Assessment of genotoxicity biomarkers in gasoline station attendants due to occupational exposure.

Gasoline station attendants are exposed to numerous chemicals that might have genotoxic and carcinogenic potential, such as benzene in fuel vapor and particulate matter and polycyclic aromatic hydrocarbons in vehicle exhaust emission. According to IARC, benzene and diesel particulates are Group 1 human carcinogens, and gasoline has been classified as Group 2A "possibly carcinogenic to humans." At gas stations, self-service is not implemented in Turkey; fuel-filling service is provided entirely by employees, and therefore they are exposed to those chemicals in the workplace during all working hours. Genetic monitoring of workers with occupational exposure to possible genotoxic agents allows early detection of cancer. We aimed to investigate the genotoxic damage due to exposures in gasoline station attendants in Turkey. Genotoxicity was evaluated by the Comet, chromosomal aberration, and cytokinesis-block micronucleus assays in peripheral blood lymphocytes. Gasoline station attendants (n = 53) had higher tail length, tail intensity, and tail moment values than controls (n = 61). In gasoline station attendants (n = 46), the frequencies of chromatid gaps, chromosome gaps, and total aberrations were higher compared with controls (n = 59). Increased frequencies of micronuclei and nucleoplasmic bridges were determined in gasoline station attendants (n = 47) compared with controls (n = 40). Factors such as age, duration of working, and smoking did not have any significant impact on genotoxic endpoints. Only exposure increased genotoxic damage in gasoline station attendants independently from demographic and clinical characteristics. Occupational exposure-related genotoxicity risk may increase in gasoline station attendants who are chronically exposed to gasoline and various chemicals in vehicle exhaust emissions.

Human epithelial lung cell toxicity assessment of collected graphite particles from an iron casting industry (in vitro study).

Workers in the iron casting industries are exposed to various chemicals, especially graphite in furnace process. This study aims to investigate the toxic effects of graphite particles on human lung cells. Particle characteristics were confirmed by electron microscope and light scattering. Cell viability and oxidative stress markers were measured. The expression of oxidative repair genes, namely OGG1, MTH1, and ITPA, was evaluated. The average particle size was determined to be 172.1 ± 11.96 nm. The median inhibition concentration (IC50) of graphite particles was 46.75 µg/mL. Notably, 25 and 50 µg/mL concentrations resulted in significant GSH depletion and MDA production. The high concentration of graphite particles (200 µg/mL) led to OGG1 suppression and increased MTH1 expression. Based on these findings, graphite exposure may induce toxicity in human lung cells by increasing oxidative stress. Further research is necessary to fully understand the mechanisms underlying graphite toxicity.

Microbial contamination and metabolite exposure assessment during waste and recyclable material collection.

Waste workers are exposed to bioaerosols when handling, lifting and dumping garbage. Bioaerosol exposure has been linked to health problems such as asthma, airway irritant symptoms, infectious, gastrointestinal and skin diseases, and cancer. Our objective was to characterize the exposure of urban collectors and drivers to inhalable bioaerosols and to measured the cytotoxic effect of air samples in order to evaluate their health risk. Personal and ambient air sampling were conducted during the summer of 2019. Workers from 12 waste trucks collecting recyclables, organic waste or compost were evaluated. Bacteria and fungi were cultured, molecular biology methods were used to detect microbial indicators, cytotoxic assays were performed and endotoxins and mycotoxins were quantified. Domestic waste collectors were exposed to concentrations of bacteria and endotoxins above the recommended limits, and Aspergillus section Fumigati was detected at critical concentrations in their breathing zones. Cytotoxic effects were observed in many samples, demonstrating the potential health risk for these workers. This study establishes evidence that waste workers are exposed to microbial health risks during collection. It also demonstrates the relevance of cytotoxic assays in documenting the general toxic risk found in air samples. Our results also suggest that exposures differ depending on the type of waste, job title and discharge/unloading locations.

