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Reviews of Environmental Contamination... 1988
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Environmental Health Perspectives Apr 1993Benzene is metabolized, primarily in the liver, to a series of phenolic and ring-opened products and their conjugates. The mechanism of benzene-induced aplastic anemia... (Review)
Review
Benzene is metabolized, primarily in the liver, to a series of phenolic and ring-opened products and their conjugates. The mechanism of benzene-induced aplastic anemia appears to involve the concerted action of several metabolites acting together on early stem and progenitor cells, as well as on early blast cells, such as pronormoblasts and normoblasts to inhibit maturation and amplification. Benzene metabolites also inhibit the function of microenvironmental stromal cells necessary to support the growth of differentiating and maturing marrow cells. The mechanism of benzene-induced leukemogenesis is less well understood. Benzene and its metabolites do not function well as mutagens but are highly clastogenic, producing chromosome aberrations, sister chromatid exchange, and micronuclei. Benzene has been shown to be a multi-organ carcinogen in animals. Epidemiological studies demonstrate that benzene is a human leukemogen. There is need to better define the lower end of the dose-response curve for benzene as a human leukemogen. The application of emerging methods in biologically based risk assessment employing pharmacokinetic and mechanistic data may help to clarify the uncertainties in low-dose risk assessment.
Topics: Animals; Benzene; Chromosome Aberrations; Hematopoiesis; Humans; Mutagens; Neoplasms
PubMed: 8354177
DOI: 10.1289/ehp.93100293 -
Chemico-biological Interactions Mar 2010Benzene has been measured throughout the environment and is commonly emitted in several industrial and transportation settings leading to widespread environmental and... (Review)
Review
Benzene has been measured throughout the environment and is commonly emitted in several industrial and transportation settings leading to widespread environmental and occupational exposures. Inhalation is the most common exposure route but benzene rapidly penetrates the skin and can contaminant water and food resulting in dermal and ingestion exposures. While less toxic solvents have been substituted for benzene, it still is a component of petroleum products, including gasoline, and is a trace impurity in industrial products resulting in continued sub to low ppm occupational exposures, though higher exposures exist in small, uncontrolled workshops in developing countries. Emissions from gasoline/petrochemical industry are its main sources to the ambient air, but a person's total inhalation exposure can be elevated from emissions from cigarettes, consumer products and gasoline powered engines/tools stored in garages attached to homes. Air samples are collected in canisters or on adsorbent with subsequent quantification by gas chromatography. Ambient air concentrations vary from sub-ppb range, low ppb, and tens of ppb in rural/suburban, urban, and source impacted areas, respectively. Short-term environmental exposures of ppm occur during vehicle fueling. Indoor air concentrations of tens of ppb occur in microenvironments containing indoor sources. Occupational and environmental exposures have declined where regulations limit benzene in gasoline (<1%) and cigarette smoking has been banned from public and work places. Similar controls should be implemented worldwide to reduce benzene exposure. Biomarkers of benzene used to estimate exposure and risk include: benzene in breath, blood and urine; its urinary metabolites: phenol, t,t-muconic acid (t,tMA) and S-phenylmercapturic acid (sPMA); and blood protein adducts. The biomarker studies suggest benzene environmental exposures are in the sub to low ppb range though non-benzene sources for urinary metabolites, differences in metabolic rates compared to occupational or animal doses, and the presence of polymorphisms need to be considered when evaluating risks from environmental exposures to individuals or potentially susceptible populations.
Topics: Animals; Benzene; Biomarkers; Environmental Exposure; Humans; Occupational Exposure
PubMed: 20056112
DOI: 10.1016/j.cbi.2009.12.030 -
Human & Experimental Toxicology Sep 2007A large population of humans is exposed to benzene from various occupational and environmental sources. Benzene is an established human and animal carcinogen. Exposure... (Review)
Review
A large population of humans is exposed to benzene from various occupational and environmental sources. Benzene is an established human and animal carcinogen. Exposure to benzene has been associated with leukaemia in humans and several types of malignancies in animals. The exact mechanism of benzene-induced toxicity is poorly understood. It is believed that benzene exerts its adverse effects by metabolic activation to toxic metabolites. Certain benzene metabolites are genotoxic and mutagenic. This consolidated short-review is composed of human and animal studies to summarize the adverse effects of benzene with special reference to molecular mechanisms involved in benzene-induced toxicity.
