Exposure of humans to a volatile organic mixture. II. Sensory.

Time-course functions for symptoms of the sick building syndrome were derived from 66 healthy males who, during separate sessions, were exposed to clean air and to a volatile organic compound (VOC) mixture. The mixture contained 22 VOCs (25 mg/m3 total concentration) commonly found airborne in new or recently renovated buildings. Subjects rated the intensity of perceived irritation, odor, and other variables before, and twice during, 2.75-h exposure periods. Eye and throat irritation, headache, and drowsiness increased or showed no evidence of adaptation during exposure, whereas odor intensity decreased by 30%. These results indicate that irritation intensity and other symptoms are not related in any simple way to odor intensity, which suggests that the symptoms may not be a psychosomatic response to the detection of an aversive odor. Instead, subthreshold levels of VOCs may interact additively or hyperadditively and stimulate trigeminal nerve receptors. Also, air quality ratings improved by 18% during exposure, which suggests that both odor and irritation intensity may influence assessments of air quality.     

Exposure of humans to a volatile organic mixture. III. Inflammatory response.

A set of symptoms has been described during the past two decades that has been called the "sick building syndrome." These symptoms include eye, nose, and throat irritation; headache; mental fatigue; and respiratory distress. It is likely that the volatile organic compounds (VOCs) present in synthetic materials used in homes and office buildings contribute to these symptoms. However, there have been very few studies in which humans have been exposed to known amounts of VOCs under carefully controlled conditions. In this study, 14 subjects were exposed to a mixture of VOCs (25 mg/m3 total hydrocarbon) that is representative of what is found in new homes and office buildings. Because irritations of the nose and throat are symptoms often associated with the upper respiratory tract and may result from an inflammatory response in the upper airways, we used nasal lavage to monitor neutrophil (PMN) influx into the nasal passages following exposure to VOCs. There were statistically significant increases in PMNs, both immediately after a 4-h exposure to VOCs and 18 h later.     

An assessment of the data quality for NHEXAS--Part I: Exposure to metals and volatile organic chemicals in Region 5.

A National Human Exposure Assessment Survey (NHEXAS) was performed in U.S. Environmental Protection Agency (U.S. EPA) Region V, providing population-based exposure distribution data for metals and volatile organic chemicals (VOCs) in personal, indoor, and outdoor air, drinking water, beverages, food, dust, soil, blood, and urine. One of the principal objectives of NHEXAS was the testing of protocols for acquiring multimedia exposure measurements and developing databases for use in exposure models and assessments. Analysis of the data quality is one element in assessing the performance of the collection and analysis protocols used in NHEXAS. In addition, investigators must have data quality information available to guide their analyses of the study data. At the beginning of the program quality assurance (QA) goals were established for precision, accuracy, and method quantification limits. The assessment of data quality was complicated. First, quality control (QC) data were not available for all analytes and media sampled, because some of the QC data, e.g., precision of duplicate sample analysis, could be derived only if the analyte was present in the media sampled in at least four pairs of sample duplicates. Furthermore, several laboratories were responsible for the analysis of the collected samples. Each laboratory provided QC data according to their protocols and standard operating procedures (SOPs). Detection limits were established for each analyte in each sample type. The calculation of the method detection limits (MDLs) was different for each analytical method. The analytical methods for metals had adequate sensitivity for arsenic, lead, and cadmium in most media but not for chromium. The QA goals for arsenic and lead were met for all media except arsenic in dust and lead in air. The analytical methods for VOCs in air, water, and blood were sufficiently sensitive and met the QA goals, with very few exceptions. Accuracy was assessed as recovery from field controls. The results were excellent (> or = 98%) for metals in drinking water and acceptable (> or = 75%) for all VOCs except o-xylene in air. The recovery of VOCs from drinking water was lower, with all analytes except toluene (98%) in the 60-85% recovery range. The recovery of VOCs from drinking water also decreased when comparing holding times of < 8 and > 8 days. Assessment of the precision of sample collection and analysis was based on the percent relative standard deviation (% RSD) between the results for duplicate samples. In general, the number of duplicate samples (i.e., sample pairs) with measurable data were too few to assess the precision for cadmium and chromium in the various media. For arsenic and lead, the precision was excellent for indoor, and outdoor air (< 10% RSD) and, although not meeting QA goals, it was acceptable for arsenic in urine and lead in blood, but showed much higher variability in dust. There were no data available for metals in water and food to assess the precision of collection and analysis.     

