The Florida Department of Health requested the Agency for Toxic Substances and
Disease Registry (ATSDR) to review the results of environmental samples collected
from different residences in St. Lucie County, Florida, and to evaluate the possible
health implications associated with exposure to the substances reported.
From January 1998 through June 1998, the Florida Department of Health collected
well water, soil, indoor air, and air conditioner dust samples from eight residences
in St. Lucie County, Florida [1].
The results indicate that most of the chemicals analyzed for in soil, indoor air,
air conditioner dust, and well water samples were not detected. The values that
were reported by the analytical laboratory for various contaminants were estimated
values that were between the method of detection limit and the practical quantitation
limit.
DISCUSSION
An evaluation of the environmental sampling data provided to ATSDR indicates that
most of the chemicals analyzed for in different media (i.e., soil, indoor air,
air conditioner dust, and well water) were not detected. The estimated concentrations
for each contaminant that were reported in soil, well water, air conditioner dust,
and air samples are within normal background levels. Additionally, the concentrations
of VOCs that were reported in the air samples are within normal background ranges
and are probably related to the use of household products. For example, the estimated
values for benzene reported by the analytical laboratory ranged from non-detect
to 1.8 ppb. An air quality study for benzene from 185 residences in the United
States reported that the median value for benzene was at 2.2 ppb in residences
of non-smokers [2]. Another study showed that the average indoor
air concentration of benzene in homes without smokers was 3.1 ppb in the fall
and winter and 1.5 ppb in the spring and summer [3]. A national
survey reported that the average outdoor air concentration of benzene was 2.8
ppb and the median outdoor air concentration was 1.7 ppb [1].
Therefore, the levels of VOCs detected in certain homes do not exceed background
levels. Additionally, the estimated concentrations for the chemicals reported
in indoor air, soil, air conditioner dust and well water do not pose a health
threat for cancerous or non-cancerous adverse health effects.
CONCLUSIONS
Based on the data reviewed, levels of contaminants detected in soil, well
water, air, and air conditioner dust samples are below concentrations that would
result in an increased cancer risk. Also, contaminants are below levels that
pose a non-cancer health threat.
RECOMMENDATION
No follow-up investigations are recommended. If further clarification is necessary,
or if additional sampling data become available, ATSDR is available to assist
upon request.
Robert L. Williams, Ph.D.
Toxicologist
Concurrence: Susan Moore
Section Chief
REFERENCES
1. Data Package for St. Lucie County Cancer Cluster Investigation,
prepared by the Florida Department of Health Bureau of Laboratories, Jacksonville,
FL, September 16, 1998.
2. ATSDR Update Toxicological Profile for Benzene, February
20,1996.
3. Exposure to the general population to gasoline, Akland, G.,
Environmental Health Perspectives 1993; 101 Suppl. 6:27-32.
