Structural isomers of polyfluorinated di- and tri-alkylated phosphate ester surfactants present in industrial blends and in microwave popcorn bags

Introduction  

In this study, we provide strategies for detecting and quantifying the structural isomers of polyfluorinated di- and tri-alkyl surfactants (PFAS) by mass spectrometry (MS). We specifically investigate polyfluorinated dialkylated phosphate ester surfactants (x:2/y:2 diPAPS, (F(CF₂) _x CH₂CH₂O-P(O)(O)⁻-OCH₂CH₂(CF₂) _y F)) and their thioether analogues (x:2/y:2 S-diPAPS, F(CF₂) _x CH₂CH₂SCH₂-C[CH₂O)₂P(O)(O)⁻]-CH₂SCH₂CH₂(CF₂) _y F), which are used for industrial applications, such as oil- and water-repellent coatings on paper and board. DiPAPS have been found in human blood and are metabolised to the persistent perfluoroalkyl carboxylic acids (PFCA) in rats.     

Application of an indicator based on taxonomic relatedness of ciliated protozoan assemblages for marine environmental assessment

Introduction  

Ciliated protozoa play important roles in aquatic ecosystems especially regarding their functions in micro-food web and have many advantages in environmental assessment compared with most other eukaryotic organisms. The aims of this study were focused on analyzing the application of an indicator based on taxonomic relatedness of ciliated protozoan assemblages for marine environmental assessment.     

Uptake and distribution of metals by water lettuce (<Emphasis Type="Italic">Pistia stratiotes</Emphasis> L.)

Background, aim and scope  

Water quality impairment by heavy metal contamination is on the rise worldwide. Phytoremediation technology has been increasingly applied to remediate wastewater and stormwater polluted by heavy metals.     

Accumulation,biotransformation, and biochemical responses after exposure to arsenite and arsenate in the estuarine polychaete <Emphasis Type="BoldItalic">Laeonereis acuta</Emphasis> (Nereididae)

Introduction  

This study aimed to analyze antioxidant responses and oxidative damage induced by two inorganic forms of arsenic (As; As^III and As^V) in an estuarine polychaete species, Laeonereis acuta (Nereididae). The capacity of arsenic biotransformation was also evaluated through the methylation process considering the activity of a key enzyme involved in the metabolization process.     

Influence of hydraulic retention time in a two-phase upflow anaerobic sludge blanket reactor treating textile dyeing effluent using sago effluent as the co-substrate

Purpose  

Textile dyeing and sago industries are the most polluting industries in South India, especially in industrial cities like Salem, Tamil Nadu, where textile dyeing and sago industries are clumped together geographically. Conventional physicochemical treatment followed by biological processes for the effluent generated from these industries are ineffective, costlier and produce huge quantities of hazardous sludge and harmful by-products which requires further treatment and safe disposal. Hence, the development of an alternative treatment method will become important. The main objective of this investigation is to establish a sustainable biotreatment technology for the treatment of textile dyeing effluent using sago effluent as co-substrate in a two-phase upflow anaerobic sludge blanket (UASB) reactor.     

Polyfluorinated surfactants (PFS) in paper and board coatings for food packaging

Introduction  

In this study, we explore the identity of a range of polyfluorinated surfactants (PFS) used for food contact materials, primarily to impart oil and water repellency on paper and board. PFS are of interest, as they can be precursors of poly- and perfluorinated alkyl substances (PFAS), of which several are persistent and are found worldwide in human blood and in the environment.     

The endocrine disrupting potential of sediments from the Upper Danube River (Germany) as revealed by in vitro bioassays and chemical analysis

Introduction  

The present study was part of a comprehensive weight-of-evidence approach with the goal of identifying potential causes for the declines in fish populations, which have been observed during the past decades in the Upper Danube River.     

