We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
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.
Although irregular-shaped secondary microplastics (SMP) account for most MPs in marine environments, little is known about their effects on marine organisms. We investigated the embryotoxicity of polyvinyl chloride SMP and primary microplastics (PMP) to the marine medaka Oryzias melastigma using mortality, heart rate, hatching rates, hatching time and malformation as endpoints. This study aimed to determine the physical impacts of MPs and elucidate underlying mechanisms of physical MP toxicity through O2 flow determination and measuring the gene expression involved in embryonic development. PMP were purchased in powder form, while SMP were prepared by milling a pristine PVC plastic water pipe; both were sieved to a size range of 53–106 μm. For the 25 day exposure assay, fertilized O. melastigma eggs were randomly assigned to 6-well plates containing 15 embryos/well. Seawater leachates generated from the PMP and SMP were also studied to account for chemical toxicity. Exposure of marine medaka embryos to PMP and SMP caused a range of negative effects, including changes in heart rate, morphological abnormalities and malformation types. At high exposure concentrations, SMP shortened hatching time and induced more significant teratogenic effects on larvae relative to the PMP. 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 their toxicity 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. Our findings indicate that although PMP exposure can lead to measurable toxic effects, their use underestimates the threat of SMP and they do not necessarily represent the toxic mechanisms observed for SMP. Also see: https://micro2022.sciencesconf.org/426781/document
More Papers Like This
Secondary PVC microplastics are more toxic than primary PVC microplastics to Oryzias melastigma embryos
AI summary Read the abstract
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.
Aging enhances the ecological toxicity of polyethylene microplastics to marine medaka larvae (Oryzias melastigma)
AI summary
Researchers found that UV- and Fenton-aged polyethylene microplastics caused greater harm to marine medaka larvae than virgin plastic, disrupting gut microbiota composition and altering microbial metabolic functions in ways that impaired growth and development, underscoring the need to assess weathered microplastics in ecological risk evaluations.
Ingestion and the toxicological effects of virgin polyethylene (PE) and PVC microplastics in commercial freshwater fish, Tilapia (Oreochromis niloticus)
AI summary Read the abstract
Researchers exposed Nile tilapia to virgin polyethylene and PVC microplastics for 21 days, finding that both types caused behavioral changes and mortality, with PVC producing greater toxicity, reduced growth rates, and histological damage to gut and liver tissue.
Recycled polyvinyl chloride microplastics: investigation of environmentally relevant concentrations on toxicity in adult zebrafish
AI summary Read the abstract
Researchers investigated the toxicity of recycled PVC microplastics at environmentally relevant concentrations in adult zebrafish, finding that these particles release chemicals that cause measurable toxic effects in exposed organisms.
Microplastics negatively impact embryogenesis and modulate the immune response of the marine medaka Oryzias melastigma
AI summary Read the abstract
Researchers exposed marine medaka embryos (Oryzias melastigma) to polystyrene microplastics at varying concentrations and found dose-dependent developmental toxicity, including reduced hatching rates and altered immune gene expression, providing mechanistic insight into early-life MP effects.
Research digests by email
When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.