Microplastic in fishes: the first report from a Himalayan River - Alaknanda.

The present study aimed to understand microplastic (MP) ingestion by five fish species with different feeding habits namely, Schizothorax richardsonii and Crossocheilus latius (herbivore),Cyprinus carpio (omnivore), Tor chelenoid (herbi-omnivore), and Botia horii (carnivore). The fishes were sampled from River Alaknanda (one of the headwaters of River Ganga) patch at Srinagar, Garhwal, Uttarakhand. The fish gut samples were digested with 30% hydrogen peroxide and vacuum filtered through glass microfiber filter. Each filter paper was observed microscopically to count MPs, and then, selected MPs were chemically characterized using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR). The results revealed that all the species were contaminated with MPs and the rate of MP ingestion varied with feeding habits. The herbi-omnivore fish, Tor chelenoid, was observed to have the highest MP ingestion. Among the analyzed particles, fibers (66%) were the dominant type of MPs. The MPs were chemically characterized as High-Density Polyethylene (HDPE), Polypropylene (PP), and Polyester. This study contributes as a reference for the forthcoming researches, as it is the pioneer work on the ingestion of MP by fishes of a Himalayan River.

Microplastics in the River Ganga and its fishes: Study of a Himalayan River.

The River Ganga has been explored for microplastics (MPs) majorly in the lower or middle course, while the upper course from where the river starts its journey remains untouched. This study investigates the occurrence and distribution of MPs in the river environment (water and sediment) and common fishes inhabiting the upper stretch of River Ganga in the Uttarakhand state of India. A volume-reduce method by using sieve filtration was used to take water and sediment samples from the study area while fish samples were collected using net method. The samples underwent alkali digestion, microscopic examination, and chemical analysis using Fourier Transformed Infrared Spectroscopy (FTIR). An average of 118.5 ± 49.65 particles per 1000 L and 131.5 ± 53.60 particles/kg dry weight were found in water and sediment respectively. While in the fishes, Tor tor, Schizothorax richardsonii, Labeo dero and Gara gotyla gotyla MPs were 53.13 ± 63.77, 36.33 ± 22.34, 15.42 ± 9.33 and 12.63 ± 5.93 particles/individual respectively. A positive correlation was observed between the number of MPs in fish and their body length, weight, and gut weight, while no correlation was found between feeding habit and MP accumulation. The majority of MPs detected were fibers ranging from 100 µm to 1 mm in size. Polymer types varied among water, sediment, and fish samples, with polyethylene (PE) predominant in water, polypropylene (PP) dominant in sediment, and polyethylene terephthalate (PET) and polystyrene (PS) most abundant in fish samples.

Evidences of microplastics in aerosols and street dust: a case study of Varanasi City, India.

Microplastics (MPs) are ubiquitous in our environment. Its presence in air, water, and soil makes it a serious threat to living organisms and has become a critical challenge across ecosystems. Present study aimed to assess the abundance of MPs in aerosols and street dust in Varanasi, a typical urban city in Northern India. Airborne particulates and street dust samples were collected from various sampling sites around Varanasi City. The physical identification of MPs was conducted by binocular microscopy, fluorescence microscopy, and scanning electron microscopy (SEM), while elemental analysis was made by energy-dispersive X-ray (EDX). Finally, Fourier-transform infrared spectroscopy (FTIR) was used for chemical characterization of MPs. Presence of MPs in both aerosols and street dust from all selected sampling sites was confirmed, however with varying magnitude. MPs of different colors having the shape of fragments, films, spherules, and fibers were recorded in the study while fragments (42%) in street dust and fibers (44%) dominated in aerosols. Majority of the MPs were < 1 mm in size and were primarily polypropylene, polystyrene, polyethylene, polyethylene terephthalate, polyester, and polyvinyl chloride types. The EDX spectra showed the presence of toxic inorganic contaminants like metallic elements on MPs, especially elements like aluminum, cadmium, magnesium, sodium, and silicon found to adsorb on the MPs. Presence of MPs in the airborne particulates and street dust in Varanasi is reported for the first time, thus initiating further research and call for a source-specific management plan to reduce its impact on human health and environment.