Customer exposure to MTBE, TAME, C6 alkyl methyl ethers, and benzene during gasoline refueling.

We studied customer exposure during refueling by collecting air samples from customers' breathing zone. The measurements were carried out during 4 days in summer 1996 at two Finnish self-service gasoline stations with "stage I" vapor recovery systems. The 95-RON (research octane number) gasoline contained approximately 2.7% methyl tert-butyl ether (MTBE), approximately 8.5% tert-amyl methyl ether (TAME), approximately 3.2% C6 alkyl methyl ethers (C6 AMEs), and 0.75% benzene. The individual exposure concentrations showed a wide log-normal distribution, with low exposures being the most frequent. In over 90% of the samples, the concentration of MTBE was higher (range <0.02-51 mg/m3) than that of TAME. The MTBE values were well below the short-term (15 min) threshold limits set for occupational exposure (250-360 mg/m3). At station A, the geometric mean concentrations in individual samples were 3.9 mg/m3 MTBE and 2. 2 mg/m3 TAME. The corresponding values at station B were 2.4 and 1.7 mg/m3, respectively. The average refueling (sampling) time was 63 sec at station A and 74 sec at station B. No statistically significant difference was observed in customer exposures between the two service stations. The overall geometric means (n = 167) for an adjusted 1-min refueling time were 3.3 mg/m3 MTBE and 1.9 mg/m3 TAME. Each day an integrated breathing zone sample was also collected, corresponding to an arithmetic mean of 20-21 refuelings. The overall arithmetic mean concentrations in the integrated samples (n = 8) were 0.90 mg/m3 for benzene and 0.56 mg/m3 for C6 AMEs calculated as a group. Mean MTBE concentrations in ambient air (a stationary point in the middle of the pump island) were 0.16 mg/m3 for station A and 0.07 mg/m3 for station B. The mean ambient concentrations of TAME, C6 AMEs, and benzene were 0.031 mg/m3, approximately 0.005 mg/m3, and approximately 0.01 mg/m3, respectively, at both stations. The mean wind speed was 1.4 m/sec and mean air temperature was 21 degreesC. Of the gasoline refueled during the study, 75% was 95 grade and 25% was 98/99 grade, with an oxygenate (MTBE) content of 12.2%.     

Gasoline vapor exposures at a high volume service station

Gasoline vapor concentrations were measured at a high volume service station for one week in May, 1983, for service station attendants, self-service customers and for various area locations. To facilitate the retention of highly volatile, low-molecular weight gasoline vapor components, 100/50 mg charcoal adsorption tubes were used with flow rates of 100 cc/min for long-term exposure samples and 900 cc/min for short-term exposures. Methylene chloride was selected as the desorption solvent. Desorbed hydrocarbons were analyzed and quantitated by capillary column gas chromatography using a flame ionization detector and a 0-100 degrees C temperature program. The data proved that the predominant ambient air hydrocarbons are those of C4 and C5 compounds. Monitoring results showed that the total gasoline vapor TWA exposures for service station attendants ranged from 0.6 to 4.8 ppm with a geometric mean of 1.5 ppm. Short-term personal samples collected while refueling ranged from not detectable to 38.8 ppm with a geometric mean of 5.8 ppm.     

Individual and population exposures to gasoline.

