RESUMEN
Umbilical cord and venous blood samples were collected at the time of delivery from 52 mothers living in urban and rural areas of the Atoya River basin, Nicaragua. In a subsample of 24 mothers that delivered by Cesarean section, abdominal adipose tissue samples were also collected, as was breast milk later in lactation. Cord and venous blood sera were analyzed for 13 organochlorine pesticides: 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (pp'-DDT); 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (pp'-DDE); pp'-dichlorophenyldichlorodiene (pp'-DDD); alpha-hexachlorocyclohexane (alpha-HCH); beta-hexachlorocyclohexane (beta-HCH); gamma-hexachlorocyclohexane (gamma-HCH); delta-hexachlorocyclohexane (delta-HCH); toxaphene; dieldrin; endrin; aldrin; heptachlor; and heptachlor epoxide. In venous blood only pp'-DDE (100% of samples), pp'-DDT (1.92%), dieldrin (15.38%), heptachlor (15.38%), gamma-HCH (7.69%), beta-HCH (11.53%), and delta-HCH (1.92%) were found, whereas in cord blood only pp'-DDE (100%), pp'-DDT (3.84%), dieldrin (19.23%), and heptachlor (9.16%), were found. The persistent DDT metabolite pp'-DDE, present in all samples of blood serum, adipose tissue, and breast milk, was studied in relation to maternal characteristics such as body mass index (BMI), age, lactation experience, and fetal pesticide acquisition. Mean venous (7.12 microg/g) and cord (6.39 microg/g) pp'-DDE concentrations were not significantly different but were significantly correlated. pp'-DDE in maternal adipose tissue was positively correlated with pp'-DDE in cord blood (P=0.0001) and breast milk (P<0.0001) and marginally correlated with changes in BMI (r=-0.03088; P=0.06). There was a higher proportion of samples (58%) with a greater concentration of DDE in venous than in cord blood. Although DDE accumulation may be less during fetal development than during breast feeding, exposure during embryogenesis may be more important than during the postnatal period.