Contribution: This article measures the impact of a service-learning project in a first-year introduction to computing course on students' understanding of engineers' roles and responsibilities and their attitudes toward plastic pollution. Background: Service learning has been integrated into classrooms for many years, but its utilization in engineering courses is lacking. Furthermore, plastic pollution is a complex and multidisciplinary problem that requires social, political, environmental, and engineering solutions. This work provides a quantitative assessment on whether service learning through a litter pickup project impacts students' views of the role of engineers in solving complex sociotechnical problems. Research Questions: 1) How does service learning change students' perception of an engineer's role in solving sociotechnical problems? and 2) how can service learning be used to increase students' environmental awareness and action? Methodology: Surveys were administered to students before and after their participation in a service-learning project. The study was conducted across five sections of an introduction to a computer programming course that is required of first-year civil, electrical, and mechanical engineering students. Findings: After the service-learning project, students were more likely to agree that engineers have the skills, knowledge, and responsibility to solve societal problems. Students also demonstrated a more holistic understanding of plastic pollution and reported changes in their waste reduction behaviors.