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Determinative Techniques to Measure Organics and Inorganics
Published in Paul R. Loconto, Trace Environmental Quantitative Analysis, 2020
Figure 4.11 is an actual GC chromatogram (gas chromatogram) and shows the importance of a properly installed and optimized GC as a determinative technique. This chromatogram, if it were a real contaminated groundwater sample would serve as a good example of enviro-chemical TEQA. A groundwater sample that has been in contact with gasoline, perhaps from a leaking underground storage tank, was placed in a 22 mL headspace vial and sealed. The temperature of the vial was brought to 65°C and kept at that temperature for approximately ½h. The headspace was sampled using a gas-tight syringe and injected into an Autosystem® GC, manufactured by PerkinElmer Corporation. The abbreviation HS-C-GC-FID refers to headspace capillary column-gas chromatograph-flame ionization detection. BTEX refers to benzene, toluene, ethyl benzene, and meta-, para-, and ortho-xylene. Figure 4.12 shows the molecular structures for the five organic compounds that comprise the BTEX mix.
Overview of Gas Plant Processing
Published in Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney, Fundamentals of Natural Gas Processing, 2019
Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney
Raw natural gas can contain compounds in low concentrations that may require removal for environmental, product specification, or processing reasons. Helium is a valuable trace component, but recovery typically is uneconomical unless the concentration is above 0.5 vol%. A brief description of helium recovery processes is given in Chapter 14. The chapter also discusses the removal of other trace components, including BTEX (benzene, toluene, ethylbenzene, and xylenes), methanol, and mercury. BTEX is primarily an environmental concern because of possible emissions from some commonly used gas treating and dehydration units that concentrate them. Although occurring at extremely low concentrations in the gas, elemental mercury can cause mechanical failure in aluminum heat exchangers. Both BTEX and mercury are toxic.
Pollution Sources and Drinking Water Protection
Published in Rong Yue, Fundamentals of Environmental Site Assessment and Remediation, 2018
Some of the treatment options for BTEX-contaminated soils include dig and haul, soil vapor extraction, and bioventing. Excavating contaminated soil from a site for ex-situ treatment is generally very expensive and is a feasible option only when the extent of contamination is very limited. Soil vapor extraction (SVE) is most commonly employed at impacted sites. This involves extracting gasoline vapor from the subsurface via strategically placed extraction wells with a vacuum blower and treating it aboveground either by combusting the vapors in a thermal/catalytic oxidizer or by passing the contaminated vapors through GAC. Bioventing involves injecting oxygen into the unsaturated zone to enhance in-situ biodegradation of the contaminants.
Probabilistic health risk assessment of occupational exposure to BTEX in a paint manufacturing plant using Monte-Carlo simulation
Published in Human and Ecological Risk Assessment: An International Journal, 2023
Maedeh Hosseinzadeh, Rasoul Hemmatjo, Zahra Moutab Sahihazar, Sadjad Galvani, Mohammad Hajaghazadeh
BTEX compounds are commonly used in industry as chemical intermediates, solvents, and adhesives (Davidson et al. 2021).The USEPA classified BTEX compounds as hazardous air pollutants (USEPA 2022a). Benzene is the most toxic member of the BTEX family that, with prolonged exposure, may increase the risk of leukemia and aplastic anemia in humans (Hazrati et al. 2016). Prolonged exposure to toluene and ethylbenzene can have adverse effects on the central nervous system (CNS), leading to brain disorders and eye irritations (Behnami et al. 2023). Xylene exposure can lead to harmful health outcomes such as respiratory tract problems, irritation of the eyes, nose, and throat, and damage to the nervous system (McKenzie et al. 2012). The International Agency for Research on Cancer (IARC) has classified benzene as a human carcinogen in Group 1 and ethylbenzene as known or probable human carcinogens in Group 2 A or 2B (IARC 2018). Therefore, it is crucial to understand the level of BTEX compounds in a workplace and determine their associated health risks.
Low-level occupational exposure to BTEX and dyschromatopsia: a systematic review and meta-analysis
Published in International Journal of Occupational Safety and Ergonomics, 2023
Younes Sohrabi, Fatemeh Rahimian, Esmaeel Soleimani, Soheil Hassanipour
Benzene, toluene, ethylbenzene and xylene (BTEX) are organic compounds. Humans are both occupationally and environmentally exposed to these chemicals and the main route of exposure to them is via inhalation [1–5]. BTEX are toxic chemicals and their effects have been demonstrated in experimental, clinical and epidemiological studies [6]. Short-term exposures to low or moderate concentrations of BTEX may result in transient symptoms of central nervous system (CNS) involvement such as headache and dizziness [7]. On the other hand, long-term exposures may result in deteriorating effects in a broad range from color vision impairments (dyschromatopsia) to chronic toxic encephalopathy [8,9]. Dyschromatopsia induced by neurotoxic chemicals has been considered an early indicator of neurotoxicity [10,11]. Several studies have been performed to investigate the relationship between BTEX exposure and dyschromatopsia [12–20]. Whether this exposure implies dyschromatopsia has been addressed in some cross-sectional [21,22] and cohort [10,20] studies.
Association between BTEX (benzene, toluene, ethylbenzene and xylene) concentration in ambient air with hematological and spirometric indices: a population-based study
Published in Human and Ecological Risk Assessment: An International Journal, 2022
Hosna Moradkhani, Mostafa Leili, Jalal Puralajal, Ashraf Mazaheri Tehrani, Ayat Hossein Panahi, Mohammd Taghi Samadi, Sara Beheshtifar
This study aimed to investigate the relationship between the concentration of BTEX in the open air with blood and spirometry indices. The results showed that participants from the high-pollution area are usually exposed to more concentrations of BTEX than those living in the low-pollution area as they are close to the petrochemical and gas industries. The results of statistical studies showed that none of the blood biomarkers measured in the high and low pollution regions were statistically significant although their mean values were different. But the results of statistical studies on spirometric indicators showed that a significant difference in FEV, FEV1/FVC, FEF25-75 and ElA parameters between high and low pollution areas existed, while difference of FVC and PEF parameters between high and low pollution areas were not statistically significant. Therefore, it is expected that there is an increased risk of respiratory dysfunction in participants who lived in the vicinity of the oil and petrochemical industries. According to the results, among BTEX, benzene concentration in high pollution area is higher than other BTEX in both winter and spring such that its value was higher than the EPA respiratory standard (average concentration of benzene in 6 months of sampling = 30.05 µg/m3; the recommended value by EPA = 0.03 mg/m³). Benzene concentrations are higher in winter than in summer, and photochemical reactions in spring and summer are possible causes due to the sunlight intensity and high temperatures.