Microplastic assessment in aquaculture feeds: Analyzing polymer variability across commercial fishfeeds from three continents.

This study analysed ten widely used commercial fishfeeds in aquaculture from six countries spanning three continents to assess microplastic (MP) contamination. MPs with an average abundance of 1130 ± 259.07 particles/kg and an average length of 2.64 ± 0.62 mm ( ± SE) were found in aquaculture feeds, with fibres (85 %) and fragments (15 %). The majority of these MPs were black. The abundance of MPs varied among the samples, with the highest in feed SP (26 %), followed by IF, GA, ELS, NT, EW, TB, GR, VR, and the least in HCF (3 %). Polymers identified consisted of Polyethylene terephthalates (PET, 20 %), Polyamide (PA, 30 %), Polymethyl methacrylate (PMMA), Polyurethane (PU), and Polystyrene (PS) with 15 % each, and Polypropylene (PP, 5 %). SEM-EDX analysis of fibres showed flakes, cracks, and pits and the presence of heavy metals Ni, Cu, Zn, Cr, Au, Hg, Cd, Ti, and Pb. Additionally, some fragments contained Nb (Niobium) alongside the naturally occurring elements. The Polymer Hazard Index (PHI) for the polymers in ten feeds was calculated, and nine were in the highly hazardous category (IV and V) with PHI values ranging from 400-394825. The work showcases the graveness of MPs in fishfeeds and advocates control measures to curtail MPs in fishfeeds for sustainable aquaculture production.

Devi SS ，Jayan S ，Kumar AB 《-》

Microplastics contamination in commercial fish meal and feed: a major concern in the cultured organisms.

The growing scale of plastic pollution causes a devastating impact on the aquatic ecosystem. The people largely depend on animal-based food for their protein requirements. In this study, we analysed 10 different fish meal samples and 20 feed samples used in farming to understand the level of microplastic (MPs) contamination and estimate the amount of MPs ingested by farmed fish, shrimp, and chicken through feed. The abundance of MPs in fish meal samples ranges from 210 ± 98.21 to 1154 ± 235.55 items/kg. The fish meal produced from dried fish is more prone to MPs contamination than that produced from fresh fish. In the case of fish feed, MP abundances range from 50 ± 22.36 to 160 ± 36.57 items/kg in shrimp feeds, 60 ± 26.74 to 230 ± 52.32 items/kg in fish feeds and 90 ± 25.11 to 330 ± 36.12 items/kg in chicken feeds. The exposure rate of MPs is higher in the grower- and finisher-stage feeds than in the starter feed. Fiber-shaped MPs of size 100-500 μm with PE and PP polymers were predominantly found in fish meal and feed samples. EDAX analysis showed the presence of Cr, Cd, Ti, Ni, Cu, As, Al, Pb, Hg, Cd, Ti, Fe, Ca, K, and Si in fish meal samples and Ca, Na, Zn, Cu, Ni, Cl, Al, Si, S, Pb, Cd, Ti, Cr, Mg and Fe in feed samples. The possible level of exposure of microplastic particles was calculated based on MP contamination in feed, feed consumption rate, and body weight. We estimated an MP exposure level of 531-1434 items/kg feed for farmed shrimp, 234-4480 items/kg feed for fishes, and 3519-434,280 items/kg feed for chicken. This study concludes that fish meal and feed are one of the important exposure routes of MPs to the farmed animals.

Jeyasanta I ，Sathish MN ，Patterson J ，Esmeralda VG ，R L L ... -  《-》

Microplastic contamination in commercial fish feeds: A major concern for sustainable aquaculture from a developing country.

Plastic pollution has become a global issue nowadays. Due to the increased population in developing countries, we largely depend on fish from our aquaculture industry to meet the required protein demand. Though several studies documented plastic ingestion in freshwater and marine organisms, very limited studies have been conducted to elucidate microplastic (MP) contamination in commercial fish feed. Therefore, this study was designed to identify, quantify, and characterize microplastics (MPs) in commercial fish feeds in Bangladesh and assess possible health risks in fish consuming different commercial fish feeds. All fish feed samples were 100 % contaminated with MPs, where the mean abundance of MPs ranged between 500 and 2200 MPs/kg. No significant differences among different types of feeds (e.g., starter, grower, and finisher) were observed in terms of MPs abundance (F = 0.999, p = 0.385). This study revealed that fiber was the most dominant shape of MPs (90 %), while the most dominant color of MPs was red (34 %), followed by black (31 %) and blue (19 %). The 100-1500 µm size class covers 88 % of the total MPs in the collected fish feed samples. Identified polymers in the samples were polyethylene (PE, 37.71 %), polyvinyl chloride (PVC, 27.14 %), polypropylene (PP, 22.08 %), and polyethylene terephthalate (PET, 13.07 %), respectively, where PE and PVC fall under the risk category IV to V. The Pollution load index (PLI) values of all fish feed samples were <10, indicating the risk category of I (low risk). Therefore, this study highly recommended avoiding plastic materials in the packaging and storing purposes of feed ingredients in the feed mills to ensure contamination-free fish feed for sustainable aquaculture.

