Workplace Air Concentrations Research Articles

A Data-Driven Approach to Estimating Occupational Inhalation Exposure Using Workplace Compliance Data.

A growing list of chemicals are approved for production and use in the United States and elsewhere, and new approaches are needed to rapidly assess the potential exposure and health hazard posed by these substances. Here, we present a high-throughput, data-driven approach that will aid in estimating occupational exposure using a database of over 1.5 million observations of chemical concentrations in U.S. workplace air samples. We fit a Bayesian hierarchical model that uses industry type and the physicochemical properties of a substance to predict the distribution of workplace air concentrations. This model substantially outperforms a null model when predicting whether a substance will be detected in an air sample, and if so at what concentration, with 75.9% classification accuracy and a root-mean-square error (RMSE) of 1.00 log10 mg m-3 when applied to a held-out test set of substances. This modeling framework can be used to predict air concentration distributions for new substances, which we demonstrate by making predictions for 5587 new substance-by-workplace-type pairs reported in the US EPA's Toxic Substances Control Act (TSCA) Chemical Data Reporting (CDR) industrial use database. It also allows for improved consideration of occupational exposure within the context of high-throughput, risk-based chemical prioritization efforts.

Evaluation and updates to the Leggett model for pharmacokinetic modeling of exposure to lead in the workplace – Part II adjustments to the adult exposure model, confirmation of Leggett+, and modeling of workplace exposure

California’s Office of Environmental Health Hazard Assessment has updated the comprehensive age-specific model of lead metabolism in humans published by Richard W. Leggett in 1993. The updated model, called Leggett+, was introduced in a peer-reviewed report in 2013. The Leggett + model simulates the relationship between blood lead and exposure in the workplace. Leggett + includes a workplace exposure model comprising respiratory tract intake (workplace lead inhaled by a worker) and uptake (lead absorbed into the blood from the respiratory tract plus uptake from ambient air and diet). The latter is calculated as intake times an inhalation transfer coefficient plus background uptake. An adjusted adult systemic model describes the metabolism of the absorbed lead. This paper provides details about the workplace exposure and uptake elements of Leggett+, an updated approach to calibrating an inhalation transfer coefficient, confirmation of the model’s performance in predicting blood lead levels from workplace studies, and predictions of blood lead levels from simulated exposures to workplace airborne lead over a working lifetime. Blood lead relative to airborne lead concentrations in a standard workplace scenario predicted by Leggett + was similar to corresponding relationships from four published workplace studies. Leggett + predictions displayed a good fit to regression equations when other key factors were considered such as pre-employment blood lead and ongoing background intake of lead, workplace air concentration, lead aerosol characteristics, and worker activity levels. The comprehensive Leggett + model can simulate plausible workplace air–blood lead relationships from a broad range of worker exposures. The inhalation transfer coefficient of 0.30, derived from empirical data described in the 2013 report has been reexamined. The original estimate continues to represent a plausible mid-point for a coefficient derived from an expanded range of theoretical particle size distributions deposited in the upper and lower regions of the respiratory tract considering intake during sedentary and outdoor activity breathing scenarios. This coefficient is slightly lower than the value of 0.35 estimated for unknown forms of lead by Leggett in 1993.

Toluene diisocyanate occupational exposure data in the polyurethane industry (2005-2020): A descriptive summary from an industrial hygiene perspective.

This article provides an overview of toluene diisocyanate (TDI) workplace air concentration data. Data were collected between 2005-2020 in workplaces across the United States, Canada, and the European Union by a number of different organizations, primarily using the sampling procedures published in OSHA Methods 42 and 5002. The data were then collated and organized by the International Isocyanate Institute. Air samples were collected from several market segments, with a large portion of the data (87%) from the flexible foam industry. The air samples (2534 in total) were categorized into "area" or "personal," and the personal samples were subcategorized into "task," "short term," and "long term." Most of the air sample concentrations (87%) were less than 5ppb. However, the presence of airborne TDI greater than 5ppb indicated the importance of respiratory protection in some situations; therefore, respirator use patterns were studied and summarized. Additionally, this article provides a summary of air sample concentrations at different flexible foam manufacturing job roles. The information on air sampling concentrations and respiratory protection during TDI applications collected in this paper could be useful for product stewardship and industrial hygiene purposes in the industries studied.

