11:20 〜 11:35
[AHW20-11] Plastic debris as a carrier of inorganic contaminants in the urban river of Mongolia
キーワード：Plastic debris, Inorganic pollutants, Polystyrene foam (PSF), Urban river, Aggregates
Plastic pollution in the aquatic environment has become a social concern by their long life in the ecosystems. Although a global survey has mainly focused on the accumulation and distribution of plastic debris, interactions between plastic debris and inorganic pollutants and the behavior of those plastics aggregates are still unclear. In this study, we addressed plastics associated with inorganic pollutants in the urban river of Mongolia. The aims of the current study are i.) identification of inorganic pollutants on the surface of plastic debris, particularly on polystyrene foam (PSF), and ii.) evaluation of the elemental association and potential sources of inorganic pollutants with the PSFs in the river environment.
The PSF samples were collected from the 6 sampling locations of the urban river shores. The concentrations of major (Al and Na) and trace (B, Cr, Cu, Mn, Mo, Ni, Pb and Zn) elements were determined in the macro (20-100 mm), meso (5-20 mm), and micro (<5 mm) sized PSFs. The mixture of hydrogen peroxide (30%, H2O2) and iron (II) catalyst solution (0.05 M) was used to digest all organic substances and separate surface adhered inorganic pollutants from the PSF samples. The digested solution was applied to determine the concentrations of major and trace elements adhered on the PSFs using an Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES).
The mean concentrations of Al, B, Cr, Cu, Mn, Mo, Na, Ni, Pb and Zn accumulated on the PSFs (n=57) were determined as 1967.0±270.5, 119.5±43.2, 16.1±7.5, 39.4±8.7, 174.2±20.7, 9.6±2.5, 1506.8±476.8, 40.8±11.2, 17.7±9.2 and 283.0±100.8 µg g-1 (mean content ± standard error), respectively. Comparing levels of elements among the different size fractions, rather higher values of elements were measured in the meso-sized PSFs except for Al and Mo, which were higher in micro-sized PSF particles. In addition, strong correlations among B, Na and Zn indicate the chemical association of those elements with the environmental PSFs. A wide range of the elemental concentrations illustrates the adsorption of the elements from the surrounding environment on the surface of PSFs which might be mediated by a biofilm. On the contrary, some elements (i.e., Zn) can be leached from additives of PSFs through degradation. The widespread plastic debris could be one of the carriers and sources of hazardous chemicals in the aquatic environment.
While the consequences of plastic debris on environmental health are poorly understood, the fate and behavior of hetero-aggregates of plastics in the aquatic environment should be continuously studied in future.
The PSF samples were collected from the 6 sampling locations of the urban river shores. The concentrations of major (Al and Na) and trace (B, Cr, Cu, Mn, Mo, Ni, Pb and Zn) elements were determined in the macro (20-100 mm), meso (5-20 mm), and micro (<5 mm) sized PSFs. The mixture of hydrogen peroxide (30%, H2O2) and iron (II) catalyst solution (0.05 M) was used to digest all organic substances and separate surface adhered inorganic pollutants from the PSF samples. The digested solution was applied to determine the concentrations of major and trace elements adhered on the PSFs using an Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES).
The mean concentrations of Al, B, Cr, Cu, Mn, Mo, Na, Ni, Pb and Zn accumulated on the PSFs (n=57) were determined as 1967.0±270.5, 119.5±43.2, 16.1±7.5, 39.4±8.7, 174.2±20.7, 9.6±2.5, 1506.8±476.8, 40.8±11.2, 17.7±9.2 and 283.0±100.8 µg g-1 (mean content ± standard error), respectively. Comparing levels of elements among the different size fractions, rather higher values of elements were measured in the meso-sized PSFs except for Al and Mo, which were higher in micro-sized PSF particles. In addition, strong correlations among B, Na and Zn indicate the chemical association of those elements with the environmental PSFs. A wide range of the elemental concentrations illustrates the adsorption of the elements from the surrounding environment on the surface of PSFs which might be mediated by a biofilm. On the contrary, some elements (i.e., Zn) can be leached from additives of PSFs through degradation. The widespread plastic debris could be one of the carriers and sources of hazardous chemicals in the aquatic environment.
While the consequences of plastic debris on environmental health are poorly understood, the fate and behavior of hetero-aggregates of plastics in the aquatic environment should be continuously studied in future.