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Tarballs are semi-solid blobs of crude-oil formed in marine environment. Microbial degradation of tarballs is poorly understood, though there are indications that tarball-associated microbes can degrade recalcitrant hydrocarbons present in tarballs. In this study, 38 tarball-associated bacteria from Betul beach, Goa, India were initially screened for crude oil degradation. Based on preliminary studies and literature survey, four bacterial strains, Alcanivorax sp. Betul-O, Marinobacter sp. Betul-26, Pseudomonas sp. Betul-14, and Pseudomonas sp. Betul-M were selected for bacterial consortia preparation. Eleven bacterial consortia were prepared and studied for degradation of n-alkanes and polycyclic aromatic hydrocarbon compounds (PAHs) of tarballs based on gravimetric and GC–MS–MS analyses. The bacterial consortia depleted 53.69–97.78% and 22.78–61.98% of n-alkanes and PAH compounds, respectively, within 45 days. Bacterial consortium comprising Pseudomonas sp. Betul-14, Pseudomonas sp. Betul-M, and Alcanivorax sp. Betul-O exhibited promising tarball degradation abilities with 97.78% and 61.98% degradation of n-alkanes and PAH, respectively, within 45 days. Further research is required to obtain insights into degradation products and possible pathways involved. [ABSTRACT FROM AUTHOR]

There have been growing apprehensions and concerns regarding the increasing presence of plastic pollutants in the holiest river of India, the Ganga, and its major tributary, Yamuna. In response to this issue, the current study aimed to conduct a comprehensive investigation of the seasonal and spatial distribution of macro to microplastics (MPs) in the surface water, water column, and sediments from the River Ganga and Yamuna. MP samples were collected from various points of these Rivers, including upstream, downstream, and drainage points around the vicinity of Haridwar, Agra, Prayagraj, and Patna cities. With a significant seasonal variation, the estimated MPs and plastic flux were higher during the wet season than during the dry season. MPs sized 300 µm-1 mm and fibre-shaped blue and black colored MPs were pre-dominant in both rivers. Polyacrylamide, polyamide, and polyvinyl chloride were the most ascertained polymers. MPs including hazardous polymers (hazard score >1000) may pose a risk to the population of Indo-Gangetic Plain via direct and indirect exposure to MPs. The information provided in this study could serve as a starting point for the action plan required by municipal corporations to mitigate plastic pollution and target the possible sources at each location. [Display omitted] • Microplastics (MPs) were detected in River Ganga from Haridwar to Patna stretch. • MPs were abundant in all matrices i.e. surface water, water column and sediments. • The MPs concentration was highest during wet (rainy) season than the dry season. • MPs sized 300 µm-5 mm, fibre-shaped, blue and polymers of PAM & PA were dominant. • The high hazard polymers in MPs may pose risk to the Indo-Gangetic plain. [ABSTRACT FROM AUTHOR]

The present study exhibits the occurrence of MPs in different matrices (water, sediment and biota) from the Sal estuary, Goa, situated on the central west coast of India. The average numbers of MPs in the water column and sediment were 48 ± 19 MP particles/L (MPs/L) and 3950 ± 930 MP particles/kg (MPs/kg), respectively. In shellfish (whole soft tissue), the average concentrations of MPs were 4 ± 2 (Crassostrea sp.), 3.2 ± 1.8 (Perna viridis) and 0.7 ± 0.3 (Paphia malbarica) MPs/g body weight (bw), respectively. The highest MPs were recorded in finfish (gastro-intestinal tract) (Mugil cephalus) 7.8 ± 4, followed by (Gerres filamentosus) 5.3 ± 4.9, (Arius jella) 4.6 ± 2.6, and (Etroplus suratensis) 1.4 ± 0.3 MP/g bw. MP fibres were predominant in all matrices. Interestingly, a dominance of small sized (10–300 μm) MPs was recorded in biota. Among the 37 polymer types identified by μ-FTIR, the most prevalent ones were, polyacrylamide (PAM) , polyacetylene, ethylene vinyl alcohol (EVOH), polyvinyl chloride (PVC) and polyamide (nylon). Notably, the polymers dominant in the gut of finfish and in whole shellfish were equally prominent in sediment and the water column. This study highlights the presence of MPs in commercially important shellfish and finfish samples from the Sal estuary. This study clearly shows the presence of MPs in various types of marine organisms in the Sal estuary. As shellfish is locally consumed as a delicacy and plays a major role in the seafood industry, the MPs may pose a hazard for human health. There is also an ecological risk as MPs are also found in water and sediment and in the digestive tract of finfish. Image 1 • Evaluation of microplastics in water, sediment and biota from Sal estuary, Goa. • MPs found in shellfish and finfish were comparable to those in water and sediment. • Fibres with different colours were most abundant MPs in all the matrices. • Smaller sized MPs (10–300 μm) were found most significantly in biota. • Major polymers found were polyacrylamide, polyacetylene and ethylene vinyl alcohol. [ABSTRACT FROM AUTHOR]

Considering the magnitude of pollution caused by marine plastics, the present study assessed their abundance, distribution, surface morphology and polymer type in ten sandy beaches spread across three states (Maharashtra, Karnataka and Goa) along the west coast of India (WCI). The total abundance of plastics (∼1–100 mm) in the studied beaches ranged from 4.1 to 23.4% (19±1–346 ± 2 items/m2). Location-wise, the abundances of both micro (43.6 ± 1.1–346 ± 2 items/m2) and macroplastics (21.6±3–195 ± 6 items/m2) were relatively higher in beaches along the Maharashtra coast. Surface morphology-wise, fragments were predominantly abundant in both micro (76±2–346 ± 2 items/m2) and macroplastics (50.6 ± 1.5–195 ± 6 items/m2) followed by pellets (43.3 ± 2.5–245.6 ± 2 items/m2). Fourier-transform infrared spectroscopy (FT-IR) analysis of plastics revealed a dominance of polyethylene (PE) followed by polypropylene (PP). IR spectra of the collected plastics at absorption band at 1750–1700 cm−1 reflect minimal surface oxidation. White-colored plastics were observed most frequently, followed by pale-yellow, dark-brown, green, blue, transparent and red. A short-term (72 h) experimental study to assess the toxicity of PE microbeads (∼1 mm) in a commercially important shrimp species, Litopenaeus vannamei revealed toxicological changes. An elevated level of lipid peroxidation (LPX)—the tagged biochemical marker, was recorded only at the maximum dose (0.15 mg/L) of PE microbeads. A moderate increase in the levels of enzymatic antioxidants (catalase and glutathione S-transferase) was also recorded at the same dose. Comprehensive information on marine plastics, including ecotoxicity provided in this study, would help in evolving strategies in minimizing plastic pollution along the WCI. Image 1 • A relatively high abundance of plastics recorded on most popular beaches along the west coast of India. • Surface morphology-wise, fragments followed by pellets were the most abundant plastic items. • Amongst diverse plastic items, white-colored polyethylene polymers dominated. • Toxicological changes in Litopenaeus vannamei were recorded at the highest exposure dose of PE microbeads. [ABSTRACT FROM AUTHOR]