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Papers
80 resultsShowing papers from University of Tennessee at Knoxville
ClearMicroplastics in ecosystems: Critical review of occurrence, distribution, toxicity, fate, transport, and advances in experimental and computational studies in surface and subsurface water
This review provides a broad overview of microplastic contamination across freshwater, marine, and land environments, finding concentrations ranging from negligible to hundreds of thousands of particles per kilogram of sediment. The most common types are polypropylene, polystyrene, polyethylene, and PET, spread by wastewater discharge, stormwater runoff, and poor waste management. The wide variability in contamination levels makes it difficult to assess overall risk to ecosystems and human health.
Earthworms Exposed to Polyethylene and Biodegradable Microplastics in Soil: Microplastic Characterization and Microbial Community Analysis
Researchers exposed earthworms to biodegradable and conventional polyethylene microplastics in natural soil and found that worms ingested both types. The biodegradable plastic showed signs of partial breakdown in the earthworm gut, while conventional polyethylene remained unchanged. Although microplastics did not significantly alter the soil or gut microbiome in this study, the results confirm that earthworms transport microplastics through soil ecosystems.
Low levels of microplastics (MP) in wild mussels indicate that MP ingestion by humans is minimal compared to exposure via household fibres fallout during a meal
Researchers measured microplastic levels in wild mussels collected around the Scottish coast and found relatively low contamination compared to other studies. They then compared this to the amount of household dust fibers that settle onto a dinner plate during a typical meal and found that airborne fiber exposure during eating likely exceeds the microplastics ingested from a serving of mussels. The study suggests that for most people, indoor dust may be a more significant source of microplastic exposure than seafood consumption.
Formation, behavior, properties and impact of micro- and nanoplastics on agricultural soil ecosystems (A Review)
This review provides a comprehensive look at how micro and nanoplastics affect agricultural soil ecosystems, covering their sources, movement through soil, and impacts on soil organisms and crop growth. The authors found that microplastics can alter soil structure, reduce beneficial microbial activity, and affect plant nutrient uptake. These changes to farmland soils could ultimately threaten food security and introduce microplastics into the human food supply.
Biodegradable Plastic Mulch Films: Impacts on Soil Microbial Communities and Ecosystem Functions
This review examines how biodegradable plastic mulch films affect soil microbial communities and ecosystem functions compared to conventional polyethylene mulches. Researchers found that while biodegradable films avoid the problem of permanent plastic accumulation, their breakdown products can still alter soil microbiomes and carbon cycling in ways that are not yet fully understood. The study highlights the need for long-term field research to determine whether biodegradable mulches are truly a sustainable alternative for agriculture.
Microplastics in agricultural soil: Polystyrene fragments inhibit soil microbial and enzymatic activities but promote nutrient concentration of Cowpea (Vigna unguiculata)
This study examined how polystyrene microplastic fragments in agricultural soil affect both soil health and cowpea plant growth. Researchers found that while microplastics significantly reduced beneficial soil microbial activity and enzyme function, the cowpea plants surprisingly showed increased nutrient concentrations. The findings highlight the complex and sometimes contradictory ways microplastics can influence agricultural ecosystems.
Mechanism of quiescent nanoplastic formation from semicrystalline polymers
Researchers uncovered the mechanism by which semicrystalline polymers, which make up about 70% of commercial plastics, spontaneously release nanoplastic particles even without mechanical force. They found that chemical bond-breaking events concentrate in the non-crystalline regions of the plastic, eventually causing those layers to fail and release stacks of crystalline fragments as nanoplastics. This discovery helps explain why plastics continuously shed tiny particles into the environment under normal conditions.
Incognito forms of polyethylene small micro and nanoplastics in solvents: Changes in molecular vibrations
Researchers investigated how very small polyethylene microplastics and nanoplastics behave when dissolved or suspended in water and organic solvents. They found that these tiny particles undergo significant structural changes that alter their spectral signatures, potentially making them invisible to standard detection methods like Raman spectroscopy. The study suggests that current monitoring efforts may be missing a substantial portion of nanoplastic pollution because the particles look different at the molecular level than expected.
Plastic Pollution of the Tennessee River: Comparing Risk Perceptions and Preferred Policy Solutions Between Stakeholders and the Public
Researchers surveyed both the general public and local stakeholders along the Tennessee River about their perceptions of plastic pollution risks and preferred policy solutions. They found that while both groups recognized the environmental and health risks of plastic and microplastic pollution, their preferred approaches to addressing the problem differed. The study highlights the importance of understanding community perspectives when designing effective policies to reduce freshwater plastic contamination.
Potential Artifacts and Control Experiments in Toxicity Tests of Nanoplastic and Microplastic Particles
This review highlighted potential measurement artifacts and the importance of proper control experiments in toxicity studies of nanoplastics and microplastics. The study cautions that antimicrobials, surfactants, and other additives present in commercial plastic particle dispersions may account for observed toxic effects rather than the particles themselves, emphasizing the need for rigorous experimental design in microplastic toxicology research.
Activities of Microplastics (MPs) in Agricultural Soil: A Review of MPs Pollution from the Perspective of Agricultural Ecosystems
This review summarizes the origins, migration, and fate of microplastics in agricultural soil ecosystems, identifying plastic mulch film, irrigation water, and organic fertilizers as major sources. The study highlights that microplastic accumulation in farmland can affect soil structure, microbial communities, and crop growth, with potential implications for food safety through the terrestrial food chain.
