Preliminary characterization and probabilistic risk assessment of microplastics and potentially toxic elements (PTEs) in garri (cassava flake), a common staple food consumed in West Africa.

Garri from cassava is one of the most consumed foods in West Africa, hence this research was conducted to examine microplastics (MPs) and potentially toxic elements (PTEs) in garri from Nigeria (West Africa) and Japan. This is the first investigation on MPs in garri samples that has been reported in the literature. The study analyzed both packaged and unpackaged vended garri samples using microscopic/spectroscopic and X-ray fluorescence techniques for MPs and PTEs respectively. Microplastic particles in the garri samples ranged from (or were between) 2.00±2.00 - 175.00±25.16 particles/50 with > 90 % as fragments and consisted of polyacrylamide, polyethylene terepthalate, polyvinyl alcohol, high density polyethylene, polyvinyl chloride acrylonitrile, polyethylene chlorinated, polypropylene with silicate mix, polychloroprene and polyethylene chlorosulphonated. The mean concentration of PTEs raged from ND to 0.07 mg/g for Cr and Mn, 0.73 to 5.63 mg/g for Fe, ND to 0.57mg/g for Co, 0.23 to 1.21 mg/g for Ni, 0.15 to 1.53 mg/g for Cu, and 0.12 to 0.63 mg/g for Zn. However, their daily intake was low for both adult and children as with the MPs. The sources of MPs and PTEs were mainly from the garri production processes, atmospheric dusts and during packaging. The non-carcinogenic risk for all samples was low for MPs while in openly vended garri, Ni and Cr in all sample poses carcinogenic risks. There is a need to improve indigenous garri processing techniques to minimize contamination. This research emphasizes the critical necessity to understand the consequences of MPs on human health.

Pollution levels and health risk assessment of potentially toxic metals of size-segregated particulate matter in rural residential areas of high lung cancer incidence in Fuyuan, China.

The highest incidence and mortality rate of lung cancer in rural area of Fuyuan has been a research hotspot, and the pathogenesis is still unclear. Therefore, atmospheric particulate matters (APMs) samples were collected between 18 February and 01 March 2017, exploring water-soluble potentially toxic metals (WSPTMs) and water-soluble inorganic ionic species (WSIIs) levels, size distribution, sources, acidity and alkalinity, and potential carcinogenic and non-carcinogenic risks, hoping to provide scientific basic data to solve this problem. In our study, the average ratio of nitrate ion (NO3-)/sulfate ion (SO42-) within PM1.1, PM1.1-2.0, PM2.0-3.3, PM3.3-7.0, and PM>7.0 were 0.22, 0.18, 0.15, 0.34 and 0.36, respectively, that revealed that combustion sources contributed to PM were more significant. The anions in equilibrium (ANE) / cations in equilibrium (CAE) < 1 for all samples within PM1.1, PM2.0-3.3, PM3.3-7.0 indicate that the APMs were alkaline, but PM1.1-2.0 particulate matter shows weak acidity. SO42- prefers to combine with NH4+ to form (NH4)2SO4, which hinders the formation of NH4NO3, the remaining SO42- and NO3- to neutralize the K+, KNO3 was formed at all particulate, however, K2SO4 can only be formed in PM<3.3. Arsenic (As) and Selenium (Se) were identified as the most enriched WSPTMs in all PM sizes, predominantly from anthropogenic emissions, were suggested that coal combustion is a significant source of PM-bound WSPTMs. Total WSPTMs exhibited high total carcinogenic risks (TCR) values (9.98 × 10-6, 1.06 × 10-5, and 1.19 × 10-5 for girls, boys and adults, respectively) in the smaller particles (< 1.1 µm). Se was considered as the major contributor (63.60%) to carcinogenic risk (CR) in PM2.0 and had an inverse relationship with PM size that should be of prime concern.

Pollution characteristics and risk assessment of potentially toxic elements of fine street dust during COVID-19 lockdown in Bangladesh.

Due to the COVID-19 pandemic, Bangladesh government took the measure like partial lockdown (PL) and complete lockdown (CL) to curb the spread. These measures gave a chance for environmental restoration. In this study, street dust samples were collected during PL and CL from four main urban land use categories in Dhaka city, such as industrial area (IA), commercial area (CA), public facilities area (PFA), and residential area (RA). Ten potentially toxic elements (Cr, Mn, Zn, Fe, Pb, Cu, Co, Ni, As, and Cd) in fine street dust particles (diameter < 20 µm) were determined following aqua-regia digestion and measured by inductively coupled plasma mass spectrometry (ICP-MS) to evaluate distribution, pollution sources, and potential risks to ecological systems and human health. Results showed that during PL, the concentrations of toxic elements in the dust were higher than that of CL. Cd and Fe were lowest and highest in concentration with 1.56 to 41,970 µg/g and 0.82 to 39,330 µg/g in partial and complete lockdown period respectively. All toxic elements were detected at high levels above background values where Fe with the highest and Cd with lowest concentrations, respectively. By land use, the levels of toxic elements pollution followed IA > PFA > RA > CA. Correlation analysis (CA), principal component analysis (PCA), and hierarchal cluster analysis (HCA) revealed that the sources of these analyzed toxic elements were mainly from anthropogenic which are related to industrial and vehicular or traffic emissions. Enrichment factor (EF), geoaccumulation index (Igeo), contamination factor (CF), and pollution load index (PLI) also suggested that the dust was more polluted during PL. Exposure of toxic elements to human was mainly via skin contact followed by ingestion and inhalation. Hazard quotient (HQ) values were < 1 except for Mn through dermal contact at all sites during partial and complete lockdown, similar to hazard index (HI), while Cr further showed high non-carcinogenic risks to children. Generally, children HI values were about 5-6 times higher than those of adults, suggesting a greater vulnerability of children to the health concerns caused by toxic elements in street dust. Carcinogenic risk (CR) values via ingestion pathway indicated all elements (except Pb) had significant health effect, while CR value by inhalation results showed no significant health effect. Cumulative carcinogenic risk (CCR) value had significant health effect except Pb in all land use categories. CCR values decreased during CL and reached at acceptable limit for most of the cases. This research provides a message to the local governments and environmental authorities to have a complete assessment of toxic elements in the street dust of Dhaka megacity in order to assuring public health safety and ecological sustainability.