Use of toxicant sensitivity distributions (TSD) for development of exposure guidelines for risk to human health from benzene.

This technique for setting guideline values differs from that currently used by regulatory agencies throughout the world. Data for benzene were evaluated from epidemiological studies on human populations (29 studies). Exposure durations were evaluated in terms of Long Term Exposure (LTE) and Lifetime Exposure. All data was reported as Lowest Observed Adverse Effect Levels (LOAEL) and converted into exposure doses using Average Daily Dose (ADD) and Lifetime Average Daily Dose (LADD). These values were plotted as a Toxicant Sensitivity Distribution (TSD) which was the cumulative probability of LOAEL-ADD and LOAEL-LADD. From the TSD plots, linear regression equations gave correlation coefficients (R2) ranging from 0.69 to 0.97 indicating normal distributions. Guideline Values (GVs) for LTE (8hr/day) and Lifetime (24hr/70yrs) exposure to benzene were calculated using data from human epidemiological studies as 5% level of cumulative probability (CP) of LOAEL-ADD and LOAEL-LADD from the cumulative probability distributions (CPD). The derived guideline values from the human epidemiological studies were 92 µg/kg/day for LTE and 3.4 µg/kg/day for lifetime exposure. GV for LTE is appropriate for occupational exposure and GV derived for lifetime exposure appropriate for the general population. The guideline value for occupational exposure limit was below all the guideline values developed by regulatory agencies. But the general population guideline is within the range of values formulated by European Union, ATSDR, EPAQS, USEPA and OEHHA for air quality for the general population. This is an alternative method which eliminates the application of safety factors and other sources of errors in deriving guideline values for benzene.

A informação como recurso estratégico de prevenção em saúde do trabalhador e uma análise do Cerest de Marília no estado de São Paulo / La información como recurso estratégico de prevención en salud del trabajador y un análisis del Cerest de Marília en el estado de São Paulo / The information as a strategic resource for prevention in worker's health and an analysis of Cerest de Marília city in São Paulo state

Objetivo: o presente artigo tem como objetivo relatar a experiência do Centro de Referência em Saúde do Trabalhador (Cerest), regional da cidade de Marília, no estado de São Paulo, como mediador informacional no âmbito da saúde do trabalhador, mais especificamente na campanha Não passe do limite! Abasteça só até o automático!, proposta do Governo do Estado de São Paulo. Métodos: durante a realização da campanha, foi efetuada a mediação de informações laborais voltadas para a saúde dos trabalhadores dos postos de combustível e por meio desta ação levantaram-se os hábitos ocupacionais que fundamentassem a orientação aos profissionais em futuras ações preventivas no contexto da saúde dos trabalhadores. Resultados: com o processo de mediação da informação alinhado à observação do processo laboral dos sujeitos que atuam nos postos de combustíveis foi possível caracterizar os riscos causados pelo benzeno à saúde desses trabalhadores diante das atividades desenvolvidas. Os resultados obtidos até o momento foram analisados à luz da literatura disponível que versa sobre saúde do trabalhador, mediação da informação e os riscos do benzeno. O processo de mediação informacional realizada por meio da execução da campanha, possibilitou além da orientação adequada sobre hábitos ocupacionais dos trabalhadores de postos de combustíveis, um maior conhecimento sobre a realidade apresentada pelas organizações e os sujeitos que as compõem. Como resultado de todo esse processo, o município de Marília, São Paulo, criou uma lei municipal com vistas à prevenção e controle da exposição dos trabalhadores dos postos de combustível ao risco químico do benzeno. Conclusão: esse resultado demonstra que por meio da mediação da informação é possível desenvolver estratégias para a captura de novas informações e com isso, desenvolver ações que extrapolam as atividades de trabalho; afinal, graças ao processo de mediação informacional foi possível a ...(AU)

