Microplastics in bottled water and human health outcomes: a systematic review of multi-organ toxicity and mechanistic pathways
TL;DR
This systematic review synthesized evidence on the health effects of microplastic exposure, with emphasis on organ-specific toxicity, molecular mechanisms, and implications for chronic disease, emphasizing the urgent need for regulatory exposure limits and long-term human cohort studies.
Abstract
Abstract This systematic review synthesized evidence on the health effects of microplastic exposure, with emphasis on organ-specific toxicity, molecular mechanisms, and implications for chronic disease. Following PRISMA 2020 guidelines, we searched PubMed, Scopus and Web of Science for peer-reviewed studies examining health outcomes associated with microplastic exposure relevant to bottled water consumption. Eligible studies included human observational studies, controlled animal experiments, and mechanistic in vitro investigations. Of 128 identified records, 15 studies met inclusion criteria: 3 human observational studies, 5 in vivo experiments, 4 in vitro investigations, and 3 mixed-design studies. Geographically, studies originated from China (40%), United States (20%), and other regions (40%). Polystyrene (10 studies), polyethylene, and polyethylene terephthalate (4 studies each) were most frequently investigated. Human biomonitoring confirmed microplastic presence in blood (3.15 ± 1.25 particles/mL), placental tissue (226-273 µg/g), and testicular samples (328 µg/g). Reproductive toxicity was the most consistently reported adverse outcome (5 studies), followed by hepatic, gastrointestinal, cardiovascular, renal, developmental, and neurological effects. Across studies, oxidative stress (reported in 12 studies), inflammatory activation (10 studies), endocrine disruption (4 studies), and mitochondrial dysfunction (4 studies) emerged as principal mechanistic pathways. Chronic exposure to microplastics from bottled water may contribute to multisystem toxicity through oxido-inflammatory mechanisms. HIGHLIGHTS Exposure Sources: Bottled water delivers major oral exposure to widespread plastic polymers like PS, PE, and PET. Bioaccumulation: Particles cross biological barriers, accumulating in human blood, placenta, and testicular tissues. Systemic Toxicity: Chronic exposure causes multi-organ damage, most notably reproductive, hepatic, and gastrointestinal injury. Key Mechanisms: Toxicity is driven by cellular oxidative stress, inflammatory activation, and mitochondrial dysfunction. Future Needs: Findings emphasize the urgent need for regulatory exposure limits and long-term human cohort studies.