Gasoline is a complex mixture of many constituents in varying proportions. Not only does the composition of whole gasoline vary from company to company and season to season, but it changes over time. The composition of gasoline vapors is dominated by volatile compounds, while "gasoline" in groundwater consists mainly of water-soluble constituents. Hydrocarbons, including alkanes, alkenes, and aromatics, make up the large majority of gasoline, but other substances, such as alcohols, ethers, and additives, may also be present. Given this inability to define "gasoline,h' exposures to individual chemicals or groups of chemicals must be defined in a meaningful exposure assessment. An estimated 111 million people are currently exposed to gasoline constituents in the course of refueling at self-service gasoline stations. Refueling requires only a few minutes per week, accruing to about 100 min per year. During that time, concentrations in air of total hydrocarbons typically fall in the range 20-200 parts per million by volume (ppmV). Concentrations of the aromatic compounds benzene, toluene, and xylene rarely exceed 1 ppmV. Some liquid gasoline is also released, generally as drops less than 0.1 g each, but with enough larger spills to raise the average loss per gallon dispensed to 0.23 g for stations with conventional nozzles and 0.14 g per refueling for stations with vapor recovery nozzles (Stage II controls). Some skin exposure may occur from these spills but the exposure has not been quantified. Two major types of vehicular emissions have been studied. Evaporative emissions include emissions while the vehicle is driven (running losses), emissions after the engine has been shut off but is still warm (hot soak), and emissions during other standing periods (diurnal) emissions. These evaporative emissions are dominated by the more volatile gasoline components. Tailpipe emissions include some unreacted gasoline constituents as well as products of combustion (including chemicals identical to some of the original constituents of the gasoline) and a variety of hydrocarbons and related compounds. Running losses are reported to fall in the range of 0.2 to 2.8 g of total hydrocarbons per mile driven, while benzene evaporative emissions range from 0.002 to 0.007 g/mile. Benzene levels inside travelling vehicles have been reported to average about 13 ppbV in Los Angeles. Tailpipe emissions amount to 0.3 to 1.0 g/mile of total hydrocarbons; emissions of benzene, polycylic aromatic hydrocarbons, and 1,3-butadiene have been reported to range from 0.015 to 0.04 g/mile, 0.00025 to 0.00046 g/mile, and 0.001 to 0.005 g/mile, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)     

Evolution of occupational exposure to environmental levels of aromatic hydrocarbons in service stations

During refuelling, people may easily be exposed to extremely high levels of gasoline vapour for a short time, although such exposure takes on more importance in the case of service station attendants. The volume of gasoline sold in refuelling operations and the ambient temperature can significantly increase the environmental level of benzene, toluene and xylene (BTX) vapours and, subsequently, the occupational risk of service station attendants. This is especially true in the case of benzene, the most important component of gasoline vapours from a toxicological point of view. The European Directive 98/70/EC, limiting the benzene composition of gasoline, and 94/63/EC, concerning the use of vapour recovery systems in the delivery of gasoline to services stations, were applied in Spain from January 2000 and 2002, respectively. In addition, a new limit value for occupational exposure of 3.25 mg/m(3) was fixed for benzene in Directive 97/42/EC, applied from June 2003. However, recent years have seen the growing use of diesel as well as of unleaded and reformulated gasoline. In this study, we analyse the differences found between air concentration levels of BTXs in 2000 and 2003, analysing samples taken from the personal breathing-zone of occupationally exposed workers in service stations. The results are compared with those obtained in a similar study carried out in 1995 (before the new regulations came into force). The study was carried out in two phases. The first phase was carried out in 2000, after application of the new legal regulation limiting the benzene concentration in gasoline. In this case, an occupationally exposed population of 28 service station attendants was sampled in July, with a mean ambient temperature of 30-31 degrees C. In the second phase, 19 exposed subjects were sampled in July 2003, one of the warmest months in recent years with mean temperatures of 35-36 degrees C during the time of exposure monitoring. The results were then compared with those obtained in 1995, for similar summer weather conditions (environmental temperature between 28 and 30 degrees C). A significant relationship between the volume of gasoline sold and the ambient concentration of aromatic hydrocarbons was found for each worker sampled in all three of the years. Furthermore, a significant decrease in the environmental levels of BTXs was observed after January 2000, especially in the case of benzene, with mean time-weighted average concentrations for 8 h of 736 microg/m(3) (range 272-1603) in 1995, 241 microg/m(3) (range 115-453) in 2000 and 163 microg/m(3) (range 36-564) in 2003, despite the high temperatures reached in the last mentioned year.     

Tank truck driver exposure to vapors from oxygenated or reformulated gasolines during loading and unloading.

