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ATSDR has evaluated all of the available environmental monitoring data to determine what environmental contaminants and which specific areas on or around the site might be of concern. Comparison Values (CV's) was used to determine which contaminants and which areas to examine more closely. CV's are health-based thresholds below which no known or anticipated adverse effect on human health should occur. The values allow an adequate margin of safety. The contaminant tables in this section identify the CV's comparison values for each contaminant. Appendix A (page 18) contains a description of the CV's used in this public health assessment.

A contaminant is further evaluated if the contaminant level in a valid environmental sample exceeds the CV. The presence of a substance in the contaminant tables does not mean that either exposures to the contaminant or adverse health effects have occurred or will occur. Inclusion in the tables indicates only a potential for human exposure to the selected substance. Later sections of this public health assessment contain more detailed discussions of the potential for adverse human health effects as a result of any exposures to the selected contaminants.

This document focuses on those contaminants which were in areas where there is a reasonable potential for human exposure. However, the environmental data for all on-site and off-site areas were evaluated.

On-Site Contamination

EPA sampled on-site surface and subsurface soil, surface water, sediment, and groundwater during the period 1991 through 1994, and in 1998 (1,2,8-10).2 The earlier sampling effort led to some cleanup actions, therefore, the 1998 data will be emphasized because it is most relevant to the existing situation.

ATSDR's review of the 1998 environmental data indicated that 131 substances were detected in surface soil, 101 in groundwater, 59 in sediment, and 23 in surface water. Of the chemicals detected, 19 in surface soil, 9 in groundwater, 7 in sediment, and 1 in surface water had at least one concentration above a CV. These chemicals are identified in Tables B1 through B4 in Appendix B. Those chemicals detected above a CV are evaluated further in the Pathways Analyses section.

Off-Site Contamination

EPA sampled off-site surface and subsurface soil in 1994 (10), and 1998 (8).2 A major focus of the 1994 off-site investigation was on dioxin in soil from residential yards near a drainage pond at the northeast edge of the site. The yards for five homes were tested on Bennett, three on Thomas, and two on Lincoln. All the different dioxin compounds for a sample were added together and evaluated as tetrachlorodibenzodioxin (TCCD) equivalents. The levels in the 10 residential yards varied from 0.03 to1.1 part per billion (ppb), and at the 5 site perimeter locations varied from 0.5 to 4.5 ppb. The comparison value used by ATSDR for TCDD equivalents was 1 ppb. Yards with elevated TCDD equivalent levels were cleaned up in 1994. The possible health impact of exposure to dioxin prior to the 1994 cleanup is evaluated further later in this document.

A wide range of chemicals other than dioxin was analyzed for during the period from 1994 through 1998. About 45 were detected in residential surface soils from the Bennett Street area. As indicated in on Table 1, only four chemicals had at least one concentration above a CV. These chemicals are evaluated further in this document.


The source of these data are the 1994 Black and Veatch investigation (10) and the 1998 data (8) provided directly to ATSDR.
1 - MG/KG is milligrams of substance per kilogram of soil.
2 - CV is comparison value.

Quality Assurance and Quality Control

ATSDR was able to obtain quality assurance and quality control (QA/QC) information for most of the data presented in this public health assessment. This information indicates appropriate QA/QC was performed for most samples. Conclusions were based on accurate, relevant, and reliable data.

Physical and Other Hazards

The site is fenced and signs are posted to prevent access, but there is always the possibility that trespassers could have entered the site. A number of physical hazards exist onsite. These hazards include old machinery and buildings that are not stable. There are also concentrated areas of chemical contamination onsite that could pose a hazard to trespassers.

Review of Toxic Chemical Release Inventory (TRI) Data

To identify other possible facilities that could have contributed to the environmental contamination in Camilla, ATSDR staff members searched the 1987 through 1996 files of the TRI databases for Mitchell County (11). TRI is a publicly-available database compiled by EPA from information that certain industries are required to provide on releases of chemicals to air, water, and soil. None of the other facilities in Mitchell County reported releases of chemicals that were contaminants of concern at the Camilla site. CWP reported releases for 1987 through 1989.


This section presents evaluations of the possible environmental pathways that help determine whether people have been, are being, or will be exposed to site-related contaminants. Environmental pathways can be categorized as either completed or potential. A completed pathway indicates that human exposure to contaminants has occurred in the past, is occurring, or will occur in the future (12). A potential exposure pathway indicates that human exposure to contaminants could have occurred in the past, could be occurring, or could occur in the future. An exposure pathway can be eliminated from consideration if exposure has never occurred and never will occur. If there is uncertainty about the site relatedness of the contaminants of concern in an exposure pathway, the pathway will be evaluated as if the contaminants were site related.

