In the jaws of pollution: quantifying micro- plastic and heavy metal burden in commercial sharks in the Andaman Islands

Abstract

The world is witnessing an unprecedented level of pollutants in the oceans today. With this rise in pollution, there is an increase in concentrations of contaminants such as heavy metals and micro- plastics, which pose a threat to marine ecosystem health and function as well as human health. This study focussed on the quantification of these heavy metal and micro-plastic contaminants in the most commonly landed shark species in the Andaman and Nicobar Islands, India. Tissue samples were collected and analyzed for contamination levels to identify habitat-specific vulnerabilities in contaminant accumulation. Results showed a wide range of micro-plastic types, with fibres and fragments being the most common while white/transparent and blue colours were observed to occur more frequently. However, no significant differences were found in contamination levels across age, sex, or tissue types of the sampled sharks. Similarly, no significant difference was observed in contamination level between habitats, but significant differences were observed between certain types of micro-plastics across two different size categories in reef-dwelling species.