Genotoxic risk assessment of pathology and anatomy laboratory workers exposed to formaldehyde by use of personal air sampling and analysis of DNA damage in peripheral lymphocytes

Genotoxicity and Cytotoxicity Assessment of Volatile Organic Compounds in Pathology Professionals Through the Buccal Micronuclei Assay

In pathology laboratories, several volatile organic compounds (VOCs) are used, such as formaldehyde, ethanol, and xylene. These substances are recognized as genotoxic and cytotoxic, which is why their handling poses risks to human health. The buccal micronucleus (MN) cytome assay is a non-invasive, useful, and simple method to detect these effects in exposed individuals. The aim of the study was to evaluate the risk of genotoxicity and cytotoxicity of VOCs in pathology professionals of S. Miguel Island, Azores, Portugal. The study comprised two groups: exposed workers (n = 21) from the three laboratories of S. Miguel, and a reference group (n = 50), randomly chosen from other hospital services without known exposure to VOCs. The exfoliated buccal cells were auto-sampled by all the participants using a cytobrush. The samples were processed in ThinPrep®, stained with modified Feulgen with Fast Green, and visualized for MN and other nuclear anomalies (ONAs), such as karyorrhexis, pyknotic, and karyolytic cells. Results showed that VOCs have a predictive significance for MN frequency, leading to the conclusion that their exposure is an increased risk factor for the health of these professionals, approximately four times greater than in the control group.

Comparing formaldehyde risk assessment in histopathology laboratory staff using three methods based on US EPA approaches in the west of Iran

Objective. In different studies, various models have been used for exposure risk assessment of formaldehyde, so this study was conducted to compare existing methods. Method. This cross-sectional analytical study was performed in the pathology section of four hospitals in the west of Iran in 2016. Personal air sampling was performed using National Institute for Occupational Safety and Health (NIOSH) method 3500. Risk assessment with existing methods and comparison between them was performed with the statistical tests. Results. 71% of participants were exposed to values above the threshold limit value. The carcinogenic risk obtained for the staff of the studied hospitals ranged from 3 × 10^-6 to 3.07 × 10^-4. The potential dose of exposure to formaldehyde varied from 73.22 to 3216.06 µg · day^-1. The hazard quotient value was more than 1 in 71.4% of cases. Conclusion. The results of the existing methods for carcinogenic risk assessment are almost similar. In general, the Risk Assessment Information System (RAIS) is recommended because of its simplicity and reduction of error probability, saving time and cost. The results of this study can be used as a guide to select the appropriate risk assessment method for planning, providing appropriate control measures and risk management.

Occupational exposure to formaldehyde, lifetime cancer probability, and hazard quotient in pathology lab employees in Iran: a quantitative risk assessment

Formaldehyde is a colorless and highly irritating substance that is used as a preservative and chemical fixative in tissue processing in pathological laboratories. Formaldehyde is mutagenic and is classified by the IARC as the definitive carcinogen (A1 group). This cross-sectional descriptive-analytical study was performed to determine the respiratory exposure of 60 employees of pathology labs with formaldehyde and to estimate carcinogenic and non-carcinogenic risk in Iran in 2018-2019. Occupational exposure to formaldehyde was assessed in summer season using the NIOSH 3500 method and a personal sampler with flow of 1 l/min connected to two Glass Midget Impingers containing 20 ml of 1% sodium bisulfate solution. The respiratory symptoms questionnaire provided by the American Thoracic Society was used to assess the health effects of formaldehyde exposure. The carcinogenic and non-carcinogenic risk assessment of inhaled exposure to formaldehyde was also performed using the USA Environmental Protection Agency (OEHHA) method. The mean respiratory exposure of employees to formaldehyde was 0.64 mg/m³ (range: 0.1474 to 1.3757). Occupational exposure in 28.3% (n = 17) of employees was above the OSHA recommended range. Wheezing (24%), burning eyes (25%), and cough (21.7%) were the most prevalent health problems. The mean ± SD of the carcinogenic risk among the employees was 3.45 × 10^-4 ± 2.27 × 10^-4. The highest mean of carcinogenic risk was found in lab workers (4.44 × 10^-4). Given the high level of carcinogenic and non-carcinogenic risk of respiratory exposure to formaldehyde in pathological employees, especially lab worker, the use of management controls, engineering controls, and respiratory protection equipment to reduce exposure levels of all workers to less than the allowed exposure limits seems necessary.

Polyvinyl alcohol modification with sustainable ketones

Water-degradable polyvinyl ketals with high glass transition temperatures (78–127 °C) were made via ketalization of polyvinyl alcohol (PVA) with sustainable ketones.

Development of a Simple and Powerful Analytical Method for Formaldehyde Detection and Quantitation in Blood Samples

Human beings are easily exposed to formaldehyde (FA) in a living environment. Entry of FA into the human body can have adverse effects on human health, depending on the FA concentration. Thus, a quantitative analysis of FA in blood is necessary in order to estimate its effect on the human body. In this study, a simple and rapid analytical method for the quantitation of FA in blood was developed. The total analysis time, including the pretreatment procedure, was less than 20 min. To ensure a stable analysis, blood samples were stabilized using tripotassium ethylenediaminetetraacetic acid solution, and FA was selectively derivatized using 2,4-dinitrophenylhydrazine as pretreatment procedures. The pretreated samples were analyzed using a high-performance liquid chromatography-UV system, which is the most common choice for analyzing small-molecule aldehydes like formaldehyde. Verification of the pretreatment methods (stabilization and derivatization) using FA standards confirmed that the pretreatment methods are highly reliable in the calibration range 0.012-5.761 ng μL-1 (slope = 684,898, R 2 = 0.9998, and limit of detection = 0.251 pg·μL-1). Analysis of FA in the blood samples of a Yucatan minipig using the new method revealed an average FA concentration of 1.98 ± 0.34 ng μL-1 (n = 3). Blood samples spiked with FA standards were analyzed, and the FA concentrations were found to be similar to the theoretical concentrations (2.16 ± 0.81% difference). The method reported herein can quantitatively analyze FA in blood at a sub-nanogram level within a short period of time and is validated for application in blood analysis.