Tank truck drivers' exposure to gasoline vapors was studied by collecting breathing zone samples during loading and unloading of gasoline. The field studies were conducted at three dispatches and at seven service stations in Finland. The gasolines included in the study (95, 98, 99 research octane number, RON) were of reformulated or oxygenated grade containing about 2% (w/w) oxygen and 0.5-1.5% (v/v) benzene. The sampling times ranged from 16 to 57 min (mean 35 min), and time-weighted average concentrations for a 30-min period were calculated. Using the time-adjusted values, geometric mean concentrations (GM) were calculated for three periods of dispatch measurements (n = 15,20,7) and a period of unloading measurements at service stations (n = 7). The GM for methyl tert-butyl ether ranged from 0.95 to 7.3 mg/m3 and that for tert-amyl methyl ether from 0.30 to 1.1 mg/m3. The GM concentrations of hexane, benzene, and toluene were in the range of 0.25-2.3 mg/m3, 0.15-0.28 mg/m3, and 0.73-1.7 mg/m3, respectively. Multiple regression analysis yielded an r2 value of 0.98 for the daily mean concentration of toluene and correspondingly 0.94 for benzene when daily wind speed (0.1-3.7 m/sec) and daily air temperature (-7.4(-)+17.2 degrees C) were used as independent variables. The average number of gasoline loads per tank truck was 2.5, corresponding to 23,000 L of gasoline.     

Service station attendants' exposure to benzene and gasoline vapors.

Service station attendants' exposure to benzene, based on 85 TWA results at 7 stations, were well below 1 ppm except one exposure of 2.08 ppm. Short term exposures were 1.21 ppm or less over 15 minutes. Attendants' TWA exposures to total gasoline vapor were 114 ppm or less, with measured 15 minute exposures no higher than 100 ppm during actual filling operations. One station had vapor recovery nozzles; exposures here were below the detectable level (0.01 ppm benzene) on 10% more days than the next lowest station. Still, the magnitude of overall exposures and the degree of reduction indicate that vapor recovery is not needed to control exposures. Some attendants had consistently higher exposures than others. This is felt to be due to work practices, such as standing close to the fill opening, plus local wind conditions around the car as it is filled with gasoline.     

Exposure to MTBE, TAME and aromatic hydrocarbons during gasoline pump maintenance, repair and inspection

The exposure of gasoline pump repairers and inspectors to gasoline was studied at service stations and repair shops in Finland in April-June 2004. The average air temperature ranged from 7 degrees C to 16 degrees C and wind speed from 2.5 to 7 m/s. The gasoline blends contained mixtures of methyl tert-butyl ether (MTBE) and tert-amyl methyl ether (TAME), the total content of oxygenates being 11-12%. The content of benzene was <1%. Breathing zone air was collected during the work task using passive monitors. The mean sampling period was 4.5 h. The mean TWA-8 h concentrations for MTBE, TAME, hexane, benzene, toluene, ethylbenzene and xylene were 4.5, 1.3, 0.55, 0.23, 2.2, 0.26 and 1.1 mg/m3, respectively. None of the individual benzene concentrations exceeded the binding limit value for benzene (3.25 mg/m3). The sum concentration of MTBE and TAME in urine was between 8.9 and 530 nmol/l in individual post-shift samples. The individual sum concentrations of the metabolites tert-butyl alcohol and tert-amyl alcohol collected the following morning after the exposure ranged from 81 to 916 nmol/l. All individual results were below corresponding biological action levels. Exposure to aromatic hydrocarbons was estimated from post-shift urine samples, with benzene showing the highest concentration (range 4.4 and 35 nmol/l in non-smokers). The exposure levels were similar to those measured in previous studies during unloading of tanker lorries and railway wagons. The results indicated a slightly higher exposure for inspectors, who calibrated fuel pump gauges at the service stations, than for pump repairers. No significant skin exposure occurred during the study.     

