Sorption effects interfering with the analysis of polycyclic aromatic hydrocarbons (PAH) in aqueous samples

Non-target analysis of crude oil photooxidation products at high latitudes and their biological effects

With new oil and gas lease sales in high-latitude regions, there exists a need to better understand the chemical fate of spilled oil and its effects on biological life. To address this need, laboratory simulations of crude oil spills under sub-Arctic conditions were conducted using artificial seawater and exposure to solar irradiation to create Hydrocarbon Oxidation Products (HOPs). HOPs characterization and their biological effects were assessed using ultra high-performance liquid chromatography (UHPLC) with high resolution mass Orbitrap spectrometry and the aryl hydrocarbon receptor (AhR) chemically activated luciferase gene expression (CALUX) assay. Non-target UHPLC-Orbitrap mass spectrometry analysis identified 251 HOPs that were in greater abundance in light-exposed samples than dark controls. Oxidized polycyclic aromatic hydrocarbons were also detected, including phenanthrene quinone, anthraquinone, hydroxyanthraquinone, and 9-fluoreneone. The composition of HOPs were consistent with photo-products of alkylated two to four ring PAHs, primarily compounds between 1 and 3 aromatic rings and 1-3 oxygens. The HOP mixture formed during photochemical weathering of Cook Inlet crude oil induced greater AhR activity than parent petroleum products solubilized in dark controls, indicating that HOPs, as a complex mixture, may contribute to petroleum toxicity more than the parent petroleum compounds. These non-targeted approaches provide the most comprehensive analysis of hydrocarbon oxidation products to date, highlighting the diversity of the complex mixture resulting from the photooxidation of crude oil and the limitations of targeted analyses for adequately monitoring HOPs in the environment. Taken together, these data identify a critical "blind spot" in environmental monitoring and spill clean-up strategies as there is a diverse pool of HOPs that may negatively impact human and ecosystem health.

Assessment of microplastic contamination in some commercial fishes of the southern Caspian Sea and its potential risks

This study examined the occurrence of microplastics (MPs) in the gastrointestinal tract (GIT) of 384 fishes classified into four species from 11 sites in 2022 from the southern part of the Caspian Sea. GITs of fishes were collected and digested in H2O2 and KOH at 45 °C for 72 h. After filtration, extracted MPs were observed under a stereomicroscope, and selected MP particles were identified using FTIR. Presence of MPs was 68.98% in the GIT of the investigated fish. The mean abundance of MPs was 5.9 ± 0.9 MPs/GIT in Rutilus kutum, 9.2 ± 1.2 MPs/GIT in Chelon auratus, 3.6 ± 0.7 MPs/GIT in Alosa braschnikowi, and 2.7 ± 0.5 MPs/GIT in Vimba vimba. The predominant form of MPs was fiber (58.21%), followed by fragment (34.77%). Black (34.4%), white (19.07%), and blue (14.58%) were the most frequently detected colors of MPs. Overall, 6 MP polymers were identified, dominantly polypropylene (42.86%), polystyrene (17.86%), and cellophane (14.28%). The western part of the Caspian Sea (mostly tourist spots and urban areas) showed more MP pollution in fish compared to the eastern part. Polymer hazard index (PHI) revealed alarming microplastic contamination in the southern Caspian Sea. The PHI value of the present study showed that PES (PHI = 8403.78) and PS (PHI = 535.80) were "Extreme danger" and "Danger" risk categories, respectively.

Environmental and ecological risk of microplastics in the surface waters and gastrointestinal tract of skipjack tuna (Katsuwonus pelamis) around the Lakshadweep Islands, India

