Journal of Environmental Health 2014 Abstracts - page 10

of 1.205 to 2.948. Conversely, O
3
was negatively related to running nose, burning nose,
dry cough, body rash, red eyes, and blurred vision with ROAORs of 0.891 to 0.979.
Spatial Variation in Ambient Benzene Concentrations Over a City Park
Samantha Fridh, MSPH,
OHC Environmental Engineering
Amy L. Stuart, MS, PhD,
Department of Environmental and Occupational Health
,
University of South Florida
Abstract
Passive diffusive samplers were used to collect ambient benzene for a one-week
sampling period (April 27 to May 4, 2011) at 11 locations throughout a city park in the
Tampa, Florida, area. Concentrations were determined through gas chromatography with
mass spectrometry. Spatial variability within the park and its contribution to uncertainty
in health risk estimates were studied. Measured concentrations ranged from 0.23 to
0.34 µg/m
3
. The relative percentage differences for samplers collocated with a regulatory
reference monitor and with a duplicate were 3% and 14%, respectively. The spatial
variability over the park was small with a coefficient of variation of 11%. The
concentration variation due to sampler placement contributes less to uncertainty in health
risk estimates than the uncertainty associated with the inhalation unit risk parameter (39%
versus 170% relative percent differences over the ranges studied). Results suggest that
there is a limit to the spatial resolution needed for risk calculations.
Transport of
E. coli
in a Sandy Soil as Impacted by Depth to Water Table
Christopher Stall, MS,
NewFields Agricultural & Environmental Resources
Aziz Amoozegar, PhD,
Soil Science Department
,
North Carolina State University
David Lindbo, PhD,
Soil Science Department
,
North Carolina State University
Alexandria Graves, PhD,
Soil Science Department
,
North Carolina State University
Diana Rashash, PhD,
North Carolina Cooperative Extension Service
Abstract
Septic systems are considered a source of groundwater contamination. In the
study described in this article, the fate of microbes applied to a sandy loam soil from
North Carolina coastal plain as impacted by water table depth was studied. Soil materials
were packed to a depth of 65 cm in 17 columns (15-cm diameter), and a water table was
established at 30, 45, and 60 cm depths using five replications. Each day, 200 mL of an
artificial septic tank effluent inoculated with
E. coli
were applied to the top of each
column, a 100-mL sample was collected at the water table level and analyzed for
E. coli
,
and 100 mL was drained from the bottom to maintain the water table. Two columns were
used as control and received 200 mL/day of sterilized effluent. Neither 30 nor 45 cm of
unsaturated soil was adequate to attenuate bacterial contamination, while 60 cm of
separation appeared to be sufficient. Little bacterial contamination moved with the water
table when it was lowered from 30 to 60 cm.
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