Environmental and biological monitoring of benzene during self-service automobile refueling

Although automobile refueling represents the major source of benzene exposure among the nonsmoking public, few data are available regarding such exposures and the associated uptake of benzene. We repeatedly measured benzene exposure and uptake (via benzene in exhaled breath) among 39 self-service customers using self-administered monitoring, a technique rarely used to obtain measurements from the general public (130 sets of measurements were obtained). Benzene exposures averaged 2.9 mg/m(3) (SD = 5.8 mg/m(3); median duration = 3 min) with a range of < 0.076-36 mg/m(3), and postexposure breath levels averaged 160 microg/m(3) (SD = 260 microg/m(3)) with a range of < 3.2-1,400 microg/m(3). Log-transformed exposures and breath levels were significantly correlated (r = 0.77, p < 0.0001). We used mixed-effects statistical models to gauge the relative influences of environmental and subject-specific factors on benzene exposure and breath levels and to investigate the importance of various covariates obtained by questionnaire. Model fitting yielded three significant predictors of benzene exposure, namely, fuel octane grade (p = 0.0011), duration of exposure (p = 0.0054), and season of the year (p = 0.032). Likewise, another model yielded three significant predictors of benzene concentration in breath, specifically, benzene exposure (p = 0.0001), preexposure breath concentration (p = 0.0008), and duration of exposure (p = 0.038). Variability in benzene concentrations was remarkable, with 95% of the estimated values falling within a 274-fold range, and was comprised entirely of the within-person component of variance (representing exposures of the same subject at different times of refueling). The corresponding range for benzene concentrations in breath was 41-fold and was comprised primarily of the within-person variance component (74% of the total variance). Our results indicate that environmental rather than interindividual differences are primarily responsible for benzene exposure and uptake during automobile refueling. The study also demonstrates that self-administered monitoring can be efficiently used to measure environmental exposures and biomarkers among the general public.     

Gasoline vapor exposures. Part I. Characterization of workplace exposures

Monitoring surveys of gasoline vapor exposures were conducted on truck drivers and terminal operators from five terminal loading facilities, on dockmen and seamen at two tanker/barge loading facilities, and on attendants at a single expressway service plaza. Results revealed wide variations in total C6+ hydrocarbon exposures for each location, with overall 8-hr time-weighted averaged (TWA) geometric means of 5.7 mg/m3 (1.4 ppm) for the terminals, and 4.0 mg/m3 (1.0 ppm) for the service plaza, respectively. The exposures ranged from 0.8 to 120.8 mg/m3 (0.2-30.1 ppm) for the terminals, and from 1.1 to 130.3 mg/m3 (0.3-32.5 ppm) for the service plaza. For the terminals, exposures were not significantly different regardless of loading method or the presence or absence of vapor recovery systems. Comprehensive chemical analyses of terminal employee exposure samples revealed that the C4 and C5 hydrocarbon components constituted 74.8 +/- 9.2% of the total exposure sample on a microgram/sample basis. The C6, C7, and C8+ components constituted 13.0 +/- 1.9, 6.2 +/- 3.0, and 5.9 +/- 7.2% of the total samples, respectively. Comprehensive analyses of the marine employee exposure samples resulted in a similar distribution of components; that is, 66.6 +/- 7.9, 17.5 +/- 4.7, 9.2 +/- 3.1, and 6.4 +/- 1.9% for the C4/C5, C6, C7, and C8+ components, respectively. The composition of the exposures, however, was weighted more toward the C5, C6 and C7 components when compared to the bulk terminal employee exposures.(ABSTRACT TRUNCATED AT 250 WORDS)     

Benzene,toluene, ethylbenzene and xylene concentrations in atmospheric ambient air of gasoline and CNG refueling stations

