Microplastics as an emerging threat to the freshwater ecosystems of Veeranam lake in south India: A multidimensional approach

In the current scenario, microplastic, as a contaminant, is becoming an ecological threat to the freshwater ecosystem. The present study attempted to determine the quality and quantity of microplastic contaminants in water and soil samples at Veeranam lake in Tamil Nadu, India. It is very important to mention that the Veeranam lake in Tamil Nadu, is a major urban water source of the capital district of Tamil Nadu. Using Van Veen grab-sampling equipment and trawl methods, the study detected the presence of microplastics in 28 sediment samples and 31 water samples from the collected samples. In addition to this, the density separation was performed with zinc chloride solution using the Sediment-Microplastic Isolation (SMI) unit. The quantum of total plastic particle present in surface water were in the range of 13-54 items/km2 with a mean value of 28 items/km2. In the case of sediment samples, the amount of total plastic particle was found in the range of 92-604 items/kg with a mean value of 309 items/kg. The abundance of microplastic particles in water and sediments in various shape, colour, and composition as in the order of nylons > polythene > fibres/PVC > fragments > foam > pellets; dominant colours as white > red > black > green > blue and yellow at the sampling sites. In term of percentage of contaminant distribution, the study found that the collected water and sediment samples deposited with polymer type of plastic particles were nylon (39%), polyethylene (23%), polystyrene (19%), polypropylene (15%), and polyvinyl chloride (4%). The research work is a baseline study for the proposed site of Veeranam lake for microplastics contamination.

Multi-Modal Compositional Analysis of Layered Paint Chips of Automobiles by the Combined Application of ATR-FTIR Imaging, Raman Microspectrometry, and SEM/EDX

For the forensic analysis of multi-layered paint chips of hit-and-run cars, detailed compositional analysis, including minor/trace chemical components in the multi-layered paint chips, is crucial for the potential credentials of the run-away car as the number of layers, painting process, and used paints are quite specific to the types of cars, color of cars, and their surface protection depending on the car manufacturer and the year of manufacture, and yet overall characteristics of some paints used by car manufacturers might be quite similar. In the present study, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) imaging, Raman microspectrometry (RMS), and scanning electron microscopy/energy-dispersive X-ray spectrometric (SEM/EDX) techniques were performed in combination for the detailed characterization of three car paint chip samples, which provided complementary and comprehensive information on the multi-layered paint chips. That is, optical microscopy, SEM, and ATR-FTIR imaging techniques provided information on the number of layers, physical heterogeneity of the layers, and layer thicknesses; EDX on the elemental chemical profiles and compositions; ATR-FTIR imaging on the molecular species of polymer resins, such as alkyd, alkyd-melamine, acrylic, epoxy, and butadiene resins, and some inorganics; and RMS on the molecular species of inorganic pigments (TiO₂, ZnO, Fe₃O₄), mineral fillers (kaolinite, talc, pyrophyllite), and inorganic fillers (BaSO₄, Al₂(SO₄)₃, Zn₃(PO₄)₂, CaCO₃). This study demonstrates that the new multi-modal approach has powerful potential to elucidate chemical and physical characteristics of multi-layered car paint chips, which could be useful for determining the potential credentials of run-away cars.

Direct and simultaneous detection of organic and inorganic ingredients in herbal powder preparations by Fourier transform infrared microspectroscopic imaging

Herbal powder preparation is a kind of widely-used herbal product in the form of powder mixture of herbal ingredients. Identification of herbal ingredients is the first and foremost step in assuring the quality, safety and efficacy of herbal powder preparations. In this research, Fourier transform infrared (FT-IR) microspectroscopic identification method is proposed for the direct and simultaneous recognition of multiple organic and inorganic ingredients in herbal powder preparations. First, the reference spectrum of characteristic particles of each herbal ingredient is assigned according to FT-IR results and other available information. Next, a statistical correlation threshold is determined as the lower limit of correlation coefficients between the reference spectrum and a larger number of calibration characteristic particles. After validation, the reference spectrum and correlation threshold can be used to identify herbal ingredient in mixture preparations. A herbal ingredient is supposed to be present if correlation coefficients between the reference spectrum and some sample particles are above the threshold. Using this method, all kinds of herbal materials in powder preparation Kouqiang Kuiyang San are identified successfully. This research shows the potential of FT-IR microspectroscopic identification method for the accurate and quick identification of ingredients in herbal powder preparations.