Microplastic contamination in endemic species: a case study on ginger prawn Metapenaeus kutchensis

Abstract

Plastic pollution has grown globally in recent decades and is considered to be an imminent risk to human health and marine life. The current investigation was carried out to assess microplastic (MP) contamination in the gastrointestinal tract (GIT) of commercial marine prawn Metapenaeus kutchensis sampled from three foremost fishing centers in Gujarat State. The samples were dissected in the laboratory, and GIT digested with 10% KOH. The MPs were floated using ZnCl2 in accordance with the density gradient technique. Later, the filtration was carried out followed by observation of filter papers using stereo zoom microscope. Subsequently, MPs underwent chemical and physical characterization (total count, shape, size, and color). From 135 individuals, 173 MPs in total were identified, with 100% contamination in all the studied individuals. It was demonstrated that the average MP abundance in the prawns' GIT was 3.94 ± 2.40 MPs/g (ranging from 1.68 ± 0.87 to 5.40 ± 1.90 MPs/g). The higher MP contamination was recorded in post-monsoon, followed by monsoon and pre-monsoon. The MP contamination varied significantly between study sites. An abundance of MP contamination in sediment and water recorded as 11.25 ± 12.23 MPs/kg and 1.38 ± 0.78 MPs/L, respectively. Findings of regression analysis between body length and abundance of MPs revealed no significant correlation. PCA shows varied environmental factors influencing prawn MP contamination. Fibers with blue and black colours were reported as the most common accounted MPs. Size-wise, the 1–2 mm size class was recorded pre-dominated in all study sites. The extracted MPs were found to contain polyethylene, polyethylene terephthalate, and polypropylene in their chemical compositions. Studying MP contamination in endemic species reveals pollution’s impact on sensitive, unique organisms, aiding biodiversity conservation and raising awareness of local ecosystem health. The current study can offer important background information for future investigations as well as data for management and conservation action for safeguarding the health of marine eco-systems in Gujarat.