Blood benzene

The identification of benzene is most easily carried out by gas chromatography (83). Gas chromatographic analysis of benzene is the method of choice for determining benzene concentrations in many diverse media such as petroleum products or reformate, water, sod, air, or blood. Benzene in air can be measured by injection of a sample obtained from a syringe directiy into a gas chromatograph (84). 

Indoor and ambient air samples were measured from December 1992 to February 1993 by the Alaska Department of Environmental Conservation (Gordian and Guay 1995). Concentration levels for methyl tertiary butyl ether (MTBE), benzene, and formaldehyde were measured in ambient and indoor air samples. Blood samples were also taken from service station workers at the same time period. Blood samples from workers showed an increase of 300% in blood benzene concentrations after MTBE reformulated fuel was discontinued. Gasoline in Alaska has a benzene concentration of 5% (average U.S. national concentration is 1.5%). 

Benzene was rapidly distributed throughout the bodies of dogs exposed via inhalation to concentrations of 800 ppm for up to 8 hours per day for 8-22 days (Schrenk et al. 1941). Fat, bone marrow, and urine contained about 20 times the concentration of benzene in blood benzene levels in muscles and organs were 1-3 times that in blood and erythrocytes contained about twice the amount of benzene found in plasma. During inhalation exposure of rats to 1,000 ppm (2 hours per/day, for 12 weeks), benzene was stored longer (and eliminated more slowly) in female and male rats with higher body fat content than in leaner animals (Sato et al. 1975). 

Popp et al. (1994) reported a mean blood benzene level in car mechanics of 3.3 pg/L. Urinary muconic acid and S-phenyl-N-acetyl cysteine (PhAC) levels increased during the work shift, and were well correlated with the blood levels and the benzene air levels, which reached a maximum of 13 mg/m3. 

Blood concentrations of benzene following inhalation exposure in mice and rats were adequately predicted. Bone marrow concentrations of benzene following subcutaneous injection in mice and inhalation exposure in rats were accurately predicted, as were blood concentrations of benzene in rats following intraperitoneal injection. For humans, the model slightly overestimated the data for benzene in expired air at the low concentration of 5 ppm. For the mid concentration of 25 ppm, excellent fit was obtained from the model for both benzene in expired air and blood benzene levels. Model agreement for expired benzene was also good at concentrations of 57 and 99 ppm. The model was also accurate in predicting the amount of phenol in the urine after a 5-hour exposure to 31.3 or 47 ppm. 

Following absorption into the blood, benzene is rapidly distributed throughout the body. Since benzene is lipophilic, it is preferentially distributed to lipid-rich tissues. The initial stage of benzene metabolism is the formation of benzene oxide via P-450 mixed-function oxidases. Detoxification pathways generally... 

Brugnone F, Perbellini L, Maranelli G, et al. 1992. Reference values for blood benzene in the occupationally unexposed general population. Int Arch Occup Environ Health 64(3) 179-184. 

Biomarkers of Exposure and Effect. Increased blood and urine lead levels, urinary thioether, urinary phenol, and blood benzene, toluene, pentane, and hexane levels can all be used as biomarkers of... 

Blood (benzene) Collect venous blood HRGC/FID NR... 

The major effect of benzene from long-term (365 days or longer) exposure is on tlie blood. Benzene causes harmful effects on the bone marrow and can cause a decrease in red blood cells leading to anemia. It can also cause excessive bleeding and can affect the immune system, increasing the chance for infection. 

Barbera N et al A fatal case of benzene poisoning. J Forensic Sd 1998 43(6) 1250-1251. [PM ID 9846407] (The postmortem blood benzene level was 31.67 mg/L, and high concentrations were also found in the lungs, liver, kidneys, brain, and heart.)... 

WEL 8-hour TWA Ippm. This excellent solvent is seldom used today because of its toxic effects. It may be inhaled or absorbed via the skin and is readily absorbed by fatty tissues. A large proportion of benzene which enters the body is stored in the bone marrow which may be damaged, causing anaemia or more rarely leukaemia. Benzene is altei chemically in the body and then excreted in the mine. For exposures about the WEL, blood benzene is a useful measmement. For lower exposures, breath benzene is suitable. Urinary excretion as a phenol test is no longer recommended. 

Aplastic anemia and leukemia are not the only health effects ascribed to benzene exposure. A number of recent studies have associated benzene exposure with chromosomal changes (aberrations) (118). Other studies have shown abnormalities in porphyrin metabolism and decrease in leucocyte alkaline phosphatase activity in apparendy healthy workers exposed to 10—20 ppm benzene (119,120). Increases in leukoagglutinins, as well as increases in blood fibrinolytic activity, have also been reported and are believed to be responsible for the persistent hemorrhages in chronic benzene poisoning (121,122). 

Benzene zero 0.005 Anemia decrease in blood platelets increased risk of cancer Discharge from factories leaching from gas storage tanks and landfills... 

Benzene is a flammable liquid and its vapors are toxic and explosive. Low concentrations are dangerous on continued inhalation because benzene affects the blood forming function of the bone marrow and it is a cancirogen. Dermatitis may result from repeated skin contact. Alkyl derivatives such as toluene and xylenes are far less toxic and are, therefore, much safer than benzene for use in solvents. Some of the symptoms of benzene poisoning are dizziness, constriction of the chest, and tightening of the leg muscles. 

