With the enormous reliance on plastics in the world today, bisphenol A, an additive used in the synthesis of many plastics, such as polycarbonate, has been found almost everywhere in our environment including in soil, in natural waters, and inside organisms including humans. A multidisciplinary experiment is presented that involves using flatworms ("Planaria"), which are model organisms common to undergraduate biology courses, to study the extent of retention or absorption of bisphenol A following exposure. "Planaria" were exposed to micromolar concentrations of deuterated bisphenol A in order to distinguish the amount of the compound retained from the (undeuterated) bisphenol A that is present as a contaminant in the environment. Liquid extraction was used to remove retained deuterated BPA from "Planaria," and the extract was derivatized and quantified using gas chromatography/mass spectrometry. This experiment is geared toward students in a laboratory research course or independent study experience. It would also be appropriate in analytical or environmental chemistry courses to help students understand how contaminants in our environment brought about from manufacturing processes can be measured and quantified. Students will learn standard techniques in extraction and analysis to quantify their findings.