HYGIENIC ASSESSMENT OF WORKPLACE ENVIRONMENTAL AIR POLLUTION OF TBILISI CITY MUNICIPAL TRANSPORT AND THEIR SERVICES.

The study aim was to observe the working conditions of individuals working on municipal transport, check the levels of dust and toxicity, and review from the hygienic point of view. The levels of dust and chemical pollutants in the working environment of Tbilisi municipal transport workers were examined. Methods used in hygienic practice were applied to analyze air samples. test in total was conducted to measure the concentration of dust in the air and samples were collected with air analyzers. The toxicity levels in the surrounding environment of the municipal motor vehicle drivers, as well as technicians (welders, electricians, turners, tinsmiths, electric arc welding). It was established that the toxicity of the air in the municipal transports and technical service establishments fluctuates between certain levels. The highest dust levels were found in the working zone of the driver, with dust levels twice accepted levels. Working conditions at this specific zone were identified as 3.1 class. Workplaces in different service stations were also classified in the same group, with dust levels 1.6 times higher than normal. In total 5 workplaces were given level 3.1 classification. Only the workplace of a tinsmith was classified as a level 2 acceptable hazard. The concentration of dust and toxic chemicals in the environment of municipal transport employees is lower than acceptable levels, but long-time exposure to these agents affects the health of individuals and may cause subclinical health effects, even if the disease does not fully manifest. These effects should be taken into consideration when planning regular medical examinations and rejuvenating procedures for the employees.

Derivation of an occupational exposure limit for benzene using epidemiological study quality assessment tools.

This paper derives an occupational exposure limit for benzene using quality assessed data. Seventy-seven genotoxicity and 36 haematotoxicity studies in workers were scored for study quality with an adapted tool based on that of Vlaanderen et al., 2008 (Environ Health. Perspect. 116 1700-5). These endpoints were selected as they are the most sensitive and relevant to the proposed mode of action (MOA) and protecting against these will protect against benzene carcinogenicity. Lowest and No- Adverse Effect Concentrations (LOAECs and NOAECs) were derived from the highest quality studies (i.e. those ranked in the top tertile or top half) and further assessed as being "more certain" or "less certain". Several sensitivity analyses were conducted to assess whether alternative "high quality" constructs affected conclusions. The lowest haematotoxicity LOAECs showed effects near 2 ppm (8 h TWA), and no effects at 0.59 ppm. For genotoxicity, studies also showed effects near 2 ppm and showed no effects at about 0.69 ppm. Several sensitivity analyses supported these observations. These data define a benzene LOAEC of 2 ppm (8 h TWA) and a NOAEC of 0.5 ppm (8 h TWA). Allowing for possible subclinical effects in bone marrow not apparent in studies of peripheral blood endpoints, an OEL of 0.25 ppm (8 h TWA) is proposed.

Mimicking the human respiratory system: Online in vitro cell exposure for toxicity assessment of welding fume aerosol.

In assessing the biological impact of airborne particles in vitro, air-liquid interface (ALI) exposure chambers are increasingly preferred over classical submerged exposure techniques, albeit historically limited by their inability to deliver sufficient aerosolized dose. A novel ALI system, the Dosimetric Aerosol in Vitro Inhalation Device (DAVID), bioinspired by the human respiratory system, uses water-based condensation for highly efficient aerosol deposition to ALI cell culture. Here, welding fumes (well-studied and inherently toxic ultrafine particles) were used to assess the ability of DAVID to generate toxicological responses between differing welding conditions. After fume exposure, ALI-cultured cells showed reductions in viability that were both distinct between welding conditions and linearly dose-dependent with respect to exposure time; comparatively, submerged cell cultures ran in parallel did not show these trends across exposure levels. DAVID delivers a substantial dose in minutes (> 100 µg/cm2), making it preferable over previous ALI systems, which require hours of exposure to deliver sufficient dose, and over submerged techniques, which lack comparable physiological relevance. DAVID has the potential to provide the most accurate assessment of in vitro toxicity yet from the perspectives of physiological relevance to the human respiratory system and efficiency in collecting ultrafine aerosol common to hazardous exposure conditions.