General Medical Conditions and Occupational Diseases in Workers Engaged in Crude Nickel and Copper Production

Introduction: Working conditions in the production of crude nickel and copper pose an increased risk of occupational diseases. Objective: To collect new data on health disorders in workers engaged in the production of crude nickel and copper in the Arctic. Materials and methods: We analyzed general medical conditions and occupational diseases in 760 workers engaged in the production of crude nickel and copper in 2008–2020. Results: Nickel compounds, workplace air concentrations of which exceed the permissible exposure limit by 7.6–157.0 times in various unit process areas, represent the main occupational hazard in converter matte processing. According to the regular check-up data for 2008, the most prevalent general medical conditions included diseases of the eye (18.4 %), musculoskeletal (14.7 %) and respiratory (12.5 %) systems. Every 10-year increment in the length of service was associated with an increase in the incidence of diseases of the musculoskeletal, circulatory and endocrine systems (p < 0.001) in the workers. In 2009–2020, 91 occupational diseases were first diagnosed in 50 of 760 employees, among which respiratory diseases prevailed (68.9 %), and the average annual incidence rate was 0.998 cases per 100 workers. Mill and smelter operators (16.7 % and 13.4 % of all workers, respectively) were at higher risk of developing an occupational disease, and their annual incidence rates were 1.389 and 1.122 cases per 100 workers, respectively. We observed a clear dose-response relationship between the exposure and occupational disease rates in the workers concerned: occupational diseases developed in 32.9 % of workers with very high occupational exposure and in 17.6 %, 12.0 %, 2.0 %, and 0.3 % of workers exposed to high, medium, moderate, and low levels of airborne nickel compounds. Conclusion: We have obtained new data on non-occupational and occupational disorders in the crude nickel and copper production workers enabling early and targeted disease prevention.

Calcium hydroxid. Determination in workplace air

Calcium hydroxide is a white color solid. It is used in construction, chemical industry, water purification and wastewater treatment, flue gas desulphurization. Calcium hydroxide causes serious damage to the eyes, irritates the skin and it can cause after-launch respiratory irritation. Maximum allowable concentration value (MAC) for calcium hydroxide in the work environment in Poland, for the inhalable and respirable fraction is 2 mg/m3 (STEL is 6 mg/m3) and 1 mg/m3 (STEL is 4 mg/m3), respectively. The aim of the study was to develop a method for determining the concentration of calcium hydroxide present in the inhalable and respirable fraction in the workplaces atmosphere, in the range from 1/10 to 2 MAC values in accordance with the requirements of European Standard PN-EN 482. The developed method is based on collecting, stopping calcium hydroxide (contained in the inhalable and the respirable fraction) on membrane filters, mineralizing filters with concentrated nitric acid and determining calcium of the resulted solution by atomic absorption spectrometry with atomization in acetylene-air flame (F-AAS). The described method allows the determination of calcium in workplace air concentrations in the range of 0.50–20.00 µg/ml. The calibration curve characterized by a high value of the correlation coefficient: R2 = 1.0000. The limit of detection (LOD) is 0.1 ng/ml and the limit of quantification (LOQ) is 0.3 ng/ml. The determined coefficient of recovery is 1.00. An analytical method allows the determination of the concentration of the calcium hydroxide present in the workplace air in the inhalable fraction in the concentration range of 0.10–4.11 mg/m3 (sample air volume 720 L) and in the reparable fraction in the concentration range 0.07–2.70 mg/m3 (for a sample air volume of 684 L), which represents 0.05–2.1 MAC value for the inhalable fraction and 0.07–2.7 MAC value for the respirable fraction. The method has good precision and accuracy and meets the requirements of European Standard PN-EN 482 for procedures for determining chemical agents. The method for determining calcium hydroxide has been recorded in the form of an analytical procedure (see Appendix). This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

