Utilization of umbilical cords to assess in utero exposure to persistent pesticides and polychlorinated biphenyls

In support of a study to relate developmental and cognitive effects with pr enatal exposure to selected environmental toxicants, we developed and appli ed an analytical method to determine the concentration of two persistent pe sticides, hexachlorobenzene (HCB) and p.p'-dichlorodiphenyldichloroethylene (DDE), and 32 specific polychlorinated biphenyl (PCB) congeners in 316 umb ilical cords taken in 1986-1987 from women of the Faroe Islands. The analyt ical method consisted of homogenization of the cords, partitioning, microsi lica gel column chromatography for clean-up, and dual-column capillary gas chromatography (DB-5 and DB-1701) with electron capture detection. Several quality control parameters were followed to monitor the performance of the method. Important criteria used before reporting unknown data were the reco very of in vitro-spiked analytes from a bovine umbilical cord (BUC) and the percentage lipid obtained for a Certified Reference Material (CRM)-350 of mackerel oil (MO). Recoveries of analytes that had been spiked at two conce ntration ranges (0.26-0.95 ng/g whole weight; 0.35-2.42 ng/g whole weight) into bovine cords ranged from 38.5% to 158% and from 50.4% to 145%, respect ively. with a median recovery of 77.7%. Measurement of the percentage lipid for CRM-350 ranged from 73.8% to 107% with a median lipid value of 96.0%. The most prevalent analytes detected (%) in unknown umbilical cords were HC B (100), DDE (100), Ballschmiter/Zell PCBs 153 ( 100), 138 (98), 180 (98), 170 (93), 118 (88), 187 (86), and 146 (83), with corresponding median conce ntrations (ng/g whole weight) of 0.17, 1.19, 0.38, 0.30, 0.17, 0.11, 0.12, 0.09, and 0.07, respectively. Total PCB-sum of all measurable PCB congeners -had a median concentration of 1.37 ng/g whole weight. The analytes, which were very low in lipid content were also quantified on a lipid-adjusted bas is, which provided an analytical challenge in these umbilical cord samples. The gravimetrically measured lipids in the human specimens ranged from 0.0 1% to 1.43% (median of 0.18%). In the pooled BUCs, our lipid measurements v aried from 0.05% to 0.33% with a median value of 0.13%. The utility of usin g the umbilical cord as a matrix to assess in utero exposure to persistent environmental pollutants, compared with the use of umbilical cord blood or mother's blood, is worthy of debate.