Analytical Chemistry
DOI: 10.1021/acs.analchem.3c02966
Model‐Assisted Interpretation of 4,4′‐Methylene Dianiline Adsorption on Soils at Micromolar Concentrations
Abstract
Adsorption kinetics and isotherms were determined for 4,4′-methylene dianiline (MDA) on five diverse soils at nominal concentrations of 0.01–1.0 mg L−1 (nominal soil loading 0.1–40 μg gs −1). The data were used to model the adsorption process based on the two-step mechanism that is characteristic of the adsorption of aromatic amines, consisting of a physical equilibrium between the aqueous phase and the soil organic matter and a chemical reaction between the adsorbed MDA and reactive sites in the soil organic matter. Generic parameters were determined that enabled application of the model to other soils, which was checked against previously published data for MDA adsorption. At the low concentrations evaluated, the adsorption process took place almost exclusively in the organic matter without the need to account for a separate ion exchange process with the soil mineral fraction. Physical adsorption was found to be mainly dependent on the protonation state of MDA and increased with decreasing pH of the soils. Because of the chemical reaction taking place, adsorption equilibrium constants (organic–carbon partition coefficient [K OC]) normalized to the organic carbon content in the soil gradually increased with time; and it was demonstrated that, at steady-state conditions, values of log K OC > 3.5 can be expected for most any soil at conservatively estimated potential environmental MDA concentrations. Environ Toxicol Chem 2023;00:1–9. © 2023 SETAC
Different Life‐Stage Exposure to Hexafluoropropylene Oxide Trimer Acid Induces Reproductive Toxicity in Adult Zebrafish (Danio rerio)
Abstract
As a novel alternative to perfluorooctanoic acid (PFOA), hexafluoropropylene oxide trimer acid (HFPO-TA) has been widely used and has caused ubiquitous water pollution. However, its adverse effects on aquatic organisms are still not well known. In the present study, zebrafish at different life stages were exposed to 0, 5, 50, and 100 μg/L of HFPO-TA for 21 days to investigate reproductive toxicity in zebrafish. The results showed that HFPO-TA exposure significantly inhibited growth and induced reproductive toxicity in zebrafish, including a decrease of the condition factor, gonadosomatic index, and the average number of eggs. Histological section observation revealed that percentages of mature oocytes and spermatozoa were reduced, while those of primary oocytes and spermatocytes increased. In addition, exposure to HFPO-TA at three stages induced a significant decrease in the hatching rate, while the heart rate and normal growth rate of F1 offspring were only significantly inhibited for the exposure from fertilization to 21 days postfertilization (dpf). Compared with the exposure from 42 to 63 dpf, the reproductive toxicity induced by HFPO-TA was more significant for the exposure from fertilization to 21 dpf and from 21 to 42 dpf. Expression of the genes for cytochrome P450 A1A, vitellogenin 1, estrogen receptor alpha, and estrogen receptor 2b was significantly up-regulated in most cases after exposure to HFPO-TA, suggesting that HFPO-TA exhibited an estrogen effect similar to PFOA. Therefore, HFPO-TA might disturb the balance of sex steroid hormones and consequently induce reproductive toxicity in zebrafish. Taken together, the results demonstrate that exposure to HFPO-TA at different life stages could induce reproductive toxicity in zebrafish. However, the underlying mechanisms deserve further investigation. Environ Toxicol Chem 2023;00:1–11. © 2023 SETAC
Influence of Particles on the Roller Discharge of Thin‐Film Filtration without Gas Throughput
The impact of a particle system on the roller discharge is investigated comparing the behavior of the inorganic white pigment titanium dioxide and the biological model organism yeast. The quality of the removal properties of the filter cakes on a laboratory drum filter is recorded. Five different track-etched membranes are used to assess the filter properties with varying particle-pore size ratios.
Abstract
If fine and compressible particle systems need to be separated, the ground layer compaction caused by the compacting of the filter cake leads to high flow resistances. Thin-film filtration is a suitable method to avoid the limiting effect of the filter cakes. Gas-impermeable filter membranes prevent shrinkage cracking, which can occur during demoisturing of the filter cakes. Titanium dioxide and baker's yeast are used as model particle systems, which are present in different concentrations and are filtered with track-etched membranes in different particle-to-pore size ratios. The parameters determined during the investigation are the residual moisture, the specific solid mass, and the completeness of the discharge. Filtration causes progressive blocking of the membrane pores, resulting in filter medium resistances that are increased by up to a factor of 175. Metabolism of yeast can cause bubbles to accumulate on the membrane and decreasing the free filter area. Without regeneration the specific solid mass flow rate is reduced by 61 % for titanium dioxide and by 13 % for yeast under ideal conditions of this experimental study.
