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A significant knowledge gap in nanotechnology is the absence of standardized protocols for examining and comparison the effect of metal oxide nanoparticles on different environment media. Despite the large number of studies on ecotoxicity of nanoparticles, most of them disregard the particles physicochemical transformation under real exposure conditions and interaction with different environmental components like air, soil, water, etc. While one of the main exposure ways is inhalation and/or atmosphere for human and environment, there is no investigation between airborne particulates and nanoparticles. In this study, some metal oxide nanoparticle (ZnO and TiO) transformation and behavior in PM2.5 air particulate media were examined and evaluated by the influence on nanoparticle physicochemical properties (size, surface charge, surface functionalization) and on bacterium (Gram-positive Bacillus subtilis, Staphylococcus aureus/Gram-negative Escherichia coli, Pseudomonas aeruginosa bacteria) by testing in various concentrations of PM2.5 airborne particulate media to contribute to their environmental hazard and risk assessment in atmosphere. PM2.5 airborne particulate media affected their toxicity and physicochemical properties when compared the results obtained in controlled conditions. ZnO and TiO surfaces were functionalized mainly with sulfoxide groups in PM2.5 air particulates. In addition, tested particles were not observed to be toxic in controlled conditions. However, these were observed inhibition in PM2.5 airborne particulates media by the exposure concentration. These observations and dependence of the bacteria viability ratio explain the importance of particulate matter-nanoparticle interaction.

Determination of heavy metals is still a relevant pursuit due to the ongoing incidents of contamination and continuous anthropogenic and industrial activities. Spectrometric methods such as atomic absorption are the most common approaches to this task because of the high accuracy and sensitivity they provide. Nevertheless, these methods are costly, time-consuming, and do not allow for on-site measurements. Considering recent developments in electrochemistry, especially voltammetric methods, conducting trace-level heavy metal analysis has become easier, faster, and cheaper. Utilizing a carbon-based electrode (CBE) for this purpose seems to further improve the performance of the above-mentioned methods. CBEs are versatile, offer a wide potential window, and possess desirable conductive and surface properties that allow sensitive determination of analytes. This review aims to examine the recent studies published between 2015 and 2020 which investigated the performance of carbon-based electrodes in heavy metal determination, by placing the four most common carbon electrodes to the center: glassy carbon electrode, graphite electrode, carbon paste electrode, and screen-printed carbon electrode.

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Lead concentrations in various plastic toys were determined directly by solid sampling high resolution continuum source graphite furnace atomic absorption spectrometry.