Toxics

Editorial

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3 pages, 197 KiB

Open AccessEditorial

Advanced Studies on Toxic Chemicals: Properties and Characteristics

by Miguel A. Esteso

Toxics 2022, 10(8), 475; https://doi.org/10.3390/toxics10080475 - 15 Aug 2022

Cited by 1 | Viewed by 1293

Abstract

Examining the toxic scope of substances used in daily life (referred to as Contaminants of Emerging Concern (CEC)) in food, medicines, utensils, work and other industries, provides us with interesting information that will help us to prevent and recover from the dangerous organic [...] Read more.

Examining the toxic scope of substances used in daily life (referred to as Contaminants of Emerging Concern (CEC)) in food, medicines, utensils, work and other industries, provides us with interesting information that will help us to prevent and recover from the dangerous organic unbalances that these substances can cause [...] Full article

(This article belongs to the Special Issue Advanced Studies on Toxic Chemicals: Properties and Characteristics)

Research

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11 pages, 2523 KiB

Open AccessArticle

Recognition of Heavy Metals by Using Resorcin[4]arenes Soluble in Water

by Edilma Sanabria, Miguel A. Esteso and Edgar F. Vargas

Toxics 2022, 10(8), 461; https://doi.org/10.3390/toxics10080461 - 9 Aug 2022

Cited by 1 | Viewed by 1621

Abstract

The complexing properties of two water-soluble resorcin[4]arenes (tetrasodium 5,11,17,23-tetrakissulfonatemethylen 2,8,14,20-tetra(butyl)resorcin[4]arene, Na₄BRA, and tetrasodium 5,11,17,23-tetrakissulfonatemethylen-2,8,14,20-tetra(2-(methylthio)ethyl)resorcin[4]arene, Na₄SRA) with polluting heavy metals such as Cu²⁺, Pb²⁺, Cd²⁺ and Hg²⁺ were studied by conductivity, and the findings [...] Read more.

The complexing properties of two water-soluble resorcin[4]arenes (tetrasodium 5,11,17,23-tetrakissulfonatemethylen 2,8,14,20-tetra(butyl)resorcin[4]arene, Na₄BRA, and tetrasodium 5,11,17,23-tetrakissulfonatemethylen-2,8,14,20-tetra(2-(methylthio)ethyl)resorcin[4]arene, Na₄SRA) with polluting heavy metals such as Cu²⁺, Pb²⁺, Cd²⁺ and Hg²⁺ were studied by conductivity, and the findings were confirmed by using other techniques to try to apply this knowledge to removing them. The results indicate that Na₄BRA is able to complex Cu²⁺ in a 1:1 ratio and Pb²⁺ in a 1:2 ratio, while Na₄SRA complexes Hg²⁺ in a 1:1 ratio. On the contrary, no indications have been observed that either of the resorcin[4]arenes studied complexes the Cd²⁺ ions. The results suggest that the bonds established between the sulfur atoms located at the lower edge of the SRA⁴⁻ and the solvent hydrogens could prevent the entry of the guest into the host cavity. However, in the case of Hg²⁺ ions, the entry is favoured by the interactions between the sulfur donor atoms present on the lower edge of Na₄SRA and the Hg²⁺ ions. Therefore, it can be said that Na₄BRA is selective for Cu²⁺ and Pb²⁺ ions and Na₄SRA is selective for Hg²⁺ ions. Full article

(This article belongs to the Special Issue Advanced Studies on Toxic Chemicals: Properties and Characteristics)

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10 pages, 337 KiB

Open AccessFeature PaperArticle

Complexation of 5-Fluorouracil with β-Cyclodextrin and Sodium Dodecyl Sulfate: A Useful Tool for Encapsulating and Removing This Polluting Drug

by Ana M. T. D. P. V. Cabral, Ana C. G. Fernandes, Neuza A. M. Joaquim, Francisco Veiga, Sara P. C. Sofio, Isabel Paiva, Miguel A. Esteso, M. Melia Rodrigo, Artur J. M. Valente and Ana C. F. Ribeiro

Toxics 2022, 10(6), 300; https://doi.org/10.3390/toxics10060300 - 1 Jun 2022

Cited by 3 | Viewed by 1899

Abstract

The formation of complexes of the drug 5-fluorouracil (5-FU) with β-cyclodextrin (β-CD) and sodium dodecyl sulphate (SDS) was studied through experimental measurements of the ternary mutual diffusion coefficients (D₁₁, D₂₂, D₁₂, and D [...] Read more.