ASSESSMENT OF OCCUPATIOAL HEALTH RISK IN FERROALLOY PLANT

Findings of comprehensive assessment of occupational health risks in high-carbon ferrochrome production workers are reported. Groups of occupation- and employment duration related risk according to the general morbidity rate depending on the age and employment duration among smelters, blast-furnace keepers, cinder-men, batchers, crane operators, ferroalloy crashers, electrode operators and other smelter workers were identified. Hygienic studies covered the measurement of the following physical and chemical workplace factors: noise, whole-body and local vibration levels, electromagnetic fields and microclimate parameters (temperature, relative humidity, air speed, heat radiation intensity, environmental heat load index), artificial illumination, aerosol concentrations in workplace air and in neutral points of workrooms, average shift aerosol concentrations being calculated, and chemicals concentrations: calcium oxide, magnesium oxide, ferric iron oxide, chromic oxide, chromium anhydride, aluminium oxide, nitrogen dioxide, sulphur dioxide and carbon monoxide. Time-keeping study to evaluate the hardness of the working process and intensity in main occupations was carried out. Our studies revealed working conditions of major smelter occupational groups to be were evaluated as harmful and dangerous: 3rd class, 2nd degree. Microclimate (heat radiation, low ambient air temperatures, noise and environmental dust pollution were reported to be the most unfavorable working conditions; the hardness of the working process heaviness of all major occupational groups were classified as 3rd class, 1st degree. Working conditions of control group workers unexposed to harmful occupational factors of smelter shop were estimated as allowable. Findings on the risk for the gain in the morbidity rate (annual gain in the risk) depending on age and employment duration for the period of 2007-2016 are reported. The direct statistically reliable relationship between the increased disease incidence on age and employment duration is revealed; annual gain in the disease incidence rate is shown.

STUDY OF WORKING CONDITIONS IN PATIENTS WITH OCCUPATIONAL POLYNEUROPATHY OF UPPER EXTREMITIES

Autonomous sensory polyneuropathy of upper extremities is one of the most common occupational diseases of peripheral nervous system. Findings of the study of working conditions in two major worker jobs in which occupational polyneuropathies of upper extremities are prevalent, namely: house-painters and plasterers, as well as mining job workers (underground miners, shaft miners, breakage face miners) are reported. Hygienic investigations envisaged detailed studies of working conditions in workers with diagnosed occupational peripheral nervous system disease. The intensity and hardness of working process, illumination level, spectral noise characteristics, noise, vibration, temperature, humidity, and air velocity levels, as well as adverse chemical concentrations in workplace air were assessed. House-painters as well as miners were found to work with pronounced physical overloads, working conditions being classified as 3.2-3.3 (2-3 degree harmful) according to indices of working process hardness. In spite of new technologies being introduced into the working process, manual labor part in these jobs still remains to be the great. Comparison of findings revealed certain differences in some characteristics of working process hardness. Working process hardness shown by dynamic and static physical load on upper extremities was found to be the most significant harmful occupational factor resulting in polyneuropathy in house-painters and plasterers. Development of polyneuropathy in miners was caused by a combination of adverse occupational factors: working process hardness, local vibration, cold microclimate. Our findings indicated the importance of the study of health state in painters and miners. Working conditions must be taken into account in the process of development of preventive and remedial measures for occupational polyneuropathy treatment.

Pentachlorophenol. Determination in workplace air by means of high performance liquid chromatography

Pentachlorophenol (PCF) in room temperature is a crystalline solid with phenol-like odor. It is soluble in most organic solvents (diethyl ether, acetone, carbon tetrachloride, methanol). It is slightly soluble in water. Pentachlorophenol is used as a fungicide, insecticide and as non-selective herbicide (defoliant) in cotton crops. It is also used as antimicrobial agent in leather, paper and textile industry. It has been widely used as wood preservative in wood and construction industry. Occupational exposure to pentachlorophenol may cause irritation of mucous membranes of the eyes and the upper respiratory tract and skin lesions. It may also lead to changes in the central nervous system like headache, insomnia, vertigo and depression. Acute poisoning may cause pulmonary edema, cardio-respiratory disorder and even death. Pentachlorophenol is also suspected to be carcinogenic to humans. The aim of this study was to develop and validate a sensitive method for determining pentachlorophenol concentrations in workplace air in the range from 1/10 to 2 MAC values, in accordance with the requirements of Standard No. PN-EN 482. The study was performed using a liquid chromatograph with spectrophotometric detection. All chromatographic analysis were performed with Zorbax SB-CN 250 × 4.6 mm analytical column, which was eluted with mixture of 0.1% phosphoric acid in acetonitrile and 0.1% phosphoric acid in water (6: 4 v/v). The method is based on the collection of pentachlorophenol on XAD 7 resin preceded by a glass fiber filter, extraction with methanol and chromatographic determination of resulted solution with HPLC technique. The method is linear (r = 0.9997) within the investigated working range 0.625–12.5 μg/ml (0.05–1.0 mg/m3 for a 25-L air sample). The calculated limit of detection (LOD) and limit of quantification (LOQ) were 0.014 μg/ml and 0.048 μg/ml, respectively. The average extraction efficiency of pentachlorophenol from filter and XAD 7 amounted to 95% and samples stored in refrigerator are stable for 14 days. The analytical method described in this paper enables determination of pentachlorophenol in workplace air. The method is precise, accurate and it meets the criteria for procedures for measuring chemical agents listed in Standard No. PN-EN 482. The method can be used for assessing occupational exposure to pentachlorophenol and associated risk to workers’ health. The developed method of determining pentachlorophenol has been recorded as an analytical procedure (see Appendix). This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

