Pervasiveness and characteristics of microplastics in surface water and sediment of the Buriganga River, Bangladesh.

Microplastics (MPs) are an emerging environmental problem due to their all-around existence and extraordinary stability. A significant number of studies are found in recent literature on the occurrence, distribution, transport, and fate of the MPs in several environmental compartments. In this study, we have investigated the occurrence and characteristics of MPs in the surface water and sediment of the Buriganga river, located beside the mega-city of Dhaka in Bangladesh. In the Buriganga river, the concentration of MPs in the surface water was found from 4.33 ± 0.58 to 43.67 ± 0.58 items L-1, and in the sediment, MPs varied from 17.33 ± 1.53 to 133.67 ± 5.51 items kg-1 of dry sediment. Fragment-type MPs were predominant in the surface water and sediment, which was 72.7% and 85.5% respectively. The most abundant polymer type polypropylene (PP) was found -to be 46% in the surface water and 61% in the sediment sample. The next major category, polyethylene (PE) was found to be 26% and 21%, respectively. Polystyrene (PS), polyvinyl chloride (PVC), polyethylene terephthalate (PET), and polyamide (PA) were other commonly detected polymer types. The MPs were found to be contaminated by Pb, Cd, Cr, Zn, Cu, and Sn from Energy dispersive-X-ray fluorescence (ED-XRF) analysis. Tannery-induced Cr was detected in the highest concentrations in the MPs, which were 20.67 ± 1.66 mg kg-1 (in surface water) and 14.2 ± 1.25 mg kg-1 (in sediment). The pollution load index (PLI) of the MPs contamination in different sampling sites along the Buriganga river was found in the risk level category of I and II. The anthropogenic influence of the city area was reflected in the PLI values, which had an increasing trend from the upstream sampling points (1.00 ± 1.00, 1.00 ± 1.00) to the downstream sites (10.09 ± 1.00, 7.71 ± 3.60).

Islam MS ，Islam Z ，Hasan MR 《-》

Abundance, distribution and composition of microplastics in sediment and fish species from an Urban River of Bangladesh.

Microplastics (MPs) are a growing concern due to its ubiquitous presence and exceptional stability. We examined the abundance, dispersion, and attributes of MPs in the sediment and fish species of the Turag River in Bangladesh, which separated the industrial city Gazipur from the Mega-city Dhaka. Collected samples were digested and the chemical structure was identified using ATR-FTIR spectroscopy. The concentration of MPs in the sediment ranged from 10 to 35 particles kg-1, with a mean abundance of 19.2 ± 2.44 particles kg-1and MPs of the fragment type account for 34 % of all. The majority of MPs were discovered in the 3-5 mm size range. MPs concentrations in freshwater fish gut from the Turag River ranged from 0.63 ± 0.18 to 7.0 ± 1.1 microplastics individual-1. Fiber was found to be the most commonly ingested MPs type (43 %), followed by fragments (41 %), film (12 %), and foam (4 %). The most common type of MPs was transparent (34 %) followed by red (28 %), white (20 %), green (9 %) and black (8 %). The results showed that demersal (1.87 ± 0.39 items individual-1) and benthopelagic (1.5 ± 0.26 items individual-1) fish species had more MPs than pelagic fish (0.63 ± 0.18 items individual-1) species. Polypropylene (PP) was found to be the most dominant polymer type in the sediment sample, and PS (39 %) in the fish sample. Polyethylene (PE) was discovered to be 30 % and PP 25 % in sediment and fish samples, respectively. Other commonly detected polymer types include polyamide (PA), polystyrene (PS), cellulose acetate (CA), and polyethylene terephthalate (PET). In different sampling sites along the Turag River, the pollution load index (PLI) of MPs contamination was found to be in the risk level category I. The PLI values reflected the city's anthropogenic influence. The findings of the study could be used to establish a baseline for MPs pollution in Bangladesh's vast freshwater ecosystem.

Khan MB ，Urmy SY ，Setu S ，Kanta AH ，Gautam S ，Eti SA ，Rahman MM ，Sultana N ，Mahmud S ，Baten MA ... -  《-》

Assessment of microplastics pollution in aquatic species (fish, crab, and snail), water, and sediment from the Buriganga River, Bangladesh: An ecological risk appraisals.

