cause adverse health effects. All 21 soil samples collected on the cotton mill site contained thallium. In U.S. soil, thallium is naturally found at levels from 0.3 to 0.7 ppm.

Polycyclic Aromatic Hydrocarbons: ATSDR has no MRLs for the PAHs of concern. Therefore, a scientific literature review was conducted to determine what adverse health effects are associated with exposure to the levels of contaminants listed in Table 2. The DHHS has determined that PAHs are reasonably anticipated to be a human carcinogen. Several of the PAHs of concern at the site have caused tumors in laboratory animals. Studies show that individuals exposed by inhalation or skin contact for long periods to mixtures that contain PAHs and other compounds also can develop some forms of cancer.

Exposure to the highest level of benzo(a)pyrene, considered one of the most potent PAHs, might increase a lifetime risk of cancer using our conservative exposure assumptions. However, no increased lifetime risk of cancer is likely if exposed to the average concentration in onsite soil. Benzo(a)pyrene was detected in 11 of the 21 soil samples.

Volatile Organic Compounds: No VOCs were selected as contaminants of concern in on-site soil; however, methylene chloride and di(2-ethylhexl) phthalate were selected for groundwater. The estimated exposure doses were below the MRLs for both; therefore, exposure to these compounds is not expected to result in noncancerous adverse health effects. Both are also considered laboratory contaminants (Table 5).

Polychlorinated Biphenyl: ATSDR has no MRL for Aroclor 1260, but the MRL for PCBs is 0.00002 mg/kg/day. The estimated exposure dose was 0.000061 mg/kg/day for adults and 0.00086 mg/kg/day for children. Both exceed the PCB MRL (Table 4). These doses are based on conservative exposure assumptions.

Studies have shown that infants born to mothers who consumed fish with high PCB content and infants born to mothers without known exposures but with a stored level in their body exhibit adverse neurobehavorial effects such as problems with motor skills, a decrease in short-term memory, and impaired visual recognition memory. Skin conditions, such as chloracne and rashes, might occur in people exposed to high levels of PCBs. Chloracne was seen in workers with an average PCB blood level of 450 ppb. PCBs might change or disrupt the body's ability to transport, bind, or eliminate natural hormones and might also play a role in breast cancer [3].

The DHHS determined Aroclor 1260 might reasonably be considered a carcinogen. PCBs are known to cause cancer in animals and occupational exposures have been associated with some forms of cancer. An increased lifetime risk of cancer might be associated with long-term ingestion of contaminated soil at this site. However, an individual would have to repeatedly ingest the contaminated soil in an area where a past spill occurred. Only 4 soil samples were collected on-site and Aroclor 1260 was detected in 3 out of the 4 samples. No other soil samples onsite were analyzed for PCBs.

Pesticides: The oral exposure doses for dieldrin and heptachlor epoxide pesticides were estimated to be below the MRLs. Therefore, noncancerous adverse health effects are not likely to occur (Table 4). The pesticides were detected in only four of the 21 samples. An increased risk of cancer from exposure to pesticides is not likely to occur due to low levels detected and limited distribution across the site.


CHILD HEALTH INITIATIVE

The ATSDR Child Health Initiative recognizes that the unique vulnerabilities of infants and children demand special emphasis in communities faced with contamination of their water, soil, air, or food. Children are at a greater risk than adults from certain kinds of exposures to hazardous substances emitted from waste sites and emergency events. They are more likely to be exposed because they play outdoors and they often bring food into contaminated areas. They are more likely to come into contact with dust, soil, and heavy vapors close to the ground. Also, they receive higher doses of chemical exposure due to lower body weights. The developing body systems of children can sustain permanent damage if toxic exposures occur during critical growth stages. As previously mentioned, the site has contaminants of concern that pose a hazard to children if they or expectant mothers ingest contaminated soil at the assumed ingestion rate over a prolonged period of time.


CONCLUSIONS

  • Currently no people are being exposed to contaminated on-site soil.

  • The cotton mill site poses a future public health hazard for people on the site if they are exposed to contaminated soil and receive the daily estimated oral doses of arsenic, PCBs (Aroclor 1260), and benzo(a)pyrene over a prolonged time period. The exposure scenarios are conservative, but demonstrate a need to address the contamination prior to developing the site.

  • Arsenic and thallium are naturally occurring metals. No site-specific background samples were collected during the assessment for comparison to levels found in soil onsite, but the levels are above average, nationwide background levels.

