The Toxicologist - Society of Toxicology

Naphthalene is routinely analyzed in soil vapor intrusion assessments for properties
overlying and surrounding former MGP sites. Naphthalene exposure from vapor
intrusion may be a public health risk. The purpose of this study was to evaluate
three sites located in the northeast United States to determine the frequency of
naphthalene detection in indoor air. A total of 76 properties were included in the
study. A total of 469 indoor air samples were analyzed for naphthalene by EPA
Method TO-14A or TO-15. The properties were sampled on 157 occasions and
some properties sampled up to 7 times. At residential properties indoor air samples
were collected in basements and crawl spaces, and in occupied areas such as living
rooms and bedrooms. At commercial properties indoor air samples were collected
in basements, sump rooms, storage closets and common areas such as lobbies, classrooms,
and offices. A typical sample collection included indoor air testing in the
basement area, living room (with a duplicate sample) and a bedroom. These data
were then used to evaluate exposure and assess public health risks. Naphthalene
concentrations ranged from 0.26 to 51 ug/ cubic meter of air. Only 3 of the 472 indoor
air samples detected naphthalene above the ninety-fifth percentile background
value of 12 ug/ cubic meter of air. These 3 detections could be explained by sources
of naphthalene not associated with vapor intrusion. Naphthalene was detected in
less than 1% of the indoor samples. Naphthalene vapor intrusion was not a public
health risk among the 76 properties built on or near the former MGP sites.
1237 EARLY LIFE MANGANESE EXPOSURE ESTIMATED
USING DECIDUOUS TOOTH DENTINE AS A
BIOMARKER.
M. Arora 1, 2 , A. Bradman 3 , K. Harley 3 , M. Vedar 3 , J. Chevrier 3 , N. Holland 3 ,
B. Eskenazi 3 and D. R. Smith 1 . 1 University of California, Santa Cruz, CA,
2 University of Sydney, Sydney, NSW, Australia and 3 University of California,
Berkeley, CA.
Rationale: The absence of a suitable retrospective biomarker of Mn exposure during
the crucial prenatal and early childhood periods, when susceptibility to adverse effects
of Mn may be heightened, remains a major obstacle for epidemiologic studies
on health effects of early environmental Mn exposure. Procedures: The Center for
the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study
recruited pregnant women before 20 weeks gestation and collected environmental
and biological matrices, including shed deciduous teeth, prospectively over a period
of approximately 8 years. Tooth Mn (as Mn:Ca ratios) was measured at 40 locations
in pre- and postnatally formed regions of 18 deciduous teeth using laser ablation-
ICPMS. Mn levels in teeth, shed at a mean age of 6.8 years, were compared with
concentrations in maternal blood and urine collected at the 26th gestational week,
cord (fetal) blood, maternal and child urine collected six months postnatally, and
Mn concentrations and loading in house dust collected at the 26th gestational
week. Results: Mn levels in both pre- and postnatal regions of dentine (as Mn:Ca
area under the curve) were significantly associated with Mn loading in house dust
(μg Mn/m2 floor area) (Spearman’s ρ-prenatal=0.57, p=0.01 and ρ-postnatal=0.48,
p=0.05, n=18). Mn concentrations in cord blood were significantly associated with
Mn levels in ablation spots in dentine on either side of the neonatal line corresponding
to the perinatal period (p