Objetivo: el presente artículo tiene como objetivo relatar la experiencia del Centro de Referencia en Salud del Trabajador, regional de la ciudad de Marília, en el estado de São Paulo, como mediador informativo en el ámbito de la salud del trabajador, más específicamente en la campaña ¡No pase del límite! ¡Abastezca solo hasta el automático!, propuesta por el Gobierno del estado de São Paulo. Métodos: durante la realización de la campaña se efectuó la mediación de informaciones laborales dirigidas a la salud de los trabajadores de los puestos de combustible y por medio de esta acción se levantaron los hábitos ocupacionales que fundamentaran la orientación a los profesionales en futuras acciones preventivas en el contexto de la salud de los trabajadores. Con el proceso de mediación de la información, junto a la observación del proceso laboral de los sujetos que actuaban en los puestos de combustibles, fue posible caracterizar los riesgos causados por el benceno a la salud de esos trabajadores ante las actividades desarrolladas. Los resultados obtenidos hasta el momento fueron analizados a la luz de la literatura disponible que versa sobre la salud del trabajador, la mediación de la información y los riesgos del benceno. Resultados: el proceso de mediación informacional realizado por medio de la ejecución de la campaña posibilitó, además de la orientación adecuada sobre hábitos ocupacionales de los trabajadores de puestos de combustibles, un mayor conocimiento sobre la realidad presentada por las organizaciones y los sujetos que las componen. Como resultado de todo ese proceso, el município de Marília, São Paulo, creó una ley municipal con vistas a la prevención y control de la exposición de los trabajadores de los puestos de combustible al riesgo químico del benzeno. Conclusión: este resultado demuestra que a través de la mediación informacional se pueden poner en práctica estrategias para el mejor desarrollo de las actividades laborales. Gracias al proceso...(AU)

Objective: this article describes the experience of the Reference Center in Worker Health, regional of Marília city, in the state of São Paulo, as an informative mediator in the field of worker's health, more specifically in the campaign Do not pass of the limit! Supply only up to automatic!, a proposal from the Government of the State of São Paulo. Methods: during the campaign mediation a labor information was carried out, aimed at the health of the workers of the fuel stations, and through this action the occupational habits were lifted that will base the orientation to the professionals in future preventive actions in the context of workers' health. With the mediation process of the information aligned to the observation of the labor process of the subjects that act in the fuel stations, it was possible to characterize the risks caused by benzene to the health of these workers before the activities developed. The results obtained so far were analyzed in the light of the available literature that deals with worker health, mediation of information and risks of benzene. as a result of all this process, the municipality of Marília created a municipal law with a view to the prevention and control of the exposure of the workers of the fuel stations to the chemical risk of benzene. Results: the informational mediation process carried out through the execution of the campaign made possible, in addition to the adequate guidance on occupational habits of fuel station workers, a greater knowledge about the reality presented by the organizations and the subjects that compose them. Conclusions: this result shows that through the informational mediation some strategies were put into practice for the best development of work activities. With the informational mediation process the construction of legal mechanisms was possible, able to provide security to the workers of jobs combustile, customers and environment(AU)

A informação como recurso estratégico de prevenção em saúde do trabalhador e uma análise do Cerest de Marília no estado de São Paulo / La información como recurso estratégico de prevención en salud del trabajador y un análisis del Cerest de Marília en el estado de São Paulo / The information as a strategic resource for prevention in worker's health and an analysis of Cerest de Marília city in São Paulo state

Objetivo: o presente artigo tem como objetivo relatar a experiência do Centro de Referência em Saúde do Trabalhador (Cerest), regional da cidade de Marília, no estado de São Paulo, como mediador informacional no âmbito da saúde do trabalhador, mais especificamente na campanha Não passe do limite! Abasteça só até o automático!, proposta do Governo do Estado de São Paulo. Métodos: durante a realização da campanha, foi efetuada a mediação de informações laborais voltadas para a saúde dos trabalhadores dos postos de combustível e por meio desta ação levantaram-se os hábitos ocupacionais que fundamentassem a orientação aos profissionais em futuras ações preventivas no contexto da saúde dos trabalhadores. Resultados: com o processo de mediação da informação alinhado à observação do processo laboral dos sujeitos que atuam nos postos de combustíveis foi possível caracterizar os riscos causados pelo benzeno à saúde desses trabalhadores diante das atividades desenvolvidas. Os resultados obtidos até o momento foram analisados à luz da literatura disponível que versa sobre saúde do trabalhador, mediação da informação e os riscos do benzeno. O processo de mediação informacional realizada por meio da execução da campanha, possibilitou além da orientação adequada sobre hábitos ocupacionais dos trabalhadores de postos de combustíveis, um maior conhecimento sobre a realidade apresentada pelas organizações e os sujeitos que as compõem. Como resultado de todo esse processo, o município de Marília, São Paulo, criou uma lei municipal com vistas à prevenção e controle da exposição dos trabalhadores dos postos de combustível ao risco químico do benzeno. Conclusão: esse resultado demonstra que por meio da mediação da informação é possível desenvolver estratégias para a captura de novas informações e com isso, desenvolver ações que extrapolam as atividades de trabalho; afinal, graças ao processo de mediação informacional foi possível a construção de mecanismos legais capazes de proporcionar uma maior segurança aos trabalhadores dos postos de combustível, clientes e meio ambiente(AU)

