Occurrence, distribution, and associated pollutants of plastic pellets (nurdles) in coastal areas of South Texas

Intrinsic interaction inferred oxidative stress and apoptosis by Biosurfactant-microplastic hybrid reduces coordinated in vivo biotoxicity in zebrafish (Danio rerio)

The proliferation of microplastics (μP) in aquatic environments poses a significant threat to ecosystem health, with repercussions extending to aquatic organisms and potentially to human health. In this study, we investigated the efficacy of a novel biosurfactant-microplastic (BSμP) hybrid in reducing in vivo green bio-toxicity of microplastics (μP) induced by oxidative stress and apoptosis in zebrafish (Danio rerio). Microplastics, ubiquitous in aquatic environments, were hybridised with Biosurfactant to evaluate their potential mitigating effects. A stable BSμP was formed with zeta potential of -10.3 ± 1.5 mV. Exposure of zebrafish embryos to μP resulted in increased oxidative stress markers, including elevated levels of reactive oxygen species and induced apoptosis, as evidenced by increased expression of apoptotic markers and morphological changes in embryonic zebrafish. However, the BSμP hybrid significantly ameliorated the observed toxic effects with reduced levels of oxidative stress markers and apoptotic activity. This effect was deduced as the intrinsic effects of hybridisation, which likely mitigated the bioavailability and toxicity of μP by reducing their molecular interaction with metabolic proteins like Sod1 and p53 through less accumulation and internalisation. Overall, our findings highlight the potential of BSμP as a promising approach for mitigating the ecological impacts of microplastic pollution.

Integrating Community Service into Student Learning: A Model Event of a Plastic Waste Cleanup

Plastic recycling has gained increasing attention due to the negative impacts of improper plastic waste management and its end-of-life outcomes. Despite growing research and educational efforts on sustainability, the integration of community service into student learning experiences remains limited. To address this gap and promote sustainable practices among the younger generation, a cleanup outreach event is developed in conjunction with pre- and post-cleanup lectures. The lectures covered the knowledge of plastic waste and recycling, relevant policies, and advancements in sustainability within industry and academia. The waste cleanup activity, held at Biloxi Beach and Hattiesburg, Mississippi, provided students with hands-on experience in addressing local plastic pollution and connected classroom learning to real-life plastic waste issues. Integrating community service with educational content provides an approach to learning about sustainable practices while raising awareness of societal needs and future technological opportunities.

Assessment of microplastics in gastrointestinal tract of cattle egret (Bubulcus ibis) from a metropolitan city Lahore, Pakistan

Ingestion of microplastic (MPs) in birds and its subsequent health effects has become one of the major environmental concerns. The current study is, therefore, designed to investigate the level of MPs in gastrointestinal tract of a semi-aquatic bird species, the cattle egret (Bubulcus ibis) and characterize their types, color and chemical composition. Samples (n = 5) from dead individuals were first digested then separated on the basis of density followed by vacuum filtration prior to quantification of MPs through stereomicroscopy. Fourier Transform Infrared Spectroscopy (FTIR) was used to identify the chemical composition of MPs. Our results showed the highest level (mean ± S.D items/sample) of sheets (37.2 ± 9.6) followed by fibers (28.8 ± 15.3), fragments (12.8 ± 16.2), and microbeads (0.4 ± 0.5) in gastrointestinal tract of cattle egret. The most frequently detected color was transparent (23%), followed by brown (19%), white (18%), black (15%), and orange (10%), respectively. Polyvinyl alcohol (PVA), polyisobutylene, polyaramid, fiberglass and PTFE coated fiberglass fiber were characterized as the major constituent compounds of MPs in gastrointestinal tracts of cattle egrets. Highest concentrations of sheets and fibers MPs in gastrointestinal tract of cattle egrets reflect their greater sources and lowest degradation. Our results depict the elevated level of MPs in the gastrointestinal tract of cattle egrets which might be posing some serious health effects. The ingestion of MPs by birds is evidently associated with their declining populations which should be mitigated effectively to avoid future worst consequences.

Laboratory-Simulated Photoirradiation Reveals Strong Resistance of Primary Macroplastics to Weathering

The photodegradation of macroplastics in the marine environment remains poorly understood. Here, we investigated the weathering of commercially available plastics (tabs 1.3 × 4.4 × 0.16 cm), including high-density polyethylene, low-density polyethylene, polypropylene, polystyrene, and polycarbonate, in seawater under laboratory-simulated ultraviolet A radiation for 3-9 months, equivalent to 25-75 years of natural sunlight exposure without considering other confounding factors. After the exposure, the physical integrity and thermal stability of the tabs remained relatively intact, suggesting that the bulk polymer chains were not severely altered despite strong irradiation, likely due to their low specific surface area. In contrast, the surface layer (∼1 μm) of the tabs was highly oxidized and eroded after 9 months of accelerated weathering. Several antioxidant additives were identified in the plastics through low temperature pyrolysis coupled with gas chromatography/mass spectrometry (Pyr-GC/MS) analysis. The Pyr-GC/MS results also revealed many new oxygen-containing compounds formed during photodegradation, and these compounds indicated the dominance of chain scission reactions during weathering. These findings highlight the strong resistance of industrial macroplastics to weathering, emphasizing the need for a broader range of plastics with varying properties and sizes to accurately estimate plastic degradation in the marine environment.