How improvements in monitoring and safety practices lowered airborne formaldehyde concentrations at an Italian university hospital: a summary of 20 years of experience

The last two decades have been crucial for the assessment of airborne formaldehyde (FA) exposure in healthcare environments due to changes in limits and reference values, definition of carcinogenicity, and new monitoring methods. The aim of this study was to analyse twenty years (1999–2019) of experience in automatic, continuous airborne FA monitoring in the Pathology Laboratory and operating rooms at the Careggi University Hospital, Florence, Italy. These 20 years saw gradual improvements in FA monitoring of exposed employees considered at maximum risk, including improvements in analytical methods of detection and sampling strategies, which came with changes in procedures and workflow operations. In 2019, after the adoption of safe practices, including a closed-circuit system using pre-loaded containers and a vacuum sealing, 94 % of the total measurements (FA concentrations) were lower than 16 μg/m³, and only 6 % ranged from 21 to 75 μg/m³. In the studied work units, the ratio between area and personal readings ranged from 0.9 to 1.0, both for long and short-term sampling. Personal sampling was simplified with a new workstation, which integrated different monitoring systems into an innovative ergonomic armchair equipped with personal sampling devices. Area monitoring was also improved with a real-time, continuous photoacoustic instrument. Over these 20 years, FA exposure significantly dropped, which coincided with optimised histology workflow and implementation of safety practices. For high-throughput screening and cost savings we propose an innovative ergonomic armchair station which allows remote continuous monitoring.

Assessment of Chemical Risks in Moroccan Medical Biology Laboratories in Accordance with the CLP Regulation

Background

Medical laboratory workers are frequently exposed to a wide range of chemicals. This exposure can have adverse effects on their health. Furthermore, a knowledge lack of the chemical risk increases the likelihood of exposure. The chemical risk assessment reduces the risk of exposure to hazardous chemicals and therefore, guarantees health and safety of the workers.

Method

The chemical risk assessment was conducted using a modified INRS method, according to the new CLP Regulation, of 11 unit laboratories in a Moroccan medical laboratory. Observation of each workstation and analysis of safety data sheets are key tools in this study.

Results

A total of 144 substances and reagents that could affect the health of the analytical technicians were identified. Among these products, 17% are concerned by the low priority risk score, with 55% concerned by the average priority risk score and 28% concerned by the high priority risk score. This study also enabled to better identify the chemical agents that have restrictive occupational exposure limit value and controls were conducted to this effect. On the basis of the results obtained, several corrective and preventive measures have been proposed and implemented.

Conclusion

Risk assessment is essential to ensure the health and safety of workers and to meet regulatory requirements. It enables to identify all the risky manipulations and to adopt appropriate preventive measures. However, it is not a one-time activity but it must be continuous in order to master the changes and thus ensure the best safety of all.

Occupational Exposure and Risk Assessment of Formaldehyde in the Pathology Departments of Hospitals

Background and Objective:

Exposure to formaldehyde has adverse effects on health both acutely and over the long term (e.g., carcinogenicity). The substance is widely used in pathology and histology departments. This study focused on cancer risk of formaldehyde in pathology department of five hospitals in Rasht.

Materials and Methods:

Sampling and determination of formaldehyde in pathology department were carried out based on the NIOSH method of 3500. The working condition and working environment were investigated and a semi quantitative risk assessment were used to health risk assessment of formaldehyde and The individual lifetime cancer probability, which is defined as the increase in the probability of developing cancer during continuous exposure to an air pollutant were used to assess health risks with formaldehyde.

Results:

The results showed that the exposure level of all subjects were higher than the Occupational Exposure Limit for 8 hours exposure time of formaldehyde. However, in the five occupational groups, the highest weekly exposure index was observed for the Lab Technicians (0.664 ppm) at Hospital no. 5, which could have been due to more daily working hours at this sampling site and a lack of adequate ventilation. The formaldehyde concentration was in the 0.0192 to 0.326 ppm ranges for five hospital pathology departments. The cancer risk ranged from 9.52×10^-5 to 1.53×10^-3, and it was greater than the WHO acceptable cancer risk level.

Conclusions:

The results of the risk assessments can be used for managing the chemical exposure of allocated resources for defining control actions. This process plays an important role in reducing the level of exposure to formaldehyde in pathology departments.

Formaldehyde Exposure and Epigenetic Effects: A Systematic Review

Formaldehyde (FA) is a general living and occupational pollutant, classified as carcinogenic for humans. Although genotoxicity is recognized as a FA mechanism of action, a potential contribution of epigenetic effects cannot be excluded. Therefore, aim of this review is to comprehensively assess possible epigenetic alterations induced by FA exposure in humans, animals, and cellular models. A systematic review of Pubmed, Scopus, and Isi Web of Science databases was performed. DNA global methylation changes were demonstrated in workers exposed to FA, and also in human bronchial cells. Histone alterations, i.e., the reduction in acetylation of histone lysine residues, in human lung cells were induced by FA. Moreover, a dysregulation of microRNA expression in human lung adenocarcinoma cells as well as in the nose, olfactory bulb and white blood cells of rodents and nonhuman primates was reported. Although preliminary, these findings suggest the role of epigenetic modifications as possible FA mechanisms of action that need deeper qualitative and quantitative investigation. This may allow to define the role of such alterations as indicators of early biological effect and the opportunity to include such information in future risk assessment and management strategies for public and occupationally FA-exposed populations.

Qualitative analysis of surgical smoke produced during burn operations

Burned tissue is necrotic and it is surrounded by a zone of stasis and hyperaemia with changed cell metabolism. The removal of burned tissue using an electric knife releases large amounts of surgical smoke. The aim of the research was to analyse volatile, nonpolar, organic compounds that are released during the excision of burned tissue using an electric knife (mono- and bipolar). The study includes analysis from 40 solid-phase microextraction (SPME) fibres, exposed during 10 interventions (6 escharotomy and 4 necrectomy). The analysis of volatile compounds was performed using mass spectrometry gas chromatography (GCxGC-ToFMS).The total analysis covered 432 compounds, whereas after the removal of the "background" compounds - 153 volatile organic substances remained. The analysis of surgical smoke showed that, including derivatives, benzene constituted as much as 17.65% of all of the studied compounds. Cyclic compounds constituted on average 22.5% of the analysed substances, out of which cycloheptatrien constituted 20.26%. Alkanes, alcohols and their derivatives constituted nearly 25% of volatile organic compounds, with chloromethane constituting as much as 13.7%. Permutational multivariate analysis of variance (PERMANOVA) revealed statistically significant differences between escharotomy and necrectomy patients (F(1.9) = 5.91, p = 0.007).Our study revealed the presence of complex toxic hydrocarbon derivatives in surgical smoke. We also observed that the content of surgical smoke is different depending on the type of the conducted intervention. So far, no studies focusing on hazards posed by surgical smoke that is released during the resection of burned tissue are in the literature.