Objetivo: el presente artículo tiene como objetivo relatar la experiencia del Centro de Referencia en Salud del Trabajador, regional de la ciudad de Marília, en el estado de São Paulo, como mediador informativo en el ámbito de la salud del trabajador, más específicamente en la campaña ¡No pase del límite! ¡Abastezca solo hasta el automático!, propuesta por el Gobierno del estado de São Paulo. Métodos: durante la realización de la campaña se efectuó la mediación de informaciones laborales dirigidas a la salud de los trabajadores de los puestos de combustible y por medio de esta acción se levantaron los hábitos ocupacionales que fundamentaran la orientación a los profesionales en futuras acciones preventivas en el contexto de la salud de los trabajadores. Con el proceso de mediación de la información, junto a la observación del proceso laboral de los sujetos que actuaban en los puestos de combustibles, fue posible caracterizar los riesgos causados por el benceno a la salud de esos trabajadores ante las actividades desarrolladas. Los resultados obtenidos hasta el momento fueron analizados a la luz de la literatura disponible que versa sobre la salud del trabajador, la mediación de la información y los riesgos del benceno. Resultados: el proceso de mediación informacional realizado por medio de la ejecución de la campaña posibilitó, además de la orientación adecuada sobre hábitos ocupacionales de los trabajadores de puestos de combustibles, un mayor conocimiento sobre la realidad presentada por las organizaciones y los sujetos que las componen. Como resultado de todo ese proceso, el município de Marília, São Paulo, creó una ley municipal con vistas a la prevención y control de la exposición de los trabajadores de los puestos de combustible al riesgo químico del benzeno. Conclusión: este resultado demuestra que a través de la mediación informacional se pueden poner en práctica estrategias para el mejor desarrollo de las actividades laborales. Gracias al proceso de mediación informacional fue posible la construcción de mecanismos legales capaces de proporcionar una mayor seguridad a los trabajadores de los puestos de combustile, clientes y medio ambiente(AU)

Objective: this article describes the experience of the Reference Center in Worker Health, regional of Marília city, in the state of São Paulo, as an informative mediator in the field of worker's health, more specifically in the campaign Do not pass of the limit! Supply only up to automatic!, a proposal from the Government of the State of São Paulo. Methods: during the campaign mediation a labor information was carried out, aimed at the health of the workers of the fuel stations, and through this action the occupational habits were lifted that will base the orientation to the professionals in future preventive actions in the context of workers' health. With the mediation process of the information aligned to the observation of the labor process of the subjects that act in the fuel stations, it was possible to characterize the risks caused by benzene to the health of these workers before the activities developed. The results obtained so far were analyzed in the light of the available literature that deals with worker health, mediation of information and risks of benzene. as a result of all this process, the municipality of Marília created a municipal law with a view to the prevention and control of the exposure of the workers of the fuel stations to the chemical risk of benzene. Results: the informational mediation process carried out through the execution of the campaign made possible, in addition to the adequate guidance on occupational habits of fuel station workers, a greater knowledge about the reality presented by the organizations and the subjects that compose them. Conclusions: this result shows that through the informational mediation some strategies were put into practice for the best development of work activities. With the informational mediation process the construction of legal mechanisms was possible, able to provide security to the workers of jobs combustile, customers and environment(AU)

Ambient air concentrations exceeded health-based standards for fine particulate matter and benzene during the Deepwater Horizon oil spill.

