In an published on January 8, 2024, in the journal PNAS, Naixin Qian from Columbia University, New York, US, and co-authors describe their development of a new hyperspectral stimulated Raman scattering that can detect plastic particles at a single particle level and identify plastics in an automated manner. The method was confirmed to identify also nanoplastics, i.e., particles smaller than 1 µm as well as to differentiate between seven polymer types. Applying their methods to bottled water, the researchers reported finding between 130,000 and 240,000 fragments in one liter of water, of which 90% were nanoplastics. This exceeds previously reported levels between 10 to 100 times; however, the earlier studies have mostly focused on larger plastic particles. The authors “envision that the data-driven hyperspectral SRS imaging platform will continue bridging the gap of knowledge on plastic pollution at the nano level with an expanded spectral library to study more complicated biological and environmental samples.” 

In another recent publication, Long Zhu from the Chinese Research Academy of Environmental Sciences, Beijing, China, and co-authors analyzed microplastics in human lung, intestine, and tonsil tissue. In their published January 12, 2024, in Science of the Total Environment, they describe collecting samples from 41 people and using laser direct infrared spectroscopy to identify microplastics with a size larger than 20 μm. The scientists detected microplastics in all tissues with average numbers of 14.19, 9.45, 7.91, and 6.3 particles/g in lung tissue, the small intestine, the large intestine, and tonsils, respectively. With 14.81 compared to 6.47 particles/L, abundance was higher in women than in men. Polymer identification showed that the particles were made of 14 different polymer types, with most being made of polyvinyl chloride (PVC). 

Microplastics are not only present in the lung, intestines, and kidneys, but also in human blood and placenta (FPF reported also here). In an published on January 3, 2024, in the journal Scientific Reports, Jenna Hanrahan from Memorial University of Newfoundland, Canada, and co-authors analyzed the effects that PE microplastic exposure has on fetal growth and placental function in pregnant mice. They exposed pregnant mice to 106 ng/L of PE particles with a size of 740-4990 nm via drinking water with surfactants and compared it to effects from exposure to just drinking water with and without surfactants. Hanrahan and co-authors reported that microplastic exposure did not affect fetal growth, but it did have an impact on placental function. Umbilical artery blood flow was increased by 43% in microplastic-exposed mice compared to the control groups. The authors conclude that this “suggests polyethylene has the potential to cause adverse pregnancy outcomes through abnormal placental function.” 

 

References 

Hanrahan, J. et al. (2024). “.” Scientific Reports. DOI: 10.1038/s41598-023-50781-2 

Qian, N. et al. (2024). “” PNAS. DOI: 10.1073/pnas.2300582121 

Zhu, L. et al. (2024). “” Science of the Total Environment. DOI: 10.1073/pnas.2300582121