Abstract:
Although approximately 123 million people may be exposed to high levels of insecticides through the use of indoor
residual spraying (IRS) for malaria control, fewstudies exist on indoor insecticide contamination due to IRS
and its relationship with human exposure. In the present study, we developed a sampling method to collect undisturbed
dust from50 homes in Limpopo, South Africa, a region where dichlorodiphenyltrichloroethane (DDT)
has been used in IRS programs to preventmalaria for ~70 years.WequantifiedDDT and its degradation products,
dichlorodiphenyldichloroethylene (DDE), and dichlorodiphenyldichloroethane (DDD) in dust samples to determine
dust loading levels and compared these levels to paired serum concentrations of p,p′-DDT and p,p′-DDE in
women residents. p,p′-DDT and p,p′-DDE had the highest detection frequencies in both dust (58% and 34% detection,
respectively) and serumsamples (98% and 100% detection, respectively). Significantly higher detection frequencies
for o,p′-DDT, p,p′-DDE, and p,p′-DDDwere observed in dust samples collected in buildings that had been
previously sprayed for malaria control.We also observed a significant, positive association between dust loading
and serumconcentrations of p,p′-DDT and p,p′-DDE (Spearman's rho=0.68 and 0.54, respectively). Despite the
lowdetection frequency in dust, our results indicate that undisturbed dustmay be a goodmetric to quantify longterm
home exposure to DDT-related compounds and that contamination of the home environment may be an
important determinant/source of DDT and DDE exposure.
