This study investigates the bioaccumulation of micro- and nanoplastics (MNPs) in human brains, kidneys, and livers using pyrolysis gas chromatography-mass spectrometry (Py-GC/MS). The research, conducted by a team from the University of New Mexico and Oklahoma State University, compared MNP concentrations in autopsy samples collected in 2016 and 2024. Key findings include: 1. **Concentration Levels**: Brain samples exhibited significantly higher MNP concentrations than liver or kidney samples. Polyethylene was the predominant polymer, with a higher proportion in brain samples (74%) compared to liver and kidney (44-57%). 2. **Temporal Trends**: Both liver and brain MNP concentrations increased from 2016 to 2024, with brain concentrations rising from 3,057 μg/g to 4,806 μg/g. 3. **Microscopic Evidence**: Transmission electron microscopy (TEM) confirmed the nanoscale nature of the isolated particles, which were mostly aged, shard-like plastics. 4. **Health Implications**: The selective accumulation of MNPs in the brain, particularly in the form of nanometer-scale particles, raises concerns about potential health impacts, especially given the increasing environmental concentrations of microplastics and the rising rates of Alzheimer's disease and related dementias. 5. **Methodological Considerations**: The study highlights the reliability and accuracy of Py-GC/MS for quantifying MNPs in human tissues, but also suggests areas for improvement, such as limiting assessments to the nanoscale range and improving sampling and weighing accuracy. The research underscores the urgent need for further studies to understand the health consequences of MNPs, particularly in the context of growing environmental pollution and neurological disorders.This study investigates the bioaccumulation of micro- and nanoplastics (MNPs) in human brains, kidneys, and livers using pyrolysis gas chromatography-mass spectrometry (Py-GC/MS). The research, conducted by a team from the University of New Mexico and Oklahoma State University, compared MNP concentrations in autopsy samples collected in 2016 and 2024. Key findings include: 1. **Concentration Levels**: Brain samples exhibited significantly higher MNP concentrations than liver or kidney samples. Polyethylene was the predominant polymer, with a higher proportion in brain samples (74%) compared to liver and kidney (44-57%). 2. **Temporal Trends**: Both liver and brain MNP concentrations increased from 2016 to 2024, with brain concentrations rising from 3,057 μg/g to 4,806 μg/g. 3. **Microscopic Evidence**: Transmission electron microscopy (TEM) confirmed the nanoscale nature of the isolated particles, which were mostly aged, shard-like plastics. 4. **Health Implications**: The selective accumulation of MNPs in the brain, particularly in the form of nanometer-scale particles, raises concerns about potential health impacts, especially given the increasing environmental concentrations of microplastics and the rising rates of Alzheimer's disease and related dementias. 5. **Methodological Considerations**: The study highlights the reliability and accuracy of Py-GC/MS for quantifying MNPs in human tissues, but also suggests areas for improvement, such as limiting assessments to the nanoscale range and improving sampling and weighing accuracy. The research underscores the urgent need for further studies to understand the health consequences of MNPs, particularly in the context of growing environmental pollution and neurological disorders.