Urinary and breast milk biomarkers to assess exposure to naphthalene in pregnant women: an investigation of personal and indoor air sources.
BACKGROUND
Naphthalene exposures for most non-occupationally exposed individuals occur primarily indoors at home. Residential indoor sources include pest control products (specifically moth balls), incomplete combustion such as cigarette smoke, woodstoves and cooking, some consumer and building products, and emissions from gasoline sources found in attached garages. The study aim was to assess naphthalene exposure in pregnant women from Canada, using air measurements and biomarkers of exposure.


METHODS
Pregnant women residing in Ottawa, Ontario completed personal and indoor air sampling, and questionnaires. During pregnancy, pooled urine voids were collected over two 24-hour periods on a weekday and a weekend day. At 2-3 months post-birth, they provided a spot urine sample and a breast milk sample following the 24-hour air monitoring. Urines were analyzed for 1-naphthol and 2-naphthol and breast milk for naphthalene. Simple linear regression models examined associations between known naphthalene sources, air and biomarker samples.


RESULTS
Study recruitment rate was 11.2% resulting in 80 eligible women being included. Weekday and weekend samples were highly correlated for both personal (r = 0.83, p < 0.0001) and indoor air naphthalene (r = 0.91, p < 0.0001). Urine specific gravity (SG)-adjusted 2-naphthol concentrations collected on weekdays and weekends (r = 0.78, p < 0.001), and between pregnancy and postpartum samples (r = 0.54, p < 0.001) were correlated.Indoor and personal air naphthalene concentrations were significantly higher post-birth than during pregnancy (p < 0.0001 for signed rank tests); concurrent urine samples were not significantly different. Naphthalene in breast milk was associated with urinary 1-naphthol: a 10% increase in 1-naphthol was associated with a 1.6% increase in breast milk naphthalene (95% CI: 0.2%-3.1%). No significant associations were observed between naphthalene sources reported in self-administered questionnaires and the air or biomarker concentrations.


CONCLUSIONS
Median urinary concentrations of naphthalene metabolites tended to be similar to (1-naphthol) or lower (2-naphthol) than those reported in a Canadian survey of women of reproductive age. Only urinary 1-naphthol and naphthalene in breast milk were associated. Potential reasons for the lack of other associations include a lack of sources, varying biotransformation rates and behavioural differences over time.
Water and Air Quality Bureau, HECSB, Health Canada, 269 Laurier Avenue West, AL 4903C, Ottawa, ON K1A 0K9, Canada. A.Wheeler@ecu.edu.au.
Amanda J
AJ
Wheeler
Nina A
NA
Dobbin
Marie-Eve
ME
Héroux
Mandy
M
Fisher
Liu
L
Sun
Cheryl F
CF
Khoury
Russ
R
Hauser
Mark
M
Walker
Tim
T
Ramsay
Jean-François
JF
Bienvenu
Alain
A
LeBlanc
Eric
E
Daigle
Eric
E
Gaudreau
Patrick
P
Belanger
Mark
M
Feeley
Pierre
P
Ayotte
Tye E
TE
Arbuckle
D000328:Adult; D000393:Air Pollutants / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D015415:Biomarkers / Q000032:analysis / Q000652:urine; D004784:Environmental Monitoring; D005260:Female; D006798:Housing; D006801:Humans; D018811:Maternal Exposure; D008895:Milk, Human / Q000737:chemistry*; D009281:Naphthalenes / Q000032:analysis*; D009284:Naphthols / Q000652:urine*; D009864:Ontario; D011247:Pregnancy / Q000652:urine
D000393:Air Pollutants; D015415:Biomarkers; D009281:Naphthalenes; D009284:Naphthols; C031721:naphthalene; C029350:1-naphthol; C028405:2-naphthol