Exposures among pregnant women near the World Trade Center site on 11 September 2001

Abstract

We have characterized environmental exposures among 187 women who were pregnant, were at or near the World Trade Center (WTC) on or soon after 11 September 2001, and are enrolled in a prospective cohort study of health effects. Exposures were assessed by estimating time spent in five zones around the WTC and by developing an exposure index (EI) based on plume reconstruction modeling. The daily reconstructed dust levels were correlated with levels of particulate matter < or = 2.5 microm in aerodynamic diameter (PM2.5; r = 0.68) or PM10 (r = 0.73-0.93) reported from 26 September through 8 October 2001 at four of six sites near the WTC whose data we examined. Biomarkers were measured in a subset. Most (71%) of these women were located within eight blocks of the WTC at 0900 hr on 11 September, and 12 women were in one of the two WTC towers. Daily EIs were determined to be highest immediately after 11 September and became much lower but remained highly variable over the next 4 weeks. The weekly summary EI was associated strongly with women's perception of air quality from week 2 to week 4 after the collapse (p < 0.0001). The highest levels of polycyclic aromatic hydrocarbon-deoxyribonucleic acid (PAH-DNA) adducts were seen among women whose blood was collected sooner after 11 September, but levels showed no significant associations with EI or other potential WTC exposure sources. Lead and cobalt in urine were weakly correlated with sigmaEI, but not among samples collected closest to 11 September. Plasma OC levels were low. The median polychlorinated biphenyl level (sum of congeners 118, 138, 153, 180) was 84 ng/g lipid and had a nonsignificant positive association with sigmaEI (p > 0.05). 1,2,3,4,6,7,8-Heptachlorodibenzodioxin levels (median, 30 pg/g lipid) were similar to levels reported in WTC-exposed firefighters but were not associated with EI. This report indicates intense bystander exposure after the WTC collapse and provides information about nonoccupational exposures among a vulnerable population of pregnant women.

Figure 1. U.S. EPA particulate air monitoring approximately six blocks northeast of WTC (290 Broadway) from 25 September through 26 March 2002. PM₁₀, n = 169 days; PM_2.5, n = 181 days. Data from Columbia University (2003) and U.S. EPA (2003).

Figure 2. (A) WTC diary study zones over ZIP codes. The five exposure zones are described in “Materials and Methods.” (B) Start point for 166 women study participants who were in zones 1–3 at 0900 hr on 11 September 2001. WTC is the blank trapezoid just south of Vesey Street.

Figure 3. Duration and levels of exposure among 187 women participants from 11 September 2001 through 9 October 2001. SS, Saturday and Sunday; weekend dates were 15–16, 22–23, and 29–30 September and 6–7 October 2001. (A) Average time spent by women in zones 1–3 (indoor and outdoor combined). Average time spent in zones 4–5 (not shown) was < 0.7 hr/day on any day. (B) Reconstructed relative intensity of dust exposure in each zone for the same time period, derived from plume reconstruction. Values less than 0.01 were considered below the limit of reliable estimate. (C) Individual daily EI values for all women (n = 187). EIs for each woman are individual values computed from relative intensity (B) and time spent at all street addresses within zones 1–5 over this time period (A). The solid line in C connects the median of nonzero EI values for each day. The numbers at the bottom of C are the n values of women whose EI was zero on this day.