The presence of microplastics (MPs) in marine ecosystems is widespread and extensive. They have even reached the deepest parts of the ocean and polar regions. The number of articles on plastic pollution has increased in recent years, but few have investigated the MPs from oceanic islands which are biodiversity hotspots. We investigated the possible microplastic contamination their source and characteristics in surface waters off Kavaratti Island and in the gastrointestinal tract (GT) of skipjack tuna, Katsuwonus pelamis collected from Kavaratti Island of the Lakshadweep archipelago. A total of 424 MP particles were isolated from the surface water samples collected from off Kavaratti Island with an average abundance of 5 ± 1nos./L. A total of 117 MPs were recovered from the GT of skipjack tuna from 30 individual fishes. This points to a potential threat of MP contamination in seafood around the world since this species has a high value in local and international markets. Fiber and blue color were the most common microplastic morphotypes and colors encountered, respectively, both from surface water and GT of fish. Smaller MPs (0.01-1 mm) made up a greater portion of the recovered materials, and most of them were secondary MPs. Polyethylene and polypropylene were the most abundant polymers found in this study. The Pollution Load Index (1.3 ± 0.21) of the surface water and skipjack tuna (1 ± 0.7) indicates a minor ecological risk for the coral islands, while the Polymer Hazard Index highlights the ecological risk of polymers, even at low MP concentrations. This pioneer study sheds preliminary light on the abundance, properties, and environmental risks of MPs to this highly biodiverse ecosystem.

Hazard index of microplastics contamination in various fishes collected off Parangipettai, Southeast coast of India

The authors of the present research aimed to assess microplastics (MPs) contamination in the gills and gut of selected fishes from various aquatic zones and also to bring out the risks of the identified polymers. Accordingly, about 200 fish specimens of 10 different species were collected from the landing center at Parangipettai, southeast coast of India. The fishes were dissected to investigate MPs contamination in their gills and gut. The dissected tissues were acid digested and filtered to observe its microplastic contamination using a stereozoom microscope. In gills, Cynoglossus arel had the least contamination (0.4 ± 0.01 particles/ind) and Mugil cephalus had highest microplastic contamination (1.7 ± 0.01 particles/ind). In gut, C. arel had the minimum contamination (0.7 ± 0.09 particles/ind) and Rastrelliger kanagurta had maximum contamination (2.3 ± 0.26 particles/ind). The size of microplastics isolated from the present study ranged from 100 to 1000 μm. Among microplastic shapes, fibers (97%) and pellets (3%) were observed. About eight colours of microplastics were observed in the fishes among which black was dominant. Three polymers such as LDPE, PP and PS were identified by μFTIR, among which LDPE (57%) was dominant. Polymer Hazard Index denotes that LDPE (6.27), PP (3.4) and PS (2.7) have a PHI score of 1-10 classifying them in the hazard category II which has a medium risk. These polymers may directly enter the human body when consumed and cause health implications which require further investigation.

Microplastic contamination in edible sea salt from the largest salt-producing states of India

The presence of microplastics in all ecological and environmental conditions has been identified as a global problem. This article aimed to study edible salt-associated microplastics from the major salt-producing states of India. The crystal and powder salt from Tamil Nadu and Gujarat (five samples of powder salt and three samples of crystal salt from each state) were collected and analyzed for their microplastic content. The total microplastic content in the salts ranged from 46 to 115 particles per 200 g in Gujarat salt and 23 to 101 particles per 200 g in Tamil Nadu salt. The microplastics are dominated by red and blue color fibrous-shaped materials. The most common microplastics identified in the edible salts were polyethylene, polyester, and polyvinyl chloride derived from marine and salt-processing units.

Microplastic contamination in salt pans and commercial salts - A baseline study on the salt pans of Marakkanam and Parangipettai, Tamil Nadu, India

We studied the abundance of microplastics from commercial table salts and table salts from salt pans at Marakkanam and Parangipettai, Tamil Nadu, India. Microplastic abundance in the salts collected from salt pans had a range of 3.67 ± 1.54 to 21.33 ± 1.53 nos./10 g of salt which were higher than the microplastics retrieved from the commercial salts which ranged from 4.67 ± 1.15 to 16.33 ± 1.53 nos./10 g of salt. All the microplastics retrieved were fibers which were secondary in origin. Black, red, blue, green, white, brown, and colorless microplastics were observed in the samples. FT-IR results showed that 4 types of polymers, namely, Nylon, Polypropylene (PP), Low Density Polyethylene (LDPE), and Polyethylene Terephthalate (PET) were present in the samples. Domestic and municipal wastewater discharges into the estuaries may contribute to microplastics in the table salts. Our study proves that table salts (processed and unprocessed) are prone to microplastic contamination.