Other important determinants of the effects of compounds, especially solvents, are their partition coefficients, e.g., blood-tissue partition coefficients, which determine the distribution of the compound in the body. The air-blood partition coefficient is also important for the absorption of a compound because it determines how quickly the compound can be absorbed from the airspace of the lungs into the circulation. An example of a compound that has a high air-blood partition coefficient is trichloroethane (low blood solubility) whereas most organic solvents (e.g., benzene analogues) have low air-blood partition coefficients (high blood solubility). 

Toxic Effects on the Blood-Forming Tissues Reduced formation of erythrocytes and other elements of blood is an indication of damage to the bone marrow. Chemical compounds toxic to the bone marrow may cause pancytopenia, in which the levels of all elements of blood are reduced. Ionizing radiation, benzene, lindane, chlordane, arsenic, chloramphenicol, trinitrotoluene, gold salts, and phenylbutazone all induce pancytopenia. If the damage to the bone marrow is so severe that the production of blood elements is totally inhibited, the disease state is termed aplastic anemia. In the occupational environment, high concentrations of benzene can cause aplastic anemia. 

The e. posure route partly determines the distribution of the chemical in die body. Like tlie chemical benzene, a single chemical may follow multiple routes of e. posure. The liver, like the skin, acts as a filter. The liver is the primary dcto.xification site. To.xicants that arc absorbed into the lungs, skin, mouth, and esophagus may temporarily bypass the liver however, toxicants absorbed tluougli the stomach and intestines follow the blood s direct path to tlie liver. 

Many valuable compounds are aromatic in part, including steroids such as estrone and well-known pharmaceuticals such as the cholesterol-lowering drug alorvastatin, marketed as Lipitor. Benzene itself has been found to cause bone marrow depression and a consequent lowered white blood ceil count on prolonged exposure. Benzene should therefore be handled cautiously if used as a laboratory solvent. 

Benzene, C6H6, used in the manufacture of plastics, is a carcinogen affecting the bone marrow. Long-term exposure has been shown to cause leukemia and other blood disorders. The combustion of benzene is given by the following equation ... 

At one time, benzene was widely used as a solvent, both commercially and in research and teaching laboratories. Its use for that purpose has largely been abandoned because of its toxicity. Chronic exposure to benzene vapor leads to various blood disorders and, in extreme cases,... 

Ethyl chloroglyoxylate (2-vinylphenyl)hydrazone (14a 0.253 g, 1 mmol) in benzene (10 mL) was treated with Et,N (0.500 g, 5 mmol) in benzene (2mL). The mixture was heated under reflux for 5 h, cooled, diluted with H20 (50 mL) and extracted with henzene. The organic phase was washed with sat. hrine, dried (MgSOt) and evaporated yield 0.197 g (91 %) blood-red crystals mp 107-108X. 

Di- and mono-esters of phthalic acid, an ortho-dicarboxylic acid derivative of benzene. These compounds are widely used as industrial plasticizers to coat polyvinylchloride surfaces of plastics used in food packaging and medical devices (iv drip bags, blood storage bags, etc.) and are common environmental contaminants. Several phthalate mono-esters are peroxisome proliferator chemicals and can activate the peroxisome proliferator-activated receptor PPAR. 

Methyl parathion was determined in dog and human serum using a benzene extraction procedure followed by GC/FID detection (Braeckman et al. 1980, 1983 DePotter et al. 1978). An alkali flame FID (nitrogen-phosphorus) detector increased the specificity of FID for the organophosphorus pesticides. The detection limit was in the low ppb (pg/L). In a comparison of rat blood and brain tissue samples analyzed by both GC/FPD and GC/FID, Gabica et al. (1971) found that GC/FPD provided better specificity. The minimum detectable level for both techniques was 3.0 ppb, but GC/FPD was more selective. The EPA-recommended method for analysis of low levels (<0.1 ppm) of methyl parathion in tissue, blood, and urine is GC/FPD for phosphorus (EPA 1980d). Methyl parathion is not thermally stable above 120 °C (Keith and Walters 1985). 

Blood, tissues Homogenize, if tissue mix sample with acetone centrifuge concentrate saturate with sodium chloride evaporate organic layer cleanup on silica gel eluting with hexane-benzene concentrate GC/FPD <100 ppb No data EPA1980d... 

The dehydrohalogenation reaction has been applied by Goldenson and Sass (32) to the determination of benzene hexachloride in impregnated cloth. Howard (39) proposed the reaction for the determination of benzene hexachloride residues in food, and Barlow (6) used it for benzene hexachloride in the blood of cattle. 

For some important insect pests there are still no satisfactory chemical controls. Such problems should be given due consideration in the development program. Many of these problems appeared to be solved with the discovery of DDT, benzene hexachlo-ride (hexachlorocyclohexane), and some of the more recent insecticides. Further studies of the toxicity of some of these products to warm-blooded animals have raised the important question of the advisability of continuing their use where food and feed products are concerned. Considerable attention is being centered on finding safer analogs, such as TDE and methoxychlor, and new and better insecticides. 

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