4. Conclusions
Pyrethroids were found in human breast milk despite the discontinuation in the use of these compounds for IRS. Their occurrence may reflect an influence from the insecticide impregnated bed nets, agricultural sources or use for IRS in some cases despite their known low efficiency for malaria control. The presence of these compounds in breast milk confirms their bioaccumulation potential in humans. Some pyrethroid compounds are accumulated with isomeric discrimination. The concentrations of some of these insecticides found in some mothers, namely λ-cyhalothrin used for IRS in Mozambique, involves EDI values close to the upper limits recommended by FAO. The presence of pyrethroids in thatch from dwellings evidences that these insecticides are still used for IRS. The observed occurrence of pyrethroids in dwellings despite the preferential use of other insecticides for IRS and the concentrations of some of these compounds found in human breast milk evidence that these compounds need to be considered in the evaluation of infant risks associated to lactation in areas where insecticides are used for elimination of malaria vectors.