Topics: Animals; Benzene; Biotransformation; Cell Transformation, Neoplastic; Chromosome Aberrations; DNA; DNA Damage; Environmental Pollutants; Fetus; Humans; Mutagens; Neoplasms; Risk Assessment; Toxicity Tests
PubMed: 17984138
DOI: 10.1177/0960327107083974 -
Journal of Occupational and... Nov 2009A systematic review of the Chinese literature was conducted from 1956 to 2005. The survey included both online and manual searching, as well as expert discussions aimed... (Review)
Review
A systematic review of the Chinese literature was conducted from 1956 to 2005. The survey included both online and manual searching, as well as expert discussions aimed at providing insight into factors affecting benzene exposure levels in paint/coatings industries. Data extracted from 204 papers included: (1) year of occurrence, (2) type of paint/coatings products, (3) type of industries where the products were used or produced, (4) job titles and work activities, (5) type of literature searched, (6) working conditions whenever data were available, and (7) exposure levels. Most benzene measurements were short-term samples for comparison with the Chinese maximum allowable concentration standard. The accuracy and precision of the sampling and analytical methods were not reported. The distribution of benzene concentrations was tested and found to fit neither normal nor lognormal distributions. Analysis of variance (comparison for more than two groups) and t-test (comparison for two groups) were conducted on Blom-transformed benzene concentration data. The overall median benzene exposure levels were 215, 82, 31, and 6 mg/m(3) during the periods 1956-1978, 1979-1989, 1990-2001, and 2002-2005, respectively. Mean benzene exposure was significantly lower for paint manufacturing than paint spraying. No significant difference was found among paint types and benzene exposure for paint application. Benzene exposure was significantly higher in workplaces judged to have poor ventilation. No significant differences were found in benzene exposure as a function of industry type. Even though substantially lower when compared with levels in the past, recent benzene exposure measurements suggested that many facilities in the paint/coatings industries in China still have benzene concentrations that are above the current China occupational exposure limit for benzene (6 mg/m(3) as a time-weighted average). Benzene concentrations from the present exercise, while not directly supporting quantitative retrospective exposure estimating, provide insight on relative benzene exposure for painting tasks in the reported industries over time.
Topics: Benzene; China; Environmental Monitoring; History, 20th Century; History, 21st Century; Humans; Occupational Exposure; Paint; Ventilation
PubMed: 19753498
DOI: 10.1080/15459620903249646 -
Environmental Health Perspectives Dec 1993Acute and chronic exposure to benzene vapors poses a number of health hazards to humans. To evaluate the probability that a specific degree of exposure will produce an... (Comparative Study)
Comparative Study Review
Acute and chronic exposure to benzene vapors poses a number of health hazards to humans. To evaluate the probability that a specific degree of exposure will produce an adverse effect, risk assessment methods must be used. This paper reviews much of the published information and evaluates the various risk assessments for benzene that have been conducted over the past 20 years. There is sufficient evidence that chronic exposure to relatively high concentrations of benzene can produce an increased incidence of acute myelogenous leukemia (AML). Some studies have indicated that benzene may cause other leukemias, but due to the inconsistency of results, the evidence is not conclusive. To predict the leukemogenic risk for humans exposed to much lower doses of benzene than those observed in most epidemiology studies, a model must be used. Although several models could yield plausible results, to date most risk assessments have used the linear-quadratic or conditional logistic models. These appear to be the most appropriate ones for providing the cancer risk for airborne concentrations of 1 ppb to 10 ppm, the range most often observed in the community and workplace. Of the seven major epidemiology studies that have been conducted, there is a consensus that the Pliofilm cohort (rubber workers) is the best one for estimating the cancer potency because it is the only one with good exposure and incidence of disease data. The current EPA, OSHA, and ACGIH cancer potency estimates for benzene are based largely on this cohort. A retrospective exposure assessment and an analysis of the incidence of disease in these workers were completed in 1991. All of these issues are discussed and the implications evaluated in this paper. The range of benzene exposures to which Americans are commonly exposed and the current regulatory criteria are also presented.