HYGIENIC ASSESSMENT OF AIR STATE IN LEAD-ACID ACCUMULATOR PRODUCTION AT DIFFERENT STAGES OF PRODUCTION UPDATING

Hygienic assessment of air pollution in workrooms for large lead-acid accumulator production is given. Studies were carried out in various conditions: in shops with outdated manufacturing equipment, after ventilation system reconstruction, and in shops with up-to-date production lines and ventilation systems. For workshop air assessment chemical analyses of air samples to detect lead and sulphuric acid aerosols were carried out at workplaces of major lead-acid accumulator production jobs. Approved techniques were used: atomic absorption to measure lead and photometric method to determine sulphuric acid concentrations in workplace air and in industrial emissions. The effectiveness of used ventilation equipment after its large-scale modernization is evaluated in accordance with current regulations. Sanitary-and-hygienic characteristics of local exhaust systems were evaluated according to economy index. Based on testing of dust-and-gas collecting plants, purification efficiency of extracted air was determined. Meteorological parameters (temperature, humidity, and air speed) in workplace areas were measured in the process of the study. The problem of further improvement of engineering decisions on removal of polluted air from workshops is still an area of current concern, as lead concentrations in workplace air remain high in spite of modifications in technological processes and various sanitary-and-engineering measures being taken.

The most important inferences from the Ekaterinburg nanotoxicology team's animal experiments assessing adverse health effects of metallic and metal oxide nanoparticles.

During 2009-2017 we have studied nanoparticles of elemental silver or gold and of iron, copper, nickel, manganese, lead, zinc, aluminium and titanium oxides (Me-NPs) using, in most cases, a single low-dose intratracheal instillation 24 h before the bronchoalveolar lavage to obtain a fluid for cytological and biochemical assessment and, in all cases, repeated intraperitoneal injections in non-lethal doses to induce subchronic intoxications assessed by a lot of toxicodynamic and toxicokinetic features. We have also studied the same effects for a number of relevant combinations of these Me-NPs and have revealed some important patterns of their combined toxicity. Besides, we have carried out long-term inhalation experiments with Fe2O3, NiO and amorphous SiO2 nano-aerosols. We have demonstrated that Me-NPs are much more noxious as compared with their fine micrometric counterparts although the physiological mechanisms of their elimination from the lungs proved to be highly active. Even if water-insoluble, Me-NPs are significantly solubilized in some biological milieus in vitro and in vivo, which may explain some important peculiarities of their toxicity. At the same time, the in situ cytotoxicity, organ-systemic toxicity and in vivo genotoxicity of Me-NPs strongly depends on specific mechanisms characteristic of a particular metal. For some of the Me-NPs studied, we have proposed standards of presumably safe concentrations in workplace air. Along with this, we have proved that the adverse effects of Me-NPs could be significantly alleviated by background or preliminary administration of adequately composed combinations of some bioprotectors.

2,2-Bis(4-hydroxyphenyl)propane – inhalation fraction. Determination method in workplace air