This study aimed to assess workers’ exposure to benzene, toluene, ethylbenzene, and xylene (BTEX) compounds in refueling stations of Ardabil city (Iran). Twenty-four refueling stations including 15 petrol and 9 compressed natural gas (CNG) stations from different regions were selected and monitored for ambient BTEX concentrations. Air samples were taken based on NIOSH Manual of Analytical Method no 1501. Target compounds were extracted using CS₂ and analyzed by GC equipped with FID. Average concentrations of benzene, toluene, ethylbenzene, and xylene were obtained 2.01, 1.80, 2.72, and 1.65 mg/m³, respectively. Benzene concentrations exceeded the occupational exposure limit set by the Iran Ministry of Health and Medical Education. Its concentrations were significantly higher in commercial areas (2.72 mg/m³) compared to suburban areas (1.89 mg/m³). BTEX concentrations in gasoline stations were slightly, but not significantly, higher than those in CNG stations. Long-term exposure cancer risk of 1884?×?10^?6?±?390?×?10^?6 and hazard index of 22.83?±?3.66 were estimated for benzene and BTEX compounds, respectively. The results declare the necessity for controlling BTEX emission (mainly benzene) and monitoring employee’s exposure in refueling stations.     

Exposure of tanker drivers to gasoline and some of its components

The purpose of this study was to measure the exposure of road tanker drivers at work to gasoline and some of its components. The occupational hygiene measurements were made in two depots (one in northern Finland and the other in southern Finland) and in 11 service stations of a Finnish oil company during the loading and delivery of road tankers. Of the 21 measurements made, four were taken during top submerged loading of the road tankers and six during bottom loading at the depot. Eleven measurements were made during delivery at service stations. The duration of measurements varied from 10 to 44 min.The exposure of road tanker drivers to C₃C₁₁ hydrocarbons of gasoline was under 300 mg m⁻³ during bottom loading measurements and during top loading exceeded 300 mg m⁻³ two measurements (50%).During delivery at service stations the exposure to C₃C₁₁ hydrocarbons of gasoline exceeded 300 mg m⁻³ in four measurements (36%). The exposure of road tanker drivers during delivery depended mainly on the distance between working area and the emission point of discharging vapours from the tank, vents and wind direction.The mean exposures of road tanker drivers to benzene during loading and delivery were 1.1–18 mg m⁻³ in various situations. The mean exposures to n-hexane, to toluene and to xylene were 0.7–6.0, 1.4–11 and 0.8–4 mg m⁻³, respectively. The exposures to methyl-tert-butyl ether were between 13 and 91 mg m⁻³. All measurements were made during the summer. However, the temperature varied between 4 and 22 °C.     

High-end exposure relationships of volatile air toxics and carbon monoxide to community-scale air monitoring stations in Atlanta,Chicago, and Houston

Evaporative and exhaust mobile source air toxic (MSAT) emissions of total volatile organic compounds, carbon monoxide, BTEX (benzene, toluene, ethylbenzene, and xylenes), formaldehyde, acetaldehyde, butadiene, methyl tertiary butyl ether, and ethanol were measured in vehicle-related high-end microenvironments (ME) under worst-case conditions plausibly simulating the >99th percentile of inhalation exposure concentrations in Atlanta (baseline gasoline), Chicago (ethanol-oxygenated gasoline), and Houston (methyl tertiary butyl either-oxygenated gasoline) during winter and summer seasons. High-end MSAT values as ratios of the corresponding measurements at nearby air monitoring stations exceeded the microenvironmental proximity factors used in regulatory exposure models, especially for refueling operations and MEs under reduced ventilation. MSAT concentrations were apportioned between exhaust and evaporative vehicle emissions in Houston where methyl tertiary butyl ether could be used as a vehicle emission tracer. With the exception of vehicle refueling operations, the results indicate that evaporative emissions are a minor component of high-end MSAT exposure concentrations.     

Health effects of gasoline refueling vapors and measured exposures at service stations