The formation of complexes of the drug 5-fluorouracil (5-FU) with β-cyclodextrin (β-CD) and sodium dodecyl sulphate (SDS) was studied through experimental measurements of the ternary mutual diffusion coefficients (D₁₁, D₂₂, D₁₂, and D₂₁) for the systems {5-FU (component 1) + β-CD (component 2) + water} and {5-FU (component 1) + SDS (component 2) + water} at 298.15 K and at concentrations up to 0.05 mol dm⁻³ by using the Taylor dispersion method, with the objective of removing this polluting drug from the residual systems in which it was present. The results found showed that a coupled diffusion of 5-FU occurred with both β-CD and SDS, as indicated by the nonzero values of the cross-diffusion coefficients, D₁₂ and D₂₁, as a consequence of the complex formation between 5-FU and the β-CD or SDS species. That is, 5-FU was solubilized (encapsulated) by both carriers, although to a greater extent with SDS (K = 20.0 (±0.5) mol⁻¹ dm³) than with β-CD (K = 10.0 (±0.5) mol⁻¹ dm³). Values of 0.107 and 0.190 were determined for the maximum fraction of 5-FU solubilized with β-CD and SDS (at concentrations above its CMC), respectively. This meant that SDS was more efficient at encapsulating and thus removing the 5-FU drug. Full article

(This article belongs to the Special Issue Advanced Studies on Toxic Chemicals: Properties and Characteristics)

10 pages, 2289 KiB

Open AccessFeature PaperArticle

Photocatalytic Degradation of Dielectric Mineral Oil with PCBs Content Coupled with Algae Treatment

by Andrés F. Suárez, Carlos E. Camargo, Miguel A. Esteso and Carmen M. Romero

Toxics 2022, 10(5), 209; https://doi.org/10.3390/toxics10050209 - 22 Apr 2022

Cited by 3 | Viewed by 2109

Abstract

Insulating oil contaminated with polychlorinated biphenyls (PCBs) is an environmentally important pollutant. This research focused on the establishment of the optimum conditions under which photocatalytic oxidation can be used together with biotreatment using the Nostoc sp. microorganism to degrade PCBs present in used [...] Read more.

Insulating oil contaminated with polychlorinated biphenyls (PCBs) is an environmentally important pollutant. This research focused on the establishment of the optimum conditions under which photocatalytic oxidation can be used together with biotreatment using the Nostoc sp. microorganism to degrade PCBs present in used dielectric oils. Among the optimal conditions studied were PCB concentration, initial pH, and titanium dioxide (TiO₂) concentration for the photocatalytic step, and PCB concentration and photoperiod for the biotreatment step. The results indicate that the optimal conditions necessary for photocatalytic degradation were a pH of 6.10, 113 mg/L TiO₂, and 765 mg/L PCBs, achieving close to 90% removal. For the biotreatment step, the results showed that PCBs progressively inhibited the microbiological growth, with the lowest cellular growth observed in the medium with the highest PCB concentration. Full article

(This article belongs to the Special Issue Advanced Studies on Toxic Chemicals: Properties and Characteristics)

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12 pages, 2978 KiB

Open AccessArticle

Removal of Toxic Metal Ions Using Poly(BuMA–co–EDMA) Modified with C-Tetra(nonyl)calix[4]resorcinarene

by Alver Castillo-Aguirre, Mauricio Maldonado and Miguel A. Esteso

Toxics 2022, 10(5), 204; https://doi.org/10.3390/toxics10050204 - 20 Apr 2022

Cited by 5 | Viewed by 2033

Abstract

A copolymer of poly(BuMA–co–EDMA) modified with C-tetra(nonyl)calix[4]resorcinarene was obtained via the impregnation method. The formation of the modified copolymer was confirmed and investigated using various techniques; in this way, the presence of calix[4]resorcinarene was confirmed by FT-IR spectroscopy and by [...] Read more.