Topics: Animals; Benzene; Dose-Response Relationship, Drug; Environmental Pollution; Evaluation Studies as Topic; Female; Forecasting; Humans; Male; Occupational Diseases; Risk Factors
PubMed: 8020442
DOI: 10.1289/ehp.93101s6177 -
Environmental Health Perspectives Dec 1996Benzene toxicity involves both bone marrow depression and leukemogenesis caused by damage to multiple classes of hematopoietic cells and a variety of hematopoietic cell... (Review)
Review
Benzene toxicity involves both bone marrow depression and leukemogenesis caused by damage to multiple classes of hematopoietic cells and a variety of hematopoietic cell functions. Study of the relationship between the metabolism and toxicity of benzene indicates that several metabolites of benzene play significant roles in generating benzene toxicity. Benzene is metabolized, primarily in the liver, to a variety of hydroxylated and ring-opened products that are transported to the bone marrow where subsequent secondary metabolism occurs. Two potential mechanisms by which benzene metabolites may damage cellular macromolecules to induce toxicity include the covalent binding of reactive metabolites of benzene and the capacity of benzene metabolites to induce oxidative damage. Although the relative contributions of each of these mechanisms to toxicity remains unestablished, it is clear that different mechanisms contribute to the toxicities associated with different metabolites. As a corollary, it is unlikely that benzene toxicity can be described as the result of the interaction of a single metabolite with a single biological target. Continued investigation of the metabolism of benzene and its metabolites will allow us to determine the specific combination of metabolites as well as the biological target(s) involved in toxicity and will ultimately lead to our understanding of the relationship between the production of benzene metabolites and bone marrow toxicity.
Topics: Animals; Benzene; Biotransformation; Bone Marrow; DNA Adducts; Humans; In Vitro Techniques; Leukemia; Microsomes, Liver; Molecular Structure; Oxidative Stress
PubMed: 9118888
DOI: 10.1289/ehp.961041165 -
Annual Review of Public Health 2010Benzene is a ubiquitous chemical in our environment that causes acute leukemia and probably other hematological cancers. Evidence for an association with childhood... (Review)
Review
Benzene is a ubiquitous chemical in our environment that causes acute leukemia and probably other hematological cancers. Evidence for an association with childhood leukemia is growing. Exposure to benzene can lead to multiple alterations that contribute to the leukemogenic process, indicating a multimodal mechanism of action. Research is needed to elucidate the different roles of multiple metabolites in benzene toxicity and the pathways that lead to their formation. Studies to date have identified a number of polymorphisms in candidate genes that confer susceptibility to benzene hematotoxicity. However, a genome-wide study is needed to truly assess the role of genetic variation in susceptibility. Benzene affects the blood-forming system at low levels of occupational exposure, and there is no evidence of a threshold. There is probably no safe level of exposure to benzene, and all exposures constitute some risk in a linear, if not supralinear, and additive fashion.
Topics: Benzene; Carcinogens, Environmental; Dose-Response Relationship, Drug; Environmental Exposure; Epidemiologic Studies; Hematologic Neoplasms; Humans; Leukemia, Myeloid, Acute; Receptors, Aryl Hydrocarbon
PubMed: 20070208
DOI: 10.1146/annurev.publhealth.012809.103646 -
Explore (New York, N.Y.) 2023
Topics: Humans; Benzene; Environmental Exposure; Outcome Assessment, Health Care
PubMed: 37291028
DOI: 10.1016/j.explore.2023.05.004 -
Nature Materials Jun 2022In principle, porous physisorbents are attractive candidates for the removal of volatile organic compounds such as benzene by virtue of their low energy for the capture...
In principle, porous physisorbents are attractive candidates for the removal of volatile organic compounds such as benzene by virtue of their low energy for the capture and release of this pollutant. Unfortunately, many physisorbents exhibit weak sorbate-sorbent interactions, resulting in poor selectivity and low uptake when volatile organic compounds are present at trace concentrations. Herein, we report that a family of double-walled metal-dipyrazolate frameworks, BUT-53 to BUT-58, exhibit benzene uptakes at 298 K of 2.47-3.28 mmol g at <10 Pa. Breakthrough experiments revealed that BUT-55, a supramolecular isomer of the metal-organic framework Co(BDP) (HBDP = 1,4-di(1H-pyrazol-4-yl)benzene), captures trace levels of benzene, producing an air stream with benzene content below acceptable limits. Furthermore, BUT-55 can be regenerated with mild heating. Insight into the performance of BUT-55 comes from the crystal structure of the benzene-loaded phase (CH@BUT-55) and density functional theory calculations, which reveal that C-H···X interactions drive the tight binding of benzene. Our results demonstrate that BUT-55 is a recyclable physisorbent that exhibits high affinity and adsorption capacity towards benzene, making it a candidate for environmental remediation of benzene-contaminated gas mixtures.
Topics: Adsorption; Benzene; Gases; Metal-Organic Frameworks; Volatile Organic Compounds
PubMed: 35484330
DOI: 10.1038/s41563-022-01237-x