Assess learners' ability to analyze primary and secondary sources of microplastics (consumer products, industrial pellets, tire wear, synthetic fibers, wastewater), identify and compare major transport pathways in freshwater systems (runoff, riverine transport, sedimentation, atmospheric deposition, wastewater effluent, stormwater), and evaluate ecological impacts (physical harm, chemical contaminant transfer, bioaccumulation, trophic transfer, habitat alteration). Tasks include interpreting monitoring data, tracing pathways from sources to receptors, and recommending targeted mitigation or management actions for freshwater environments.