-
Regulatory Toxicology and Pharmacology... Jun 2023The Lower Olefins and Aromatics (LOA) REACH Consortium, which includes toluene registrants in the EU, established a Working Group (WG) to conduct a review of the... (Review)
Review
The Lower Olefins and Aromatics (LOA) REACH Consortium, which includes toluene registrants in the EU, established a Working Group (WG) to conduct a review of the occupational exposure limit (OEL) for toluene. The review focussed on CNS and neuro-behavioural toxicity, ototoxicity, effects on colour vision, reproductive and developmental effects, as safety signals for these effects were identified. The WG also examined the need for a skin notation and/or a short-term exposure limit (STEL). The WG critically reviewed and discussed the strengths and weaknesses of the available published information describing the effects of toluene in animals and humans, to assess its adequacy as a potential point of departure for the establishment of an OEL for toluene and to derive an OEL. As a result, the WG recommendation for a toluene OEL is 20 ppm 8-h TWA, with a 15-min STEL of 100 ppm and a skin notation.
Topics: Animals; Humans; Toluene; Occupational Exposure; Threshold Limit Values
PubMed: 37169161
DOI: 10.1016/j.yrtph.2023.105387 -
International Journal of Environmental... Jul 2021Pesticide adjuvants (PAs) denote the general term for auxiliaries in pesticide preparations except for the active components. Toluene, chloroform, and trichloroethylene...
Pesticide adjuvants (PAs) denote the general term for auxiliaries in pesticide preparations except for the active components. Toluene, chloroform, and trichloroethylene are the three most commonly used PAs as organic solvents. The residues of the three chemicals in the process of production and application of pesticides may endanger the ecosystem. In the present study, the mutagenicity of toluene, chloroform, and trichloroethylene as well the mixture of the three chemicals was tested by the reverse mutation test (Ames test) with TA97, TA98, TA100, and TA102 strains in the system with and without rat liver microsomal preparations (S9). The four tester strains have been used for more than 40 years to detect mutagenic compounds in chemicals, cosmetics, and environmental samples. The mutagenicity was detected on tester strains in the separated experiment from the three chemicals. The addition of S9 decreased the mutation ratios of toluene to four strains, except for the TA100 strain, but increased the mutation ratios of chloroform to four strains except for the TA98 strain. Trichloroethylene caused positive mutagenicity to become negative on the TA102 strain. In the mixed experiment, positive effects were detected only on the TA102 strain in the absence of S9. The addition of S9 increased the mutagenicity except for the TA102 strain. The mixture of toluene, chloroform, and trichloroethylene showed antagonism in mutagenicity to tester strains, except for the TA102 strain without S9. However, the mixture showed a synergistic effect to tester strains after adding S9 except for the TA98 strain.
Topics: Animals; Chloroform; Ecosystem; Mutagenicity Tests; Mutagens; Pesticides; Rats; Toluene; Trichloroethylene
PubMed: 34360388
DOI: 10.3390/ijerph18158095 -
British Medical Journal (Clinical... Sep 1981Nineteen children aged 8-14 years were admitted over a six-year period with an acute encephalopathy due to toluene intoxication. Seven had a history of euphoria and...
Nineteen children aged 8-14 years were admitted over a six-year period with an acute encephalopathy due to toluene intoxication. Seven had a history of euphoria and hallucinations. The remainder presented with coma (4), ataxia (3), convulsions (3), and behaviour disturbance with diplopia (2), A history of glue sniffing was elicited in 14, but in the remainder toluene assay confirmed the diagnosis. Thirteen children recovered completely; five still had psychological impairment and personality change on discharge from hospital but were lost to follow-up, and one has a persistent cerebellar ataxia one year after the acute episode, despite absence of further exposure. Toluene inhalation is an important cause of encephalopathy in children and may lead to permanent neurological damage. Diagnosis is most important if further damage due to continued abuse is to be prevented, and toluene assay is a valuable aid to diagnosis.
