The overarching goal of the proposed research effort is to develop an inexpensive and field-deployable sensing platform forreal-time quantification of pesticides in agricultural runoff. To achieve this goal, we have developed a research plan that consists of two interconnected research objectives. Objective 1: Quantify typical pesticides and pesticide metabolites at environmentally relevant concentrations using hot spot normalized surface-enhanced Raman spectroscopy (HSN-SERS). In Objective 1, we will leverage the high SERS "hot spot" density of a bacterial cellulose plasmonic passive sampler and the exceptional reproducibility of HSN-SERS to quantify five parent pesticides and their major metabolites down to medium-to-high ng/L level. Objective 2: Develop and validate a flow-through sensing platformfor real-time analysis of pesticides in field samples. In Objective 2, we will integrate the plasmonic passive sampler and HSN-SERS into a flow-through sensing platform that enables real-time analysis of target pesticides in field samples collected from the Central Sands region in Wisconsin. We will also validate the performance of the proposed sensing platform using the standard analytical method based on liquid chromatography-tandem mass spectrometry.