Inhalation and dietary exposure to PCBs in urban and rural cohorts via congener-specific measurements

Abstract

Polychlorinated biphenyls (PCBs) are a group of 209 persistent organic pollutants, whose documented carcinogenic, neurological, and respiratory toxicities are expansive and growing. However, PCB inhalation exposure assessments have been lacking for North American ambient conditions and lower-chlorinated congeners. We assessed congener-specific inhalation and dietary exposure for 78 adolescent children and their mothers (n = 68) in the Airborne Exposure to Semi-volatile Organic Pollutants (AESOP) Study. Congener-specific PCB inhalation exposure was modeled using 293 measurements of indoor and outdoor airborne PCB concentrations at homes and schools, analyzed via tandem quadrupole GS-MS/MS, combined with questionnaire data from the AESOP Study. Dietary exposure was modeled using Canadian Total Diet Survey PCB concentrations and National Health and Nutrition Examination Survey (NHANES) food ingestion rates. For ∑PCB, dietary exposure dominates. For individual lower-chlorinated congeners (e.g., PCBs 40+41+71, 52), inhalation exposure was as high as one-third of the total (dietary+inhalation) exposure. ∑PCB inhalation (geometric mean (SE)) was greater for urban mothers (7.1 (1.2) μg yr(–1)) and children (12.0 (1.2) μg yr(–1)) than for rural mothers (2.4 (0.4) μg yr(–1)) and children (8.9 (0.3) μg yr(–1)). Schools attended by AESOP Study children had higher indoor PCB concentrations than did homes, and account for the majority of children’s inhalation exposure.

Figure 1

Sampling and analysis scheme for AESOP Study. Artist: Jeanne DeWall. Air sampling, questionnaires, subject enrollment, and GC-MS/MS analysis are described in this paper. Collection and analysis of saliva and blood complete the AESOP Study data set, but are described elsewhere.

Figure 2

Screening and selection process for modeled cohort. QA/QC criteria include recovery of surrogate standards between 40 and 150% and concurrent collection of field blanks.

Figure 3

Mean airborne PCB concentrations, derived from Harner passive air samplers deployed for ∼90 days (homes) or ∼45 days (schools). PCB masses were measured via tandem quadrupole GC-MS/MS. Different y-axis scales are used. Error bars are standard error. Indoor school samples were normally distributed and are thus presented as an arithmetic mean ± SE. Other samples were log-normally distributed and are presented as a geometric mean (SE).

Figure 4

Inhalation (bar) and dietary (pie) exposure by location and food group excluding houses with extreme values. “Other” dietary sources include butter, fats and oils, margarine, and eggs. “Other” inhalation sources include time spent at locations not measured directly, such as churches, places of work, and other public areas.