Quantification and morphological characterization of plastic litter (0.30-100 mm) in surface waters of off Colombo, west coast of Sri Lanka.

This study focused on quantification and morphological characterization of plastics (0.30-100 mm) at seven sites, namely, Uswetakeiyawa, Kerawalapitiya, Dikowita, Modera, Kollupitiya, Bambalapitiya, and Wellawatta along the west coast, off Colombo, in August, October, and November, 2017. Samples were collected by dragging the floating net with a mesh size of 300 µm horizontally at the surface. The collected samples were analyzed using standard methods to quantify the plastics in terms of size, color, and shape. The mean abundance (± SE) of total plastics recovered from off Colombo was 140.34 ± 15.23 items/m3 (0.30-100 mm) by number and 0.66 ± 0.16 mg/m3 (1-100 mm) by weight (n = 63). The significantly higher abundance (± SE) of total plastics (0.30-100 mm) was found at Wellawatta (229.40 ± 46.39 items/m3) and Modera (201.28 ± 62.13 items/m3) than that of other sites (p < 0.05). Nevertheless, the 99.60% of the plastics collected were small microplastics within the size range of 0.30-1 mm. Only mesoplastics were significantly varied among sites by weight with significantly high abundance in Kerawalapitiya (0.71 ± 0.31 mg/m3) than that of other sites (p < 0.05). The composition analysis of shape categories indicated that filaments were dominated in coastal area off Colombo with 61% followed by fragments (25%) and films (14%). The color categorization of plastics revealed that colored plastics are predominant with 47% by the number of items followed by white, transparent, and black in off Colombo. According to the results, all study sites are affected by plastic contamination and cause significant health risk on coastal biota. Microplastic contamination level in surface waters acts as a key indicator on high pollution level in the west coast.

Plastic pollution in the marine environment.

Plastic pollution is recognized as a severe anthropogenic issue in the coastal and marine ecosystems across the world. Unprecedented and continuous accumulation of growing plastic contaminants into any respective aquatic ecosystem by the anthropogenic sources causes direct and/or indirect interruption to ecosystem structure, functions, and consequently, services and values. Land-based and sea-based sources are the primary sources of these contaminants in various modes that enter the ocean. In this review paper, we focused on highlighting different aspects related to plastic pollution in coastal and marine environments. Plastic pollutants are distributed in the ecosystems in different forms, with different size variations as megaplastic, macroplastic, mesoplastic, and microplastic. Microplastics in primary and secondary forms reveal a widespread distribution in the water, sediment, and biota of the marine and coastal habitats. The microplastic level of different coastal and marine ecosystems nearly ranged from 0.001-140 particles/m3 in water and 0.2-8766 particles/m3 in sediments at different aquatic environments over the world. The microplastic accumulation rate of coastal and marine organisms varied at 0.1-15,033 counts. Accordingly, plastic pollution creates several kinds of negative consequences combined with ecological and socio-economic effects. Entanglement, toxicological effects via ingestion of plastics, suffocation, starvation, dispersal, and rafting of organisms, provision of new habitats, and introduction of invasive species are significant ecological effects with growing threats to biodiversity and trophic relationships. Degradation (changes in the ecosystem state) and modifications of marine systems are associated with loss of ecosystem services and values. Consequently, this emerging contaminant affects the socio-economic aspects through negative impacts on tourism, fishery, shipping, and human health. Preventing accumulation sources of plastic pollutants, 3Rs (Reduce-Recycle-Reuse), awareness & capacity building, and producer/manufacturer responsibility are practical approaches toward addressing the issue of plastic pollution. Existing and adopted policies, legislations, regulations, and initiatives at global, regional, and national level play a vital role in reducing plastic debris in the marine and coastal zones. Development of proposals/solutions on key research gaps can open a novel pathway to address this environmental issue in an effective scientific manner. In conclusion, this paper demonstrates the current status of plastic pollution in the marine ecosystem to make aware people of a plastic-free, healthy blue ocean in the near future.

Plastics in surface water of southern coastal belt of Sri Lanka (Northern Indian Ocean): Distribution and characterization by FTIR.

This study focused on investigating the occurrence, quantification, and the spatial and temporal distribution of plastics in coastal surface water from 12 coastal regions in southern part of Sri Lanka. The overall average densities of macroplastics and mesoplastics were recorded as 0.23 and 0.33 items/m3, respectively. Sampling locations had no significant difference (p > 0.05) on total microplastics (MPs) density (overall mean MPs density: 17.45 ± 3.35 items/m3). MPs debris of less than 1 mm size consisted of >45% of the total number of MPs, whereas the maximum size of microscopically observed plastic debris was 11.04 mm, a filament. Filaments were the most common MPs followed by films. Relatively, blue-colored MPs were highly abundant in this coastal line. The type of MPs was further confirmed by Fourier-Transform Infrared (FTIR) method. Potential plastic pollution factors are hydrodynamics and man-made activities like unsustainable harbor operations, fisheries, and tourism. More attention is needed to reduce plastic pollution regionally.