No abstract

Streams are regarded as a pathway for spreading microplastics from land to various aquatic systems. The contamination of streams connected to the Rawa Jombor Reservoir may increase microplastic concentrations in the reservoir. The water coming out of the reservoir carries microplastics that spread out into the stream networks around the reservoir. Heavy metals have a high affinity for microplastics, increasing metal burdens on the surface of microplastics. The transfer of microplastics along the food chain leads to the possibility of increased adverse effects on organisms, mainly top predators. This research evaluated the accumulation and characterization of microplastics in water, sediment, and aquatic fauna (zooplankton, benthos, and fish); interactions with heavy metals (Pb, Cu, Cd, and Zn); and health risk assessment. Microplastics were collected from six sampling locations. The density, type of polymers, and color of microplastics were analyzed, as well as heavy metal concentrations on the surface of microplastics and a health risk assessment. The results showed microplastic contamination at a moderate level. The accumulation of microplastics in aquatic fauna showed the same pattern as microplastics in the environment. Microplastic concentrations in aquatic fauna showed an increase through trophic transfer and indications of biomagnification. Heavy metals were adsorbed on the surface of microplastics in high concentrations. Based on the health risk assessment, microplastic contamination of fish at the inlet and outlet of the Rawa Jombor Reservoir is still safe, but further monitoring is needed because of the possible long-term health hazards that may arise.

This study aims to determine the effect of problem-based learning (PBL) on the scientific argumentation of class X students at Senior High School in Indralaya, Indonesia, on biodiversity education. The research method was quasi-experimental with a non-equivalent control group research design. This research was conducted in class X-science-3 (n=33) as an experiment and X-science 4 (n=33) as a control at Senior High School in Indralaya, Indonesia. The data collection instrument was a test question that included scientific argumentation skills in essay questions and recorded class discussions. Data on writing scientific arguments are analyzed using cohesion and coherence, sentence effectiveness, concept correctness, critical analysis of problems and problem-solving. Data on the ability of scientific argumentation in writing and oral are also analyzed based on Toulmin's claim, data, warrant, backing, rebuttal, and qualifier. Furthermore, based on the Toulmin aspect, the students' quality level of scientific argumentation is determined. The result showed that the level of argumentation quality of students who applied the PBL model was mainly at level 3, while the control class was mainly at level 1. The effect being studied is significant. The PBL can significantly influence the ability of scientific argumentation in class X students at senior high school in Indralaya, Indonesia.