Maritime pollution in the Indian Ocean after the MV X-Press Pearl accident

The MV X-Press Pearl marine debacle severely affected the marine environment in the Indian Ocean. The objective of this study is to monitor environmental pollution along the west coast of Sri Lanka. Beach sand samples were collected from 40 locations. Visual and microscopic observations, plastic pellets pollution index (PPI), and degradation effects of plastic nurdles were examined. Chemical and thermal characteristics were investigated using Inductively Coupled Plasma Mass Spectrometric analysis (ICP-MS) and Fourier Transform Infra-Red Spectroscopic analysis (FTIR) analyses, respectively. Cylindrical-shaped plastic nurdles (>0.2 cm in size) were observed in off-white (mainly), yellow, and black colours. The white colour plastic nurdles change to yellow at 240 °C and black at 300 °C. Epamulla (PPI = 1940-3364) and Sarakkuwa (PPI = 2158-3466) beaches were recognized as the most contaminated beaches during the initial sampling (i.e., after six to eight days of the explosion of the vessel). Well-rounded small plastic nurdles (i.e., after one year of the disaster) can indicate degradation effects. FTIR results confirm (i) plastic nurdles as low-density polyethylene (LDPE) and (ii) alteration of the chemical composition of nurdles at a low temperature of 60 °C. In this case, a significant amount of microplastics have been added to the environment under the influence of UV irradiation and abrasion against beach sand. In addition, the presence of heavy metals (e.g., arsenic, cadmium, lead, and copper) in swash zone sediments is a great threat to marine animals and plants. Consequently, the ingestion of microplastics and heavy metals would be increased in a wide range of marine organisms and can be bio-accumulated in humans through seafood and salt.