Application of Infrared and Near-Infrared Microspectroscopy to Microplastic Human Exposure Measurements

Deposition characteristics of microplastics in coral reef fish with different feeding habits from the Xisha Islands Waters, South China Sea

Over the past decade, awareness of plastic pollution has significantly increased, leading to a focus on its potential adverse effects on biota, including the ingestion of microplastics by fish. This study investigates the abundance, composition, and characteristics of microplastics in the gills and gastrointestinal tracts (GITs) of 96 coral reef fish with different feeding habits (herbivorous fish: Scarus rivulatus, Naso lituratus, and Acanthurus triostegus; omnivorous fish: Abudefduf vaigensis; carnivorous fish: Epinephelus merra) from the Xisha Islands Waters, South China Sea. The relationships between microplastic abundance and fish length, weight, and feeding habits were also analyzed. Results show that 97.92% of the sampled coral reef fish contained microplastics. The average abundance of microplastics in the gills and GITs was 1.09 ± 0.25 items individual-1 and 1.74 ± 0.26 items individual-1, respectively. The predominant shapes of microplastics were fibers, with black and blue being the most common colors. Most microplastics (90%) were smaller than 1 mm, and the main polymer types were PET, CP, PE, and PP. Additionally, the GITs contained more microplastics than the gills. Unlike the scope of previous studies, this study newly found the following two points: 1.Herbivorous fish had higher microplastic content than omnivorous fish, while carnivorous fish had the lowest, likely due to herbivorous fish feeding primarily on microplastic-polluted coral reefs. 2.The abundance of microplastics in the gills and GITs was not related to gill weight or GITs weight, however, the abundance of microplastics was significantly correlated with fish body length and body weight.

Assessing the Efficacy of Pyrolysis-Gas Chromatography-Mass Spectrometry for Nanoplastic and Microplastic Analysis in Human Blood

Humans are constantly exposed to micro- and nanosized plastics (MNPs); however, there is still limited understanding of their fate within the body, partially due to limitations with current analytical techniques. The current study assessed the appropriateness of pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) analysis for the quantification of a range of polymers in human blood. An extraction protocol that reduced matrix interferences (false positives) of polyethylene (PE) and polyvinyl chloride (PVC) was developed and validated. Extraction recoveries ranged 7-109%, although surface-modified polystyrene (carboxylated) increased nanoparticle recoveries from 17 to 52%. Realistic detection limits were calculated for each polymer, accounting for matrix suppression and extraction recovery. These were up to 20 times higher than nominal detection limits calculated with Milli-Q water. Finally, the method was tested with a pilot study of the Australian population. PE interferences were reduced but still present, and no other polymers were above detection limits. It was concluded that Py-GC-MS is currently not a suitable analysis method for PE and PVC in biological matrices due to the presence of interferences and nonspecific pyrolysis products. Furthermore, while it is plausible to detect some polymers in blood, the estimated exposure concentrations needed are approaching the detection limits of the technique.

Analytical Challenges and Strategies for Particle-Based Analysis of Airborne Micro(nano)plastics in Size-Fractionated Samples Using Microscopy, SEM/EDX, and Raman Spectroscopy

