Evidences of Microplastic in Air 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. The present study aimed to assess the availability of MPs in air and street dust of a metropolitan city Varanasi, India. Suspended dust samples and street dust samples were collected from various sampling sites. The assessment of MPs was conducted by for physical identification binocular microscopy, fluorescence microscopy and Scanning Electron Microscopy (SEM), while elemental analysis done by Energy Dispersive X-Ray Analysis (EDX). and finally, Fourier-transform infrared spectroscopy (FTIR) was used for functional group analysis. the presence of MPs in both suspended dust and street dust samples of all selected sampling sites was confirmed by results. MPs of different color with the shape of Fragments, Films, Spherules and Fibers were observed in the study. However, most of the MPs were less than 1mm in size. The MPs identified in our study were majorly polypropylene, polystyrene, polyethylene, polyethylene terephthalate, polyester, and polyvinyl chloride. EDX analysis showed presence of trace elements like aluminum, cadmium, magnesium, sodium, and silicon apart from carbon and oxygen, which indicates the presence of additives or adsorption capacity of MPs. Confirmation of MPs in the air of a locality of Varanasi explains the need of deep research in this concerned field to protect our future from negative impacts of breathing MPs.

Characteristics and Risk Assessment of 16 Metals in Street Dust Collected from a Highway in a Densely Populated Metropolitan Area of Vietnam

The present study focused on investigating the contamination and risk assessment for 16 metals in street dust from Ha Noi highway, Ho Chi Minh City. The results indicated that the concentrations of metals (mg/kg) were found, in decreasing order, to be Ti (676.3 ± 155.4) > Zn (519.2 ± 318.9) > Mn (426.6 ±113.1) > Cu (144.7 ± 61.5) > Cr (81.4 ± 22.6) > Pb (52.2 ± 22.9) > V (35.5 ± 5.6) > Ni (30.9 ± 9.5) > Co (8.3 ± 1.2) > As (8.3 ± 2.5) > Sn (7.0 ± 3.6) > B (5.7 ± 0.9) > Mo (4.1 ± 1.7) > Sb (0.8 ± 0.3) > Cd (0.6 ± 0.2) > Se (0.4 ± 0.1). The geo-accumulation index (Igeo) showed moderate contamination levels for Pb, Cd, Cu, Sn, Mo, and Zn. The enrichment factor (EF) values revealed moderate levels for Cd, Cu, Mo, and Sn but moderate–severe levels for Zn. The pollution load index of the heavy metals was moderate. The potential ecological risk (207.43) showed a high potential. Notably, 40.7% and 33.5% of the ecological risks were contributed by Zn and Mn, respectively. These findings are expected to provide useful information to decision-makers about environmental quality control strategies.

Distribution Characteristics and Risk Assessment of Heavy Metals in Soil and Street Dust with Different Land Uses, a Case in Changsha, China

Rapid urbanization and industrialization have led to the accumulation of heavy metals in urban areas. The distribution and health risk of heavy metals in soil and street dust were studied by collecting the samples in pairs from different land uses in Changsha, China. The results showed that the average contents of the heavy metals Pb, Cd, Cu, Zn, Cr and Ni in the soil were 45.3, 0.69, 46.3, 220.4, 128.7 and 32.9 mg·kg−1, and the corresponding heavy metal contents in the street dust were 130.1, 3.9, 130.8, 667.2, 223.2, 50.5 mg·kg−1, respectively. The soils in the parks and roadsides have higher heavy metal contents than those in the residential and agricultural areas. The street dust collected from parks, roadsides and residential areas contained higher heavy metal contents than agricultural areas. Significant correlations were found between heavy metals, suggesting similar sources. However, most of the heavy metals in the soil were uncorrelated with those in the street dust. The contents of heavy metals in soil are the results of long-term pollution. Street dust is easily affected by natural or human disturbances, reflecting pollution emissions in a short period. The health risks posed by heavy metals in the soil are acceptable, but the street dust may threaten children’s health, especially in residential areas. Pb, Cr and Cd are the main risk contributors. Reducing the emissions from industrial plants and traffic may reduce the risk of exposure to heavy metals in the street dust.