Chitosan/albumin/CaCO3 as mimics for membrane bioreactor fouling: genesis of structural mineralized-EPS-building blocks and cake layer compressibility

Membrane bioreactor biofouling is usually described as an extracellular matrix in which biopolymers, inorganic salts and active microbes co-exist. For that reason, biomineralization (BM) models can be useful to describe the spatial organization and environmental constraints within the referred scenario. BM arguments were utilized as background in order to (1) evaluate CaCO₃ influence on flux decline; pore blocking and cake layer properties (resistance, permeability and compressibility) in a wide range of Chitosan/Bovine serum albumin (BSA) mixtures during step-pressure runs and, (2) perform membrane autopsies in order to explore the genesis of mineralized extracellular building blocks (MEBB) during cake layer build up. Using low molecular weight chitosan (LC) and BSA, 2 L of 5 LC/BSA mixtures (0.25-1.85 ratio) were pumped to an external ultra filtration (UF) membrane (23.5 cm², hydrophobic, piezoelectric, 100 kDa as molecular weight cut-off). Eight different pressure steps (40 ± 7 to 540 ± 21 kPa) were applied. Each pressure step was held for 900 s. CaCO₃ was added to LC/BSA mixtures at 0.5, 1.5 and 3 mM in order to create MEBB during the filtration tests. Membrane autopsies were performed after the filtration tests using thermo gravimetric, scanning microscopy and specific membrane mass (mg cm⁻²) analyses. Biopolymer-CaCO₃ step-pressure filtration created compressible cake layers (with inner voids). The formation of an internal skeleton of MEBB may contribute to irreversible fouling consolidation. A hypothesis for MEBB genesis and development was set forth.     

Phenol depletion by thermally activated peroxydisulfate at 70°C

The ability of thermal activated peroxydisulfate (PS) of mineralizing phenol at 70 °C from contaminated waters is investigated. Phenol in concentrations of 10⁻⁴ to 5 × 10⁻⁴ M is quantitatively depleted by 5 × 10⁻³ to 10⁻² M activated PS in 15 min of reaction. However, mineralization of the organic carbon is not observed. Instead, an insoluble phenol polymer-type product is formed. A reaction mechanism including the formation of phenoxyl radicals and validated by computer simulations is proposed. High molecular weight phenolic products are formed by phenoxyl radical H-abstraction reactions. This is not the case for the room temperature degradation of phenol by sulfate radicals where sulfate addition to the aromatic ring mainly leads to the generation of hydroxycyclohexadienyl radicals leading to hydroxybenzenes and oxidized open chain products. Therefore, a change in the reaction mechanism is observed with increasing temperature, and thermal activation of PS at 70 °C does not lead to the mineralization of phenol. Thus PS activation at 70 °C may be considered a potential method to reduce the load of phenol in polluted waters by polymerization.     

Biochemical biomarkers in Nile tilapia (Oreochromis niloticus) after short-term exposure to diesel oil, pure biodiesel and biodiesel blends

Fossil fuels such as diesel are being gradually replaced by biodiesel, a renewable energy source, cheaper and less polluting. However, little is known about the toxic effects of this new energy source on aquatic organisms. Thus, we evaluated biochemical biomarkers related to oxidative stress in Nile tilapia (Oreochromis niloticus) after two and seven exposure days to diesel and pure biodiesel (B100) and blends B5 and B20 at concentrations of 0.01 and 0.1 mL L⁻¹. The hepatic ethoxyresorufin-O-deethylase activity was highly induced in all groups, except for those animals exposed to B100. There was an increase in lipid peroxidation in liver and gills in the group exposed to the higher concentration of B5. All treatments caused a significant increase in the levels of 1-hydroxypyrene excreted in the bile after 2 and 7 d, except for those fish exposed to B100. The hepatic glutathione-S-transferase increased after 7 d in animals exposed to the higher concentration of diesel and in the gill of fish exposed to the higher concentration of pure diesel and B5, but decreased for the two tested concentrations of B100. Superoxide dismutase, catalase and glutathione peroxidase also presented significant changes according to the treatments for all groups, including B100. Biodiesel B20 in the conditions tested had fewer adverse effects than diesel and B5 for the Nile tilapia, and can be suggested as a less harmful fuel in substitution to diesel. However, even B100 could activate biochemical responses in fish, at the experimental conditions tested, indicating that this fuel can also represent a risk to the aquatic biota.