Dynamics of plastic debris and its density change between river compartments in the Tuul River system, Mongolia

Munkhbat, D.*; Battulga, B.; Oyuntsetseg, B.*; Kawahigashi, Masayuki*

Environmental Science and Pollution Research, 31(57), p.65548 - 65558, 2024/11

https://doi.org/10.1007/s11356-024-35584-w

Plastic pollution in river environments has become an emerging concern in recent decades, and river plastic studies have received worldwide attention. However, most plastics research has focused on the dynamics of microsized plastics in surface water and sediments, whereas less research has been conducted on the gradual degradation and size reduction of plastics in the environment. Additionally, the migration of plastic debris between river compartments and changes in its properties are less understood despite their impact on its fate. In this study, we investigated changes in plastic debris distribution in terms of abundance, size, shape, polymer types, and photodegradation stages in the floodplain, surface water, and sediment compartments of the Tuul River system in Mongolia. The plastic abundance was 5.463.53 items/m in the floodplain, 155100.7 items/m in the surface water, and 128.476.3 items/kg in the sediment.

Plastic-associated metal(loid)s in the urban river environments of Mongolia

Battulga, B.; Atarashi-Andoh, Mariko; Koarashi, Jun; Bolormaa, O.*; Kawahigashi, Masayuki*

Ecotoxicology and Environmental Safety, 261, p.115100_1 - 115100_10, 2023/08

https://doi.org/10.1016/j.ecoenv.2023.115100

The widespread distribution of plastic debris in the riverine environment is one of the major concerns of environmental pollution because of its potential impact on the aquatic ecosystem. In this study, we investigated accumulation of metal(loid)s on polystyrene foam (PSF) plastics collected from the Tuul River shore of Mongolia. Sorbed metal(loid)s on plastics have been extracted from collected PSF by sonication after peroxide oxidation. Size-dependent association of metal(loid)s indicated that PSFs act as vectors for the pollutants in the urban river environment. In addition, images from scanning electron microscopy (SEM) indicated not only the degraded surface of plastics showing fractures, holes, and pits, but also adhered mineral particles and microorganisms on PSFs. Interaction of metal(loid)s with plastics may be facilitated by altered surface physical and chemical properties of the plastics through photodegradation followed by an increase in surface area by size reduction and/or biofilm development in the aquatic environment. Enrichment ratio (ER) of metals on PSF samples suggested continuous accumulation of heavy metals on plastics. Our results demonstrate that the widespread plastic debris could be one of the carriers for hazardous chemicals in the environment. Since the influences of plastic debris on environmental health are major concerns to be solved, the fate and behavior of hetero-aggregates of plastics in aquatic environments should be continuously studied.

Plastic fluxes and composition change in transportation and accumulation process of the urban river, Mongolia

Munkhbat, D.*; Battulga, B.; Oyuntsetseg, B.*; Kawahigashi, Masayuki*

no journal, , 

Changes in distribution and types of plastic debris in urban river shores, Ulaanbaatar city, Mongolia

Munkhbat, D.*; Kawahigashi, Masayuki*; Battulga, B.; Bolormaa, O.*; Sainjargal, B.*

no journal, ,