Siddique MAM ，Tahsin T ，Hossain I ，Hossain MS ，Shazada NE ... -  《-》

Microplastic contamination in Ashtamudi Lake, India: Insights from a Ramsar wetland.

Estuaries function as temporary storage sites for plastic debris, influencing the distribution of microplastics (MPs) across ecosystems. This research delves into the presence of MPs in the water, sediment, fish, and shellfish of Ashtamudi Lake, a Ramsar wetland with brackish water located on the southwest coast of India. Given the lake's significance in supporting the livelihoods of numerous fishers and acting as a vital source of fishery resources for both local consumption and export, examining the contamination of the system by MPs becomes particularly pertinent. The highest percentage composition of MPs was found in macrofauna at 60.6% (with fish at 19.6% and shellfish at 40.9%), followed by sediment (22.8%) and water (16.7%). The primary types of MPs identified in all samples were fibers (35.6%), fragments (33.3%), and films (28%), with beads being the least represented at 3.03%. ATR-FTIR and Raman spectra analysis identified five polymers from shellfish (polypropylene, polyethylene, polystyrene, nylon, and polyvinyl chloride), five from fish guts (nylon, polypropylene, polyethylene, polyurethane, and polysiloxane), four in sediment (polypropylene, polyethylene, nylon, rayon), and four in water samples (polypropylene, polyethylene, nylon, and polystyrene). SEM-EDAX analysis of MPs obtained from the samples revealed degradation and the presence of inorganic elements such as Na, Mg, Al, Si, S, K, Cl, P, and Ca, as well as heavy metals like Pb, Mo, Rh, Pd, Ti, and Fe. The existence of these plastic polymers and heavy metals in microplastic samples poses a threat to vulnerable biota; people consume contaminated fish and shellfish, underscoring the importance of monitoring MPs in lake water. This investigation of MPs in Ashtamudi Lake highlights the system's susceptibility to plastic pollution and the bioavailability of smaller MPs to aquatic organisms. Identified sources of MPs in the lake include fishing and aquaculture activities, sewage pollution, improper solid waste management in lake watersheds, and unsustainable tourism. Upstream and downstream management interventions are recommended to address MP pollution in Ashtamudi Lake.

Devi SS ，Gouri BR ，Anjali S ，Kumar AB ... -  《-》

Seasonal variation, polymer hazard risk and controlling factors of microplastics in beach sediments along the southeast coast of India.

Microplastics (MPs) and its associated organic and inorganic contaminants are one among the significant health hazards to almost all biota, including human. We investigated the polymer hazard risk and its adsorbed contaminants in MPs at six prominent beaches of Chennai on the southeast coast of India. The spatial variation of MPs during the northeast (NE) monsoon (range: 76-720 items/kg, mean: 247.4 items/kg) was higher than that during southwest (SW) monsoon (range: 84-498 items/kg, mean: 302.7 items/kg). In both the seasons, polyethylene (PE) and polypropylene (PP) were the dominant polymers and fibre was the predominant shape of MPs, likely to be derived from fishing, textile and urban activities in this region. Scanning electron microscope (SEM) images exhibited various surface weathering features including grooves, cracks, fractures, adhering particles, pits, vermiculate textures and fibre reinforcements. Energy dispersive X-ray spectrometer (EDS) results showed that MPs have adsorbed major (Si, Al, Na, Mg, Ca, Fe and Ti) and trace (Cu, Cr, Ni, Pb and Zn) metals. Though pollution load index (PLI) presented low degree of MP contamination in the beach sediments, hazardous polymers such as polyvinyl chloride (PVC), polyamide (PA) and polystyrene (PS) contributed to high polymer hazard index (PHI) and potential ecological risk index (PERI), posing very high risk to the biota. The trajectories obtained from particle-tracking coupled with hydrodynamic simulation clearly showed that 20% of MPs settled along the coast and the remaining moved towards north, alongshore and offshore (∼50 km) within 30 days, and in NE monsoon due to current reversal, the floating debris and MPs have drifted towards south, ∼40 km in 30 days, indicating the role of circulation in the fate and transport pathways of plastic debris.

Ranjani M ，Veerasingam S ，Venkatachalapathy R ，Jinoj TPS ，Guganathan L ，Mugilarasan M ，Vethamony P ... -  《-》