Microplastics in the Surface Water and Gastrointestinal Tract of Salmo trutta from the Mahodand Lake, Kalam Swat in Pakistan

Abstract

Microplastic pollution is becoming an increasingly severe environmental problem. As compared to the marine ecosystem, freshwater ecosystems at high-altitude, remote regions are less studied and lag far behind. Thus, the present study aims to highlight this issue and fill the gap in this regard. The presence of microplastics (MPs) in the surface water and the gastrointestinal tracts (GITs) of brown trout (Salmo trutta) from Lake Mahodand, Kalam Swat, Pakistan, at a high altitude of 2865 m above sea level was investigated. For microplastic extraction, samples were digested with H2O2, NaCl solution was added for density separation, and then samples were filtered with a cellulose nitrate filter (pore size 0.45 µ). After this, visual observation and polymer detection with Fourier transform infrared spectroscopy, microplastics were characterized by their shapes, sizes, colors, and polymer types. In the surface water sample, MP particles were found in the range of 0–5 MPs/L, where the mean concentration of MPs was 2.3 ± 1.52 MPs/L and 1.7 ± 1.05 MPs/gastrointestinal tract (GIT) isolated from the GIT of brown trout. Particles of relatively larger size (500–300 µm) were more abundant than other ranges of particles (300–150 and 150–50 µm) in the surface water and fish samples. The fiber was the most abundant shape of MP particles, followed by sheets and fragments in surface water and fish samples (fibers > sheets > fragments). Four types of polymer viz. low-density polyethylene (LDPE) (44.4%), polypropylene homopolymer (PPH) (19.4%), polyvinyl chloride (PVC) (30.5%), and high-density polyethylene (HDPE) (5.5%) were detected by FTIR spectroscopy. The findings of the present study showed that MPs reached into higher altitudes in remote areas due to tourism activities.

Microplastics in and Near Landlocked Countries of Central and East Asia: A Review of Occurrence and Characteristics

“…This implies the significant variability of MP even for samples taken from locations in proximity, probably due to factors such as human activities and water flow, which demonstrate significant spatial and temporal variations. The lakes near the northeastern border of Kazakhstan and the northwest of Mongolia recorded a mean MP concentration of 11 ± 7 items/l [17], while Mahodand Lake in the northeast vicinity of Afghanistan contained a mean of 2.3 ± 1.52 MP/l [20]. The latter, though located remotely, is, in fact, a tourist spot.…”

“…However, with Iran sharing the southern perimeter of the Caspian Sea, few studies on the southern Caspian Sea were conducted near the southwestern border of Turkmenistan [18,19]. Similarly, for Afghanistan, a study was conducted for the Mahodand Lake of Pakistan, near its northeastern border [20].…”

“…The MP in and near the landlocked countries were dominated by those of the smaller fractions. The most common fraction is >500 µm [18,20,21]. Within this fraction, Malygina et al reported that MP sized 31-60 nm were most common [17], while D'Hont et al found those < 35 µm were most abundant [11].…”

Some Behavioural and Physiological Effects of Plastics (Polyethylene) on Fish

“…It has been demonstrated that deteriorated polymer structures have a greater biological activity [42] due to the increased leaching of endocrine-disrupting chemicals produced from plastic and their capacity to interfere with energy metabolism. According to a field study by Bilal et al [43], up to thirty percent of persons have plastic in their gastrointestinal systems. Similarly, Prakash et al [44] found that Japanese medaka exposed to mm-sized polyethylene particles exhibited early indicators of endocrine disruption.…”

Presence of microplastic in personal care and cosmetic products from markets in Punjab, Pakistan

“…In recent times, a number of studies have appeared that analyzed for MP concentrations in different environmental compartments in Pakistan, predominately in aquatic environments such as in nearshore waters (Ahmed et al, 2022), and along the coastline of the Arabian Sea (Ahmed et al,, 2022;Akhter and Panhwar, 2022;Arshad et al, 2023), but also in relatively secluded lakes such as the Mahodand Lake, Swat, Khyber Pakhtunkhwa District (Bilal et al, 2023) and Rawal Lake, Margalla Hills, Islamabad Capital territory (Nousheen et al, 2022;Irfan et al, 2020). MP concentrations were found to be signi cant.…”