Interaction of chemical contaminants with microplastics: Principles and perspectives

Scientific evidences abound of the occurrence of plastic pollution, from mega- to nano-sized plastics, in virtually all matrixes of the environment. Apart from the direct effects of plastics and microplastics pollution such as entanglement, inflammation of cells and gut blockage due to ingestion, plastics are also able to act as vectors of various chemical contaminants in the aquatic environment. This paper provides a review of the association of plastic additives with environmental microplastics, how the structure and composition of polymers influence sorption capacities and highlights some of the models that have been employed to interpret experimental data from recent sorption studies. The factors that influence the sorption of chemical contaminants such as the degree of crystallinity, surface weathering, and chemical properties of contaminants. and the implications of chemical sorption by plastics for the marine food web and human health are also discussed. It was however observed that most studies relied on pristine or artificially aged plastics rather than field plastic samples for studies on chemical sorption by plastics.

Microplastics in Spanish Table Salt

Marine debris is widely recognized as a global environmental problem. One of its main components, microplastics, has been found in several sea salt samples from different countries, indicating that sea products are irremediably contaminated by microplastics. Previous studies show very confusing results, reporting amounts of microparticles (MPs) in salt ranging from zero to 680 MPs/kg, with no mention of the possible causes of such differences. Several errors in the experimental procedures used were found and are reported in the present work. Likewise, 21 different samples of commercial table salt from Spain have been analyzed for MPs content and nature. The samples comprise sea salts and well salts, before and after packing. The microplastic content found was of 50–280 MPs/kg salt, being polyethylene-terephthalate (PET) the most frequently found polymer, followed by polypropylene (PP) and polyethylene (PE), with no significant differences among all the samples. The results indicate that even though the micro-particles might originate from multiple sources, there is a background presence of microplastics in the environment.

Organic compounds in concrete from demolition works

This study aims to verify the effect of physically removing the outer surface of contaminated concrete on total contents and on potential mobility of pollutants by means of leaching tests. Reclaimed concrete from 3 industrial sites in Sweden were included: A tar impregnated military storage, a military tar track-depot, as well as concrete constructions used for disposing of pesticide production surplus and residues. Solid materials and leachates from batch and column leaching tests were analysed for metals, Cl, F, SO4, DOC and contents of suspected organic compounds (polycyclic aromatic hydrocarbons, PAH, and pesticides/substances for pesticide production such as phenoxy acids, chlorophenols and chlorocresols, respectively). In case of PAH contaminated concrete, results indicate that removing 1 or 5 mm of the surface lead to total concentrations below the Swedish guidelines for recycling of aggregates and soil in groundwork constructions. 3 out of 4 concrete samples contaminated with pesticides fulfilled Swedish guidelines for contaminated soil. Results from batch and column leaching tests indicated, however, that concentrations above environmental quality standards for certain PAH and phenoxy acids, respectively, might occur at site when the crushed concrete is recycled in groundwork constructions. As leaching tests engaged in the study deviated from leaching test standards with a limited number of samples, the potential impact of the leaching tests' equipment on measured PAH and pesticide leachate concentrations has to be evaluated in future work.

Protective and curative effects of the sea cucumber Holothuria atra extract against DMBA-induced hepatorenal diseases in rats

Oxidative stress is a common mechanism contributing to the initiation and progression of hepatic damage. Hence there is a great demand for the development of agents with potent antioxidant effect. The aim of the present study is to evaluate the efficacy of Holothuria atra extract (HaE) as an antioxidant against 7,12-dimethylbenz[a]anthracene- (DMBA-) induced hepatorenal dysfunction. Experimental animals were divided into two main groups: protective and curative. Each group was then divided into five subgroups pre- or posttreated either with distilled water (DMBA subgroups) or with HaE (200 mg/kg body weight) for seven and fourteen days. Single oral administration of DMBA (15 mg/kg body weight) to Wistar rats resulted in a significant increase in the serum liver enzymes and kidney function's parameters. DMBA increased level of liver malondialdehyde (MDA), decreased levels of reduced glutathione (GSH), glutathione-S-transferase (GST), superoxide dismutase (SOD), and catalase (CAT) in the liver tissue, and induced liver histopathological alterations. Pre- or posttreatment with HaE orally for 14 days significantly reversed the hepatorenal alterations induced following DMBA administration. In conclusion, HaE exhibits good hepatoprotective, curative, and antioxidant potential against DMBA-induced hepatorenal dysfunction in rats that might be due to decreased free radical generation.