UNLABELLED: The Deepwater Horizon oil spill is considered one of the largest marine oil spills in the history of the United States. Air emissions associated with the oil spill caused concern among residents of Southeast Louisiana. The purpose of this study was to assess ambient concentrations of benzene (n=3,887) and fine particulate matter (n=102,682) during the oil spill and to evaluate potential exposure disparities in the region. Benzene and fine particulate matter (PM2.5) concentrations in the targeted parishes were generally higher following the oil spill, as expected. Benzene concentrations reached 2 to 19 times higher than background, and daily exceedances of PM2.5 were 10 to 45 times higher than background. Both benzene and PM2.5 concentrations were considered high enough to exceed public health criteria, with measurable exposure disparities in the coastal areas closer to the spill and clean-up activities. These findings raise questions about public disclosure of environmental health risks associated with the oil spill. The findings also provide a science-based rationale for establishing health-based action levels in future disasters. IMPLICATIONS: Benzene and particulate matter monitoring during the Deepwater Horizon oil spill revealed that ambient air quality was a likely threat to public health and that residents in coastal Louisiana experienced significantly greater exposures than urban residents. Threshold air pollution levels established for the oil spill apparently were not used as a basis for informing the public about these potential health impacts. Also, despite carrying out the most comprehensive air monitoring ever conducted in the region, none of the agencies involved provided integrated analysis of the data or conclusive statements about public health risk. Better information about real-time risk is needed in future environmental disasters.

Occupational exposure to benzene and chromosomal structural aberrations in the sperm of Chinese men.

BACKGROUND: Benzene is an industrial chemical that causes blood disorders, including acute myeloid leukemia. We previously reported that occupational exposures near the U.S. Occupational Safety and Health Administration permissible exposure limit (8 hr) of 1 ppm was associated with sperm aneuploidy. OBJECTIVE: We investigated whether occupational exposures near 1 ppm increase the incidence of sperm carrying structural chromosomal aberrations. METHODS: We applied a sperm fluorescence in situ hybridization assay to measure frequencies of sperm carrying partial chromosomal duplications or deletions of 1cen or 1p36.3 or breaks within 1cen-1q12 among 30 benzene-exposed and 11 unexposed workers in Tianjin, China, as part of the China Benzene and Sperm Study (C-BASS). Exposed workers were categorized into low-, moderate-, and high-exposure groups based on urinary benzene (medians: 2.9, 11.0, and 110.6 µg/L, respectively). Median air benzene concentrations in the three exposure groups were 1.2, 3.7, and 8.4 ppm, respectively. RESULTS: Adjusted incidence rate ratios (IRRs) and 95% confidence intervals (CIs) for all structural aberrations combined were 1.42 (95% CI: 1.10, 1.83), 1.44 (95% CI: 1.12, 1.85), and 1.75 (95% CI: 1.36, 2.24) and for deletion of 1p36.3 alone were 4.31 (95% CI: 1.18, 15.78), 6.02 (95% CI: 1.69, 21.39), and 7.88 (95% CI: 2.21, 28.05) for men with low, moderate, and high exposure, respectively, compared with unexposed men. Chromosome breaks were significantly increased in the high-exposure group [IRR 1.49 (95% CI: 1.10, 2.02)]. CONCLUSIONS: Occupational exposures to benzene were associated with increased incidence of chromosomally defective sperm, raising concerns for worker infertility and spontaneous abortions as well as mental retardation and inherited defects in their children. Our sperm findings point to benzene as a possible risk factor for de novo 1p36 deletion syndrome. Because chromosomal aberrations in sperm can arise from defective stem cells/spermatogonia, our findings raise concerns that occupational exposure to benzene may have persistent reproductive effects in formerly exposed workers.

Biomonitoring Equivalents for benzene.

