Assessment of pesticide deposition in household dust based on passive Petri dish sampling followed by QuEChERS extraction

Pesticide exposure is a major public health concern worldwide, particularly affecting individuals living near agricultural fields. Household dust can be a significant source of exposure; however, most currently used sampling protocols capture pesticide contamination in dust only at discrete time points and are not always easily scalable to a large number of households. There is therefore a strong need to develop a cost-effective, integrative sampling approach to assess pesticide exposure in large-scale studies. This study proposes a new method to quantify 51 pesticides in household dust using passive Petri dish sampling, followed by QuEChERS extraction and liquid chromatography-mass spectrometry analysis. The method was optimized to improve pesticide recovery from the Petri dish and to reduce matrix effects. The use of synthetic dust for matrix-matched calibration and the removal of the cleanup step were evaluated. Internal standard calibration was ultimately selected, and the method was validated. For more than 94% of analytes, precision (RSD < 18%), trueness (relative bias < 20%), and linearity (R² > 0.99) met acceptable criteria. The method was applied to samples (n = 75) collected from residences located near agricultural areas in Québec, Canada. At least one pesticide was detected in all homes, with up to 21 compounds found in a single residence. Individual loading rates varied widely, ranging from 1.3 × 10^-3 to 1.4 × 10³ ng/m²/day. Insecticides were the most frequently quantified class, with generally higher loading rates than herbicides and fungicides. Overall, this method provides an accessible sampling approach and an efficient extraction suitable for large-scale studies.