Occupational exposure to formaldehyde and early biomarkers of cancer risk, immunotoxicity and susceptibility

Formaldehyde (FA) is a high-volume production chemical manufactured worldwide to which many people are exposed to both environmentally and occupationally. FA was recently reclassified as a human carcinogen. Several epidemiological studies have revealed an increased risk of cancer development among workers exposed to FA. Although FA genotoxicity was confirmed in a variety of experimental systems, data from human studies are conflicting. The aim of the present study was to evaluate the occupational exposure to FA in a multistage approach relating the exposure with different biomarkers (dose and effect) and individual susceptibility. Air monitoring was performed to estimate the level of exposure to FA during shift work. Eighty-five workers from hospital anatomy-pathology laboratories exposed to FA and 87 controls were tested for cytogenetic alterations in lymphocytes (micronucleus, MN; sister-chromatid exchange, SCE) and T-cell receptor (TCR) mutation assay. The frequency of MN in exfoliated buccal cells, a first contact tissue was also assessed. Percentages of different lymphocyte subpopulations were selected as immunotoxicity biomarkers. The level of formic acid in urine was investigated as a potential biomarker of internal dose. The effects of polymorphic genes of xenobiotic metabolising enzymes and DNA repair enzymes on the endpoints studied were determined. The mean level of FA exposure was 0.38 ± 0.03 ppm. MN (in lymphocytes and buccal cells) and SCE were significantly increased in FA-exposed workers compared to controls. MN frequency positively correlated with FA levels of exposure and duration. Significant alterations in the percentage of T cytotoxic lymphocytes, NK cells and B lymphocytes were found between groups. Polymorphisms in CYP2E1, GSTP1 and FANCA genes were associated with increased genetic damage in FA-exposed subjects. The obtained information may provide new important data to be used by health and safety care programs and by governmental agencies responsible for setting the acceptable levels for occupational exposure to FA.

Increase of global DNA methylation patterns in beauty salon workers exposed to low levels of formaldehyde

Formaldehyde (FA) is a carcinogenic aldehyde illegally added to creams as a hair straightening agent for the Brazilian blowout (BB). This study aimed to investigate the possible effects of occupational exposure to FA on global DNA methylation in salon workers with different exposure levels. FA exposure was monitored using environmental and biological measurements. The study included 49 salon workers divided by FA levels in the workplace into group A (FA < 0.01 ppm; n = 8), group B (0.03 ppm < FA < 0.06 ppm; n = 15), and group C (0.08 ppm < FA < 0.24 ppm; n = 26). The global DNA methylation levels were 3.12%, 4.55%, and 4.29% for groups A, B, and C, respectively, with statistically higher values for groups B and C compared to group A (p = 0.002). A correlation was found between FA in passive samplers and global DNA methylation (r_s = 0.307, p = 0.032). Additionally, when only taking into account the hairdressers that performed the BB on clients instead of the whole group, a stronger correlation was observed between FA in personal passive samplers and global DNA methylation (r_s = 0.764, p = 0.006). For the first time, an increase in DNA methylation was observed in subjects occupationally exposed to FA. In conclusion, our results indicated that even low levels of FA exposure could cause a disturbance in DNA methylation, leading to epigenetic changes, which is associated with cancer development. These data suggest a possible contribution of FA to cancer development through occupational exposure.

Bio-monitoring of DNA damage in matchstick industry workers from Peshawar Khyber Pakhtunkhwa, Pakistan

BACKGROUND

Safety protocols are usually neglected in most of the matchstick industries rendering the laborer prone to various occupational hazards.

OBJECTIVE

The present study highlights DNA damage among matchstick factory workers (n = 92) against a control group (n = 48) of healthy individuals.

METHODS

Genotoxicity was measured in peripheral blood lymphocytes of the test subjects using a Single Cell Gel Electrophoresis assay (SCGE/comet assay).

RESULTS

Our results substantiate a high Total Comet Score (TCS) for factory workers (74.5 ± 47.0) when compared to the control group (53.0 ± 25.0) (P ≤ 0.001). Age and duration of occupational exposure had no significant effect (P > 0.05) on TCS value. As for job function, the TCS value was greatest in sweepers (91.0 ± 56.1) and lowest in box-making operators (26.0 ± 25.0) indicating that waste disposal poses the higher risk of DNA damage.

CONCLUSIONS

Our study corroborates that matchstick chemicals can potentially damage the DNA of exposed subjects.

Hair straightening products and the risk of occupational formaldehyde exposure in hairstylists

Hair straitening products are widely used by hairstylists. Many keratin-based hair smoothing products contain formaldehyde. This study aimed to investigate occupational formaldehyde exposure among hairstylists dealing with hair straightening products and the relation between genotoxicity biomarkers and the short-term formaldehyde exposure concentrations and the working years. The study was carried out in Cairo, Egypt on 60 hairstylists use hair straightening products divided into two groups according to the working years. All hairstylists were subjected to micronucleus (MN) frequencies in both epithelial buccal cells (EBC) and peripheral blood lymphocytes (PBL). Fifteen-minute (min) formaldehyde exposure concentrations were measured at workplace during hair straightening procedure. Fifteen-minute formaldehyde concentrations in both groups exceeded the National Institute for Occupational Safety and Health and the American Conference of Governmental Industrial Hygienist thresholds levels. The MN frequencies in EBC and PBL showed a significant increase in group II in comparison to control and group I, which in turn showed a significant increase in MN frequency in PBL and a nonsignificant increase in the MN frequency in EBC when compared to control. A positive correlation was found between genotoxicity biomarkers and working years. Occupational exposures to hair straightening products in the studied hairstylist were found to expose them to formaldehyde concentrations that exceeded the standard limits. All selected genotoxicity biomarkers showed a significant increase in exposed workers and were positively correlated to the duration of exposure.

Volatile Organic Compounds in Anatomical Pathology Wards: Comparative and Qualitative Assessment of Indoor Airborne Pollution

The impact of volatile organic compounds (VOCs) on indoor air quality and on human health is widely recognized. However, VOC contamination in hospital indoor air is rarely studied and chemical compounds that singularly do not show high toxicity are not submitted to any regulation. This study aimed to compare VOC contamination in two different anatomical pathology wards in the same hospital. Hydrocarbons, alcohols, and terpenes were sampled by passive diffusive samplers. Analytical tests were performed by thermal desorption coupled with gas chromatography and mass spectrometry detector. Results highlighted a different VOC pollution in the two wards, due to the structural difference of the buildings and different organizational systems. The scarcity of similar data in the literature shows that the presence of VOCs in pathology wards is an underestimated problem. We believe that, because of the adverse effects that VOCs may have on the human health, this topic is worth exploring further.