Biomonitoring Equivalents (BEs) are defined as the concentration or range of concentrations of a chemical or its metabolite in a biological medium (blood, urine, or other medium) that is consistent with an existing health-based exposure guideline such as a reference dose (RfD) or tolerable daily intake (TDI). BE values can be used as a screening tool for the evaluation of population-based biomonitoring data in the context of existing risk assessments. This study reviews available health based risk assessments and exposure guidance values for benzene from the United States Environmental Protection Agency (US EPA), Texas Commission on Environmental Quality (TCEQ), California's Office of Environmental Health Hazard Assessment (OEHHA) and the Agency for Toxic Substances and Disease Registry (ATSDR) to derive BE values for benzene in blood and urine. No BE values were derived for any of the numerous benzene metabolites or hemoglobin and albumin adducts. Using existing physiologically based pharmacokinetic (PBPK) models, government risk assessment values were translated into corresponding benzene levels in blood assuming chronic steady-state exposures. BEs for benzene in urine were derived using measured correlations between benzene in urine with benzene in blood. The BE values for benzene in blood range from 0.04 to 1.29 µg/L, depending upon the underlying non-cancer risk assessment used in deriving the BE. Sources of uncertainty relating to both the basis for the BE values and their use in evaluation of biomonitoring data, including the transience of the biomarkers relative to exposure frequency, are discussed. The BE values derived here can be used as screening tools for evaluation of population biomonitoring data for benzene in the context of the existing risk assessment and can assist in prioritization of the potential need for additional risk assessment efforts for benzene relative to other chemicals.

Assessing the impact of the duration and intensity of inhalation exposure on the magnitude of the variability of internal dose metrics in children and adults.

The objective of this study was to assess the impact of the exposure duration and intensity on the human kinetic adjustment factor (HKAF). A physiologically based pharmacokinetic model was used to compute target dose metrics (i.e. maximum blood concentration (C(max)) and amount metabolized/L liver/24 h (Amet)) in adults, neonates (0-30 days), toddlers (1-3 years), and pregnant women following inhalation exposure to benzene, styrene, 1,1,1-trichloroethane and 1,4-dioxane. Exposure scenarios simulated involved various concentrations based on the chemical's reference concentration (low) and six of U.S. EPA's Acute Exposure Guideline Levels (AEGLs) (high), for durations of 10 min, 60 min, 8 h, and 24 h, as well as at steady-state. Distributions for body weight (BW), height (H), and hepatic CYP2E1 content were obtained from the literature or from P3M software, whereas blood flows and tissue volumes were calculated from BW and H. The HKAF was computed based on distributions of dose metrics obtained by Monte Carlo simulations [95th percentile in each subpopulation/median in adults]. At low levels of exposure, ranges of C(max)-based HKAF were 1-6.8 depending on the chemical, with 1,4-dioxane exhibiting the greatest values. At high levels of exposure, this range was 1.1-5.2, with styrene exhibiting the greatest value. Neonates were always the most sensitive subpopulation based on C(max), and pregnant women were most sensitive based on Amet in the majority of the cases (1.3-2.1). These results have shown that the chemical-specific HKAF varies as a function of exposure duration and intensity of inhalation exposures, and sometimes exceeds the default value used in risk assessments.

Benzene and human health: A historical review and appraisal of associations with various diseases.

Over the last century, benzene has been a well-studied chemical, with some acute and chronic exposures being directly associated with observed hematologic effects in humans and animals. Chronic heavy exposures to benzene have also been associated with acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) in humans. Other disease processes have also been studied, but have generally not been supported by epidemiologic studies of workers using benzene in the workplace. Within occupational cohorts with large populations and very low airborne benzene exposures (less than 0.1­1.0 ppm), it can be difficult to separate background disease incidence from those occurring due to occupational exposures. In the last few decades, some scientists and physicians have suggested that chronic exposures to various airborne concentrations of benzene may increase the risk of developing non-Hodgkin's lymphoma (NHL) (Savitz and Andrews, 1997, Am J Ind Med 31:287­295; Smith et al., 2007, Cancer Epidemiol Biomarkers Prev 16:385­391), multiple myeloma (MM) (Goldstein, 1990, Ann NY Acad Sci 609:225­230; Infante, 2006, Ann NY Acad Sci 1076:90­109), and various other hematopoietic disorders. We present a state-of-the-science review of the medical and regulatory aspects regarding the hazards of occupational exposure to benzene. We also review the available scientific and medical evidence relating to benzene and the risk of developing various disorders following specific levels of exposure. Our evaluation indicates that the only malignant hematopoietic disease that has been clearly linked to benzene exposure is AML. Information from the recent "Benzene 2009," a symposium of international experts focusing on the health effects and mechanisms of toxicity of benzene, hosted by the Technical University of Munich, has been incorporated and referenced.

Solid phase microextraction as a short-term sampling technique for BTEX occupational exposure.