occupational exposure to aromatic hydrocarbons at a coke plant: Part II. Exposure assessment of volatile organic compounds

The objective of the study is to assess the external and internal exposures to aromatic hydrocarbons in the tar and oil naphthalene distillation processes at a coke plant. 69 workers engaged as operators in tar and oil naphthalene distillation processes and 25 non-exposed subjects were examined. Personal analyses of the benzene, toluene, xylene isomers, ethylbenzene, naphthalene, indan, indene and acenaphthene in the breathing zone air allowed us to determine the time weighted average exposure levels to the aromatic hydrocarbons listed above. The internal exposure was investigated by measurement of the urinary excretion of naphthols, 2-methylphenol and dimethylphenol isomers by means of gas chromatography with a flame ionization detection (GC/FID). Urine metabolites were extracted after enzymatic hydrolysis by solid-phase extraction with styrene-divinylbenzene resin. The time-weighted average concentrations of the hydrocarbons detected in the breathing zone air shows that the exposure levels of the workers are relatively low in comparison to the exposure limits. Statistically significant differences between average concentrations of aromatic hydrocarbons (benzene, toluene, xylene isomers) determined at the workplaces in the tar distillation department have been found. Concentrations of the naphthalene and acenaphthene detected in workers from the oil distillation department are higher that those from the tar distillation department. Concentrations of naphthols, 2-methoxyphenol and dimethylphenol isomers in the urine of occupationally exposed workers were significantly higher than those of non-exposed subjects. Concentrations of the 2-methoxyphenol and dimethylphenol isomers in urine were significantly higher for the tar distillation workers, whereas concentrations of naphthols were higher for the oil naphthalene distillation workers. Operators at the tar and naphthalene oil distillation processes are simultaneously exposed to a mixture of different hydrocarbons, mainly benzene and naphthalene homologues.     

Exposure to volatile organic solvents in a group of carpentry craftsmen

BACKGROUND: The wide use of volatile organic solvent-based products in wood carpentry and the possible effects of long-term exposure to low dose mixtures of these solvents prompted an investigation in a group of small enterprises. OBJECTIVES: The investigation aimed at estimating risk in wood carpentry work via assessment of exposure. METHODS: Exposure to solvents was studied in a group of 13 enterprises (selected from a group of 52), via personal samplings, both active and passive. The solvents to be examined were selected on the basis of the information contained in the technical-toxicity sheets of the products used in these factories. RESULTS: The results show an average exposure generally within the TLV-TWA recommended by the various industrial hygiene associations. However, considering the wide variability of the concentration values observed, the possibility that these limits might be exceeded in the long term cannot be excluded. Comparison of the results of active and passive samplings, showed a substantial similarity of the two systems, with evident advantages of the passive system, as far as ease of use, workers' acceptance and costs are concerned. CONCLUSIONS: The results of this study can be a useful reference for all those (employers, occupational physicians, technicians, workers' representatives) who are required to take preventive measures especially in cases where environmental investigations are hindered by technical difficulties or are not regularly used in evaluation systems.     

Exposure of workers to a mixture of toluene and xylenes. I. Metabolism.

The urinary excretion of hippuric acid and methylhippuric acid was studied in workers (233 subjects; 122 men and 111 women) exposed to toluene and xylenes in combination and in non-exposed controls (281 subjects; 141 men and 140 women) recruited from the same factories or factories of the same regions. Smoking and drinking habits of the subjects were obtained by medical interviews. From each worker, one urine sample was collected at the end of a shift and analysed for hippuric and methylhippuric acids by high performance liquid chromatography. Air samples for the estimation of toluene and xylenes were collected with diffusive personal samplers. There was a linear correlation between the time weighted average exposure either to toluene or xylene isomers and the concentrations of hippuric acid or methylhippuric acid isomers in urine. Essentially no difference was found in the correlation between quantitative exposure and excretion in the three xylene isomers. Comparison of the slopes of regression lines indicated the absence of metabolic interaction between toluene and xylenes at the measured concentrations. The metabolism of toluene and xylenes was significantly reduced among smokers or drinkers compared with non-smokers and non-drinkers.     