Induction of centrosome amplification by formaldehyde, but not hydroquinone, in human lymphoblastoid TK6 cells

Benzene and formaldehyde (FA) are important industrial chemicals and environmental pollutants that cause leukemia by inducing DNA damage and chromosome aberrations in hematopoietic stem cells (HSC), the target cells for leukemia. Our previous studies showed that workers exposed to benzene and FA exhibit increased levels of aneuploidy in their blood cells. As centrosome amplification is a common phenomenon in human cancers, including leukemia, and is associated with aneuploidy in carcinogenesis, we hypothesized that benzene and FA would induce centrosome amplification in vitro. We treated human lymphoblastoid TK6 cells with a range of concentrations of hydroquinone (HQ, a benzene metabolite) or FA for 24 h, allowed the cells to recover in fresh medium for 24 h, and examined centrosome amplification; chromosomal gain, loss, and breakage; and cytotoxicity. We included melphalan and etoposide, chemotherapeutic drugs that cause therapy-related acute myeloid leukemia and that have been shown to induce centrosome amplification as well as chromosomal aneuploidy and breakage, as positive controls. Melphalan and etoposide induced centrosome amplification and chromosome gain and breakage in a dose-dependent manner, at cytotoxic concentrations. HQ, though cytotoxic, did not induce centrosome amplification or any chromosomal aberration. FA-induced centrosome amplification and cytotoxicity, but did not induce chromosomal aberrations. Our data suggest, for the first time, that centrosome amplification is a potential mechanism underlying FA-induced leukemogenesis, but not benzene-induced leukemogenesis, as mediated through HQ. Future studies are needed to delineate the mechanisms of centrosome amplification and its association with DNA damage, chromosomal aneuploidy and carcinogenesis, following exposure to FA.

Evaluation of genotoxicity in workers exposed to low levels of formaldehyde in a furniture manufacturing facility

Formaldehyde (FA) is a chemical widely used in the furniture industry and has been classified as a potential human carcinogen. The purpose of this study was to evaluate the occupational exposure of workers to FA at a furniture manufacturing facility and the relationship between environmental concentrations of FA, formic acid concentration in urine, and DNA damage. The sample consisted of 46 workers exposed to FA and a control group of 45 individuals with no history of occupational exposure. Environmental concentrations of FA were determined by high-performance liquid chromatography. Urinary formic acid concentrations were determined by gas chromatography with flame ionization detector. DNA damage was evaluated by the micronucleus (MN) test performed in exfoliated buccal cells and comet assay with venous blood. The 8-h time-weighted average of FA environmental concentration ranged from 0.03 ppm to 0.09 ppm at the plant, and the control group was exposed to a mean concentration of 0.012 ppm. Workers exposed to higher environmental FA concentrations had urinary formic acid concentrations significantly different from those of controls (31.85 mg L(-1) vs. 19.35 mg L(-), p ≤ 0.01 Mann-Whitney test). Significant differences were found between control and exposed groups for the following parameters: damage frequency and damage index in the comet assay, frequency of binucleated cells in the MN test, and formic acid concentration in urine. The frequency of micronuclei, nuclear buds, and karyorrhexis did not differ between groups. There was a positive correlation between environmental concentrations of FA and damage frequency (Spearman's rank correlation coefficient [r s] = 0.24), damage index (r s = 0.21), binucleated cells (r s = 0.34), and urinary formic acid concentration (r s = 0.63). The results indicate that, although workers in the furniture manufacturing facility were exposed to low environmental levels of FA, this agent contributes to the observed increase in cytogenetic damage. In addition, urinary formic acid concentrations correlated strongly with occupational exposure to FA.

Increased levels of chromosomal aberrations and DNA damage in a group of workers exposed to formaldehyde

Formaldehyde (FA) is a commonly used chemical in anatomy and pathology laboratories as a tissue preservative and fixative. Because of its sensitising properties, irritating effects and cancer implication, FA accounts probably for the most important chemical-exposure hazard concerning this professional group. Evidence for genotoxic effects and carcinogenic properties in humans is insufficient and conflicting, particularly in regard to the ability of inhaled FA to induce toxicity on other cells besides first contact tissues, such as buccal and nasal cells. To evaluate the effects of exposure to FA in human peripheral blood lymphocytes, a group of 84 anatomy pathology laboratory workers exposed occupationally to FA and 87 control subjects were tested for chromosomal aberrations (CAs) and DNA damage (comet assay). The level of exposure to FA in the workplace air was evaluated. The association between genotoxicity biomarkers and polymorphic genes of xenobiotic-metabolising and DNA repair enzymes were also assessed. The estimated mean level of FA exposure was 0.38±0.03 ppm. All cytogenetic endpoints assessed by CAs test and comet assay % tail DNA (%TDNA) were significantly higher in FA-exposed workers compared with controls. Regarding the effect of susceptibility biomarkers, results suggest that polymorphisms in CYP2E1 and GSTP1 metabolic genes, as well as, XRCC1 and PARP1 polymorphic genes involved in DNA repair pathways are associated with higher genetic damage in FA-exposed subjects. Data obtained in this study show a potential health risk situation of anatomy pathology laboratory workers exposed to FA (0.38 ppm). Implementation of security and hygiene measures may be crucial to decrease risk. The obtained information may also provide new important data to be used by health care programs and by governmental agencies responsible for occupational health and safety.

Chromosome-wide aneuploidy study of cultured circulating myeloid progenitor cells from workers occupationally exposed to formaldehyde

Formaldehyde (FA) is an economically important industrial chemical to which millions of people worldwide are exposed environmentally and occupationally. Recently, the International Agency for Cancer Research concluded that there is sufficient evidence that FA causes leukemia, particularly myeloid leukemia. To evaluate the biological plausibility of this association, we employed a chromosome-wide aneuploidy study approach, which allows the evaluation of aneuploidy and structural chromosome aberrations (SCAs) of all 24 chromosomes simultaneously, to analyze cultured myeloid progenitor cells from 29 workers exposed to relatively high levels of FA and 23 unexposed controls. We found statistically significant increases in the frequencies of monosomy, trisomy, tetrasomy and SCAs of multiple chromosomes in exposed workers compared with controls, with particularly notable effects for monosomy 1 [P = 6.02E-06, incidence rate ratio (IRR) = 2.31], monosomy 5 (P = 9.01E-06; IRR = 2.24), monosomy 7 (P = 1.57E-05; IRR = 2.17), trisomy 5 (P = 1.98E-05; IRR = 3.40) and SCAs of chromosome 5 (P = 0.024; IRR = 4.15). The detection of increased levels of monosomy 7 and SCAs of chromosome 5 is particularly relevant as they are frequently observed in acute myeloid leukemia. Our findings provide further evidence that leukemia-related cytogenetic changes can occur in the circulating myeloid progenitor cells of healthy workers exposed to FA, which may be a potential mechanism underlying FA-induced leukemogenesis.

