This dataset contains outputs from two sets of simulations from an ocean-biogeochemistry (NEMO v.4.0.4 - ERSEM) model over the Sri Lanka region. In both simulations, the model is forced with ERA5 atmosphere, and a Nucleus for European Modelling of the Ocean (NEMO) dataset (ocean only, 3 year run) as lateral ocean boundary and initial conditions. Passive tracers (urea - organic nitrogen) are released from the region of the MV X-Press Pearl accident (approximately 7.0546N, 79.7589E). The outputs are stored in monthly files on grid-u, grid-v, grid-w, grid-t, and tracer variables containing hourly averages. For these simulations, 1100T of passive tracers (urea, organic nitrogen compound) are released at different rates - over 1 hour and over 6 hours. The start date of the release is 25th of May 2021. These simulation start and end on: 01/05/2021 - 30/06/2021. A complementary dataset with daily release of tracers is also public. The model configuration is named SRIL34. The outputs were generated under the Climate Linked Atlantic Sector Science (CLASS) and the South Asian Nitrogen Hub (SANH; NE/S009019/1) projects.