挥发性有机物混合标准气体的配制

介绍一种简单、易操作、方便、灵活的配制标准有机气体混合物装置。以恒定压力作用在挥发性有机物混合液液面上,液体以恒定流速穿过一根长毛细管流出,由此制成标准发生源,流速的平均相对标准差为３．０％。将毛细管出口插入零空气流中,使液体挥发并混匀,以配成恒定浓度的有机物混合气体,改变发生源压力及稀释气流量即可改变混合气浓度,用气相色谱法测定浓度值,混合气浓度的平均相对标准差为５．７％,绝对误差±８％。比较实测值与计算值,两者无显著性差异。此配气方法适合于沸点在１５０℃以下有机混合物气体的配制     

Exposure to volatile organic compounds in residences adjacent to dyeing industrial complex

Objectives The present study was designed to evaluate residential exposure to selected volatile organic compounds (VOCs) relative to the proximity of the Daegu dyeing industrial complex (DDIC).Methods A series of surveys was conducted to measure the concentrations of five aromatic VOCs (toluene, benzene, m-xylene, p-xylene, and o-xylene) and methyl tertiary-butyl ether (MTBE) in the industrial outdoor air within the DDIC and in residential outdoor and indoor air based on the relative proximity of the DDIC.Results The geometric mean (GM) toluene value for the outdoor air samples from residential area R1 located near the DDIC (255 g/m³) was about seven-times higher than that from residential area R2 located further away from the DDIC (36.9 g/m³), whereas no significant difference was found in the outdoor air concentrations of the other target compounds between the two residential areas. Moreover, the elevated outdoor toluene levels outweighed the indoor sources with respect to the environmental exposure of residents near the DDIC. However, for the other target VOCs there was no significant difference between the residential exposure of residents living close to and a certain distance away from the DDIC.Conclusions The present study confirmed that residents in neighborhoods near the DDIC were exposed to elevated outdoor toluene levels compared with residents living further away from such a source. Furthermore, it appeared that the DDIC was a potential contributor to the nearby residential outdoor toluene levels.Essential results have not been and will not be published elsewhere     

Exposure to organic solvent mixture and hearing loss: literature overview

The chemical sector is the third largest industry in Europe. There is increasing evidence from epidemiological and clinical studies that occupational exposures to organic solvents may have detrimental effect on hearing. Most of the literature data concern one of the three following types of exposure to industrial solvents: mixed solvent exposure (the most common type); styrene-only exposure; and toluene-only exposure. This paper overviews the effects of industrial exposure to a mixture of organic solvents on hearing, with special regard to the dose-response relationship. Although the existing data make it difficult to derive a correlation between solvent concentration and hearing outcome, the current occupational exposure limits for solvents seem to be inadequate with respect to the effect that solvents may have on the auditory system.     

Sensory eye irritation in humans exposed to mixtures of volatile organic compounds

Eight subjects participated in a controlled eyes-only exposure study of human sensory irritation in ocular mucosal tissue. The authors investigated dose-response properties and the additive effects of three mixtures of volatile organic compounds. The dose-response relationships for these mixtures showed increases in response intensity as concentration increased. Replication of exposure did not result in significantly different dose- response relationships. Moreover, the result implied that components of the three mixtures interacted additively to produce ocular irritation, a result referred to as simple agonism. Finally, the authors addressed the comparability of two methods to measure sensory irritation intensity (visual analogue scale and a comparative scale). The results indicated that the two rating methods produced highly comparable results.     

Nasal effects of a mixture of volatile organic compounds and their ozone oxidation products

OBJECTIVE: Our objective was to determine if low levels of a mixture of volatile organic compounds (VOCs) and their ozone (O3) oxidation products, similar to what might be found in "sick buildings," cause nasal irritation and inflammation under controlled exposure conditions. METHODS: Healthy, nonsmoking women (n=130) completed 2-hour controlled exposures to VOCs, VOCs and O3, and a masked air "MA" control in random order at least 1 week apart. VOCs and O3 concentrations were approximately 25 mg/m and approximately 40 ppb, respectively. Nasal symptoms were rated before, during, and after exposure. Nasal lavage fluid was analyzed for polymorphonuclear cells, total protein, interleukin-6, and interleukin-8. RESULTS: We found no significant differences in symptoms or markers of nasal inflammation between exposure conditions. CONCLUSIONS: Results suggest that VOCs and their oxidation products may not cause acute nasal effects at low concentrations.     