Impact of aquatic microplastics and nanoplastics pollution on ecological systems and sustainable remediation strategies of biodegradation and photodegradation
This review covers the impact of microplastics and nanoplastics on aquatic ecosystems and evaluates emerging remediation strategies. Researchers examined how these particles enter food chains and pose health risks when ingested by aquatic organisms or humans. The study highlights promising biodegradation and photodegradation approaches, including microbial, enzymatic, and metal oxide-assisted methods, as eco-friendly ways to break down microplastic contamination.
Use of fluorescent-labelled nanoplastics (NPs) to demonstrate NP absorption is inconclusive without adequate controls
Researchers demonstrated that fluorescent dyes used to label polystyrene nanoplastics can leach from particles and independently accumulate in zebrafish tissues, warning that many prior studies claiming nanoplastic absorption into internal organs may have been detecting dye rather than particles — and calling for stricter controls in nanoplastic uptake research.
Microplastic Analysis in Soil Using Ultra-High-Resolution UV–Vis–NIR Spectroscopy and Chemometric Modeling
Researchers tested a new method using UV-visible-near infrared spectroscopy combined with machine learning to identify microplastics in soil samples. They found the technique could rapidly and accurately distinguish between different plastic polymers and natural soil particles. The study offers a promising alternative to current labor-intensive identification methods, potentially making large-scale microplastic soil monitoring more practical.
Racial Disparities in the Heavy Metal Contamination of Urban Soil in the Southeastern United States
Researchers analyzed urban soil samples from eight cities across the southeastern United States to examine racial disparities in heavy metal contamination exposure. They found that soil in predominantly minority and low socioeconomic communities contained significantly higher levels of certain heavy metals. The study provides field-based evidence that environmental contamination disproportionately burdens communities of color and lower socioeconomic status.
Assessment of microplastic-sorbed contaminant bioavailability through analysis of biomarker gene expression in larval zebrafish
Researchers examined whether contaminants sorbed to microplastics become bioavailable when ingested by larval zebrafish, using phenanthrene and ethinylestradiol as test chemicals. The study found that microplastics can alter the bioavailability of co-contaminants, as evidenced by changes in biomarker gene expression in the fish larvae.
Are micro- and nanoplastics from soil-biodegradable plastic mulches an environmental concern?
Researchers examined whether micro- and nanoplastics generated from soil-biodegradable plastic mulches pose environmental risks comparable to those from conventional plastics. They argue that when disposed of properly in soil or compost, biodegradable mulch plastics degrade relatively quickly, limiting the accumulation of their micro- and nanoplastic fragments. However, the study cautions that if these materials end up in aquatic or atmospheric environments where degradation is slower, they could still cause environmental harm.
Polyvinyl chloride (PVC) plastic fragments release Pb additives that are bioavailable in zebrafish
Researchers investigated whether PVC microplastic fragments release lead additives that are bioavailable to zebrafish. The study found that PVC fragments leached lead into the water, and this lead was taken up by zebrafish during early life stages, while HDPE and PET microplastics did not release significant amounts of toxic additives, highlighting that the chemical composition of different plastic types determines their toxicity potential.
Mechanical formation of micro- and nano-plastic materials for environmental studies in agricultural ecosystems
Researchers developed a mechanical method for producing micro- and nanoplastic particles from agricultural plastic films, creating materials more representative of real-world soil contaminants than the idealized spheres commonly used in lab studies. They successfully generated polydisperse fragments from low-density polyethylene mulch film using cryogenic milling. The study provides the research community with more realistic plastic materials for studying the environmental fate and ecological effects of agricultural plastic pollution.
Scientists’ Warning to Humanity: Rapid degradation of the world’s large lakes
Scientists issued a comprehensive warning that the world's large lakes — critical freshwater sources supporting biodiversity and billions of people — are degrading rapidly due to warming temperatures, habitat destruction, invasive species, and accelerating pollution including microplastics. The review calls for urgent conservation action and a global network of long-term lake monitoring stations to detect and respond to ongoing changes.
Assessment of cryogenic pretreatment for simulating environmental weathering in the formation of surrogate micro- and nanoplastics from agricultural mulch film
Researchers evaluated whether cryogenic pretreatment of biodegradable agricultural mulch films can simulate the natural weathering that produces micro- and nanoplastics in fields. The study developed a procedure combining mechanical milling and wet grinding to create surrogate plastic particles that mimic those forming naturally in agricultural soils, providing a standardized approach for controlled ecotoxicity studies.
Dark Reduction of Hg(II) by Dissolved Organic Matter Derived from Aging Microplastics: Mechanisms and Implications
Researchers discovered that dissolved organic matter released from photoaged microplastics can convert toxic mercury into a less reactive form through dark chemical reactions. The organic matter from aged polystyrene, PVC, and polylactic acid reduced over 30% of mercury within 10 minutes, outperforming natural river organic matter. The findings suggest that as microplastic pollution increases in waterways, it may significantly alter mercury cycling in aquatic environments.
Aggregation kinetics and stability of biodegradable nanoplastics in aquatic environments: Effects of UV-weathering and proteins
Researchers investigated the aggregation behavior of biodegradable nanoplastics (PBAT) in aquatic environments, finding that UV weathering and protein presence significantly alter their colloidal stability and aggregation kinetics, which influences their environmental fate and transport.
Unveiling the Microbial Realm with VEBA 2.0: A modular bioinformatics suite for end-to-end genome-resolved prokaryotic, (micro)eukaryotic, and viral multi-omics from either short- or long-read sequencing
Researchers introduced VEBA 2.0, an open-source bioinformatics software suite for analyzing complex microbial communities including bacteria, archaea, eukaryotes, and viruses from sequencing data. The tool enables comprehensive microbiome research, which is relevant to understanding how microbial communities interact with environmental contaminants like microplastics.