2,2-Bis(4-hydroxyphenyl)propane (bisphenol A BPA) is a substance in a form of a solid crystals or flakes with a mild phenolic odor. BPA is commonly used in the production of epoxide, polycarbonate or polysulfone resins, glues, breaks fluids or as a flame retardants and fungicides. Exposure to BPA can cause irritation of skin, BPA can also act as a nefro or hepatotoxic factor and upper respiratory tract or mucous membranes of the eye. BPA has a negative effects on human fertility. The aim of this study was to develop and validate a sensitive method for determining BPA concentrations in workplace air in the range from 1/10 to 2 MAC values, in accordance with the requirements of Standard No. PN-EN 482. The study was performed using a liquid chromatograph with spectrophotometric (UV-VIS) and spectrofluorimetric (FLD) detection. All chromatographic analyses were performed with Supelcosil LC 18 (150 × 3 mm) analytical column, which was eluted with mixture of acetonitrile and water (1:1). This method was based on collecting BPA on glass fiber filter, extracting with acetonitrile, and chromatographic determining resulted solution with HPLC technique. The average extraction efficiency of BPA from filters was 90%. The method was linear (r = 0.9996) within the investigated working range 0.125–5 mg/m3 for a 720-L air sample. The calculated limit of detection (LOD) and the limit of quantification (LOQ) was to 0.02 μg/ml (UV-VIS) and 0.013 μg/ml (FLD), and 0.068 μg/ml (UV-VIS) and 0.042 μg/ml (FLD), respectively. The analytical method described in this paper enables specific and selective determination of BPA in workplace air in presence of other compounds. The method is precise, accurate and it meets the criteria for measuring chemical agents listed in Standard No. PN-EN 482+A1:2016-01. The method can be used for assessing occupational exposure to BPA and associated risk to workers’ health. The developed method of determining BPA has been recorded as an analytical procedure (see appendix).

Cyclophosphamide. Determination method in workplace air

Cyclophosphamide (CP) at room temperature is a fine white crystalline odorless powder. It is used mainly as a cytostatic drug in anticancer therapy. Acute exposure to CP can cause bone marrow damage, hemorrhagic cystitis and cardiomyopathy. Cyclophosphamide has a negative influence on reproducibility in humans. International Agency for Research on Cancer (IARC) has classified CP as carcinogenic to humans (Group 1). In the European Union, cyclophosphamide has been classified as carcinogenic category 1.A and mutagenic category 2.B. Occupational exposure to CP may occur during its production and during preparation and application of CP in oncology wards. Cyclophosphamide may be absorbed mainly by inhalation or skin contact. The aim of this study was to develop and validate a sensitive method for determining cyclophosphamide concentrations in workplace air in the range from 1/10 to 2 MAC values, in accordance with the requirements of Standard No. PN-EN 482. The study was performed using a liquid chromatograph with a tandem mass detection (HPLC-MS/MS). All chromatographic analyses were performed with Supelcosil LC 18 150 × 3 mm analytical column, which was eluted with a mixture of methanol and water with 0.1% of formic acid. The method was based on collecting CP on glass fiber filter, extracting with a mixture of methanol: water with addition of formic acid (0.1%), and chromatographic determining of resulted solution with HPLC-MS/MS technique. The average extraction efficiency of CP from filters was 90%. The method was linear (r = 0.999) within the investigated working range 0.01–0.5 μg/ml. The calculated limit of detection (LOD) and the limit of quantification (LOQ) were 0.00046 and 0.0015 μg/ml, respectively. The analytical method described in this paper, thanks to HPLC MS/MS technique, enables specific and selective determination of CP in workplace air in the presence of other compounds at concentrations from 0.0004 mg/m3 (1/25 proposed MAC value). The method precise, accurate and it meets the criteria for measuring chemical agents listed in Standard No. PN-EN 482. The method can be used for assessing occupational exposure to CP and associated risk to workers’ health. The developed method of determining CP has been recorded as an analytical procedure (see appendix).

Dust exposure and lung function of workers in the brick and clay pottery factories in the Northeast of Thailand

This study aimed to determine the particulate matter concentrations (PM10) in workplace air and personal dust, and their effects on the respiratory health of exposed workers. The lung function of 449 exposed workers was examined. The concentration of PM10 in workplace air and personal dust exposure was measured. Spirometry was used to evaluate the lung function capacity included forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), forced expiratory volume ratio (FEV%) and peak expiratory flow rate (PEF). The forced expiratory flow at 25% to 75% of the FVC (FEF 25-75%) was determined. The PM10 concentration in workplace air (6 study sites) and personal dust (4 study sites) exceeded the standard (REL) of 0.12 mg/m3. The results of this study showed a decrease in the mean values and percent predicted value of FVC, FEV1, FEV1%, PEF and FEF 25-75%. The lung capacity of participants revealed that 24.50%, 4.45% and 7.13% had mildly, moderately restrictive and small airway disease. The respiratory symptoms were dyspnoea (22.49%), wheezing (10.69%), chest pain (10.69%) and chronic cough (2.90%). Factors influencing lung capacity included mask usage (Adj.OR: 0.44 CI: 0.25-0.79 p-value: 0.006) and chest pain (Adj.OR: 2.68 CI: 1.14-6.30 p-value: 0.024).