Assessment of the future mesothelioma disease burden from past exposure to asbestos in ship recycling yards in India.

The recycling of end-of-life vessels is a complex activity that generates an enormous amount of hazardous waste, including asbestos-containing materials (ACM). Efforts by the Government of India to comply with national and international regulations and improved standard operating procedures are expected to lower the exposure risk of the workforce to hazardous substances, including asbestos. The current workers are likely to face lesser risks than did those exposed in the past. The present study assesses the health risks from past exposure of asbestos for those workers engaged in handling and removing ACM in ship recycling yards before environmentally sound recycling of obsolete ships was introduced in the early 2000s. Estimates were made of the number of workers exposed, and the intensity of exposure and these data were used to estimate the likely number of mesothelioma deaths in the future. It was estimated that nearly 15% of the total workforce engaged in ship recycling will suffer from mesothelioma which translates to about 4,513 mesothelioma deaths among the total of 31,000 workers estimated to be ever employed in the yards from 1994 till 2002. Recommendations are made for a practical approach to the safe handling of ACMs in Indian ship recycling yards.

Assessment of the toxicity of firefighter exposures using the PAH CALUX bioassay.

Firefighters can be exposed to a complex set of contaminants while at a fire scene. Identifying new ways to monitor and assess exposure, particularly relating to toxicity is essential to determine the effectiveness of intervention techniques to reduce exposure. This study investigated the use of the polycyclic aromatic hydrocarbon (PAH) CALUX® bioassay for the assessment of exposure and associated toxicity firefighters might encounter. This was done through analysis of extracts of dermal wipes and urine samples collected from firefighters before and after a controlled fire. An increased bioassay response was observed from post-fire neck and calf samples, indicating a greater concentration of PAH-like compounds on the skin. The use of a baby wipe to clean the face and neck during rehab resulted in the attenuation of the observed bioassay response from the neck post-fire. Though a correlation was observed between the bioassay response and hydroxylated PAH concentrations found in the urine, the increased bioassay response from the post-fire urine samples was likely due to unknown compounds other than the hydroxylated PAHs tested. Our results suggest that this bioassay provides a useful measure of firefighter exposure, particularly relating to the potential toxicity of contaminants.

Does exposure to bentonite dust during tunnel hyperbaric interventions increase health risks for compressed air workers? A prospective qualitative and quantitative safety assessment.

INTRODUCTION: The mining and tunneling industries are historically associated with hazardous exposures that result in significant occupational health concerns. Occupational respiratory exposures causing pneumoconiosis and silicosis are of great concern, silicosis being non-curable. This work demonstrates that compressed-air workers (CAWs) performing tunnel hyperbaric interventions (HIs) may be at risk for hazards related to bentonite exposure, increasing the likelihood of developing harmful illnesses including cancer. Bentonite dust inhalation may result in respiratory levels of silica exceeding acceptable industrial hygiene standards. METHODS: A qualitative observational exposure assessment was conducted on CAWs while they were performing their HI duties. This was followed by quantitative data collection using personal and area air sample techniques. The results were analyzed and interpreted using standard industrial hygiene principles and guidelines from NIOSH and OSHA. RESULTS: Our work suggests bentonite dust exposure may be an emerging particulate matter concern among CAWs in the tunneling industry. Aerosolized bentonite particles may have potential deleterious effects that include pneumoconiosis and silicosis. Silicosis can result in the development of pulmonary carcinoma. CONCLUSIONS: The modern tunneling industry and required hyperbaric interventional tasks represent a potential public health and occupational concern for CAWs. This paper introduces the modern tunneling industry and the duties of CAWs, the hazardous environment in which they perform their duties, and describes the risks and potential harmful health effects associated with these hazardous exposures.

Quantitative and semi-quantitative risk assessment of occupational exposure to lead among electrical solderers in Neyshabur, Iran.

