Solução do problema inverso para a estimativa da área de emissão do microplástico: o estudo de caso da Baía de Sepetiba

Occasionally, contaminants are found on beaches (oil, plastic, etc.), and determining their origin can be challenging. However, the adaptation of computational tools with the capability of mathematical modelling of the motion of Lagrangian tracers can offer a practical and objective solution. In this study, it is presented a solution for the inverse problem of contaminant emission, with a focus on microplastic. For that matter, the computational platform MOHID was used to simulate the movement of Lagrangian tracers along the estuary connecting Sepetiba and Ilha Grande in Rio de Janeiro/Brazil. Two methods for tracing the origin of the particle were used, traditional backtracking, and a mapping method, both based on box and instantaneous emissions. The outputs were analysed and both methods yielded promising results, though additional criteria-based decision was found to be significantly relevant. In addition, it was observed the complex hydrodynamic ruling the particle motion, with significant longitude and latitude parameter sensitivity for a microplastic search. The mapping method observed the advantage of potentially reducing the time dependence of the model, while backtracking showed faster results. At last, the time and detail of each model output showed important differences, reinforcing the necessity for a criteria-based decision over the use of the model. This work contributes as a support tool for microplastic mitigation and cleansing-related activities and can be extrapolated to address other types of litter.