A copolymer of poly(BuMA–co–EDMA) modified with C-tetra(nonyl)calix[4]resorcinarene was obtained via the impregnation method. The formation of the modified copolymer was confirmed and investigated using various techniques; in this way, the presence of calix[4]resorcinarene was confirmed by FT-IR spectroscopy and by high resolution transmission electron microscopy. The modified copolymer was used for the removal of highly toxic cations (Pb²⁺, Hg²⁺, and Cd²⁺) from aqueous solutions. To perform the removal, we used the batch sorption technique and the effects of time of contact, pH, and volume of sample on the effective sorption were determined. The best results were observed for Pb²⁺ extraction, which was comparatively more efficient. Adsorption–desorption experiments revealed that the modified copolymer could be used for several cycles without significant loss of adsorption capacity. Finally, the results showed that the modified copolymer application is highly efficient for the removal of lead ions from aqueous solutions. Full article

(This article belongs to the Special Issue Advanced Studies on Toxic Chemicals: Properties and Characteristics)

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13 pages, 2204 KiB

Open AccessArticle

Classification of Various Marijuana Varieties by Raman Microscopy and Chemometrics

by Luis Ramos-Guerrero, Gemma Montalvo, Marzia Cosmi, Carmen García-Ruiz and Fernando E. Ortega-Ojeda

Toxics 2022, 10(3), 115; https://doi.org/10.3390/toxics10030115 - 28 Feb 2022

Cited by 14 | Viewed by 4266

Abstract

The Raman analysis of marijuana is challenging because of the sample’s easy photo-degradation caused by the laser intensity. In this study, optimization of collection parameters and laser focusing on marijuana trichome heads allowed collecting Raman spectra without damaging the samples. The Raman spectra [...] Read more.

The Raman analysis of marijuana is challenging because of the sample’s easy photo-degradation caused by the laser intensity. In this study, optimization of collection parameters and laser focusing on marijuana trichome heads allowed collecting Raman spectra without damaging the samples. The Raman spectra of Δ⁹-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN) standard cannabinoids were compared with Raman spectra of five different types of marijuana: four Sativa varieties (Amnesia Haze, Amnesia Hy-Pro, Original Amnesia, and Y Griega) and one Indica variety (Black Domina). The results verified the presence of several common spectral bands that are useful for marijuana characterization. Results were corroborated by the quantum chemical simulated Raman spectra of their acid-form (tetrahydrocannabinol acid (THCA), cannabidiol acid (CBDA)) and decarboxylated cannabinoids (THC, CBD, and CBN). A chemometrics-assisted method based on Raman microscopy and OPLS-DA offered good classification among the different marijuana varieties allowing identification of the most significant spectral bands. Full article

(This article belongs to the Special Issue Advanced Studies on Toxic Chemicals: Properties and Characteristics)

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13 pages, 973 KiB

Open AccessArticle

Screening of a Novel Solvent for Optimum Extraction of Anionic Surfactants in Water

by Jung-Hwan Yoon, Yong Geon Shin, Hyuck Soo Kim, M. B. Kirkham and Jae E. Yang

Toxics 2022, 10(2), 80; https://doi.org/10.3390/toxics10020080 - 8 Feb 2022

Cited by 3 | Viewed by 2811

Abstract

Anionic surfactants (AS) are detrimental aquatic pollutants due to their well-characterized toxicity to aquatic organisms. The concentration of AS in aquatic environments is increasing because of their extensive use in many industries and households. The standard reference method for AS analysis is to [...] Read more.

Anionic surfactants (AS) are detrimental aquatic pollutants due to their well-characterized toxicity to aquatic organisms. The concentration of AS in aquatic environments is increasing because of their extensive use in many industries and households. The standard reference method for AS analysis is to determine a methylene blue active substance (MBAS) complex formed between AS and the methylene blue (MB) cation by using chloroform. However, chloroform has a low AS extraction efficiency and other limiting properties, such as a high density and volatility, which make the conventional AS analytical method time-consuming and labor-intensive. In an effort to replace the use of chloroform, this study was carried out to screen novel solvents for their ability to extract AS in water samples. Criteria were based on AS extraction efficiency, physicochemical properties, and the stability of the solvent under different environmental conditions. Organic solvents, such as methyl isobutyl ketone (MIBK), 1,2-dichloroethane (DCE), dichloromethane, benzene, and n-hexane, were assessed. In extraction of the anionic surfactant sodium dodecyl sulfate (SDS), the mixture of MIBK-DCE (3:1) proved to be an optimum solvent as an alternative to chloroform. It not only enhanced SDS extractability but also improved properties, such as having a lower volatility, a lower density than water, and a quicker phase separation. Among solvents screened, no one single solvent in SDS extraction could meet such criteria. The performance of the MIBK-DCE (3:1) mixture in SDS extraction was stable, irrespective of pH and ionic strength of the SDS solution, washing process, and presence of cations. Anionic interference from halogen and polyatomic and organic anions in SDS extraction by MIBK-DCE (3:1) existed only at an elevated concentration, which is not occurring in the natural aquatic environment. Results demonstrated that a MIBK-DCE (3:1) mixture solvent could be used in AS analysis for a wide range of aquatic samples and it could be the basis for the development of a new analytical method to replace conventional chloroform. Full article

