DDT contamination from indoor residual spraying for malaria control

Area of Science:

• Environmental Science
• Toxicology
• Public Health

Background:

• DDT (dichlorodiphenyltrichloroethane) is used for malaria vector control in South Africa via indoor residual spraying (IRS).
• Local populations may be exposed to DDT residues through various environmental pathways.

Purpose of the Study:

• To quantify DDT contamination levels in homesteads after IRS.
• To identify potential human exposure routes to DDT and its metabolites.

Main Methods:

• Collected human serum, indoor air, dust, soil, water, leafy vegetables, and chicken samples from exposed and reference villages.
• Analyzed samples for o,p'- and p,p'-isomers of DDT, DDD, and DDE using gas chromatography.

Main Results:

• DDT and its metabolites were detected in all analyzed media, confirming multiple exposure pathways.
• The exposed village showed higher DDT levels in most samples compared to the reference village.
• Seventy-nine percent of residents in the exposed village had detectable serum DDT levels, primarily p,p'-DDD and p,p'-DDE.

Conclusions:

• DDT IRS results in widespread environmental contamination and human exposure in South African homesteads.
• Both dietary and non-dietary routes contribute to DDT uptake.
• Findings raise concerns about potential health effects on residents exposed to DDT residues.