Solid phase microextraction (SPME) has been widely used for many years in various applications, such as environmental and water samples, food and fragrance analysis, or biological fluids. The aim of this study was to suggest the SPME method as an alternative to conventional techniques used in the evaluation of worker exposure to benzene, toluene, ethylbenzene, and xylene (BTEX). Polymethylsiloxane-carboxen (PDMS/CAR) showed as the most effective stationary phase material for sorbing BTEX among other materials (polyacrylate, PDMS, PDMS/divinylbenzene, Carbowax/divinylbenzene). Various experimental conditions were studied to apply SPME to BTEX quantitation in field situations. The uptake rate of the selected fiber (75 microm PDMS/CAR) was determined for each analyte at various concentrations, relative humidities, and airflow velocities from static (calm air) to dynamic (> 200 cm/s) conditions. The SPME method also was compared with the National Institute of Occupational Safety and Health method 1501. Unlike the latter, the SPME approach fulfills the new requirement for the threshold limit value-short term exposure limit (TLV-STEL) of 2.5 ppm for benzene (8 mg/m(3)).

Potential uses of petrochemical products can result in significant benzene exposures: MSDSs must list benzene as an ingredient.

According to 29 CFR1910.1200 (Hazard Communication Standard [HCS]), a material safety data sheet (MSDS) must list a carcinogen as an ingredient if its concentration in a product is 0.1% or more by weight. However, according to the HCS, when the concentration of a carcinogen in a product is less than 0.1% (by weight) it may not be necessary to list it as an ingredient on the MSDS. The standard stipulates that if potential uses of the product can result in exposures to the carcinogen that exceed the Occupational Safety and Health Administration (OSHA) permissible exposure limit or the ACGIH threshold limit value (TLV), then it must be listed. This article focuses on the failure of MSDSs to report benzene as a listed ingredient in products that incorporate petroleum-derived ingredients such as toluene and hexane. In the United States, approximately 238,000 people are occupationally exposed to benzene each year. Only rarely is benzene listed as an ingredient on MSDSs even though it often comprises more than 0.1% of petroleum solvents and, when its concentrations in petroleum-derived products are much less than 0.1%, inhalation exposures to benzene can be much higher that its OSHA PEL of one part per million (ppm) by volume (v/v) andACGIH TLV of/one-half ppm (v/v). As a consequence of benzene's omission from MSDSs as a listed ingredient, employers are frequently unaware of their requirement to implement 29 CFR 1910.1028 (Benzene Standard) and of the need to address employee exposures to benzene in the workplace. This article demonstrates that benzene should be listed as an ingredient on MSDSs, even at concentrations in benzene-containing products that are between one and two orders of magnitude below OSHA's 0.1% threshold. An exposure assessment methodology is presented that is applicable to employees whose conditions of exposure are similar to those in the published study. These workers make up a similar exposure group. The information and methodology presented here are germane to preparation of accurate MSDSs for benzene-containing products, employers who must comply with 29 CFR 1910.1028, and retrospectively estimating exposures to benzene.

[Effects of the accuracy of reference data on NIR prediction results].

Reference data are indispensable to build near-infrared spectroscopy (NIR)calibration models. In the present paper, the effects of the accuracy of reference data on NIR calibration models and its prediction results were studied through two routine applications based on partial least square regression methods. The results indicate that the best NIR calibration statistics and the most accurate prediction results were aligned with the most accurate reference data. However, based on statistical analysis of numerous calibration samples, it is possible for NIR calibration models to obtain more accurate prediction results than the laboratory reference data used in the calibration sets. It is better to make less search for high accurate reference data and instead to introduce more calibration samples to improve the ruggedness of the calibration models.

An overview of occupational benzene exposures and occupational exposure limits in Europe and North America.

