Common laboratory reagents: Are they a double-edged sword in microplastics research?

Understanding and communicating instances of microplastic contamination is critical for enabling plastic-free transitions. While microplastics research uses a variety of commercial chemicals and laboratory liquids, the impact of microplastics on these materials remains unknown. To fill this knowledge gap, the current study investigated microplastics abundance and their characteristics in laboratory waters (distilled, deionized, and Milli-Q), salts (NaCl and CaCl2), chemical solutions (H2O2, KOH and NaOH), and ethanol from various research laboratories and commercial brands. The mean abundance of microplastics in water, salt, chemical solutions, and ethanol samples was 30.21 ± 30.40 (L-1), 24.00 ± 19.00 (10 g-1), 187.00 ± 45.00 (L-1), and 27.63 ± 9.53 (L-1), respectively. Data comparisons revealed significant discrepancies between the samples in terms of microplastic abundance. Fibers (81 %) were the most common microplastics, followed by fragments (16 %) and films (3 %); 95 % of them were <500 µm, with the smallest and largest particle sizes recorded being 26 µm and 2.30 mm, respectively. Microplastic polymers discovered included polyethylene, polypropylene, polyester, nylon, acrylic, paint chips, cellophane, and viscose. These findings lay the groundwork for identifying common laboratory reagents as a potential contributor to microplastic contamination in samples, and we offer solutions that should be integrated into data processing to produce accurate results. Taken together, this study shows that commonly used reagents not only play a key role in the microplastic separation process but also contain microplastic contamination themselves, requiring the attention of researchers to promote quality control during microplastic analysis and commercial suppliers in formulating novel prevention strategies.

First evidence of microplastic contamination in ready-to-use packaged food ice cubes.

Concern over microplastics has grown tremendously, and they have been found in all environmental compartments; yet, much remains unknown regarding their impact on a variety of human-consuming food products. Here, we contribute to ongoing research by screening the 15 most popular commercial brands of packaged food ice cubes in Mexico City for microplastics. Microplastics were detected in 100% of the samples evaluated, with concentrations ranging from 19 ± 4 to 178 ± 78 L-1. There was a significant difference in the microplastic concentration across samples. The mean microplastic concentration was 79 ± 47 L-1, and the main types were polypropylene, polyethylene, polyvinyl alcohol, tygon polymer, sealing ring gardena 2824 large, polyamide 6, and cellophane. Moreover, microplastics that are fibrous (87%), non-colored (54%), and less than 300 µm in size (63%), were found to be more prevalent. The SEM-EDX analysis showed heterogeneous structural and morphological characteristics of microplastics, as well as traces of Si, S, Ti, Ca, Al, and Na. Furthermore, we estimate that ice cube consumption in Mexico City can result in the inadvertent ingestion of 4.9 × 102 ± 3.4 × 102-1 × 104 ± 7.2 × 103 microplastics annually. The findings of the study revealed that microplastics were identified in ice cubes and can be conveyed to humans, stressing the need of managing and eradicating such contamination from our food.

Free, but not microplastic-free, drinking water from outdoor refill kiosks: A challenge and a wake-up call for urban management.

Free refill drinking water kiosks are an essential sustainable water supply system for people in metropolitan areas worldwide. Despite their importance in urban settings, the impact of microplastic contamination remains elusive. Here, we investigated the occurrence and characteristics of microplastics in drinking-water samples collected from 22 self-distributed refill kiosks located in 14 multiuse urban parks spread across nine municipalities in Mexico City (Mexico). The results showed that microplastics were detected in all the samples, with an overall mean concentration of 74.18 ± 48.76 microplastics L-1. The abundance of microplastics was significantly different between sampled kiosks, ranging from 23 ± 11.31 to 202 ± 28.39 microplastics L-1. There were more fibrous microplastics (88%) than fragments (9%) and films (3%), with the majority (56%) being <200 µm in length. They were predominantly transparent (85%), with only a few being colored (15%; blue, red, green, and brown). Attenuated Total Reflection-Fourier-transform infrared spectroscopy further revealed microplastics of various polymer types, including polyvinyl alcohol, high-density polyethylene, polypropylene, polyvinyl acetate, ethylene vinyl alcohol, acrylic, alkyd resin, and viscose. Based on our findings, drinking water from urban refill kiosks exposes children more than adults to microplastics. Furthermore, the steps that should be taken at urban refill kiosks to prevent microplastic pollution while offering recreational services to people have been highlighted. Therefore, this first study serves as a wake-up call to urban water management to improve the safety of water from emerging pollutants like microplastics in the infrastructure of refill kiosks.

Review of current trends, advances and analytical challenges for microplastics contamination in Latin America.

Microplastics accumulation is an emerging environmental issue and a threat to marine life and human health. There is a growing number of investigations on the abundance and distribution of microplastics in different water bodies and biota worldwide, with relatively few studies conducted in Latin America, however, the current knowledge of microplastics sources, occurrence, transport, fate and potential impacts remains largely unexplored. This review presents the current trends and advances of microplastics on a lesser known region of the world by compiling the research performed to date in different environmental compartments. The sampling techniques and methods for microplastics extraction in the existing literature data are also summarized. Among 78 published studies reviewed, 34% of studies were from Brazil and 46% of studies have mainly focused on biota. The main findings showed that microplastics are not negligible across Latin America significantly varying in their distribution, with the prevalence of fibers comprising 62% of the total. Polyethylene, polypropylene, polyethylene terephthalate and polystyrene have been identified as the most common polymer types, accounting for 80% of the total. Limited studies and lack of standardized methodologies render difficulties to establish fundamental information on microplastics abundance and types in most countries of this region. Therefore, this review will primarily serve as a baseline when evaluating the environmental relevance of microplastics in Latin America and would stimulate discussions focusing on this topic, calling for more research in future.