Exposure of workers to a mixture of toluene and xylenes. II. Effects.

The health effects of exposure to a mixture of toluene and xylene isomers was studied on the fourth or fifth days of a working week in factories in China. The study population comprised 233 subjects (122 men and 111 women), who were exposed to the time weighted geometric mean (maximum) concentrations of toluene (3 (203) ppm) and xylenes (4 (103) ppm). For comparison, 241 non-exposed controls (116 men and 125 women) were recruited from the same regions. The prevalence of some subjective symptoms significantly increased in the exposed population, and the symptom profiles were similar to those found after exposure to toluene or xylenes alone. Haematology and serum biochemistry did not show notable changes. It seems reasonable to conclude that the effects of the toxicities of toluene and xylenes in combination are additive.     

Exposure assessment and sensitisation in workers exposed to organic acid anhydrides

Objectives: To clarify whether the intensity of exposure to organic acid anhydrides (OAAs) is associated with the risk of sensitisation to these allergens. Methods: The investigations were carried out in three different manufacturing plants (A, B, and C) where OAAs were used in the production of epoxy resins. Methyltetrahydrophthalic acid anhydride (MTHPA) was used in all three plants. The exposure assessment included stationary and ambient air monitoring (OAAs in the air) and biological monitoring (metabolites in urine). In plant A 20, in plant B 86 and in plant C 113 employees were examined by a physician (anamnesis, skin-prick test, specific IgE, spirometry). In plants B and C, the exposure areas were classified as high, medium, and low, without the results of the exposure assessment being known. Results: The ambient air concentrations (in μg/m³) of MTHPA were 37.2 and 58.5 in plant A (number of samples n=2), ranged from <0.5–26.2 in plant B (n=5) and from 2.1–57.9 in plant C (n=3) with stationary air collecting, and from 8–45 (n=6), from <4.7–35.7 (n=3) and from 2–37.8 (n=3) with personal air collection. The metabolites of OAAs in urine (in nmol/mmol creatinine) ranged from 5.7–645 (median of MTHPA: 346) in plant A, from <1–213 (median of MTHPA: 10.1) in plant B and from 0.1–830 (median of the sum of the OOA metabolites: 108.6) in plant C. The prevalence of sensitisation was 35% in plant A, 21% in plant B and 29% in plant C. A higher prevalence in the highly exposed areas, however, could not be seen. Levels of IgE specific for conjugates of MTHPA were not associated with the metabolites in the end of shift urine. Levels of IgG specific for conjugates of MTHPA, however, were associated with the metabolites in the end of shift urine. Conclusions: The data showed that biological monitoring is a useful tool in the exposure assessment of OAAs. Comparing the prevalence of sensitisation and the results of biological monitoring, between the three plants, we found that sensitisation increased with increasing exposure. Within a plant a higher risk of sensitisation in persons working in highly exposed areas at the time of the examination could not be seen, possibly due to frequent job rotation. Received: 2 August 1999 / Accepted: 29 January 2000     

Risk assessment of exposure to volatile organic compounds in different indoor environments

The lifetime cancer risks of exposure of cooks and food service workers, office workers, housewives, and schoolchildren in Hong Kong to volatile organic compounds (VOCs) in their respective indoor premises during normal indoor activities were assessed. The estimated cancer risk for housewives was the highest, and the second-highest lifetime cancer risk to VOC exposure was for the groups of food service and office workers. Within a certain group of the population, the lifetime cancer risk of the home living room was one to two orders of magnitude higher than that in other indoor environments. The estimated lifetime risks of food service workers were about two times that of office workers. Furthermore, the cancer risks of working in kitchen environments were approximately two times higher than the risks arising from studying in air-conditioned classrooms. The bus riders had higher average lifetime cancer risks than those travelling by Mass Transit Railway. For all target groups of people, the findings of this study show that the exposures to VOCs may lead to lifetime risks higher than 1 x 10(-6). Seven indoor environments were selected for the measurement of human exposure and the estimation of the corresponding lifetime cancer risks. The lifetime risks with 8-h average daily exposures to individual VOCs in individual environments were compared. People in a smoking home had the highest cancer risk, while students in an air-conditioned classroom had the lowest risk of cancer. Benzene accounted for about or more than 40% of the lifetime cancer risks for each category of indoor environment. Nonsmoking and smoking residences in Hong Kong had cancer risks associated with 8-h exposures of benzene above 1.8 x 10(-5) and 8.0 x 10(-5), respectively. The cancer risks associated with 1,1-dichloroethene, chloroform, methylene chloride, trichloroethene, and tetrachloroethene became more significant at selected homes and restaurants. Higher lifetime cancer risks due to exposure to styrene were only observed in the administrative and printing offices and air-conditioned classrooms. Higher lifetime cancer risks related to chloroform exposures were observed at the restaurant and the canteen.     