Benzene has become one of the most intensely regulated substances in the world. Its ubiquitous use as a solvent has led to many working populations being exposed; in the early days often in uncontrolled conditions, leading to high exposures. Current occupational exposures are tightly controlled and are largely confined to workers in the petrochemical industry, vehicle mechanics, firefighters, workers exposed to automobile emissions, and some other occupational groups. Typically, occupational exposure levels are currently at or below 3.25 mg/m3 (1 ppm), and environmental exposures are typically below 50 microg/m3 (15 ppb). Smoking remains a significant source of exposure in both occupationally and non-occupationally exposed individuals. The early experiences of high occupational exposures led to the identification of haematopoietic effects of benzene and the need for improved control and regulation. As with most occupational standards, there has been a reduction in exposure limits as effects have been identified at ever-lower levels, accompanied by a societal concern for improved standards of occupational health. In 1946, the United States occupational exposure limit for benzene, promulgated by the American Conference of Governmental Industrial Hygienists, was 325 mg/m3 (100 ppm), but nowadays most European and North American countries have harmonised at 1.63-3.25mg/m3 (0.5-1 ppm). This latter figure was agreed within the European Union in 1997 and was adopted within national legislation by all Member States. The data on which this limit is set are essentially the same as those used by other standard-setting committees; this is an excellent example of how standards are set using science, pragmatism and societal values in the absence of complete information.

Occupational exposure to benzene in South Korea.

Benzene has been used in various industries as glues or solvents in Korea. Since 1981, a preparation containing more than 1% benzene is not allowed to be manufactured, used or dealt with in the workplace, except in laboratories and in those situations benzene must be used in a completely sealed process as specified in Industrial Safety and Health Act (ISHA). Claims for compensation of hematopoietic diseases related to benzene have been rising even though the work environment has been improved. This study was conducted to assess the status of benzene exposure in different industries in Korea. We reviewed the claimed cases investigated by the Korea Occupational Safety and Health Agency (KOSHA) between 1992 and 2000. The Survey of National Work Environment Status in 1998 was analyzed to assume the number of workers and factories exposed to benzene. In 2000, six factories were investigated to evaluate benzene exposure. Personal air monitoring was performed in 61 workers and urine samples were collected from 57 workers to measure trans,trans-muconic acid (t,t-MA). Hematologic examination has performed. Thirty-four cases of hematopoietic diseases were investigated by KOSHA including eight cases of myelodysplastic syndrome and eight cases of acute myelocytic leukemia. Eight cases were accepted as related to benzene exposure. The number of workers possibly exposed to benzene can be estimated to be 196,182 workers from 6219 factories based on the database. The geometric mean of benzene in air was 0.094 (0.005-5.311) ppm. Seven samples were higher than 1 ppm but they did not go over the 10 ppm occupational exposure limit (OEL) value in Korea. The geometric mean of trans,trans-muconic acid in urine was 0.966 (0.24-2.74) mg/g creatinine. The benzene exposure level was low except in a factory where benzene was used to polymerize other chemicals. The ambient benzene from 0.1 to 1 ppm was significantly correlated with urine t,t-MA concentration (r=0.733, p<0.01). Hematologic parameters did not show significant difference among groups divided into the level of exposure. Korean workers were not highly exposed to benzene and the level of exposure was mostly less than 1 ppm. However, there might be an excessive risk of hematopoietic disorders due to relatively high past exposure. The OEL value of benzene was amended to 1 ppm from 10 ppm in 2002 and was effective since July 2003.

A note on comparing exposure data to a regulatory limit in the presence of unexposed and a limit of detection.

In some occupational health studies, observations occur in both exposed and unexposed individuals. If the levels of all exposed individuals have been detected, a two-part zero-inflated log-normal model is usually recommended, which assumes that the data has a probability mass at zero for unexposed individuals and a continuous response for values greater than zero for exposed individuals. However, many quantitative exposure measurements are subject to left censoring due to values falling below assay detection limits. A zero-inflated log-normal mixture model is suggested in this situation since unexposed zeros are not distinguishable from those exposed with values below detection limits. In the context of this mixture distribution, the information contributed by values falling below a fixed detection limit is used only to estimate the probability of unexposed. We consider sample size and statistical power calculation when comparing the median of exposed measurements to a regulatory limit. We calculate the required sample size for the data presented in a recent paper comparing the benzene TWA exposure data to a regulatory occupational exposure limit. A simulation study is conducted to investigate the performance of the proposed sample size calculation methods.

A simplified HPTLC screening method for the estimation of the PAH content in soil samples.