Lead is one of the most widely used elements in the world. Lead can cause acute and chronic complications such as abnormal hemoglobin synthesis, kidney damage, abortion, nervous system disorders, male infertility, loss of learning ability, behavioral disorders, and even death. The aim of this study was to carry out quantitative and semi-quantitative risk assessments of exposure to lead among the solderers of the Neyshabur electronics industry. This cross-sectional, descriptive, and analytical study was conducted in 2017 and 2018 on 40 female soldering workers exposed to lead. Semi-quantitative risk assessment was carried out according to the Singapore Health Department and quantitative risk assessment according to the Office of Environmental Health Hazard Assessment (OEHHA) method. The average occupational exposure to lead in the electronics manufacturing industry was 93.89 ± 33.40 µg m-3 with a range from 9 to 150 µg m-3. Occupational exposure to lead in the industrial groups of initial soldering with an average of 130.37 ± 40.23 µg m-3 and cutting wires, electroplating, and coating bare parts with an average of 110.24 ± 30.11 µg m-3 was higher than the secondary soldering groups with an average of 90.78 ± 20.22 and shift supervisors with an average of 43.86 ± 10.97 µg m-3. The mean excess lifetime cancer risk (ELCR) was 0.11 per 1000 people and the mean non-carcinogenic risk (HQ) was 7.20. The results of this study indicate that there is a risk of non-carcinogenic complications among electronic solderers. Therefore, managers and employers should reduce lead exposure through engineering controls (substituting lead-free alloys, efficient ventilation) and management strategies such as reducing exposure hours.

Assessment of DNA damage in welders using comet and micronucleus assays.

Welding technology is widely used in pressurized containers, thermal power plants, refineries, chemical facilities and steel structures. Welders are exposed to a number of hazardous compounds such as ultraviolet (UV) radiation, electromagnetic fields, toxic metals and polycyclic aromatic hydrocarbons (PAHs). In the present study, 48 welders and an equal number of control subjects were evaluated for DNA damage in the whole blood and isolated lymphocytes using the comet assay. The genotoxic damage in buccal epithelial cells of subjects was determined by micronucleus (MN) assay. Metal(loids) such as Cr, Mn, Ni, Cu, As, Cd and Pb levels in blood samples were evaluated by using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). Results of this study showed that DNA damage in blood, isolated lymphocytes, and buccal epithelial cells were significantly higher in workers compared to the controls. Also, these workers had remarkably higher blood Cr, Cu, Cd, Ni and Pb levels. These results showed that occupational exposure to welding fumes may cause genotoxic damage that can lead to important health problems in the workers. More extensive epidemiological studies should be performed that enable the assessment of health risk in welding industry.

Benchmark dose assessment for coke oven emissions-induced telomere length effects in occupationally exposed workers in China.

Telomeres are DNA-protein structures that protect chromosome ends from degradation and fusion, which are shortened by oxidative stress, for example air pollution including benzene, toluene, Coke Oven Emissions (COEs), and so on. As a biomarker of health and disease, telomere length is associated with cardiovascular, diabetes and cancers. The aim of this study was to estimate the effects of COEs exposure on telomere length and the benchmark dose (BMD) of COEs. A total of 542 coke oven workers and 235 healthy controls without exposure to toxicants were recruited. Quantitative PCR was used to determine the telomere length in human peripheral blood leukocytes DNA. Propensity scoring was used to match coke oven workers to healthy controls. Linear regression models and trend tests were used to the relationship between COEs exposure and telomere length. Telomere length in COEs exposed group 0.764 (0.536, 1.092) was significantly shorter than that in the control group 1.064(0.762, 1.438), (P < 0.001). There were significantly dose-response relationships between COEs exposure and telomere damage with telomere length as a biomarker. A BMDL value lower than the present occupational exposure limits (OELs) of COEs exposure was evaluated using the BMD approach in coke oven workers. Our results suggested that shorter telomere length is related to occupational exposure to COEs and the level of COEs exposure lower than the current national OELs in China and many other countries could induce telomere damage.