Sensory irritating potency of some microbial volatile organic compounds (MVOCs) and a mixture of five MVOCs.

The authors investigated the ability/potencies of 3 microbial volatile organic compounds and a mixture of 5 microbial volatile organic compounds to cause eye and upper respiratory tract irritation (i.e., sensory irritation), with an animal bioassay. The authors estimated potencies by determining the concentration capable of decreasing the respiratory frequency of mice by 50% (i.e., the RD50 value). The RD50 values for 1-octen-3-ol, 3-octanol, and 3-octanone were 182 mg/m3 (35 ppm), 1359 mg/m3 (256 ppm), and 17586 mg/m3 (3360 ppm), respectively. Recommended indoor air levels calculated from the individual RD50 values for 1-octen-3-ol, 3-octanol, and 3-octanone were 100, 1000, and 13000 microg/m3, respectively-values considerably higher than the reported measured indoor air levels for these compounds. The RD50 value for a mixture of 5 microbial volatile organic compounds was also determined and found to be 3.6 times lower than estimated from the fractional concentrations and the respective RD50s of the individual components. The data support the conclusion that a variety of microbial volatile organic compounds may have some synergistic effects for the sensory irritation response, which constrains the interpretation and application of recommended indoor air levels of individual microbial volatile organic compounds. The results also showed that if a particular component of a mixture was much more potent than the other components, it may dominate the sensory irritation effect. With respect to irritation symptoms reported in moldy houses, the results of this study indicate that the contribution of microbial volatile organic compounds to these symptoms seems less than previously supposed.     

工业用混合有机溶剂挥发性化学组分分析

目的 分析工业用混合有机溶剂挥发性化学组分,为职业病危害因素识别提供依据.方法 对2008-2011年采用气相色谱-质谱联用仪进行检测的6种无注册商品名或成分说明的118份混合有机溶剂样品的挥发性化学组分检测结果进行汇总分析.结果 ①“开油水”主要检出甲苯、甲醇和正己烷,部分样品检出苯与二甲苯;②“洗板水”主要检出甲苯、正己烷和甲醇,部分样品检出苯、三氯乙烯和四氯化碳,个别检出1,2-二氯乙烷;③“天那水”主要检出甲苯、二甲苯和苯,部分检出甲醇,个别检出1,2-二氯乙烷;④“清洗剂”主要检出正己烷、三氯乙烯和二甲苯,部分样品检出甲醇,个别检出苯和1,2-二氯乙烷;⑤“去污水”主要检出正己烷、苯和甲苯,部分检出甲醇和三氯乙烯;⑥“白电油”以检出正己烷为主.结论 工业用混合有机溶剂挥发性组分复杂,均不同程度地检出三氯乙烯、正己烷、苯或1,2-.二-氯乙烷等高风险职业病危害因素.     

Exposure of humans to electromagnetic fields. Standards and regulations

Biological and health effects of electromagnetic fields (EMF) have been investigated for many years. Exposure standards have been developed internationally, that provide adequate protection against all known adverse effects of exposure to EMF. The guidelines developed by the International Commission on Non Ionizing Radiation Protection (ICNIRP) are widely recognized and have formed the basis for national regulations in several countries. The two-level structure, with basic restrictions and reference levels, allows the standards to be adapted to virtually any exposure condition, including complex situations at workplaces. However, concerns for hypothesized, but unproven, long-term effects of chronic exposure to low-level EMF have created a demand for precautionary measures beyond the standards for recognized, acute effects. Such measures, if deemed justified by social considerations, including public anxiety, should be separate from exposure standards, and adopted with special care to avoid undermining the credibility of science-based guidelines, and of health authorities.