Water-soluble synthetic polymers (WSPs), including polyacrylamide, polyvinyl alcohol, and polyethylene glycol, are widely used in consumer and industrial applications such as detergents, cosmetics, and textile processing. Global demand for WSPs is increasing by over 5.4% annually and is expected to reach 12.8 million metric tons within the next decade. After their use, millions of tons of WSPs dissolve and enter environmental systems each year; however, their environmental fate and potential long-term impacts remain poorly understood. While conventional plastics fragment into particles that can be isolated and quantified, dissolved WSPs leave no comparable physical trace, complicating the assessment of their degradation. This seminar reviews three recent studies that investigate distinct aspects of WSPs' environmental behavior and underscores the need to integrate research on polymer fate with studies of biological effects.