(This article belongs to the Special Issue Advanced Studies on Toxic Chemicals: Properties and Characteristics)

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17 pages, 4623 KiB

Open AccessArticle

Effect of Carbamazepine, Ibuprofen, Triclosan and Sulfamethoxazole on Anaerobic Bioreactor Performance: Combining Cell Damage, Ecotoxicity and Chemical Information

by Mabel Díaz-Cubilla, Pedro Letón, Carlos Luna-Vázquez, Marta Marrón-Romera and Karina Boltes

Toxics 2022, 10(1), 42; https://doi.org/10.3390/toxics10010042 - 17 Jan 2022

Cited by 11 | Viewed by 3653

Abstract

Pharmaceuticals and personal care products (PPCPs) are partially degraded in wastewater treatment plants (WWTPs), thereby leading to the formation of more toxic metabolites. Bacterial populations in bioreactors operated in WWTPs are sensitive to different toxics such as heavy metals and aromatic compounds, but [...] Read more.

Pharmaceuticals and personal care products (PPCPs) are partially degraded in wastewater treatment plants (WWTPs), thereby leading to the formation of more toxic metabolites. Bacterial populations in bioreactors operated in WWTPs are sensitive to different toxics such as heavy metals and aromatic compounds, but there is still little information on the effect that pharmaceuticals exert on their metabolism, especially under anaerobic conditions. This work evaluated the effect of selected pharmaceuticals that remain in solution and attached to biosolids on the metabolism of anaerobic biomass. Batch reactors operated in parallel under the pressure of four individual and mixed PPCPs (carbamazepine, ibuprofen, triclosan and sulfametoxazole) allowed us to obtain relevant information on anaerobic digestion performance, toxicological effects and alterations to key enzymes involved in the biodegradation process. Cell viability was quantitatively evaluated using an automatic analysis of confocal microscopy images, and showed that triclosan and mixed pollutants caused higher toxicity and cell death than the other individual compounds. Both individual pollutants and their mixture had a considerable impact on the anaerobic digestion process, favoring carbon dioxide production, lowering organic matter removal and methane production, which also produced microbial stress and irreversible cell damage. Full article

(This article belongs to the Special Issue Advanced Studies on Toxic Chemicals: Properties and Characteristics)

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17 pages, 2610 KiB

Open AccessArticle

Respiratory Safety Evaluation in Mice and Inhibition of Adenoviral Amplification in Human Bronchial Endothelial Cells Using a Novel Type of Chlorine Dioxide Gas Reactor

by Hae-Sung Yang, Kyeong-Min Kim, Napissara Boonpraman, Sun-Mi Yoon, Jeong-Eun Seo, Min-Woo Park, Jong-Seok Moon, Su-Young Yoo and Sun-Shin Yi

Toxics 2022, 10(1), 38; https://doi.org/10.3390/toxics10010038 - 13 Jan 2022

Cited by 3 | Viewed by 3693

Abstract

Since the onset of the COVID-19 pandemic, there has been a growing demand for effective and safe disinfectants. A novel use of chlorine dioxide (ClO₂) gas, which can satisfy such demand, has been reported. However, its efficacy and safety remain unclear. [...] Read more.

Since the onset of the COVID-19 pandemic, there has been a growing demand for effective and safe disinfectants. A novel use of chlorine dioxide (ClO₂) gas, which can satisfy such demand, has been reported. However, its efficacy and safety remain unclear. For the safe use of this gas, the stable release of specific concentrations is a must. A new type of ClO₂ generator called Dr.CLO^TM has recently been introduced. This study aimed to investigate: (1) the effects of Dr.CLO^TM on inhibiting adenoviral amplification on human bronchial epithelial (HBE) cells; and (2) the acute inhalation safety of using Dr.CLO^TM in animal models. After infecting HBE cells with a recombinant adenovirus, the inhibitory power of Dr.CLO^TM on the virus was expressed as IFU/mL in comparison with the control group. The safety of ClO₂ gas was indirectly predicted using mice by measuring single-dose inhalation toxicity in specially designed chambers. Dr.CLO^TM was found to evaporate in a very constant concentration range at 0–0.011 ppm/m³ for 42 days. In addition, 36–100% of adenoviral amplification was suppressed by Dr.CLO^TM, depending on the conditions. The LC₅₀ of ClO₂ gas to mice was approximately 68 ppm for males and 141 ppm for females. Histopathological evaluation showed that the lungs of female mice were more resistant to the toxicity from higher ClO₂ gas concentrations than those of male mice. Taken together, these results indicate that Dr.CLO^TM can be used to provide a safe indoor environment due to its technology that maintains the stable concentration and release of ClO₂ gas, which could suppress viral amplification and may prevent viral infections. Full article