  • PCB sampling was limited to an area adjacent to the electrical switch room where a past PCB spill had occurred onsite; therefore, the extent of its presence on the entire site is unknown.

RECOMMENDATIONS

  • Prior to development of the site, the owner should take measures to reduce the potential for human exposure to current arsenic, Aroclor 1260, and benzo(a)pyrene levels in on-site soil.

  • Collect background samples in the area to determine if levels of naturally occurring arsenic and thallium are representative of levels detected in onsite soil.

  • Expand PCB soil sampling to determine the extent of its presence on the entire Cotton Mill site.

PUBLIC HEALTH ACTION PLAN

  • GDPH will provide this health consultation to U.S. EPA Region IV to target needed clean-up issues prior to redevelopment or to guide owners on possible land uses.

  • The U.S. Army Corps of Engineers will publish a final targeted brownfield assessment of the Social Circle Cotton Mill site.

REFERENCES

1. US Army Corps of Engineers. Draft targeted brownfield assessment for the Social Circle Cotton Mill, Social Circle, Walton County, Georgia. Washington, DC: US]Army Corps of Engineers; 2001 Sep.

2. Agency for Toxic Substances and Disease Registry. Public health assessment guidance manual. Atlanta: US Department of Health and Human Services; 1992.

3. Agency for Toxic Substances and Disease Registry. Toxicological profiles on CD-ROM. Atlanta: US Department of Health and Human Services; 2000. ]

4. US Geological Survey. Chemical analyses of soils and other surficial materials of the conterminous United States. Report 81-197. Denver, Colorado: US Geological Survey; 1981.


PREPARERS AND REVIEWERS OF REPORT

Author

Maurice Redmond
Program Consultant
Georgia Division of Public Health
Chemical Hazards Program

Reviewers

Gail Godfrey
ATSDR Technical Project Officer

Bob Safay
ATSDR Regional Representative

Olga Perry
U.S. EPA, Region IV


CERTIFICATION

The Georgia Department of Human Resources prepared this Social Circle Cotton Mill health consultation under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the public health assessment was begun.

Gail D. Godfrey
Technical Project Officer


The Division of Health Assessment and Consultation, ATSDR, has reviewed this public health consultation and concurs with the findings.

Roberta Erlwein
Chief, SPS, SSAB, DHAC, ATSDR


TABLES

Table 1. Metal Contaminants of Concern in On-Site Soil and Applicable ATSDR Comparison Value. (See Appendix B for definitions)

Contaminant Highest Concentration
(mg/kg)
Average Concentration
(mg/kg)
EPA PRG Residential
(mg/kg)
Comparison Value
(mg/kg)
Source Frequency of Detection
Arsenic 530 46.8 0.39 0.5 CREG 21/21
Thallium 60 23.3 5.2 41 RMEG 21/21

1RMEG for thallium sulfate
mg/kg = milligrams per kilogram
CREG = cancer risk evaluation guide
EPA = Environmental Protection Agency
PRG = preliminary remediation goals


Table 2. PAH Contaminants of Concern in On-Site Soil and Applicable ATSDR Comparison Value.

Contaminant Highest Concentration
(mg/kg)
Average Concentration
(mg/kg)
EPA PRG Residential
(mg/kg)
Comparison Value
(mg/kg)
Frequency of Detection
Benzo(a)anthracene 17 2.99 0.62 - 16/21
Benzo(a)pyrene 14 2.24 0.06 0.1 CREG 11/21
Benzo(a)fluoranthene 13 2.30 0.62 - 13/21
Benzo(k)fluoranthene 12 1.69 6.2 - 8/21
Indeno(123-cd) pyrene 7.5 0.98 0.62 - 5/21

mg/kg = milligrams per kilogram
CREG = cancer risk evaluation guide
EPA= Environmental Protection Agency
PRG= preliminary remediation goals


Table 3. Chlorinated Pesticide and PCB Contaminants of Concern in On-Site Soil and Applicable ATSDR Comparison Value.

Contaminant Highest Concentration
(mg/kg)
Average Concentration
(mg/kg)
EPA PRG Residential
(mg/kg)
Comparison Value
(mg/kg)
Source Frequency of Detection
Dieldrin 0.470 0.026 0.030 0.04 CREG 3/4
Heptachlor epoxide 0.190 0.00905 0.053 0.08 CREG

1/4

Aroclor 1260

43.0 - 0.220 - - 3/4

mg/kg = milligrams per kilogram
CREG = cancer risk evaluation guide
EPA = Environmental Protection Agency
PRG = preliminary remediation goals


Table 4. Contaminant Exposure Doses Compared to an Applicable ATSDR MRL or Other Health Guideline.