Seasonality of mercury and its fractions in microplastics biofilms -comparison to natural biofilms, suspended particulate matter and bottom sediment

Biofilms can enhance the sorption of heavy metals onto microplastic (MP) surfaces. However, most research in this field relies on laboratory experiments and neglects metal fractions and seasonal variations. Further studies of the metal/biofilm interaction in the aquatic environment are essential for assessing the ecological threat that MPs pose. The present study used in situ experiments in an environment conducive to biofouling (Vistula Lagoon, Baltic Sea). The objective was to investigate the sorption of mercury and its fractions (thermodesorption technique) in MP (polypropylene-PP, polystyrene-PS, polylactide-PLA) biofilms and natural matrices across three seasons. After one month of incubation, the Hg concentrations in MP and natural substratum (gravel grains-G) biofilms were similar (MP: 145 ± 45 ng/g d.w.; G: 132 ± 23 ng/g d.w.) and approximately twofold those of suspended particulate matter (SPM) (63 ± 27 ng/g d.w.). Hg concentrations in biofilms and sediments were similar, but labile fractions dominated in biofilms and stable fractions in sediments. Seasonal Hg concentrations in MP biofilms decreased over summer>winter>spring, with significant variation for mineral and loosely bound Hg fractions. Multiple regression analysis revealed that hydrochemical conditions and sediment resuspension played a crucial role in the observed variability. The influence of polymer type and morphology (pellets, fibres, aged MP) on Hg sorption in biofilms was visible only in high summer temperatures. In this season, PP fibres and aged PP pellets encouraged biofilm growth and the accumulation of labile Hg fractions. Additionally, high concentrations of mineral (stable and semi-labile) Hg fractions were found in expanded PS biofilms. These findings suggest that organisms that ingest MPs or feed on the biofilms are exposed to the adverse effects of Hg and the presence of MPs in aquatic ecosystems may facilitate the transfer of mercury within the food chain.

Distribution and Fate of Polyethylene Microplastics Released by a Portable Toilet Manufacturer into a Freshwater Wetland and Lake

A portable toilet manufacturer in northwest Indiana (USA) released polyethylene microplastic (MP) pollution into a protected wetland for at least three years. To assess the loads, movement, and fate of the MPs in the wetland from this point source, water and sediment samples were collected in the fall and spring of 2021-2023. Additional samples, including sediment cores and atmospheric particulates, were collected during the summer of 2023 from select areas of the wetland. The MPs were isolated from the field samples using density separation, filtration, and chemical oxidation. Infrared and Raman spectroscopy analyses identified the MPs as polyethylene, which were quantified visually using a stereomicroscope. The numbers of MPs in 100 mL of the marsh water closest to the source ranged from several hundred to over 400,000, while the open water samples contained few microplastics. Marsh surface sediments were highly contaminated with MPs, up to 18,800 per 30.0 g dry mass (dm), compared to core samples in the lower depths (>15 cm) that contained only smaller MPs (<200 µm), numbering 0-480 per 30.0 g (dm). The wide variations in loads of MP contaminants indicate the influence of numerous factors, such as proximity to the point source pollution, weather conditions, natural matter, and pollution sinks, namely sediment deposition. As proof of concept, we demonstrated a novel remediation method using these real-world samples to effectively agglomerate and remove MPs from contaminated waters.

Fire and Oil Led to Complex Mixtures of PAHs on Burnt and Unburnt Plastic during the M/V X-Press Pearl Disaster

In May 2021, the M/V X-Press Pearl container ship burned for 2 weeks, leading to the largest maritime spill of resin pellets (nurdles). The disaster was exacerbated by the leakage of other cargo and the ship's underway fuel. This disaster affords the unique opportunity to study a time-stamped, geolocated release of plastic under real-world conditions. Field samples collected from beaches in Sri Lanka nearest to the ship comprised nurdles exposed to heat and combustion, burnt plastic pieces (pyroplastic), and oil-plastic agglomerates (petroplastic). An unresolved question is whether the 1600+ tons of spilled and recovered plastic should be considered hazardous waste. Due to the known formation and toxicity of combustion-derived polycyclic aromatic hydrocarbons (PAHs), we measured 20 parent and 21 alkylated PAHs associated with several types of spilled plastic. The maximum PAH content of the sampled pyroplastic had the greatest amount of PAHs recorded for marine plastic debris (199,000 ng/g). In contrast, the sampled unburnt white nurdles had two orders of magnitude less PAH content. The PAH composition varied between the types of spilled plastic and presented features typical of and conflicting with petrogenic and pyrogenic sources. Nevertheless, specific markers and compositional changes for burning plastics were identified, revealing that the fire was the main source of PAHs. Eight months after the spill, the PAH contents of sampled stray nurdles and pyroplastic were reduced by more than 50%. Due to their PAH content exceeding levels allowable for plastic consumer goods, classifying burnt plastic as hazardous waste may be warranted. Following a largely successful cleanup, we recommend that the Sri Lankans re-evaluate the identification, handling, and disposal of the plastic debris collected from beaches and the potential exposure of responders and the public to PAHs from handling it. The maritime disaster underscores pyroplastic as a type of plastic pollution that has yet to be fully explored, despite the pervasiveness of intentional and unintentional burning of plastic globally.