Assessment of genotoxic effects in nurses handling cytostatic drugs

Several antineoplastic drugs have been classified as carcinogens by the International Agency for Research on Cancer (IARC) on the basis of epidemiological findings, animal carcinogenicity data, and outcomes of in vitro genotoxicity studies. 5-Fluorouracil (5-FU), which is easily absorbed through the skin, is the most frequently used antineoplastic agent in Portuguese hospitals and therefore may be used as an indicator of surface contamination. The aims of the present investigation were to (1) examine surface contamination by 5-FU and (2) assess the genotoxic risk using cytokinesis-block micronucleus assay in nurses from two Portuguese hospitals. The study consisted of 2 groups: 27 nurses occupationally exposed to cytostatic agents (cases) and 111 unexposed individuals (controls). Peripheral blood lymphocytes (PBL) were collected in order to measure micronuclei (MN) in both groups. Hospital B showed a higher numerical level of contamination but not significantly different from Hospital A. However; Hospital A presented the highest value of contamination and also a higher proportion of contaminated samples. The mean frequency of MN was significantly higher in exposed workers compared with controls. No significant differences were found among MN levels between the two hospitals. The analysis of confounding factors showed that age is a significant variable in MN frequency occurrence. Data suggest that there is a potential genotoxic damage related to occupational exposure to cytostatic drugs in oncology nurses.

Amended Safety Assessment of Formaldehyde and Methylene Glycol as Used in Cosmetics

Formaldehyde and methylene glycol may be used safely in cosmetics if established limits are not exceeded and are safe for use in nail hardeners in the present practices of use and concentration, which include instructions to avoid skin contact. In hair-smoothing products, however, in the present practices of use and concentration, formaldehyde and methylene glycol are unsafe. Methylene glycol is continuously converted to formaldehyde, and vice versa, even at equilibrium, which can be easily shifted by heating, drying, and other conditions to increase the amount of formaldehyde. This rapid, reversible formaldehyde/methylene glycol equilibrium is distinguished from the slow, irreversible release of formaldehyde resulting from the so-called formaldehyde releaser preservatives, which are not addressed in this safety assessment (formaldehyde releasers may continue to be safely used in cosmetics at the levels established in their individual Cosmetic Ingredient Review safety assessments).

Effects of formaldehyde exposure on human NK cells in vitro

Natural killer (NK) cells play a pivotal role in human immunologic surveillance. Formaldehyde (FA), a ubiquitous environmental contaminant, has been classified as a carcinogen to humans. Although it is known that immune cells are sensitive to FA, so far little is known about how it's affecting the activity of human NK cells. To probe it, the primary human NK cells were treated with different concentrations of FA (3200, 1600, 800, 400, 200, 100, 50, and 0 μM) in vitro. The morphology, viability, apoptosis, cytotoxicity (killing tumor cell activity) and cytokine and cytolytic proteins secretion of NK cells were evaluated respectively. Our results reveal that FA could induce NK cells death obviously in a concentration-dependent manner. With the decreased concentrations of FA from 3200 μM to 800 μM, accordingly, the viability of NK cells increased from 65. 2 ± 12.1% to 78.48 ± 10.3% (p<0.05), and the cytotoxicity of NK cells recovered from 29.2 ± 8.5% to 63.9 ± 5.9% (p<0.05). The secretion of perforin was affected significantly by FA, whereas the secretion of IFN-γ and granzyme-B altered slightly. It is concluded that human NK cell is sensitive to FA, 800 μM may be a critical concentration of FA inhibiting the activity of human NK cell.

A cytogenetic approach to the effects of low levels of ionizing radiation (IR) on the exposed Tunisian hospital workers

OBJECTIVES

The aim of this study is to assess chromosomal damage in Tunisian hospital workers occupationally exposed to low levels of ionizing radiation (IR).

MATERIALS AND METHODS

The cytokinesis-block micronucleus (CBMN) assay in the peripheral lymphocytes of 67 exposed workers compared to 43 controls matched for gender, age and smoking habits was used. The clastogenic/aneugenic effect of IR was evaluated using the CBMN assay in combination with fluorescence in situ hybridization with human pan-centromeric DNA in all the exposed subjects and controls.

RESULTS

The study showed a significant increase of the micronucleus (MN) frequency in the lymphocytes of the exposed workers compared to the control group (13.63 ± 4.9‰ vs. 6.52 ± 4.21‰, p < 0.05). The centromere analysis performed in our study showed that MNs in hospital staff were predominantly centromere negative (72%) and the mean negative labeled micronucleus (C-MN) frequency was significantly higher in the exposed subjects than in the controls (9.04 ± 4.57‰ vs. 1.17 ± 0.77‰). The multivariate regression analysis, taking into account all confounding factors, showed that only the time of exposure to IR had a significant effect on the level of MNs and C-MN.

CONCLUSION

The present study shows that chromosomal damage leading to the formation of micronucleated lymphocytes is more frequent in the hospital workers exposed to IR than in the controls, despite the low levels of exposure. The results of the study confirm the well-known clastogenic properties of ionizing radiation. In regards to health monitoring, detection of early genotoxic effects may allow for the adoption of preventive biological control measures, such as hygienic improvements in the workplace or reduction of hours of occupational exposure.