Topics: Adhesives; Adolescent; Brain Chemistry; Brain Diseases; Child; Female; Humans; Male; Substance-Related Disorders; Toluene
PubMed: 6790121
DOI: 10.1136/bmj.283.6292.663 -
Nature Apr 2016In the classic Diels-Alder [4 + 2] cycloaddition reaction, the overall degree of unsaturation (or oxidation state) of the 4π (diene) and 2π (dienophile) pairs of...
In the classic Diels-Alder [4 + 2] cycloaddition reaction, the overall degree of unsaturation (or oxidation state) of the 4π (diene) and 2π (dienophile) pairs of reactants dictates the oxidation state of the newly formed six-membered carbocycle. For example, in the classic Diels-Alder reaction, butadiene and ethylene combine to produce cyclohexene. More recent developments include variants in which the number of hydrogen atoms in the reactant pair and in the resulting product is reduced by, for example, four in the tetradehydro-Diels-Alder (TDDA) and by six in the hexadehydro-Diels-Alder (HDDA) reactions. Any oxidation state higher than tetradehydro (that is, lacking more than four hydrogens) leads to the production of a reactive intermediate that is more highly oxidized than benzene. This increases the power of the overall process substantially, because trapping of the reactive intermediate can be used to increase the structural complexity of the final product in a controllable and versatile manner. Here we report an unprecedented overall 4π + 2π cycloaddition reaction that generates a different, highly reactive intermediate known as an α,3-dehydrotoluene. This species is in the same oxidation state as a benzyne. Like benzynes, α,3-dehydrotoluenes can be captured by various trapping agents to produce structurally diverse products that are complementary to those arising from the HDDA process. We call this new cycloisomerization process a pentadehydro-Diels-Alder (PDDA) reaction-a nomenclature chosen for chemical taxonomic reasons rather than mechanistic ones. In addition to alkynes, nitriles (RC≡N), although non-participants in aza-HDDA reactions, readily function as the 2π component in PDDA cyclizations to produce, via trapping of the α,3-(5-aza)dehydrotoluene intermediates, pyridine-containing products.
Topics: Benzene; Cyclization; Cycloaddition Reaction; Diynes; Hydrogen; Hydrogenation; Isomerism; Nitriles; Oxidation-Reduction; Pyridines; Terminology as Topic; Toluene
PubMed: 27088605
DOI: 10.1038/nature17429 -
IARC Monographs on the Evaluation of... 2000
Review
Topics: Animals; Carcinogenicity Tests; Carcinogens; Coloring Agents; Disease Models, Animal; Environmental Exposure; Humans; Mice; Neoplasms, Experimental; Rats; Toluene
PubMed: 11100406
DOI: No ID Found -
IARC Monographs on the Evaluation of... 1999
Review
Topics: Animals; Carcinogenicity Tests; Carcinogens; Humans; Mutagenicity Tests; Mutagens; Neoplasms; Neoplasms, Experimental; Occupational Exposure; Toluene
PubMed: 10476474
DOI: No ID Found -
IARC Monographs on the Evaluation of... 1989
Review
Topics: Animals; Carcinogens; Carcinogens, Environmental; Chemical Phenomena; Chemistry; Humans; Risk Factors; Toluene
PubMed: 2699906
DOI: No ID Found -
Chemosphere Sep 2023Aromatic volatile organic compounds (VOCs) are an important precursor of secondary organic aerosol (SOA) in the urban environment. SOA formed from the oxidation of...