Inhalable micro(nano)plastics (MNPs) have emerged as a significant global concern due to their abundance and persistence in the atmosphere. Despite a growing body of literature addressing the analytical requirements of airborne MNPs, the issue of inhalable fractions and analysis of slotted substrates remains unclear. Therefore, the objective of this study is to perform a systematic particle-based analysis and characterization of inhalable microplastics (MPs) collected by a high-volume sampler equipped with a five-stage cascade impactor with a size range of 10 μm to <0.49 μm. The efficacy of collection substrates (Teflon and aluminum) was evaluated, as was the impact of particle transfer from the slotted filters on the analysis area and pretreatment methods including chemical digestion for further analysis. The distribution of MNP particles across different slots of a Teflon filter was investigated using Raman microspectrometry to select an appropriate subsample. The results showed the suitability of Teflon filters without any pretreatment for particles down to a single micrometer. As observed by the SEM/EDX analysis, the airborne particles collected in a filter with a submicrometer range (<0.95 μm) showed a decrease in carbon-rich components compared to those stages with higher cutoff sizes. A minimum of 20 particles were analyzed per 1 cm2 of the slotted filter using Raman spectrometry, which revealed a homogeneous distribution of MPs across different slots and yielded a concentration of 452 ± 134 MP/m3 in the first stage of the cascade sampler. The detected MPs were morphologically classified into two main groups: fragments with a size range of 2.8-24.8 μm and fibers with a size range of 28.6-212 μm. Subsequently, the particles were chemically identified as carbon black (tires) and polypropylene. In conclusion, particle-based analysis of size-segregated airborne MNPs presents certain challenges when attempting to analyze particles as small as a single micrometer due to the fact that the aerodynamic diameter of the particles in question and the corresponding analytical limitations that result from this become particularly problematic, especially for cutoffs smaller than 3 μm.

Abundance, characterization, and health risk evaluation of microplastics in borehole water in Birnin Kebbi, Nigeria

Microplastic pollution has become a global menace, and water, being a major "sink" for pollutants, represents a significant source of human exposure. This study aimed to assess the safety of borehole water in Birnin Kebbi, Nigeria, specifically concerning microplastic pollution. Water samples were collected from boreholes in selected areas, including Bayan Kara, Malali, Rafin Atiku, Aliero Quarters, GwadanGaji, FUBK Takeoff Site, Kalgo Market, and Tarasa. Microplastics were extracted from the water samples through filtration using glass fiber filter papers, and were subsequently subjected to spectroscopy and microscopy to determine concentrations, shapes, and polymer types. Health risks associated with the microplastics were also calculated. The results revealed that the samples from Tarasa exhibited the highest concentrations of microplastics (96.967 particles/L), followed by Bayan Kara (92.70 particles/L), Rafin Atiku (92.33 particles/L), GwadanGwaji (92.30 particles/L), FUBK Takeoff Site (91.07 particles/L), Aliero Quarters (90.43 particles/L), Kalgo Market (88.00 particles/L), and Malali (86.40 particles/L). The most dominant shape was fibers (73 %), followed by fragments (16 %), foams (6 %), and filaments (5 %). Polyethylene and polyamide, in that order, were the most dominant polymers, while polystyrene was the least common. The majority of risk scores were classified as III. It can be inferred from the results that microplastic pollution in borehole water poses a health hazard in the city. Consumers of borehole water in the studied areas are advised to treat the water before consumption to mitigate potential health risks.

Effects of Benzo (a) Pyrene and 2,2',4,4'-Tetrabromodiphenyl Ether Exposure on the Thyroid Gland in Rats by Attenuated Total Reflection Fourier-Transform Infrared Spectroscopy

Benzo[a]pyrene (B[a]P) and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) are widespread environmental pollutants and can destroy thyroid function. We assessed the biochemical changes in the thyroid tissue of rats exposed to B[a]P and BDE-47 using attenuated total reflection Fourier-transform infrared spectroscopy combined with support vector machine(SVM). After B[a]P and BDE-47 treatment in rats, the structure of thyroid follicles was destroyed and epithelial cells were necrotic, indicating that B[a]P and BDE-47 may lead to changes of the thyroid morphology of the rats. These damages are mainly related to C=O stretch vibrations of lipids (1743 cm-1), as well as the secondary structure of proteins [amide I (1645 cm-1) and amide II (1550 cm-1)], and carbohydrates [C-OH (1138 cm-1), C-O (1106 cm-1, 1049 cm-1, 991 cm-1), C-C (1106 cm-1) stretching] and collagen (phosphodiester stretching at 922 cm-1) vibration modes. When SVM was used for classification, there was a substantial separation between the control and the exposure groups (accuracy = 96%; sensitivity = 98%; specificity = 87%), and there was also a major separation between the exposed groups (accuracy = 93%; sensitivity = 94%; and specificity = 92%).