In vitro toxicity assessment of emitted materials collected during the manufacture of water pipe plastic linings.

Objectives: US water infrastructure is in need of widespread repair due to age-related deterioration. Currently, the cured-in-place (CIPP) procedure is the most common method for water pipe repair. This method involves the on-site manufacture of a new polymer composite plastic liner within the damaged pipe. The CIPP process can release materials resulting in occupational and public health concerns. To understand hazards associated with CIPP-related emission exposures, an in vitro toxicity assessment was performed. Materials and Methods: Mouse alveolar epithelial and alveolar macrophage cell lines and condensates collected at 3 worksites utilizing styrene-based resins were utilized for evaluations. All condensate samples were normalized based on the major emission component, styrene. Further, a styrene-only exposure group was used as a control to determine mixture related toxicity. Results: Cytotoxicity differences were observed between worksite samples, with the CIPP worksite 4 sample inducing the most cell death. A proteomic evaluation was performed, which demonstrated styrene-, worksite-, and cell-specific alterations. This examination of protein expression changes determined potential biomarkers of exposure including transglutaminase 2, advillin, collagen type 1, perilipin-2, and others. Pathway analysis of exposure-induced proteomic alterations identified MYC and p53 to be regulators of cellular responses. Protein changes were also related to pathways involved in cell damage, immune response, and cancer. Conclusions: Together these findings demonstrate potential risks associated with the CIPP procedure as well as variations between worksites regarding emissions and toxicity. Our evaluation identified biological pathways that require a future evaluation and also demonstrates that exposure assessment of CIPP worksites should examine multiple chemical components beyond styrene, as many cellular responses were styrene-independent.

Environmental Assessment and Evaluation of Oxidative Stress and Genotoxicity Biomarkers Related to Chronic Occupational Exposure to Benzene.

Environmental and occupational exposure to benzene from fuels is a major cause for concern for national and international authorities, as benzene is a known carcinogen in humans and there is no safe limit for exposure to carcinogens. The objective of this study was to evaluate the genotoxic effects of chronic occupational exposure to benzene among two groups of workers: filling station workers (Group I) and security guards working at vehicles entrances (Group II), both on the same busy highway in Rio de Janeiro, Brazil. Sociodemographic data on the workers were evaluated; the concentration of benzene/toluene (B/T) in atmospheric air and individual trans,trans-muconic acid (ttMA) and S-phenylmercapturic acid (S-PMA) were measured; oxidative stress was analyzed by catalase (CAT), glutathione S-transferase (GST), superoxide dismutase (SOD), thiol groups (THIOL) and malondialdehyde (MDA); genotoxicity was measured by metaphases with chromosomal abnormalities (MCA) and nuclear abnormalities, comet assay using the enzyme formamidopyrimidine DNA glycosylase (C-FPG), and methylation of repetitive element LINE-1, CDKN2B and KLF6 genes. Eighty-six workers participated: 51 from Group I and 35 from Group II. The B/T ratio was similar for both groups, but Group I had greater oscillation of benzene concentrations because of their work activities. No differences in ttMA and S-PMA, and no clinical changes were found between both groups, but linearity was observed between leukocyte count and ttMA; and 15% of workers had leukocyte counts less than 4.5 × 109 cells L-1, demanding close worker's attention. No differences were observed between the two groups for THIOL, MDA, MCA, or nuclear abnormalities. A multiple linear relationship was obtained for the biomarkers MCA and C-FPG. A significant correlation was found between length of time in current job and the biomarkers C-FPG, MCA, GST, and MDA. Although both populations had chronic exposure to benzene, the filling station workers were exposed to higher concentrations of benzene during their work activities, indicating an increased risk of DNA damage.

Health Risk Assessment of Photoresists Used in an Optoelectronic Semiconductor Factory.