Aromatic volatile organic compounds (VOCs) are an important precursor of secondary organic aerosol (SOA) in the urban environment. SOA formed from the oxidation of anthropogenic VOCs can be substantially more abundant than biogenic SOA and has been shown to account for a significant fraction of fine particulate matter in urban areas. A potential aerosol mass (PAM) chamber was used to investigate the oxidised products from the photo-oxidation of m-xylene and toluene. The experiments were carried out with OH radical as oxidant in both high- and low-NO conditions and the resultant aerosol samples were collected using quartz filters and analysed by GC × GC-TOFMS. Results show the oxidation products derived from both precursors included ring-retaining and -opening compounds (unsaturated aldehydes, unsaturated ketones and organic acids) with a high number of ring-opening compounds observed from toluene oxidation. Glyoxal and methyl glyoxal were the major ring-cleavage products from both oxidation systems, indicating that a bicyclic route plays an important role in their formation. SOA yields were higher for both precursors under high-NO (toluene: 0.111; m-xylene: 0.124) than at low-NO (toluene: 0.089; m-xylene: 0.052), likely linked to higher OH concentrations during low-NO experiments which may lead to higher degree of fragmentation. DHOPA (2,3-dihydroxy-4-oxo-pentanoic acid), a known tracer of toluene oxidation, was observed in both oxidation systems. The mass fraction of DHOPA in SOA from toluene oxidation was about double the value reported previously, but it should not be regarded as a tracer solely for oxidation of toluene as m-xylene oxidation gave a similar relative yield.
Topics: Toluene; Xylenes; Particulate Matter; Aerosols; Volatile Organic Compounds; Air Pollutants
PubMed: 37220797
DOI: 10.1016/j.chemosphere.2023.139002 -
Biological Chemistry Feb 2021Plastids are specialized organelles found in plants, which are endowed with their own genomes, and differ in many respects from the intracellular compartments of... (Review)
Review
Plastids are specialized organelles found in plants, which are endowed with their own genomes, and differ in many respects from the intracellular compartments of organisms belonging to other kingdoms of life. They differentiate into diverse, plant organ-specific variants, and are perhaps the most versatile organelles known. Chloroplasts are the green plastids in the leaves and stems of plants, whose primary function is photosynthesis. In response to environmental changes, chloroplasts use several mechanisms to coordinate their photosynthetic activities with nuclear gene expression and other metabolic pathways. Here, we focus on a redox-based regulatory network composed of thioredoxins (TRX) and TRX-like proteins. Among multiple redox-controlled metabolic activities in chloroplasts, tetrapyrrole biosynthesis is particularly rich in TRX-dependent enzymes. This review summarizes the effects of plastid-localized reductants on several enzymes of this pathway, which have been shown to undergo dithiol-disulfide transitions. We describe the impact of TRX-dependent control on the activity, stability and interactions of these enzymes, and assess its contribution to the provision of adequate supplies of metabolic intermediates in the face of diurnal and more rapid and transient changes in light levels and other environmental factors.
Topics: Disulfides; Oxidation-Reduction; Plants; Tetrapyrroles; Thioredoxins; Toluene
PubMed: 33068374
DOI: 10.1515/hsz-2020-0308 -
International Journal of Environmental... Jan 2023The emission inventory, emission factor, and spatial concentration distribution of volatile organic compounds (VOCs) from a petrochemical industry (aromatics plant) were...
The emission inventory, emission factor, and spatial concentration distribution of volatile organic compounds (VOCs) from a petrochemical industry (aromatics plant) were intensively evaluated in this study to elucidate the potential sources of BTX emission and their contribution to ambient concentrations. Five emission groups were quantified through direct measurement and emission models. These data were then used as input for the AERMOD dispersion model for the source apportionment analysis. The source to ambient contribution analysis revealed that a wastewater treatment facility and organic liquid storage tank were major contributors accounting for about 20.6-88.4% and 10.3-75.4% to BTX environmental concentrations, respectively. The highest annual ambient concentrations of benzene (B), toluene (T), and xylenes (X) were predicted as 9.0, 2.8, and 57.9 µg/m at the fence line of the plant boundary, respectively. These findings assist policymakers in prioritizing the appropriate control measures to the right source by considering not just the amount released but also their contribution to ambient concentrations. This study suggested that the wastewater treatment unit should be changed to the closed system which will benefit reduction in its emission (45.05%) as well as effectively minimizing ambient VOC concentration by 49.96% compared to its normal operation.
Topics: Air Pollutants; Environmental Monitoring; Air Pollution; Toluene; Volatile Organic Compounds; China; Ozone
PubMed: 36767648
DOI: 10.3390/ijerph20032280