Based on a highly significant correlation between the visual fluorescing fraction of PAH on the one hand and the total EPA-PAH16 content in mineral soils on the other hand, a deliberately incomplete RP-TLC separation of these compounds into a few fingerprint-like compressed bands within a determined "PAH window" has been achieved. The resulting band-pattern does not interfere normally with the more or less non-polar phenolic compounds which are associated with natural soil humic substances. The extraction step has been extremely simplified with regard to the quantity of the soil sample and of the extractant. The accuracy of this procedure has been ascertained by means of recovery experiments with an artificial soil enriched with PAH. A single spot application mode and an evaluation scheme allow the estimation of EPA-PAH16 contents of soil samples in relation to threshold values (1 or 5 or 10 mg/kg). This HPTLC screening method has been compared against standard HPLC methods. The simplified extraction step and the separation by HPTLC minimizes the actual costs and the time spent per sample.

Phenylacetylene as a new surrogate standard for the determination of BTEX by GC/FID.

Benzene, toluene, ethylbenzene, xylene (short form: BTEX) and other monoaromatic compounds are environmental contaminants which are often analyzed by GC/FID. For the calculation of BTEX concentrations in water samples normally external quantification with defined BTEX solutions is sufficient. However, for accurate quantification of BTEX in complex matrices it is necessary to use internal standards, e.g. 1-chlorohexane. Isotopes of BTEX are usually the best alternative but they are only applicable to GC/MS, because their retention times are similar to the original BTEX. 1-Chlorohexane and phenylacetylene were compared with respect to their quality as internal standards. Good results were obtained with the monoaromatic phenylacetylene as a surrogate standard. The physical properties of phenylacetylene are very similar to BTEX species and it normally does not occur in environmental samples. 1-Chlorohexane was more strongly adsorbed on the used soil than BTEX during sample preparation. This fact suggests that the single aromatic rings of BTEX and phenylacetylene are mainly responsible for the adsorption behavior.

Valor de referência tecnológico (VRT): a nova abordagem do controle da concentraçäo de benzeno nos ambientes de trabalho / Technological Reference Value (TRV): a new approach to benzene concentration control in the work environment

A finalidade deste artigo é apresentar um novo conceito de controle da concentração de benzeno nos ambientes de trabalho, adotado recentemente no Brasil com a concordância de empregadores, trabalhadores e governo. Trata-se do Valor de Referência Tecnológico (VRT). O artigo apresenta um breve histórico do processo de concepção e adoção do VRT no país, seguido da discussão conceitual de "Limite de Tolerância" adotado legalmente no Brasil, que atribui aos valores definidos o caráter de segurança e proteção à saúde do trabalhador, mesmo tratando-se de substâncias reconhecidamente cancerígenas, como o benzeno. Apresenta também o conceito estabelecido para o VRT que incorpora a classificação da carcinogenicidade do benzeno e a necessidade da redução permanente de seu valor, indicando-o como "guia" para as ações de prevenção em higiene ocupacional. Por fim conclui que a concepção adotada introduz na realidade brasileira a participação dos trabalhadores na discussão do risco decorrente do uso de um produto químico tão importante como o benzeno.

Benzene health effects: unanswered questions still not addressed.

Data which could have helped answer many of the scientific questions posed in 1983 concerning the carcinogenicity of benzene are not yet available. Since we do not know of any safe level above zero, the problems that have been plaguing the health protection process relative to benzene can perhaps be best resolved by setting current recommended maximum levels of exposure to 0.004 to 0.1 ppm, and, to the extent possible, avoiding any exposure at all to benzene and benzene-containing products.

Law and regulation of benzene.

OSHA has created final benzene regulations after extensive rulemakings on two occasions, 1978 and 1987. These standards have been the subject of extensive litigation for nearly 20 years. This article examines in detail the conceptual underpinnings of the Benzene Case, (which was decided by the U.S. Supreme Court in 1980) in light of U.S. administrative law precedents that have set limits upon administrative discretion under the test for "substantial evidence" and the "hard look doctrine." This article also addresses recent developments in the wake of the Benzene Case and their implications for benzene regulations following the "significant risk" doctrine in that case. This article briefly describes other national, regional, and international laws governing the use of benzene. This article concludes that the revisions of the benzene regulation and subsequent rulemaking provide substantial evidence of scientific underpinnings for regulatory action and that laws from other nations reflect an international consensus that occupational exposure to benzene is a proper subject of regulation. Such regulations and policies are therefore likely to withstand scrutiny and remain enforceable as widely accepted norms.