Detecting microplastics in human samples

Detecting microplastics in human samples

As billions of tons of plastics continue to be deposited on and in our planet's land and water systems, they break down into microplastics (MPs) ranging in size from one micrometer (μm) to five millimeters (mm). MPs are capable of penetrating a wide range of organisms, including microbes, plants and animals.

A new one Science of the entire environment The study discusses how to examine MEPs' human exposure from sampling to quantitative assessment. The researchers also evaluate possible preventative measures and future opportunities in MP research.

Learn: Microplastic diagnostics in humans: “The 3Ps” progress, problems and perspectives. Photo credit: Larina Marina / Shutterstock.com

introduction

MPs are created either by design or by breaking down larger plastics. These materials are present everywhere and are easily absorbed by living organisms on land and in water, eventually becoming part of their tissues and organs. Unfortunately, MPs transport pollutants into host tissues, which can affect both survival and reproduction.

A variety of foods and beverages have been reported to be contaminated by MPs, including food fish, drinking water, milk, soft drinks, canned foods, and even sugar and salt. Therefore, people inadvertently ingest MPs daily, inhale them, and are exposed to these substances after passing through the skin barrier.

Recent estimates suggest that humans are exposed to 100,000 particles annually, many of which can enter human cells and cause oxidative stress, inflammation, metabolic disorders and reproductive toxicity. The current study examines advances in this area, including research approaches, current knowledge, and challenges.

What did the review reveal?

MPs were found to be present at varying concentrations in 15 human tissues. Most of these tissues consistently showed the presence of MPs, while stool samples were positive in up to 60% of samples. However, feces contained the highest concentration of MPs, followed by sputum, both around 100 MPs/gram, while concentrations in breast milk, saliva and skin were low.

MPs in human tissues were mostly in the form of fibers and fragments, most commonly transparent, white or blue, and ranging in size from 700 nm to five mm. Larger fragments were present in human hair, hands, skin, colon and feces, indicating their excretion, in contrast to cell entry achieved by smaller MPs.

A wide range of over 45 plastics contributed to the presence of MP in the human body. A connection was found between the types of plastics contaminating food and hygiene products and those found in the tissue samples.

The presence of microplastics in the human body at any time is the result of combined routes of exposure.”

Some diseases were associated with higher MP levels in the affected organs or tissues. These included liver cirrhosis, cancer and inflammatory bowel disease. Further research is needed to determine causality and its direction.

The lungs of stillborn infants did not contain MP; However, meconium, placental and breast milk MPs indicate prenatal and early neonatal exposure.

Implications

Converging evidence suggests that humans are exposed to microplastics through various food chains and through inhalation, suggesting potential health risks.”

With advanced techniques for identifying and extracting MPs from human tissues, it has become possible to study a wide range of samples. However, there is a high risk of cross-contamination leading to false positive results, which would require the use of high efficiency particulate air (HEPA) filters at the sampling site. In fact, a simple step like using surgical masks when collecting or preparing the sample could result in microfibers contaminating the sample.

A similar lack of attention to careful pre-cleaning and inspection steps and a plastic-free protocol could bias the results. Equally important, the need for such precautions and the ways to ensure that they are followed are communicated to all departments and professionals involved in such studies.

Standardized procedures are also essential in this area, as are larger studies, both of which should be specific to each tissue type. Investing in the development of these methods is valuable as it will encourage research in this area. For example, the use of 65% nitric acid to treat tissue samples for MP extraction was quite common; However, this method is associated with the formation of an oily residue, which limits an accurate estimate of microplastic content.

Reference:

• Kutralam-Munisamy, G., Shruti, VC, Perez-Guevara, F. & Roy, PD (2022). Mikroplastik-Diagnostik beim Menschen: „Die 3Ps“ Fortschritte, Probleme und Perspektiven. Wissenschaft der gesamten Umwelt. doi: 10.1016/j.scitotenv.2022.159164. https://www.sciencedirect.com/science/article/abs/pii/S0048969722062635?via%3Dihub

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