The distribution and abundance of microplastics into the world are so extensive that many scientists use them as key indicators of the recent and contemporary period defining a new historical epoch: The Plasticene. However, the implications of microplastics are not yet thoroughly understood. There is considerable complexity involved to understand their impact due to different physical–chemical properties that make microplastics multifaceted stressors. If, on the one hand, microplastics carry toxic chemicals in the ecosystems, thus serving as vectors of transport, they are themselves, on the other hand, a cocktail of hazardous chemicals that are added voluntarily during their production as additives to increase polymer properties and prolong their life. To date, there is a considerable lack of knowledge on the major additives of concern that are used in the plastic industry, on their fate once microplastics dispose into the environment, and on their consequent effects on human health when associated with micro and nanoplastics. The present study emphasizes the most toxic and dangerous chemical substances that are contained in all plastic products to describe the effects and implications of these hazardous chemicals on human health, providing a detailed overview of studies that have investigated their abundance on microplastics. In the present work, we conducted a capillary review of the literature on micro and nanoplastic exposure pathways and their potential risk to human health to summarize current knowledge with the intention of better focus future research in this area and fill knowledge gaps.

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The photocatalytic properties of anatase TiO(2) nanorods (NRs) and noble metal-semiconductor nanocomposites (TiO(2) NRs/Ag) prepared by colloidal chemistry routes and immobilized onto suitable substrates were investigated. Photocatalytic experiments were performed under UV irradiation in order to test the degradation of a target compound (the azo dye, methyl red) in aqueous solution using TiO(2) P25 Degussa as a reference material. Absorbance spectroscopy and liquid chromatography/mass spectrometry (LC/MS) measurements pointed out that, according to pH conditions, TiO(2) NRs and TiO(2) NRs/Ag presented a photoactivity up to 1.3 and 2 times higher than TiO(2) P25 Degussa, respectively. Notably, the TiO(2) NRs/Ag-based catalysts demonstrated a photocatalytic activity 2-fold higher than bare TiO(2) NRs. Remarkably, only a negligible dependence on pH conditions was detected for the nanocomposite catalyst, whereas both TiO(2) NRs and TiO(2) P25 Degussa showed much higher photoactivity at acidic pH. In all the investigated cases, the identified byproducts pointed out the occurrence of the same reaction mechanism, basically relying on the hydroxyl radical attaching on the benzene ring and on the homolytic rupture of the nitrogen-carbon bond of the dimethyl-amino moiety

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The structural elucidation of carbonyl-containing by-products arising from Uniblu-OH ozonation has been investigated by liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) employing a quadrupole time-of-flight mass spectrometer. The by-products were derivatized with 2,4-dinitrophenylhydrazine, allowing the formation of [M-H](-) ions of the derivatives in the electrospray source. Exact mass measurements of both the [M-H](-) ions and their product ions allowed the elemental formulae and related structures of ten by-products to be determined confidently. The main degradation pathway were decarboxylation followed by further oxidation. It is noteworthy that the experimental procedure employed allowed the identification of both nitrogen- and sulphur-containing carbonyl by-products during Uniblu-OH ozonation. This result is of environmental relevance for monitoring the balance of organic nitrogen and sulphur during the ozonation of organic pollutants. These atoms, in fact, do not undergo complete mineralization.

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