(This article belongs to the Special Issue Advanced Studies on Toxic Chemicals: Properties and Characteristics)

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11 pages, 3258 KiB

Open AccessArticle

The Research of Toxicity and Sensitization Potential of PEGylated Silver and Gold Nanomaterials

by Dong-Han Lee, Seo-Yoon Choi, Ki-Kyung Jung, Jun-Young Yang, Ja-young Jeong, Jae-Ho Oh, Sung-Hyun Kim and Jin-Hee Lee

Toxics 2021, 9(12), 355; https://doi.org/10.3390/toxics9120355 - 16 Dec 2021

Cited by 5 | Viewed by 2859

Abstract

Polyethylene glycol (PEG) is a polymer used for surface modification of important substances in the modern pharmaceutical industry and biopharmaceutical fields. Despite the many benefits of PEGylation, there is also the possibility that the application and exposure of the substance may cause adverse [...] Read more.

Polyethylene glycol (PEG) is a polymer used for surface modification of important substances in the modern pharmaceutical industry and biopharmaceutical fields. Despite the many benefits of PEGylation, there is also the possibility that the application and exposure of the substance may cause adverse effects in the body, such as an immune response. Therefore, we aimed to evaluate the sensitization responses that could be induced through the intercomparison of nanomaterials of the PEG-coated group with the original group. We selected gold/silver nanomaterials (NMs) for original group and PEGylated silver/gold NMs in this study. First, we measured the physicochemical properties of the four NMs, such as size and zeta potential under various conditions. Additionally, we performed the test of the NM’s sensitization potential using the KeratinoSens™ assay for in vitro test method and the LLNA: 5-bromo-2-deoxyuridine (BrdU)-FCM for in vivo test method. The results showed that PEGylated-NMs did not lead to skin sensitization according to OECD TG 442 (alternative test for skin sensitization). In addition, gold nanomaterial showed that cytotoxicity of PEGylated-AuNMs was lower than AuNMs. These results suggest the possibility that PEG coating does not induce an immune response in the skin tissue and can lower the cytotoxicity of nanomaterials. Full article

(This article belongs to the Special Issue Advanced Studies on Toxic Chemicals: Properties and Characteristics)

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10 pages, 2517 KiB

Open AccessCase Report

Identification of 2C-B in Hair by UHPLC-HRMS/MS. A Real Forensic Case

by José Manuel Matey, Adrián López-Fernández, Carmen García-Ruiz, Gemma Montalvo, Félix Zapata and María A. Martínez

Toxics 2021, 9(7), 170; https://doi.org/10.3390/toxics9070170 - 15 Jul 2021

Cited by 5 | Viewed by 4380

Abstract

The analysis of drugs of abuse in hair and other biological matrices of forensic interest requires great selectivity and sensitivity. This has been traditionally achieved through target analysis, using one or more analytical methods that include different preanalytical stages, and more complex procedures [...] Read more.

The analysis of drugs of abuse in hair and other biological matrices of forensic interest requires great selectivity and sensitivity. This has been traditionally achieved through target analysis, using one or more analytical methods that include different preanalytical stages, and more complex procedures followed by toxicological laboratories. There is no exception with 2C-series drugs, such as 2C-B, a new psychoactive substance (NPS), which use has emerged and significantly increased, year by year, in the last decades. Continuously new analytical methods are required to selectively detect and identify these new marketed substances at very low concentrations. In this case report, one former case of a polydrug consumer (charged of a crime against public health in Spain) was reanalyzed in hair matrix. In this reanalysis, 2C-B has been positively detected and identified using liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS/MS). The most selective analytical UHPLC-HRMS/MS method alongside a universal and simpler pretreatment methodology has opened up more possibilities for the detection of substances of different chemical structure and optimization of different HRMS/MS detection approaches allowing the identification of 2-CB in the hair of a real forensic case. Full article

(This article belongs to the Special Issue Advanced Studies on Toxic Chemicals: Properties and Characteristics)

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