Emerging Issue of Microplastic in Sediments and Surface Water in South Asia: A Review of Status, Research Needs, and Data Gaps

Abstract

Plastic particles <5 mm come under the category of microplastics (MPs) that can be primary or secondary in nature. Microplastic pollution is a major concern because the world’s shores served as a major sink. Previously, the researchers focused on marine ecosystem, whereas the data on beach sediments and water are limited, especially in South Asia. Several research articles have been published in South Asia, including India, Pakistan, Sri Lanka, Maldives, and Bangladesh. Furthermore, Nepal, Afghanistan, and Bhutan lack information regarding MPs on beach sediments and surface water. Therefore, the review in South Asia will help mitigate and raise awareness on the severity of MPs within the research community and local public. Here, we review the abundance, fate, spatial distribution, research need, and gaps regarding MPs. In Pakistan, only two research articles are published despite the higher concentration of MPs there compared with the other South Asian countries. High concentrations of MPs on sediments (3726 particles/m2) and fresh water (2074 particles/m3) were observed in Ravi River, Lahore, whereas low MP concentrations on sediments (22.8 particles/m2) and fresh water (0.32/m3) were observed in Faafu Atoll, Maldives. In terms of shape, fragments were dominant with the polyethylene polymer type. MP pollution mainly depends on population density, where land-based sources, i.e., industrial, municipal, fishing, tourism, and recreational activities, are the major contributors. Consumption of MPs is life-threatening. The chronic biological effects in aquatic organisms are due to the accumulation of MPs in their cells and tissues. Understanding of these areas is essential to raise awareness and establish management policies for decision-making in this perspective.