Citarum River Microplastics: Development of an ESSI-Based Learning Material for Elementary Students’ Scientific Literacy

Microplastic pollution poses severe threats to ecosystems and human health, yet remains underrepresented in elementary school science curricula. This study developed and validated contextual science learning materials based on the Environmental Socio-Scientific Issues (ESSI) framework, using microplastic contamination in the Citarum River as a real-world case for elementary students' scientific literacy. The development employed the ADDIE instructional design model through five iterative stages: analysis, design, development, implementation, and evaluation. Validation involved three subject matter experts (content, media, and language), two elementary school teachers, and five purposively selected grade V students. Data were collected using expert validation sheets and response questionnaires with five-point Likert scales. The resulting material integrated scientific content, authentic local environmental data, and inquiry-based activities through narrative storytelling and infographics. Expert validation yielded mean scores ranging from 4.54 to 4.77 across the content, media, and language dimensions, all classified as "very feasible." Teachers rated the material's practicality highly (M = 4.63), particularly for its local contextualization, relevance, and language appropriateness, while students reported strongly positive perceptions (M = 4.65), particularly valuing the material's real-world relevance and its contribution to scientific literacy development. These findings demonstrate that the developed material provides a feasible and practical resource for integrating local socio-environmental issues into elementary science learning, contributing to more contextualized scientific literacy instruction.