Current work focus on microplastic (MPs) occurrence in the water, sediment, and aquatic species (fish, crab, and snail) of the Buriganga River, Bangladesh, with an ecological risk assessment perspective. It also includes the distribution of MPs in different river ecosystem segments and the presence of heavy metal (loid)s (HMs) in water, sediments, and MPs surface. The MPs were inspected by stereomicroscope to identify the shapes, color, and size, and Fourier transform infrared (FTIR) spectroscopy was used to characterize polymer types. The samples concentration of four HMs viz., As, Cd, Cr, and Pb were determined by atomic absorption spectrometry (AAS). The possible MPs content in water, sediment, fish, crab, and snail were varied from 0.250 to 0.117 MPs/mL, 3.5-8.17 MPs/g, 0.65-3.82 MPs/g, 3.75-4.28 MPs/g, and 0.84-1.12 MPs/g, respectively. Fibers and fragments were the most dominant shape, less than 0.5 mm was dominant in size, and blue was the dominant color. In the evaluation of the chemical composition of MPs in water, sediment, fish, snail, and crab samples, Polyethylene terephthalate (PETE), Ethylene-vinyl acetate (EVA), High-density polyethylene (HDPE), Acrylonitrile butadiene styrene (ABS), Cellulose acetate (CA), and Nylon were identified. Regarding HMs load, the river demonstrated a highly polluted environment following the abundance pattern Cr > Pb > As>Cd. SEM-EDAX of MPs was conducted to investigate the surface MP's surface and elemental composition. It reveals that the MPs surface has characteristic flakes, cracks, and adhering particles along with Si, K, Au, C, and O on the surface studied MPs. There is no significant relationship found among the ecosystem segments. However, Ompok bimaculatus species show a negative relationship of MPs distribution with water and sediment. Moreover, according to the ecological risk of MPs pollution in the Buriganga River, it was in category-I, indicating considerable pollution load due to the presence of MPs.

Haque MR ，Ali MM ，Ahmed W ，Siddique MAB ，Akbor MA ，Islam MS ，Rahman MM ... -  《-》

Microplastics pollution in the Surma River, Bangladesh: A rising hazard to upstream water quality and aquatic life.

The ecological health of freshwater rivers is deteriorating globally due to careless human activities, for instance, the emission of plastic garbage into the river. The current research was the first assessment of microplastics (MPs) pollution in water, sediment, and representative organisms (fish, crustacean, and bivalve) from the Surma River. Water, sediment, and organisms were sampled from six river sites (Site 1: Charkhai; Site 2: Golapganj; Site 3: Alampur; Site 4: Kazir Bazar; Site 5: Kanishail and Site 6: Lamakazi), and major water quality parameters were recorded during sampling. Thereafter, MPs in water, sediment, and organism samples were extracted, and then microscopically examined to categorize selected MPs types. The abundance of MPs, as well as size, and color distribution, were estimated. Polymer types were analyzed by ATR-FTIR, the color loss of MPs was recorded, the Pollution Load Index (PLI) was calculated, and the relationship between MPs and water quality parameters was analyzed. Sites 4 and 5 had comparatively poorer water quality than other sites. Microplastic fibers, fragments, and microbeads were consistently observed in water, sediment, and organisms. A substantial range of MPs in water, sediment, and organisms (37.33-686.67 items/L, 0.89-15.12 items/g, and 0.66-48.93 items/g, respectively) was recorded. There was a diverse color range, and MPs of <200 μm were prevalent in sampling areas. Six polymer types were identified by ATR-FTIR, namely Polyethylene (PE), Polyamide (PA), Polypropylene (PP), Cellulose acetate (CA), Polyethylene terephthalate (PET), and Polystyrene (PS), where PE (41%) was recognized as highly abundant. The highest PLI was documented in Site 4 followed by Site 5 both in water and sediment. Likewise, Sites 4 and 5 were substantially different from other study areas according to PCA. Overall, the pervasiveness of MPs was evident in the Surma River, which requires further attention and prompt actions.

Jahan I ，Chowdhury G ，Baquero AO ，Couetard N ，Hossain MA ，Mian S ，Iqbal MM ... -  《-》

Distribution, characterization and contamination risk assessment of microplastics in the sediment from the world's top sediment-laden estuary.

Microplastics (MPs) have gained a serious attention as an emerging contaminant throughout the world because of their persistence and possible risks to aquatic ecosystems and human well-being. However, knowledge on MPs contamination from sub-tropical coastal systems is limited, and no study has been conducted on the MPs contamination in sediment from one of the highest sediment-laden estuaries, Meghna River, in the world. This is the first study to examine the quantity, morpho-chemical characteristics and contamination risk level of MPs from this large scale river. MPs were extracted from the sediment samples of 10 stations along the banks of the estuary by density separation, and then characterized using a stereomicroscope and Fourier Transform Infrared (FTIR) spectroscopy. The incidence of MPs varied from 12.5 to 55 item/kg dry sediment with an average of 28.67 ± 10.80 item/kg. The majority (78.5%) of the MPs were under 0.5 mm in size, with fibers being the most (74.1%) prevalent MPs type. Polypropylene (PP) was found to be the predominant polymer (53.4%), followed by polyethylene (PE, 20%), polystyrene (PS, 13.3%), and polyvinyl chloride (PVC, 13.3%). The highest occurrence of PP indicted the MPs in the estuary might be originated from clothing and dying industries, fishing nets, food packages, and pulp industries. The sampling stations were contaminated with MPs as shown by the contamination factor (CF) values and pollutant load index (PLI), both of which were >1. This study exposed new insights on the status of MPs in the sediments of the Meghna River, laying the groundwork for future research. The findings will contribute to estimate the global share of MPs to the marine environment.

Hossain MB ，Yu J ，Nur AU ，Banik P ，Jolly YN ，Mamun MA ，Paray BA ，Arai T ... -  《-》