A combination of micronucleus assay and fluorescence in situ hybridization analysis to evaluate the genotoxicity of formaldehyde

A genotoxic effect of formaldehyde (FA), particularly micronucleus (MN) induction, has been shown in several previous studies. The aim of the present study was to assess the frequency of micronuclei and to identify the type of chromosomal damage in Tunisian staff members working in the Pathologic Anatomy Laboratory of Farhat Hached hospital (Sousse, Tunisia) who were exposed to FA. Assessment of chromosomal damage was performed in peripheral lymphocytes of 31 FA-exposed employees compared with 31 control employees working in the administrative department of the same hospital. The clastogenic/aneugenic effect of FA was evaluated using the standard MN assay in combination with fluorescence in situ hybridization (FISH) using pan-centromeric probes. The mean level of exposure to FA was 3.4 ppm. The results showed a significant increase of MN frequency in lymphocytes of exposed workers compared with the control group (25.35 ± 6.28 ‰ vs. 7.08  ± 4.62 ‰, p < 0.05). As assessed by FISH, the frequency of centromeric micronuclei (C+MN) was greater in exposed subjects than in controls (18.38 ± 5.94 ‰ vs. 5.03 ± 3.64 ‰). Among the C+MN, the frequency of MN containing one centromere (C1+MN) was significantly greater in pathologists and anatomists than in controls (15.35 ± 6.0 ‰ vs. 3.33 ± 2.74 ‰, p < 0.05). The results showed an effect of sex and time of FA exposure with significantly increased frequencies of all end points measuring aneuploidy (C+MN, C1+MN, and Cx+MN [more then one MN]). The increased frequency of C1+MN observed in the exposed group may suggest a slight aneugenic effect of FA exposure.

Cytogenetic and immunological effects associated with occupational formaldehyde exposure

Formaldehyde (FA) is a widely used industrial chemical for which exposure is associated with nasopharyngeal and sinonasal cancer. Based on sufficient evidence of carcinogenicity from human investigations, supporting studies on mechanisms underlying carcinogenesis, and experimental evidence in animals, FA status was recently revised and reclassified as a human carcinogen. The highest level of exposure to FA occurs in occupational settings. Although several studies reported FA ability to induce genotoxic responses in exposed workers, not all findings were conclusive. In addition, published studies on the immunological effects of FA indicate that this compound may be able to modulate immune responses, although data in exposed subjects are still preliminary. In this study a group of pathology anatomy workers exposed to FA was evaluated for cytogenetic and immunological parameters. A control group with similar sociodemographic characteristics and without known occupational exposure to FA was also included. Genotoxicity was evaluated by means of micronucleus (MN) test, sister chromatid exchanges (SCE), and T-cell receptor (TCR) mutation assay. Percentages of different lymphocyte subpopulations were selected as immunotoxic biomarkers. The mean level of FA environmental exposure was 0.36 ± 0.03 ppm. MN and SCE frequencies were significantly increased in the exposed group. A significant decrease of the percentage of B cells in the exposed group was also found. Data obtained in this study indicate that genotoxic and immunotoxic increased risk due to FA occupational exposure cannot be excluded. Implementation of effective control measures along with hazard prevention campaigns may be crucial to decrease the risk.

Environmental nitration processes enhance the mutagenic potency of aromatic compounds

This work is an attempt to establish if aromatic nitration processes are always associated with an increase of genotoxicity. We determined the mutagenic and genotoxic effects of Benzene (B), Nitrobenzene (NB), Phenol (P), 2-Nitrophenol (2-NP), 2,4-Dinitrophenol (2,4-DNP), Pyrene (Py), 1-Nitropyrene (1-NPy), 1,3-Dinitropyrene (1,3-DNPy), 1,6-Dinitropyrene (1,6-DNPy), and 1,8-Dinitropyrene (1,8-DNPy). The mutagenic activities were evaluated with umuC test in presence and in absence of metabolic activation with S9 mix. Then, we used both cytokinesis-blocked micronucleus (CBMN) assay, in combination with fluorescent in situ hybridization (FISH) of human pan-centromeric DNA probes on human lymphocytes in order to evaluate the genotoxic effects. Analysis of all results shows that nitro polycyclic aromatic hydrocarbons (PAHs) are definitely environmental genotoxic/mutagenic hazards and confirms that environmental aromatic nitration reactions lead to an increase in genotoxicity and mutagenicity properties. Particularly 1-NPy and 1,8-DNPy can be considered as human potential carcinogens. They seem to be significant markers of the genotoxicity, mutagenicity, and potential carcinogenicity of complex PAHs mixtures present in traffic emission and industrial environment. In prevention of environmental carcinogenic risk 1-NPy and 1,8-DNPy must therefore be systematically analyzed in environmental complex mixtures in association with combined umuC test, CBMN assay, and FISH on cultured human lymphocytes. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.

Re-evaluation of a reported increased micronucleus frequency in lymphocytes of workers occupationally exposed to formaldehyde

A replicate evaluation of increased micronucleus (MN) frequencies in peripheral lymphocytes of workers occupationally exposed to formaldehyde (FA) was undertaken to verify the observed effect and to determine scoring variability. May-Grünwald-Giemsa-stained slides were obtained from a previously performed cytokinesis-block micronucleus test (CBMNT) with 56 workers in anatomy and pathology laboratories and 85 controls. The first evaluation by one scorer (scorer 1) had led to a highly significant difference between workers and controls (3.96 vs 0.81 MN per 1000 cells). The slides were coded before re-evaluation and the code was broken after the complete re-evaluation of the study. A total of 1000 binucleated cells (BNC) were analysed per subject and the frequency of MN (in ‰) was determined. Slides were distributed equally and randomly between two scorers, so that the scorers had no knowledge of the exposure status. Scorer 2 (32 exposed, 36 controls) measured increased MN frequencies in exposed workers (9.88 vs 6.81). Statistical analysis with the two-sample Wilcoxon test indicated that this difference was not significant (p=0.17). Scorer 3 (20 exposed, 46 controls) obtained a similar result, but slightly higher values for the comparison of exposed and controls (19.0 vs 12.89; p=0.089). Combining the results of the two scorers (13.38 vs 10.22), a significant difference between exposed and controls (p=0.028) was obtained when the stratified Wilcoxon test with the scorers as strata was applied. Interestingly, the re-evaluation of the slides led to clearly higher MN frequencies for exposed and controls compared with the first evaluation. Bland-Altman plots indicated that the agreement between the measurements of the different scorers was very poor, as shown by mean differences of 5.9 between scorer 1 and scorer 2 and 13.0 between scorer 1 and scorer 3. Calculation of the intra-class correlation coefficient (ICC) revealed that all scorer comparisons in this study were far from acceptable for the reliability of this assay. Possible implications for the use of the CBMNT in human biomonitoring studies are discussed.