Liquid gasoline is a complex mixture of at least 150 hydrocarbons with about 60-70% alkanes (paraffins), 25-30% aromatics, and 6-9% alkenes. In order to evaluate the potential for health effects from inhaling gasoline vapors, it is essential to understand the major differences in the composition of vapors versus liquid gasoline. The small chain, low carbon-numbered components are more volatile and thus in higher percentages in the vapor phase than the larger and heavier molecules. It is noteworthy that the concentrations of aromatics (the more toxic of the gasoline components), are depleted to about 2% in the vapor phase, with the light paraffins (the less toxic) enriched to about 90%. Actual measurements of vapor exposure at service stations confirm that the vapor composition is primarily to low weight alkanes although benzene is also emitted and represents the chemical of greatest concern. A perceived health concern from inhaling gasoline vapors is the potential for carcinogenicity based on the induction of kidney tumors in male rats and liver tumors in female mice exposed to wholly-vaporized gasoline. However, the results of the animal studies are of questionable relevance for human risk assessment due to the unique mechanism operative only in the male rat and since the exposure was to wholly-vaporized gasoline rather than the gasoline vapor mixture to which humans are exposed. Recent research supports the hypothesis that branched-chain-alkanes bind to a globulin specific to make rats, alpha 2-u-globulin. The protein complex can not be degraded in the usual manner so that protein accumulation occurs in renal cells, leading to cytotoxicity, death, proliferation, and with prolonged exposure, kidney cancer. The results of epidemiology studies fail to link an increase in cancer to exposure to gasoline vapors.     

The MTBE air concentrations in the cabin of automobiles while fueling.

Methyl tertiary-butyl ether (MTBE) is the most commonly used oxygenated compound added to gasoline to reduce ambient carbon monoxide levels. Complaints about perceived MTBE exposures and adverse health symptoms have been registered in several states, including New Jersey (NJ). Fueling automobiles is the activity thought to cause the highest environmental MTBE exposures. The current study was conducted to determine the MTBE concentrations inside automobile cabins during fueling, which represents the peak exposure that can occur at full service gasoline service stations, such as those that exist in NJ. Air samples were collected at service stations located on the NJ and PA turnpikes from March 1996 to July 1997 during which the MTBE content in gasoline varied. A bimodal distribution of MTBE concentrations was found in the cabin of the cars while fueling. The median MTBE, benzene and toluene in cabin concentrations were 100, 5.5 and 18 ppb, respectively, with the upper concentrations of the distribution exceeding 1 ppm for MTBE and 0.1 ppm for benzene and toluene. The highest in cabin concentrations occurred in a car that had a malfunctioning vapor recovery system and in a series of cars sampled on an unusually warm, calm winter day when the fuel volatility was high, the evaporation maximal and the dispersion by wind minimal. The in-cabin concentrations were typically higher when the car window was opened during the entire fueling process. Thus, exposure to MTBE during fueling can be reduced by properly maintaining the integrity of the fuel system and keeping the windows closed during fueling.     

Environmental exposure to volatile organic compounds among workers in Mexico City as assessed by personal monitors and blood concentrations.

Benzene, an important component in gasoline, is a widely distributed environmental contaminant that has been linked to known health effects in animals and humans, including leukemia. In Mexico City, environmental benzene levels, which may be elevated because of the heavy traffic and the poor emission control devices of older vehicles, may pose a health risk to the population. To assess the potential risk, portable passive monitors and blood concentrations were used to survey three different occupational groups in Mexico City. Passive monitors measured the personal exposure of 45 workers to benzene, ethylbenzene, toluene, o-xylene and m-/p-xylene during a work shift. Blood concentrations of the above volatile organic compounds (VOCs), methyl tert-butyl ether, and styrene were measured at the beginning and the end of a work shift. Passive monitors showed significantly higher (p > 0.0001) benzene exposure levels among service station attendants (median = 330 microg/m3; range 130-770) as compared to street vendors (median = 62 microg/m3; range 49-180) and office workers (median = 44 microg/m3, range 32-67). Baseline blood benzene levels (BBLs) for these groups were higher than those reported for similar populations from Western countries (median = 0.63 microg/L, n = 24 for service station attendants; median = 0.30 microg/L, n = 6 for street vendors; and median = 0.17 microgr;g/L, n = 7 for office workers). Nonsmoking office workers who were nonoccupationally exposed to VOCs had BBLs that were more than five times higher than those observed in a nonsmoking U.S. population. BBLs of participants did not increase during the work shift, suggesting that because the participants were chronically exposed to benzene, complex pharmacokinetic mechanisms were involved. Our results highlight the need for more complete studies to assess the potential benefits of setting environmental standards for benzene and other VOCs in Mexico.     