Maleic anhydride. Determination in workplace air

Maleic anhydride is a crystalline solid. Maleic anhydride is an important intermediate in the chemical industry. It is harmful, irritating and sensitizing.The aim of this study was to develop a new method for the determination of maleic anhydride concentrations in workplace air in the range from 1/10 to 2 MAC values, in accordance with the requirements of the standard EN 482.Throughout the study, an Agilent Technologies series 1200 liquid chromatograph with a diode array detector (DAD) were used. The determination was carried out in the reverse-phase system (mobile phase: acetonitrile: solution of phosphoric acid) using an Ultra C18 column; dimensions: (250 × 4.6 mm) with dp = 5 μm, with precolumn, dimensions: 10 × 4 mm. The method was based on passing air through a glass fiber filter coated of 3,4-di-methoxybenzylamine. Samples were extracted with acetonitrile/ammonia and analyzed by HPLC-DAD.Validation of the method was carried out in accordance with European Standard EN 482. The following validation parameters were determined: measuring range: 0,05  1 mg/m3, limit of detection (LOD): 8,18 ng/ml, the limit of quantification (LOQ): 24,5 ng/ml, the overall accuracy of the method – 5,53%, the relative total uncertainty of the method – 12,02%.The analytical method described in this paper makes it possible to selectively determine maleic anhydride in workplace air in the presence of other substances at concentrations from 0,05 mg/m³ (1/10 MAC value). The method is characterized by good precision and accuracy and meets the criteria for the performance of procedures for the measurement of chemical agents, listed in EN 482. The developed method of determining maleic anhydride has been recorded as an analytical procedure (see appendix).

Assessment of workplace air concentrations of formaldehyde during and before working hours in medical facilities.

Workplace air concentrations of formaldehyde (FA) in medical facilities where FA and FA-treated organs were stored and handled were measured before and during working hours and assessed by the official method specified by Work Environment Measurement Law. Sixty-percent of the total facilities examined were judged as inappropriately controlled work environment. The concentrations of FA before working hours by spot sampling were found to exceed 0.1 ppm in some facilities, and tended to increase with increasing volume of containers storing FA and FA-treated materials. Regression analysis revealed that logarithmic concentrations of FA during working hours by the Law-specified analytical method were highly correlated with those before working hours by spot sampling, suggesting the importance for appropriate storing methods of FA and FA-treated materials. The concentrations of FA during working hours are considered to be lowered by effective ventilation of FA-contaminated workplace air and appropriate storage of FA and FA-treated materials in plastic containers in the medical facilities. In particular, such improvement by a local exhaust ventilation system and tightly-sealed containment of FA-treated material were urgently needed for the dissecting room where FA-treated cadavers were prepared and handled for a gross anatomy course in a medical school.

Comparative Human Health Impact Assessment of Engineered Nanomaterials in the Framework of Life Cycle Assessment.

For safe innovation, knowledge on potential human health impacts is essential. Ideally, these impacts are considered within a larger life-cycle-based context to support sustainable development of new applications and products. A methodological framework that accounts for human health impacts caused by inhalation of engineered nanomaterials (ENMs) in an indoor air environment has been previously developed. The objectives of this study are as follows: (i) evaluate the feasibility of applying the CF framework for NP exposure in the workplace based on currently available data; and (ii) supplement any resulting knowledge gaps with methods and data from the life cycle approach and human risk assessment (LICARA) project to develop a modified case-specific version of the framework that will enable near-term inclusion of NP human health impacts in life cycle assessment (LCA) using a case study involving nanoscale titanium dioxide (nanoTiO2 ). The intent is to enhance typical LCA with elements of regulatory risk assessment, including its more detailed measure of uncertainty. The proof-of-principle demonstration of the framework highlighted the lack of available data for both the workplace emissions and human health effects of ENMs that is needed to calculate generalizable characterization factors using common human health impact assessment practices in LCA. The alternative approach of using intake fractions derived from workplace air concentration measurements and effect factors based on best-available toxicity data supported the current case-by-case approach for assessing the human health life cycle impacts of ENMs. Ultimately, the proposed framework and calculations demonstrate the potential utility of integrating elements of risk assessment with LCA for ENMs once the data are available.

Asthma caused by potassium aluminium tetrafluoride: a case series.