Identifying an indoor air exposure limit for formaldehyde considering both irritation and cancer hazards

Formaldehyde is a well-studied chemical and effects from inhalation exposures have been extensively characterized in numerous controlled studies with human volunteers, including asthmatics and other sensitive individuals, which provide a rich database on exposure concentrations that can reliably produce the symptoms of sensory irritation. Although individuals can differ in their sensitivity to odor and eye irritation, the majority of authoritative reviews of the formaldehyde literature have concluded that an air concentration of 0.3 ppm will provide protection from eye irritation for virtually everyone. A weight of evidence-based formaldehyde exposure limit of 0.1 ppm (100 ppb) is recommended as an indoor air level for all individuals for odor detection and sensory irritation. It has recently been suggested by the International Agency for Research on Cancer (IARC), the National Toxicology Program (NTP), and the US Environmental Protection Agency (US EPA) that formaldehyde is causally associated with nasopharyngeal cancer (NPC) and leukemia. This has led US EPA to conclude that irritation is not the most sensitive toxic endpoint and that carcinogenicity should dictate how to establish exposure limits for formaldehyde. In this review, a number of lines of reasoning and substantial scientific evidence are described and discussed, which leads to a conclusion that neither point of contact nor systemic effects of any type, including NPC or leukemia, are causally associated with exposure to formaldehyde. This conclusion supports the view that the equivocal epidemiology studies that suggest otherwise are almost certainly flawed by identified or yet to be unidentified confounding variables. Thus, this assessment concludes that a formaldehyde indoor air limit of 0.1 ppm should protect even particularly susceptible individuals from both irritation effects and any potential cancer hazard.

Occupational exposure to formaldehyde in an institute of morphology in Brazil: a comparison of area and personal sampling

BACKGROUND, AIMS, AND SCOPE

Formaldehyde (FA) is a harmful chemical, which is classified as carcinogenic to humans (Group 1) by the International Agency for Research on Cancer. Solutions of FA that are used to preserve cadavers in research and education morphological institutes represent a risk to occupational health of professionals and students. During the dissection of cadavers in the anatomy laboratories, FA vapors are emitted, resulting in the exposure of students and their instructors to elevated levels of FA. The World Health Organization recommends an air quality guideline value of 0.1 mg m(-3) for exposure to FA. The limit of occupational exposure adopted by the Brazilian legislation (2.3 mg m(-3)) is markedly higher than those adopted by institutions of other countries around the world. The purpose of this study was to determine the levels of personal exposure and the area concentration of FA in the morphology department of the Federal Fluminense University, Brazil, and investigate and compare the relationship between them.

METHODS

Four rooms distributed in the three floors of the Morphology Department were evaluated: the embalming laboratory, the anatomy laboratories, the corridor of the teachers' rooms, and the entrance hall. Thirty-six samples in total were collected in the second semester of 2010 and first semester of 2011. The air sampling and FA analysis were performed according to the EPA TO-11A Protocol, using a diffusive sampling device for carbonyl compounds. Personal samples were collected from monitors using a sampling device pinned on each person's lapel. The samples were analyzed using rapid resolution liquid chromatography with UV-DAD detection at 360 nm.

RESULTS AND DISCUSSION

The concentrations of FA ranged from 0.20 and 0.18 mg m(-3) in the corridor between the teachers' rooms, 0.03 to 0.37 mg m(-3) in the entrance hall, 0.22 to 2.07 mg m(-3) in the anatomy laboratory, 2.21 to 2.52 mg m(-3), in the embalming room. The levels found in the corridor between the teachers' rooms and in the entrance hall were lower than in other compartments because of their large distances to the sources of FA and better ventilation. The other rooms presented higher levels of FA because of the activities carried there (embalming and dissection procedures). Even in the rooms that showed the lowest levels of FA, the values found were higher than those established by all international guideline limits, except the Brazilian legislation limit, although, the concentration level in the embalming room was even greater than the Brazilian guideline. These concentrations are 100-1,000-fold higher than those reported in an FA outdoor study. The exposure levels of monitors and students ranged from 1.89 to 4.82 mg m(-3), indicating that current practices at the Morphology Department at the university would represent a health risk. The simultaneous monitoring of area concentrations and personal exposure showed that the characteristics of classes and of cadavers' parts, the number of students in the room and even the activities of the monitors influence the FA concentrations.

CONCLUSION

This study revealed that the concentration of FA was low in the ventilated areas of the Morphology Department, and that the personal exposure when the person was close to the cadavers during the dissection procedure was higher than the mean FA concentration. This should be considered in the risk assessment of FA during these activities without effective protection equipment. It is suggested that the Brazilian legislation of exposure to formaldehyde requires an urgent update considering international legislation.

Detection of environmental clastogens and aneugens in human fibroblasts by cytokinesis-blocked micronucleus assay associated with immunofluorescent staining of CENP-A in micronuclei

The cytokinesis-blocked micronucleus (CBMN) assay, in combination with fluorescent in situ hybridization (FISH) of human pan-centromeric DNA probes, or with CREST antibodies that specifically stain kinetochore proteins, is widely used on several cell types. It distinguishes micronuclei containing one or several whole chromosomes, which are positively labeled (centromere positive micronucleus, C+MN, due to aneugenic effect), or acentric chromosome fragments, which are unlabeled due to the absence of centromere (centromere negative micronucleus, C-MN, due to clastogenic effect). However, the very slight level of the centromeric signals obtained with the FISH technique on primary human fibroblasts, a cell type commonly used in environmental genetic toxicology, leads to great difficulties in distinguishing C+MN and C-MN. Furthermore, the CREST technique may lead to inappropriate results particularly with regards to variations in antibody composition between patient sera. Our results show that the in vitro CBMN, in combination with immunofluorescence staining of CENP-A (centromere protein A), efficiently screens genotoxicants for their ability to induce clastogenic and/or aneugenic effects. We propose the in vitro CBMN assay in combination with immunofluorescence staining of CENP-A as a suitable tool in environmental genotoxicity testing of primary human fibroblasts.