佛山市加油站员工血铅水平调查

目的调查佛山市加油站员工血铅水平与铅中毒状况。方法采用伏安溶出方法对247例佛山市加油站员工与500例佛山市无职业性铅接触史的健康人员的血标本进行血铅水平检测;采用火焰原子吸收光谱法对5个佛山加油站的30个采样点空气样品以及佛山非加油站区域的100个空气样品进行空气铅尘测定。结果受检测的247例加油站员工的血铅平均值为(0.29±0.06)μmol/L,500例无职业性铅接触史的健康人员血铅平均值为(0.23±0.05)μmol/L,两者差异有统计学意义(P0.01)。其中加油站员工高铅血症率为1.2%(3/247),对照组高铅血症率为0.2%(1/500),两者阳性率差异无统计学意义(P0.05);30个加油站采样点空气中铅尘平均值为(0.0025±0.0006)mg/m3,100个非加油站区域空气中铅尘平均值为(0.0020±0.0006)mg/m3,两者差异有统计学意义(P0.01)。结论佛山市加油站空气中铅、员工血中铅的平均水平均在正常参考值和国家容许标准范围内,证实该市推广无铅汽油,治理铅污染有效。加油站空气中铅和员工血中铅平均水平均显著高于对照,提示应继续做好环境铅污染的治理工作。     

Ulcerative colitis reactivation after mercury vapor inhalation

BACKGROUND: After exposure to mercury vapor at three consecutive 10-month intervals, an electrician in an electroplating plant had flare-ups of ulcerative colitis within 24 hr, that subsided in several days, then returned upon re-exposure 10 months later. METHODS: The patient and his workplace were both evaluated for mercury exposure. In addition to workplace inspection, both personal and area monitoring for environmental mercury was performed, using both multiple mercury diffusion badges and direct (instantaneous) readings, during maintenance of mercury-filled electrical blocks. RESULTS: Eight-hour time weighted average (TWA) mercury vapor exposure was measured at 0.41 mg/m3 (ACGIH and NIOSH recommended TWA = 0.025 mg/m3; OSHA permissible exposure limit -0.1 mg/m3) for 5 years since stopping overexposure to mercury, the patient remained symptom free in clinical remission. CONCLUSIONS: In a patient with chronic ulcerative colitis in remission, occupational exposure to mercury vapor led to episodes of disease reactivation.     

Beurteilung von Innenraumluftkontaminationen mittels Referenz- und Richtwerten

Assessment of indoor air contaminants is recommended to be based on toxicologically derived guideline values (GV, German: Richtwerte, RW) for single substances, TVOC levels, and statistically derived reference values. This recommendation refers to private and public indoor environments and workplaces without production-related handling of hazardous substances. According to the working group's current assessments, the GV I (RW I) is a concentration below which no adverse health effects are to be expected even at life-long exposure to the respective single substance. Concentrations exceeding GV II (RW II) are likely to represent a threat to health, especially for sensitive people. According to a general scheme, guideline values I and II have been derived for - toluene (0.3 and 3 mg/m(3)), - pentachlorophenol (0.1 and 1 microg/m(3)), - dichloromethane (0.2 and 2 mg/m(3)), - styrene (0.03 and 0.3 mg/m(3)), - tris(2-chloroethyl)phosphate (0.005 and 0.05 mg/m(3)), - bicyclic terpenes (0.2 and 2 mg/m(3), - naphthalene (0.002 and 0.02 mg/m(3)), - aliphatic hydrocarbons (0.2 and 2 mg/m(3)). In case of concentrations exceeding GV II, immediate measures are to be taken, among them restrictions of the time spent in the room and measures to remove or reduce emission sources. At levels between GV I and GV II, increased air exchange and cleaning are adequate first steps. However, if concentrations continue to exceed GV I, more intensive measures are recommended. Based on the TVOC concept (cf. Seifert 1990), 5 stages with specific recommendations are defined provided that the special GVs ("Richtwerte") are not exceeded: Level 1: TVOC < 0. 3 mg/m(3): No hygienic objections, target value. Level 2: TVOC > 0.3-1 mg/m(3): No relevant objections, but increased ventilation recommended. Level 3: TVOC > 1-3 mg/m(3): Concerning hygienic aspects, some objections due to elevated concentration level. Upper range for a maximum of 12 months. Search for sources, increased ventilation recommended. Level 4: TVOC > 3-10 mg/m(3): Major objections. Should not be tolerated for > 1 month. Restricted use only. Search for sources, intensified ventilation necessary. Level 5: TVOC > 10-25 mg/m(3): Situation not acceptable. Use only if unavoidable and then for short periods (hours) only with intensified ventilation. An assessment based on reference values does not imply any health risk assessment. It only provides information on exposure relative to the exposure of the reference group. For comparison, regularly updated and representative reference values are recommended. In case of exceeded reference values, plausibility should be checked. Considering concentration and known toxicological data, health relevance should be estimated in order to decide on the necessity of measures to be taken. Since results of indoor air measurements are strongly influenced by sampling strategy, ventilation and climatic factors, recommendations are given in order to standardise sampling procedures and conditions.     

