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Secondary PVC microplastics are more toxic than primary PVC microplastics to Oryzias melastigma embryos
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Researchers compared the toxicity of weathered secondary PVC microplastics to pristine primary particles using marine fish embryos. They found that the secondary microplastics caused earlier hatching, more developmental abnormalities, and greater oxidative stress than the primary ones. The study demonstrates that the irregular, partially degraded microplastics found in the ocean are likely more harmful to marine life than the smooth manufactured particles typically used in laboratory tests.
Irregular-shaped and partially degraded secondary microplastics (SMP) account for the majority of MPs in marine environments, yet little is known about their effects on marine organisms. In this study, we investigated the embryotoxicity of polyvinyl chloride SMP and primary microplastics (PMP) to the marine medaka Oryzias melastigma. This study aimed to determine the physical impacts of MPs and, for the first time, elucidate the underlying mechanisms of physical toxicity. SMP shortened hatching time and induced higher teratogenic effects on larvae relative to PMP, indicating a higher toxicity from SMP. Physical damage from SMP to the chorion surface appears to be the main toxicity mechanism, caused by their irregular shape and reduced aggregation relative to PMP. In contrast, real-time changes in oxygen demonstrated that hypoxia caused by greater PMP adsorption to the chorion surface contributes to the toxicological responses of this material relative to SMP. Modulation of genes involved in hypoxia-response, cardiac development and hatching confirmed the toxicity mechanisms of PMP and SMP. The chemical contribution to observed toxicity was negligible, confirming impacts derived from physical toxicity. Our findings highlight the negative effects of environmentally relevant SMP on the marine ecosystems.
More Papers Like This
Secondary PVC microplastics are more toxic than primary PVC microplastics to Oryzias melastigma embryos
AI summary Read the abstract
Researchers found that secondary PVC microplastics — irregular fragments resembling those found in marine environments — were more toxic to marine medaka fish embryos than primary microplastics, causing greater mortality, heart rate changes, and developmental malformations by physically restricting oxygen flow.
Impact of virgin and weathered microplastics on zebrafish: Bioaccumulation, developmental toxicity and molecular pathway disruptions
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Researchers compared the effects of brand-new versus environmentally weathered microplastics on zebrafish larvae and found that weathered particles were far more toxic, causing 80% mortality compared to 20% for new plastics. The weathered microplastics triggered more severe disruptions to oxidative stress pathways, cell death signaling, and DNA repair mechanisms. The study emphasizes that laboratory tests using only pristine microplastics may significantly underestimate the real-world dangers of plastic pollution.
Aged polystyrene microplastics exposure affects apoptosis via inducing mitochondrial dysfunction and oxidative stress in early life of zebrafish
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Zebrafish embryos exposed to UV-aged polystyrene microplastics at environmental concentrations showed more severe developmental problems than those exposed to fresh microplastics. The aged particles caused greater oxidative stress and mitochondrial damage, triggering increased cell death during early development -- suggesting that weathered microplastics in the real environment may be more harmful than the pristine particles typically used in lab studies.
Environmental samples of microplastics induce significant toxic effects in fish larvae
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Researchers collected microplastic samples from beaches on Easter Island, Guam, and Hawaii, then fed them to Japanese medaka fish at concentrations reflecting real ocean conditions. Larvae exposed to these environmental microplastics experienced increased mortality, developmental abnormalities, DNA damage, and behavioral changes. The study demonstrates that realistic concentrations of weathered, real-world microplastics can cause significant harm to fish during their most vulnerable early life stages.
Assessing the embryotoxicity of polypropylene micro- and nanoplastics generated through simulated environmental weathering in zebrafish (Danio rerio)
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Researchers generated environmentally weathered polypropylene micro- and nanoplastics through combined UV and mechanical degradation and exposed zebrafish embryos, finding accelerated hatching, abnormal spontaneous movements, altered swimming behavior, and particle accumulation on the egg surface — indicating meaningful developmental and behavioral toxicity during early life stages.
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