Photoresist materials are indispensable in photolithography, a process used in semiconductor fabrication. The work process and potential hazards in semiconductor production have raised concerns as to adverse health effects. We therefore performed a health risk assessment of occupational exposure to positive photoresists in a single optoelectronic semiconductor factory in Taiwan. Positive photoresists are widely used in the optoelectronic semiconductor industry for photolithography. Occupational exposure was estimated using the Stoffenmanager® model. Bayesian modeling incorporated available personal air sampling data. We examined the composition and by-products of the photoresists according to descriptions published in the literature and patents; the main compositions assessed were propylene glycol methyl ether acetate (PGMEA), novolac resin, photoactive compound, phenol, cresol, benzene, toluene, and xylene. Reference concentrations for each compound were reassessed and updated if necessary. Calculated hazard quotients were greater than 1 for benzene, phenol, xylene, and PGMEA, indicating that they have the potential for exposures that exceed reference levels. The information from our health risk assessment suggests that benzene and phenol have a higher level of risk than is currently acknowledged. Undertaking our form of risk assessment in the workplace design phase could identify compounds of major concern, allow for the early implementation of control measures and monitoring strategies, and thereby reduce the level of exposure to health risks that workers face throughout their career.

Burden of lung cancer attributable to occupational diesel engine exhaust exposure in Canada.

OBJECTIVE: To estimate the population attributable fraction (PAF) and number of incident and fatal lung cancers in Canada from occupational exposure to diesel engine exhaust (DEE). METHODS: DEE exposure prevalence and level estimates were used with Canadian Census and Labour Force Survey data to model the exposed population across the risk exposure period (REP, 1961-2001). Relative risks of lung cancer were calculated based on a meta-regression selected from the literature. PAFs were calculated using Levin's equation and applied to the 2011 lung cancer statistics obtained from the Canadian Cancer Registry. RESULTS: We estimated that 2.4% (95% CI 1.6% to 6.6%) of lung cancers in Canada are attributable to occupational DEE exposure, corresponding to approximately 560 (95% CI 380 to 1570) incident and 460 (95% CI 310 to 1270) fatal lung cancers in 2011. Overall, 1.6 million individuals alive in 2011 were occupationally exposed to DEE during the REP, 97% of whom were male. Occupations with the highest burden were underground miners, truck drivers and mechanics. Half of the attributable lung cancers occurred among workers with low exposure. CONCLUSIONS: This is the first study to quantify the burden of lung cancer attributable to occupational DEE exposure in Canada. Our results underscore a large potential for prevention, and a large public health impact from occupational exposure to low levels of DEE.

Pulmonary Impairment and Risk Assessment in a Diacetyl-Exposed Population: Microwave Popcorn Workers.

OBJECTIVES: The butter flavoring additive, diacetyl (DA), can cause bronchiolitis obliterans (BO) by inhalation. A risk assessment was performed using data from a microwave popcorn manufacturing plant. METHODS: Current employees' medical history and pulmonary function tests together with air sampling over a 2.7-year period were used to analyze forced expiratory volume in 1 second (FEV1) and FEV1/forced vital capacity (FVC). The exposure responses for declining pulmonary function and for possible early onset of BO were estimated using multiple regression methods. Several exposure metrics were investigated; benchmark dose and excess lifetime risk of impairment were calculated. RESULTS: Forty-six percent of the population had less than 6 months exposure to DA. Percent-of-predicted FEV1 declined with cumulative exposure (0.40 per ppm-yr, P < 10) as did percent FEV1/FVC (0.13 per ppm-yr, P = 0.0004). Lifetime respiratory impairment prevalence of one per thousand resulted from 0.005 ppm DA and one per thousand lifetime incidence of impairment was predicted for 0.002 ppm DA. CONCLUSION: DA exposures, often exceeding 1 ppm in the past, place workers at high risk of pulmonary impairment.

Probabilistic risk assessment of emerging materials: case study of titanium dioxide nanoparticles.