Plastic debris, persistent organic pollutants and their toxicity impacts in coastal areas in Central Chile

The chemical components of plastic wastes have made their disposal a major economic, social, and environmental problem worldwide. This study evaluated the acute toxicity and genotoxicity of marine plastic debris on the beaches of Concepción Bay, Central Chile, taken during three periods (spring, summer, and winter). An integrated approach was used, including chemical and toxicological data, using the Microtox® test with Vibrio fischeri and SOS chromotest with Escherichia coli and concentrations of polychlorinated biphenyls (PCBs), Organochlorine Pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs). The results presented here exclusively include the novel data obtained from the winter campaign, revealing high concentrations of PBDEs (238 ± 521 ng g-1). In addition, the genotoxicity and acute toxicity tests were sensitive for most of the samples studied. This investigation is the first attempt to analyse the toxicity of plastic debris in coastal areas along the Chilean coast.

Microplastic-sorbed persistent organic pollutants in coastal Mediterranean Sea areas of Tunisia

Microplastics (MPs) are emerging pollutants of global concern due to their pervasiveness, high sorption ability for persistent organic pollutants (POPs) and direct and indirect toxicity to marine organisms, ecosystems, as well as humans. As one of the major coastal interfaces, beaches are considered among the most affected ecosystems by MPs pollution. The morphological characteristics of MPs (pellets and fragments) collected from four beaches along the Tunisian coast and sorbed POPs, including polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), were investigated in this study. The results showed that the MPs varied greatly in color, polymer composition and degradation degree. The color varied from colored to transparent and the most prevalent polymer identified using Raman spectroscopy was polyethylene. Scanning electron microscope (SEM) images exhibited various surface degradation features including cavities, cracks, attached diatom remains, etc. The concentrations of Σ12PCBs over all beaches ranged from 14 to 632 ng g-1 and 26 to 112 ng g-1 in the pellets and fragments, respectively, with a notable presence and dominance of highly-chlorinated PCBs such as CB-153 and -138. Among the OCPs, γ-HCH is the only compound detected with concentrations ranging from 0.4 to 9.7 ng g-1 and 0.7 to 4.2 ng g-1 in the pellets and fragments, respectively. Our findings indicate that MPs found on the Tunisian coast may pose a chemical risk to marine organisms as the concentrations of PCBs and γ-HCH in most of the analysed samples exceeded the sediment-quality guidelines (SQG), especially the effects range medium (ERM) and the probable effects level (PEL). As the first report of its kind, the information gathered in this study can serve as the baseline and starting point for future monitoring work for Tunisia and neighbouring countries, as well as for stakeholders and coastal managers in decision-making processes.

Seasonal variation and spatial distribution of microplastic pellets and their associated contaminants along the central east coast of India

Microplastic pellets (MPPs) are one of the significant sources of plastic pollution on shorelines worldwide. In this study, for the first time, we have examined the occurrence of MPPs and their spatial and seasonal distributions, adsorbed contaminants, polymer composition, and ecological risks at eight renowned beaches of Andhra Pradesh, central east coast of India. A total of 3950 MPPs were collected from eight beaches along the central east coast of India during October 2020, representing pre-northeast monsoon (pNEM), and during January 2021, representing the northeast monsoon (NEM). The abundance of MPPs was higher during the NEM than those found in the pNEM. ATR-FTIR and SEM analyses were conducted to characterize the polymer types and weathering patterns of MPPs. Energy-Dispersive X-ray spectrometer (EDS) results show the MPP adsorbance of heavy metals such as Ni, Cr, Cu, Pb, and Zn. The degree of contamination and polymer hazard risks of MPPs were assessed using the pollution load index (PLI) and polymer hazard index (PHI). The conducive wind and currents during the NEM lead to higher MPP abundance than during the pNEM. However, the spatial variations of MPPs showed significant differences among the beaches. This study revealed that the presence of MPPs on the beaches along the central east coast of India might pose a considerable polymer hazard risk to the ecosystem. The substantial surface weathering features of MPPs would lead to more toxic nanoplastics in the future.