Plastics in the Indian Ocean – sources, transport, distribution, and impacts

Abstract

Abstract. Plastic debris is the most common and exponentially increasing human pollutant in the world's ocean. The distribution and impact of plastic in the Pacific and Atlantic oceans have been the subject of many publications but not so the Indian Ocean (IO). Some of the IO rim countries have the highest population densities globally and mismanagement of plastic waste is of concern in many of these rim states. Some of the most plastic-polluted rivers empty into the IO, with all this suggesting that the IO receives a tremendous amount of plastic debris each year. However, the concentration, distribution, and impacts of plastics in the IO are poorly understood as the region is under-sampled compared to other oceans. In this review, we discuss sources and sinks, which are specific to the IO. We also discuss unique atmospheric, oceanographic, and topographic features of the IO that control plastic distribution, such as reversing wind directions due to the monsoon, fronts, and upwelling regions. We identify hotspots of possible plastic accumulation in the IO, which differ between the two hemispheres. In the southern IO, plastics accumulate in a garbage patch in the subtropical gyre. However, this garbage patch is not well defined, and plastics may leak into the southern Atlantic or the Pacific Ocean. There is no subtropical gyre and associated garbage in the northern IO due to the presence of landmasses. Instead, the majority of buoyant plastics most likely end up on coastlines. Finally, we identify the vast knowledge gaps concerning plastics in the IO and point to the most pressing topics for future investigation.

Accumulation of Microplastics and Histological Analysis on Marine Fish from Coastal Waters of Baru and Trisik Beaches, Special Region of Yogyakarta

“…The shape of MPs found in surface seawater was dominated by films (73.30%), followed by fibers (13.09%), fragments (12.39%), foams (1.05%), and pellets (0.17%) (Figure 4(b)). Similar results were reported by Pattiaratchi et al (2022), where film and fiber were the most dominant MPs in the Indian Ocean from various regions. However, in the dorsal muscle of marine fish, the most dominant MP shapes were fragments (70.62%) and fiber (14.29%).…”

Three-Dimensional Dispersion of Neutral “Plastic” Particles in a Global Ocean Model

“…Due to the seasonal catchment runoff, there are very large seasonal variations in these inputs, the total amount for August being almost 5 times that of January for instance (Lebreton et al, 2017). These variations were important to take into account in conjunction with the large seasonal cycle of ocean currents, such as the monsoon in the Indian Ocean that severely affects plastic pollution (van der Mheen et al, 2019;Pattiaratchi et al, 2022). These data were downloaded from the global model inputs for monthly midpoint estimates (Lebreton and Reisser, 2018).…”

Fire and Oil Led to Complex Mixtures of PAHs on Burnt and Unburnt Plastic during the M/V X-Press Pearl Disaster

“…This determination is necessary because recovered plastic remains siloed in warehouses, and its disposal method is undetermined. Stray spilled plastic continues to wash up on Sri Lankan beaches, and a fraction is expected to reach foreign coastlines …”

“…Stray spilled plastic continues to wash up on Sri Lankan beaches, and a fraction is expected to reach foreign coastlines. 32 Herein, we address the abundance, source, and persistence of PAHs associated with the spilled nurdles and pyroplastic and the plastic's potential for classification as hazardous waste. Our analyses of parent and alkylated PAHs associated with white, orange, and gray nurdles, burnt plastic pieces, and excised fragments of combustion remnants (Figure 1) reveal the amount, composition, source, and weathering of PAHs associated with the spilled plastic exposed to the marine environment.…”