中山市某石油运输服务企业加油站作业工人血常规和血糖调查

目的 了解中山市某石油运输服务企业加油站作业环境的职业病危害以及人员的职业健康状况。
方法 选择中山市某石油运输服务企业18~40岁的在职人员作为研究对象, 以油枪作业岗位315名工人为研究组, 307名非油枪作业岗位人员为对照组; 收集其一般情况和职业史等资料, 以及职业性体检结果进行分析。
结果 该企业加油站存在的化学毒物有苯、甲苯、二甲苯、溶剂汽油和正己烷, 其中加油作业岗位空气中苯、溶剂汽油、甲苯、二甲苯、正己烷的时间加权平均浓度(C_TWA)值分别为(0.25 ±0.03) mg/m3、(76.73 ±7.03) mg/m3、(0.63 ±0.13) mg/m3、(0.26 ±0.04) mg/m3、(1.25 ±0.09) mg/m3, 办公人员岗位空气中苯、溶剂汽油、甲苯、二甲苯、正己烷浓度均未检出。所有检测点空气中苯、溶剂汽油的C_TWA值均未超标。研究组工人的血红蛋白水平低于对照组(P < 0.05), 血红蛋白异常率高于对照组(P < 0.05);研究组工人的血糖浓度和异常率高于对照组(P < 0.05)。
结论 该石油运输服务企业员工职业病防护管理未到位, 工人血糖、血红蛋白浓度异常检出率升高, 长期接触汽油对作业人员健康造成一定损害, 应加强加石油作业工人的职业健康监护。
     

Effects of exposure to vehicle exhaust on health

Exposure to combustion engine exhaust and its effect on crews of roll-on roll-off ships and car ferries and on bus garage staff were studied. The peak concentrations recorded for some of the substances studied were as follows: total particulates (diesel only) 1.0 mg/m3, benzene (diesel) 0.3 mg/m3, formaldehyde (gasoline and diesel) 0.8 mg/m3, and nitrogen dioxide (diesel) 1.2 mg/m3. The highest observed concentration of benzo(a)pyrene was 30 ng/m3 from gasoline and diesel exhaust. In an experimental study volunteers were exposed to diesel exhaust diluted with air to achieve a nitrogen dioxide concentration of 3.8 mg/m3. Pulmonary function was affected during a workday of occupational exposure to engine emissions, but it normalized after a few days with no exposure. The impairment of pulmonary function was judged to have no appreciable, adverse, short-term impact on individual work capacity. In the experimental exposure study, no effect on pulmonary function was observed. Analyses of urinary mutagenicity and thioether excretion showed no sign of exposure to genotoxic compounds among the occupationally exposed workers or among the subjects in the experimental study.