Undisturbed dust as a metric of long-term indoor insecticide exposure: Residential DDT contamination from indoor residual spraying and its association with serum levels in the VHEMBE cohort

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, few studies 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 from 50 homes in Limpopo, South Africa, a region where dichlorodiphenyltrichloroethane (DDT) has been used in IRS programs to prevent malaria for ~70 years. We quantified DDT 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 serum samples (98% and 100% detection, respectively). Significantly higher detection frequencies for o,p’-DDT, p,p’-DDE, and p,p’-DDD were 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 serum concentrations of p,p’-DDT and p,p’-DDE (Spearman’s rho = 0.68 and 0.54, respectively). Despite the low detection frequency in dust, our results indicate that undisturbed dust may be a good metric 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.

Association between prenatal exposure to multiple insecticides and child body weight and body composition in the VHEMBE South African birth cohort

“…We also explored the joint effects of exposure to both classes of insecticides using a multipollutant Bayesian statistical method (Bobb et al, 2015; Coker et al, 2017; Valeri et al, 2017). We have previously shown in this cohort that IRS-treated homes have higher dust contamination of DDT and DDE which are related to higher maternal serum levels (Gaspar et al, 2015).…”

Dichlorodiphenyltrichloroethane exposure and anogenital distance in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) birth cohort study, South Africa

“…Dust samples collected in buildings previously sprayed for malaria control had significantly higher detection frequencies of p,p ’ -DDT (34%) and p,p ’ - DDE (58%), while o,p ’ -DDE and o,p ’ -DDD (14 and 16%, respectively) were the least commonly detected analytes. However, VHEMBE mothers women living in a home with dust levels of p, p ’ -DDT, o,p ’ -DDT, p,p ’ -DDE, and o,p ’ -DDE above the LOQ had significantly higher serum concentrations of those chemicals (Gaspar et al 2015). Although it remains possible that the shorter AF associated with higher exposures could be related to a feminizing effect, the mechanism is not clear and health effects of o,p ’ -DDE have yet to be identified.…”

DDT exposure of frogs: A case study from Limpopo Province, South Africa

“…From decades of use, residues of DDT associated with malaria control have accumulated in the environment and in human and animal tissues. DDT residues have been measured in human milk (Bouwman et al 1990, Bouwman et al 2006, Sereda et al 2009) and blood (Aneck-Hahn et al, 2007, Whitworth et al, 2014Gaspar et al 2015) from inhabitants to the east of Thohoyandou, Vhembe District, Limpopo Province ( Fig. 1).…”