Contaminant Maximum Level
(mg/kg)
Estimated Exposure Dose

ATSDR MRL*
(mg/kg/day)

Child
(mg/kg/day)

Adult
(mg/kg/day)

Aroclor 1260 43 0.00086 0.000061 0.000021
Arsenic 530 0.011 0.00075 0.0003
Benzo(a)pyrene 14 0.00028 0.00002 -
Dieldrin 0.470 0.0000094 0.00000067 0.00005
Heptachlor Epoxide 0.190 0.0000038 0.00000027 0.000013
Thallium 60 0.0012 0.000085 0.000082

mg/kg/day = milligrams per kilogram per day
MRL = minimal risk level. All MRLs are based on chronic duration oral exposure unless otherwise indicated.
* Source: ATSDR, Health Guidelines Comparison Values (expires 03/3/02)
1 PCB MRL
2 Thallium sulfate, oral RfD


Table 5. Contaminants of Concern in On-Site Groundwater and Applicable ATSDR Comparison Value.

Contaminant Highest Concentration
(µg/L)
EPA PRG Residential
(µg/L)
Comparison Value
(ppb)
Source Exposure Dose
mg/kg/day
ATSDR MRL
mg/kg/day
Adult Children
bis (2-ethylhexl) phthalate 12 12 6 MCL 0.003 0.001 0.01
methylene chloride 180 4.3 5 CREG 0.005 0.01 0.06

CREG = cancer risk evaluation guide
PRG = preliminary remediation goals
µg/L = micrograms per liter


Table 6. Potential Exposure Pathway

Pathway Name Source Medium Exposure Point Exposure Route Receptor Population Time of Exposure
Onsite soil contaminated soil soil cotton mill site ingestion residents future


APPENDIX A: COMPARISON VALUES AND MINIMAL RISK LEVELS

Comparison values are contaminant concentrations that are found in specific media (air, soil, and drinking water) that are used to select contaminants for further evaluation if people are exposed to the contamination. Comparison values used in this document are defined in the following paragraphs.

Cancer risk evaluation guideline (CREGs) are estimated contaminant concentrations that would be expected to cause no more than 1 excess cancer in 1 million (1 x 10-6) persons exposed over a lifetime (70 years). CREGs are calculated from the U.S. Environmental Protection Agency's cancer slope factors.

Environmental media evaluation guide (EMEGs) is based on minimal risk levels (MRL, see definition). Contaminants present in environmental media below the EMEG are safe levels.

Reference dose media evaluation guideline (RMEGs) is based on the Environmental Protection Agency's (EPA) Reference Dose. Like the EMEG, contaminants present in environmental media below the RMEG are safe levels.

Maximum contaminant levels (MCLs) represent the maximum permissible level of a contaminant in water delivered to any user of a public water system that the U.S. Environmental Protection Agency (EPA) deems protective of public health over a lifetime (70 years) at an exposure rate of drinking 2 liters of water per day for an adult and 1 liter of water per day for a child. In establishing MCLs, EPA is required to consider factors, such as whether the technology is available to achieve the level, other than public health alone.

A minimal risk level (MRL) is an estimate of daily human exposure to a chemical (in mg/kg/day) that is likely to be without an appreciable risk of deleterious effects (noncarcinogenic) over a specified duration of exposure. MRLs are based on human and animal studies of noncancer effects, and are reported for acute (14 days), intermediate (15-364 days), and chronic (365 days or more) exposures. Where sufficient toxicological information is available, the Agency for Toxic Substances and Disease Registry (ATSDR) has derived MRLs for inhalation and oral routes of entry at each duration of exposure (acute, intermediate, and chronic). MRLs are published in ATSDR's Toxicological Profiles for specific chemicals.


APPENDIX B: EXPOSURE DOSE CALCULATION

Exposure doses are derived by calculating the amount of a contaminant that is absorbed by the body of an exposed human over a period of time. The following equation was used in this public health assessment to estimate the exposure dose resulting from ingestion of contaminated soil:

IDs = C times IR times EF divided by BW

where:

IDs = exposure dose soil
C = contaminant concentration (highest level found in a specific medium)
IR = ingestion rate (100 mg for an adult; 200 mg for a child)
EF = exposure factor
BW = body weight (based on average weights for adults: 70 kg; children: 10 kg)


Soil Sampling Locations
Figure 1. Soil Sampling Locations



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