Rothboury Doung

Project title: Enhancing Pesticide Exposure Monitoring in Agricultural Workers using Dried Blood Spots and Adductomics

Degree: MPH | Program: Environmental and Occupational Hygiene (EOHY) | Project type: Thesis/Dissertation
Completed in: 2023 | Faculty advisor: Judit Marsillach


The use of chemical agents to eradicate pests and weeds is prevalent across both developing and developed countries, and it plays a crucial role in the agricultural sector by enhancing crop yields and minimizing losses. However, the Environmental Protection Agency (EPA) estimates that over 20,000 agricultural workers in the United States suffer from pesticide poisoning annually, making them one of the most vulnerable occupations to chemical-related injuries worldwide. In light of this alarming statistic, it is imperative to monitor the exposure of workers in the agricultural industry to organophosphates (OP), which are commonly present in pesticides, to ensure their safety and well-being. Despite the importance of monitoring OP exposure, the conventional biomonitoring methods that rely on measurement of cholinesterase inhibition via the Ellman colorimetric assay have several limitations, including the requirement of measuring pre-exposure baseline activity levels, reduced accuracy at lower levels of inhibition, and a demanding sample collection and shipping process.


To address these drawbacks, this study aims to 1) evaluate the use of advanced mass spectrometry technology for biomonitoring OP exposures, which offers higher sensitivity than the standard Ellman colorimetric assay, and 2) assess the use of dried blood spots (DBS) as a biospecimen for monitoring OP exposures, which allows for simpler and less-invasive sample collection and storage. The results obtained from the current study showed a correlation between the OP adducts in DBS and plasma samples, indicating that DBS can serve as a reliable and convenient biospecimen for biomonitoring OP exposures. Furthermore, the mass spectrometry-based analysis demonstrated higher sensitivity in detecting OP exposure compared to the standard Ellman assay. In conclusion, the use of DBS paired with OP protein adduct analyses by mass spectrometry provides a more efficient and practical method for assessing worker health and safety in the agricultural industry.