The objective of this study is to describe a case-series of potassium aluminium tetrafluoride (KAlF4)-induced occupational asthma (OA) and/or occupational rhinitis (OR). The study involves five patients from a heat-exchanger production line who were examined (including specific inhalation challenge tests) for suspected OA and/or OR caused by a flux containing almost 100% KAlF4 − with fluorides’ workplace air concentrations ranging between 1.7 and 2.8 mg/m3. No subject had a previous history of asthma. All five patients had a positive specific challenge test (three patients were diagnosed with OA alone, one with OR and one with both OR and OA). At the follow-up visit, after three years on average, all patients needed permanent corticosteroid therapy (four topical, one oral). After elimination from the exposure, only one of the observed subjects gave an indication of an improvement, two subjects stabilized and two worsened. Our case series focuses on the correlation between patients’ exposure to fluorides in air-conditioner production and the subsequent occurrence of OR/OA. Currently, it is uncertain whether these OR/OA were caused by hypersensitivity or irritation.

Historical occupational trichloroethylene air concentrations based on inspection measurements from Shanghai, China.

Trichloroethylene (TCE) is a carcinogen that has been linked to kidney cancer and possibly other cancer sites including non-Hodgkin lymphoma. Its use in China has increased since the early 1990s with China's growing metal, electronic, and telecommunications industries. We examined historical occupational TCE air concentration patterns in a database of TCE inspection measurements collected in Shanghai, China to identify temporal trends and broad contrasts among occupations and industries. Using a database of 932 short-term, area TCE air inspection measurements collected in Shanghai worksites from 1968 through 2000 (median year 1986), we developed mixed-effects models to evaluate job-, industry-, and time-specific TCE air concentrations. Models of TCE air concentrations from Shanghai work sites predicted that exposures decreased 5-10% per year between 1968 and 2000. Measurements collected near launderers and dry cleaners had the highest predicted geometric means (GM for 1986 = 150-190 mg m(-3)). The majority (53%) of the measurements were collected in metal treatment jobs. In a model restricted to measurements in metal treatment jobs, predicted GMs for 1986 varied 35-fold across industries, from 11 mg m(-3) in 'other metal products/repair' industries to 390 mg m(-3) in 'ships/aircrafts' industries. TCE workplace air concentrations appeared to have dropped over time in Shanghai, China between 1968 and 2000. Understanding differences in TCE concentrations across time, occupations, and industries may assist future epidemiologic studies in China.

Distribution of PCDD/Fs in the fly ash and atmospheric air of two typical hazardous waste incinerators in eastern China.

Distribution of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) in the fly ash and atmospheric air of one medical waste incinerator (MWI) and one industrial hazardous waste incinerator (IHWI) plants were characterized. The PCDD/F concentrations of the stack gas (fly ash) produced from MWI and IHWI were 17.7 and 0.7 ng international toxic equivalent (I-TEQ)/Nm(3) (4.1 and 2.5 ng I-TEQ/g), respectively. For workplace air, the total concentrations of PCDD/Fs were 11.32 and 0.28 pg I-TEQ/Nm(3) (819.5 and 15.3 pg/Nm(3)). We assumed that the large differences of PCDD/F concentrations in workplace air were due to the differences in chlorine content of the waste, combustion conditions, and other contamination sources. With respect to the homologue profiles, the concentrations of PCDFs decreased with the increase of the substituted chlorine number for each site. Among all of the PCDD/F congeners, 2,3,4,7,8-PeCDF was the most important contributor to the I-TEQ value accounting for ca. 43 % of two sites. The gas/particle partition of PCDD/Fs in the atmosphere of the workplace in the MWI was also investigated, indicating that PCDD/Fs were more associated in the particle phase, especially for the higher chlorinated ones. Moreover, the ratio of the I-TEQ values in particle and gas phase of workplace air was 11.0. At last, the relationship between the distribution of PCDD/Fs in the workplace air and that from stack gas and fly ash was also analyzed and discussed. The high correlation coefficient might be a sign for diffuse gas emissions at transient periods of fumes escaping from the incinerator.

Alteration of Th1/Th2/Th17 cytokine profile and humoral immune responses associated with chromate exposure

BackgroundThe role of chromate exposure in the deregulation of total lymphocyte and other immune factors is largely unclear.ObjectivesWe aimed to examine alteration of the Th1/Th2/Th17 cytokine profile and humoral indicators...