OPTIMIZING PESTICIDE EXTRACTION IN NON-HUMAN PRIMATE FECES USING SIMPLIFIED ULTRASONICATION APPROACH FOR RELIABLE QUANTITATION

Abstract

Nonhuman primate feces provide a non-invasive matrix for monitoring pesticide exposure. However, the complex composition of feces proves to be a challenge for the measurement of pesticides. This study optimized extraction and cleanup methods for the analysis of 63 current-use pesticides (CUPs) and 19 organochlorine pesticides (OCPs) in non-human primate fecal samples. Multiple extraction approaches were evaluated based on QA/QC parameters including extract cleanliness and surrogate recoveries. The optimized workflow consisting of 15 minutes ultrasonication and multilayer column cleanup showed the best overall performance with improved surrogate recoveries (~80% for 13C- Atrazine and ~120% for Pyraclostrobin-d6), cleaner extracts, and reduced processing steps, while also providing a single workflow for both CUPs and OCPs. Application of the optimized method on non-human primate feces collected from red colobus and black-and-white colobus monkeys (n = 24) in Kibale National Park Uganda in three different habitats (e.g. interior, edge, and fragments) showed detectable CUPs and OCPs residues across all habitats. Fragmented habitats exhibited higher average total CUPs (26.3  12.9 ng/g dw) compared to edge (5.53  3.79 ng/g dw) and Interior habitats ( 8.57  9.17ng/g dw). Similar trends were observed for OCPs, with fragmented habitats showing the highest concentrations across species and sex groups. Dinotefuran, a neonicotinoid insecticide and OIET (Hydroxyatrazine), a metabolite of atrazine herbicide were the dominant compound across the groups, especially within the fragmented habitat. Although more data are needed, these results suggest higher pesticide exposure in fragmented habitats compared to edge and interior habitats. The compound profile suggests that neonicotinoid insecticides and herbicide residues are the major contributors to pesticide exposure in colobus monkeys across the studied habitats.