Completed Environmental Exposure Pathways

Table C1 (Appendix C) lists the components of the Bennett Street area soil pathway, the only completed environmental pathway identified where human exposure has occurred or is occurring. This pathway is considered complete because exposure to chemicals at levels above a CV is occurring or had occurred from contact with contaminated soil. The chemicals are arsenic, dibenz(a,h)anthracene, benzo(a)pyrene, pentachlorophenol, and dioxin (TCDD equivalents). Dioxin exposure is not ongoing because the contaminated soil was cleaned up in 1994. The possible health impact of this completed exposure pathway is evaluated in the Public Health Implications section.

Potential Environmental Exposure Pathways

Table C2 lists the components of the two potential environmental exposure pathways and the estimated number of people exposed to each pathway. These possible environmental exposure pathways are offsite surface water and offsite sediment.

Off-Site Surface Water Exposure Pathway

Based on the contaminant levels identified in on-site surface water samples, individuals could be exposed to chemicals from the site through contact with surface water leaving the CWP in drainage ditches. This pathway is considered potential because the contaminant levels offsite were not known. The number of people who potentially could have been or could be exposed to this pathway is small because the CWP drains into a nonresidential area where there would be little opportunity for regular contact.

Off-Site Sediment Exposure Pathway

Based on the contaminant levels identified in on-site sediment samples, people could be exposed to chemicals from the site through contact with sediment leaving the CWP in drainage ditches. This pathway is considered potential because the contaminant levels offsite are not known. The number of people who potentially could have been or could be exposed to in this pathway is small because the CWP drains into a nonresidential area where there would be little opportunity for regular contact.

These two potential pathways will not be evaluated further.

Eliminated Environmental Exposure Pathways

Groundwater and the food chain were eliminated as exposure pathways because significant human contact with contaminants in these pathways does not appear to be possible.


The groundwater pathway was eliminated because it is very unlikely for exposure to occur. Every household in Camilla is connected to the Camilla Municipal Water Supply which is not contaminated. There appears to be little or no potential for CWP contaminants to reach the municipal wells, even though two are located approximately 0.25 miles, northeast and one is 0.5 miles west of the site (6,9). None of the site contaminants have been found in the routine sampling of the Camilla municipal wells.

There is one private well located in the vicinity of the CWP. However, it is used only for watering plants. This well was sampled in the first phase of the remedial investigation (RI), and no contaminants were detected.

Food Chain

The food chain exposure pathway was eliminated because there appears to be little opportunity for fish, game animals, and crops to contact site contaminants moving offsite in surface water and sediment. In addition, it appears that the contaminant levels in onsite surface water and sediment are too low to result in significant contamination of the food chain.


As discussed in the Pathways Analyses section, the Bennett Street area soil exposure pathway is considered completed ( that human exposure occurred). The contaminants of concern in the pathway are arsenic, dibenz(a,h)anthracene, benzo(a)pyrene, pentachlorophenol, and dioxin (TCDD equivalents).

Toxicological Evaluation


Typically, the toxicological evaluation in a public health assessment is a comparison of the exposure dose (that's the amount of a substance individuals in an exposure pathway are exposed to daily) with an appropriate health guideline. In Table D1, the exposure doses are compared with the health guidelines for each substance. There is a discussion of the methodology for calculating the exposure doses in Appendix D.

Discussion of the Possibility of Health Consequences

Health assessors determine the possibility of health consequences of a chemical by comparing the exposure to the results of epidemiologic evaluations of human exposures to that substance. If they do not have valid human data, they use information from properly conducted animal studies. The type of data used for an evaluation is indicated for each substance. Usually, there is little or no information for a site on how much exposure is actually occurring, so it's assumed that maximum exposure has taken place to ensure that public health is protected.

Health effects, from past and ongoing exposures to arsenic, benzo(a)pyrene, dibenz(a,h)anthracene, and pentachlorophenol and past exposure to dioxin in Bennett Street area soils, appears to be very unlikely. The child and adult exposure doses for arsenic and pentachlorophenol were well below the health guidelines for the two contaminants (Table D1). The other three contaminants did not have a noncarcinogenic health guideline. The additional maximum lifetime cancer risk is not elevated for exposure to the five substances (Table D1).

Health Outcome Data Evaluation

No health outcome databases, such as cancer mortality, cancer incidence, or birth defects, were evaluated in this public health assessment because the number of people exposed (fewer than 100) is too small to be evaluated.

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