Numerical modeling of diffusion of leaked soluble hazardous chemicals in the Daya Bay, China

Abstract

Based on observation data and temperature diffusion experiment of soluble hazardous chemicals, propylene oxide was taken as a typical hazardous chemical to simulate diffusion after leakage in conditions of variable locations, source intensities, and tides in the Daya Bay by FVCOM model. The results show no unsafe concentration (0.02 mg/L) area after 24 hours for leakage of 100 tons occurring in channel and anchorage, and over 3 km2 unsafe area for the same amount of leakage occurring in port. There are more than 5 km2 and 10 km2 unsafe areas after 24 hours in all locations for 500 t and 1000 t leakage, respectively. Maximum diffusion distance and range increase with increasing diffusion space and current velocity, while the dilution effect becomes stronger, which results in maximum diffusion distance and range in channel, followed by anchorage and port, and reversed maximum concentration distribution. Current velocity acts more as a disincentive within 1 hour and an incentive for diffusion after 1 hour. Diffusion simulation of typical hazardous chemicals will provide technical supports to improve ability of handling environmental emergency in the Daya Bay.

Seasonal Migration Characteristics of Pollutants in Daya Bay: A Case Study in 2015 Based on Observations

“…Zhang et al [7] carried out tracer field experiments in DYB, and the observation-based estimations showed that the diffusion coefficient of pollutants was much larger in the meridional direction than in the zonal direction. Through model experiments, Ge et al [8] investigated the potential distributions of oil films in the DYB after different oil spill amounts. But the simulation time only lasted for 24 hours, which was probably not able to reflect the long-term dispersion trend of pollutants.…”