Assessing the Toxicity of Sea Salt to Early Life Stages of Freshwater Mussels: Implications for Sea Level Rise in Coastal Rivers
Abstract
Sea levels across the planet are rising, particularly along the eastern coast of the United States. Climate-induced sea level rise can result in the inundation and intrusion of seawater into freshwater drainages. This would alter salinity regimes and lead to the salinization of coastal freshwater ecosystems. Increased salinity levels in freshwater can negatively affect freshwater-dependent species, including native mussels belonging to the order Unionida, which are highly sensitive to changes in water quality. Sea salt is largely made up of sodium and chloride ions, forming sodium chloride, a known toxicant to freshwater mussels. However, sea salt is a mixture that also contains other major ions, including potassium, sulfate, calcium, strontium, and magnesium, among others. Freshwater mussels exposed to sea salt would be exposed to each of the sea salt ions at the same time, resulting in a mixture toxicity effect. The mixture toxicity of these ions on early life stages of freshwater mussels is largely unknown because most research to date has evaluated individual salt ions in relative isolation. Therefore, we conducted acute toxicity tests on early life stages (glochidia and juvenile) of three freshwater mussel species that inhabit Atlantic Slope drainages (nonsalinity-adapted Atlanticoncha ochracea, salinity-adapted A. ochracea, Sagittunio nasutus, and Utterbackiana implicata). Glochidia and juveniles of each species were exposed to a control and six concentrations of Instant Ocean® Sea Salt (IOSS), a synthetic sea salt that closely resembles the ionic composition of natural sea salt. Exposure concentrations were 1 part(s) per thousand (ppt), 2 ppt, 8.5 ppt, 12.5 ppt, 17 ppt, and 34 ppt. We calculated the median effect concentration (EC50) for each of the eight acute toxicity tests and found that glochidia were more sensitive than juveniles to IOSS. At hour 24 EC50s for the glochidia ranged from 0.38 to 3.6 ppt, with the most sensitive freshwater mussel being the nonsalinity-adapted A. ochracea, exhibiting an EC50 of 0.38 ppt (95% confidence interval [CI] 0.33–0.44). Juvenile freshwater mussels exhibited EC50s at hour 96 ranging from 5.0 to 10.4 ppt, with the least sensitive freshwater mussel being the nonsalinity-adapted A. ochracea, exhibiting an EC50 of 10.4 ppt (95% CI 9.1–12.0). Our results show that acute exposure to sea salt adversely affects freshwater mussel viability, particularly glochidia. This information can be used to enhance freshwater mussel conservation strategies in regions that are or will be impacted by climate-induced sea level rise and associated freshwater salinization. Environ Toxicol Chem 2023;00:1–12. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
Photocatalysis of pharmaceuticals and organic dyes in the presence of silver-doped TiO2 photocatalyst–A critical review
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Development of a disposable hollow fibre-solid phase microextraction device using chitosan functionalised MWCNTs and a polyoxometalate for the simultaneous extraction of angiotensin II receptor blocker drugs
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Emerging Insights into the Use of Advanced Nanomaterials for the Electrochemiluminescence Biosensor of Pesticide Residues in Plant-Derived Foodstuff
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Enhancement of zinc (II) phthalocyanine photophysical properties in water by sulfonatocalix[4]arene‐based micelles
Zinc phthalocyanines have demonstrated a wide range of applications as photosensitisers, particularly in organic synthesis, photocatalysis and photodynamic therapy. Although the introduction of ionic groups on the macrocycle periphery increases their water solubility, aggregation phenomena remain as a significant drawback for their application. In this study, amphiphilic sulfonatocalix[4]arene-based micelles were used to promote the monomerization of a cationic phthalocyanine through host–guest interactions. A comprehensive spectroscopic characterization was conducted, varying the concentration of sulfonatocalix[4]arene, and binding parameters were calculated to determine the optimal conditions for complete monomerization of the photosensitizer in water. Under these conditions, the combination of sulfonatocalix[4]arene and the photosensitizer activated its photophysical activity in aqueous media, showing significant singlet oxygen photoproduction, photocatalytic capability and photostability.
Ex‐Situ Generation of Bis(trifluoromethyl)disulfide and Applications to Trifluoromethylthiolation Reactions
Herein, a convenient and operationally simple protocol for the ex-situ generation of bis(trifluoromethyl)disulfide from the readily available and commercial Langlois reagent is reported. The one-step synthesis of the toxic and volatile CF3SSCF3 is performed in a two-chamber reactor with simple PPh3 and N-bromosuccinimide as the activator, allowing for the safe handling and tandem utilization in direct trifluoromethylthiolation reactions. The versatility of the ex-situ generated CF3SSCF3 is demonstrated in known electrophilic, nucleophilic, and a radical trifluoromethylthiolation reactions. Furthermore, the application of the CF3SSCF3 in a copper-catalyzed cross-coupling with boronic acids is disclosed, showing good to excellent yields of trifluoromethyl-substituted aryl products, including pharmaceutically relevant molecules.