The development and use of emerging technologies such as nanomaterials can provide both benefits and risks to society. Emerging materials may promise to bring many technological advantages but may not be well characterized in terms of their production volumes, magnitude of emissions, behaviour in the environment and effects on living organisms. This uncertainty can present challenges to scientists developing these materials and persons responsible for defining and measuring their adverse impacts. Human health risk assessment is a method of identifying the intrinsic hazard of and quantifying the dose-response relationship and exposure to a chemical, to finally determine the estimation of risk. Commonly applied deterministic approaches may not sufficiently estimate and communicate the likelihood of risks from emerging technologies whose uncertainty is large. Probabilistic approaches allow for parameters in the risk assessment process to be defined by distributions instead of single deterministic values whose uncertainty could undermine the value of the assessment. A probabilistic approach was applied to the dose-response and exposure assessment of a case study involving the production of nanoparticles of titanium dioxide in seven different exposure scenarios. Only one exposure scenario showed a statistically significant level of risk. In the latter case, this involved dumping high volumes of nano-TiO2 powders into an open vessel with no personal protection equipment. The probabilistic approach not only provided the likelihood of but also the major contributing factors to the estimated risk (e.g. emission potential).

Assessment of personal airborne exposures and surface contamination from x-ray vaporization of beryllium targets at the National Ignition Facility.

This article presents air and surface sampling data collected over the first two years since beryllium was introduced as a target material at the National Ignition Facility. Over this time, 101 experiments with beryllium-containing targets were executed. The data provides an assessment of current conditions in the facility and a baseline for future impacts as new, reduced regulatory limits for beryllium are being proposed by both the Occupational Safety and Health Administration and Department of Energy. This study also investigates how beryllium deposits onto exposed surfaces as a result of x-ray vaporization and the effectiveness of simple decontamination measures in reducing the amount of removable beryllium from a surface. Based on 1,961 surface wipe samples collected from entrant components (equipment directly exposed to target debris) and their surrounding work areas during routine reconfiguration activities, only one result was above the beryllium release limit of 0.2 µg/100 cm2 and 27 results were above the analytical reporting limit of 0.01 µg/100 cm2, for a beryllium detection rate of 1.4%. Surface wipe samples collected from the internal walls of the NIF target chamber, however, showed higher levels of beryllium, with beryllium detected on 73% and 87% of the samples during the first and second target chamber entries (performed annually), respectively, with 23% of the samples above the beryllium release limit during the second target chamber entry. The analysis of a target chamber wall panel exposed during the first 30 beryllium-containing experiments (cumulatively) indicated that 87% of the beryllium contamination remains fixed onto the surface after wet wiping the surface and 92% of the non-fixed contamination was removed by decontaminating the surface using a dry wipe followed by a wet wipe. Personal airborne exposures assessed during access to entrant components and during target chamber entry indicated that airborne beryllium was not present in workers' breathing zones. All the data thus far have shown that beryllium has been effectively managed to prevent exposures to workers during routine and non-routine work.

Volatile compounds emission and health risk assessment during composting of organic fraction of municipal solid waste.

Degradation of mechanically sorted organic fraction (MSOF) of municipal solid waste in composting facilities is among the major contributors of volatile compounds (VCs) generation and emission, causes nuisance problems and health risks on site as well as in the vicinages. The aim of current study was to determine the seasonal (summer and winter) variation and human health risk assessment of VCs in the ambient air of different processing units in MSOF at composting plant in China. Average concentration of VCs was 58.50 and 138.03mg/m3 in summer and winter respectively. Oxygenated compounds were found to be the highest concentration (46.78-91.89mg/m3) with ethyl alcohol as the major specie (43.90-85.31mg/m3) in the two seasons respectively. Nevertheless, individual non-carcinogenic (Hazard relation i.e HR<1) and carcinogenic risk (CR<1.0E-04) of the quantified VCs were within acceptable limit except naphthalene at biofilter unit. In addition, cumulative non-carcinogenic risk exceeded from the threshold limit both in summers and winters in all units except at biofilter unit during winter. Furthermore cumulative carcinogenic risk also exceeded at same unit during the summer season. Therefore special attention should be made to minimize cumulative non-carcinogenic and carcinogenic risk as people are well exposed to mixture of compounds, not to individual.