In vitro study of lymphocyte antiproliferation and cytogenetic effect by occupational formaldehyde exposure

Formaldehyde is the chemical substance illegally used for food preservation in meat, vegetables and fruit. A study on the antiproliferative effect and cytogenetic effect of formaldehyde on human lymphocyte was undertaken. Heparinized blood from 30 volunteers was collected and treated with formaldehyde concentrations of 0.036, 0.072, 0.15, 0.3, 0.576, 0.8 and 1.152 mg/mL, respectively, for 24 hours. Viable lymphocyte count by hemocytometer and MTT assay were carried out for detecting the antiproliferative effect of formaldehyde on human lymphocyte. Lymphocyte culture and G-banding technique were carried out for detecting the cytogenetic effect of formaldehyde. The results showed that the numbers of viable lymphocyte in the control group were 3.45 × 10(4) cells/mL. The numbers of viable lymphocyte in the experimental subgroups were 3.03 × 10( 4), 2.69 × 10(4), 2.36 × 10(4), 2.17 × 10(4), 1.92 × 10(4), 1.68 × 10(4) and 1.04 × 10(4) cells/mL, respectively, at 24 hours. The value of IC(50) was 0.92 mg/mL. The formaldehyde concentrations of 0.036, 0.072, 0.15, 0.3, 0.576, 0.8 and 1.152 mg/mL effect the lymphocyte antiproliferation (p < 0.05). Loss of chromosome was the cytogenetic effect by the formaldehyde concentration of 0.036 and 0.072 mg/mL in this study. It is concluded that formaldehyde has the antiproliferative effect and cytogenetic effect on human lymphocyte.

The in vivo or ex vivo origin of micronuclei measured in human biomonitoring studies

The micronucleus test (MNT) is a well-established assay in genotoxicity testing and human biomonitoring. The cytokinesis-block micronucleus test (CBMNT) is the preferred method for measuring MN in cultured human lymphocytes from human subjects exposed to genotoxins. However, it is unclear to what extent mutagen exposure either leads to the formation of MN already in vivo or to the formation of MN ex vivo during cell culture as a consequence of persisting DNA damage. MN that were already induced in vivo can be determined by scoring MN in mononuclear lymphocytes 24 h after the start of the lymphocyte culture (i.e. in lymphocytes that did not divide yet). Results obtained for cancer patients after chemotherapy suggest that mutagen exposure in vivo mainly leads to the formation of MN during ex vivo proliferation of lymphocytes as a consequence of mis-repair of persistent damage. If these results also apply to other kinds of mutagen exposure, increased MN frequencies in the CBMNT can only be expected for exposures leading to a sufficient amount of damage that persists during ex vivo lymphocyte culture. For a better understanding of the origin of increased MN frequencies and the correct interpretation of results obtained with the CBMNT, further research is recommended: MN in mononuclear lymphocytes should be additionally scored 24 h after the start of the cultures, comparative investigation with the CBMNT and the MNT with reticulocytes should be performed and the kinetics of MN formation in lymphocyte cultures and the repair capacity of lymphocytes for different kinds of DNA damage should be characterised.

Determination of trace formaldehyde in blood plasma by resonance fluorescence technology

A novel method for the determination of trace formaldehyde in blood plasma has been established by using resonance fluorimetry technique. It was based on the fact that oxidation of pyronine Y by potassium bromate was catalyzed by formaldehyde in sulfuric acid. When the wavelength interval was at Δλ=0 nm, it was found that the decreased intensity (ΔF) of resonance fluorescence at 574.6 nm was proportional to the concentration of formaldehyde in the range of 1.27×10(-2) to 2.28 μg mL(-1). The limit of detection and the average recovery for formaldehyde were 3.80 ng mL(-1) and 101.6% (n=6), respectively. The present method had been applied to the determination of trace formaldehyde in blood plasma, and the obtained results were in good agreement with those obtained by the resonance light scattering method.

Malondialdehyde-deoxyguanosine adduct formation in workers of pathology wards: the role of air formaldehyde exposure

Formaldehyde is an ubiquitous pollutant to which humans are exposed. Pathologists can experience high formaldehyde exposure levels. Formaldehyde-among other properties-induce oxidative stress and free radicals, which react with DNA and lipids, leading to oxidative damage and lipid peroxidation, respectively. We measured the levels of air-formaldehyde exposure in a group of Italian pathologists and controls. We analyzed the effect of formaldehyde exposure on leukocyte malondialdehyde-deoxyguanosine adducts (M(1)-dG), a biomarker of oxidative stress and lipid peroxidation. We studied the relationship between air-formaldehyde and M(1)-dG adducts. Air-formaldehyde levels were measured by personal air samplers. M(1)-dG adducts were analyzed by a (32)P-postlabeling assay. Reduction room pathologists were significantly exposed to air-formaldehyde with respect to controls and to the pathologists working in other laboratory areas (p < 0.001). A significant difference for M(1)-dG adducts between exposed pathologists and controls was found (p = 0.045). The effect becomes stronger when the evaluation of air-formaldehyde exposure was based on personal samplers (p = 0.018). Increased M(1)dG adduct levels were only found in individuals exposed to air-formaldehyde concentrations higher than 66 microg/m(3). When the exposed workers and controls were subgrouped according to smoking, M(1)-dG tended to increase in all of the subjects, but a significant association between M(1)-dG and air-formaldehyde was only found in nonsmokers (p = 0.009). Air-formaldehyde played a role positive but not significant (r = 0.355, p = 0.075, Pearson correlation) in the formation of M(1)-dG, only in nonsmokers. Working in the reduction rooms and exposure to air-formaldehyde concentrations higher than 66 microg/m(3) are associated with increased levels of M(1)-dG adducts.

Modelling the time profiles of organic solvent concentrations for occupational exposure assessment purposes

OBJECTIVES

Confronted by variable exposure scenarios characterized by intermittent concentration peaks, our study aimed to develop methods and determine mathematical functions reproducing organic solvent concentration profiles in order to assess health risks.

METHODS

Two similar repetitive decanting tasks using either formalin or toluene (TOL) were studied at a teaching hospital pathology laboratory. Real-time air monitoring performed in the immediate vicinity of pollutant sources over a 1-year period identified intermittent concentration peaks. In order to describe these specific exposure profiles, two different methods were used. In a first descriptive approach, concentration peaks were either assimilated to an equivalent series of rectangle functions or described by a mathematical bell-shaped function. As an alternative approach, a model based on the schedule of decanting tasks was constructed. To this end, a time-varying emission function was incorporated into three deterministic exposure models of increasing complexity (well-mixed room, two-zone, spherical turbulent diffusion) and field-derived emission parameters were estimated by fitting model outputs to measured concentration profiles.

RESULTS

Real-time measurements revealed highly variable concentration profiles, consisting of 1-8 peaks ranging from 5 to 220 s per decanting task, and average concentrations within peaks varying over 1-2 orders of magnitude. Acceptable fits were obtained by both descriptive approaches. The tested emission function seemed relevant in reproducing intermittent pollutant releases. Only advanced models (two-zone and diffusion) gave satisfying fits within assigned input parameter ranges. Average emission rate estimates varied in the range 10-47 mg min(-1) for formaldehyde and 360-1780 mg min(-1) for TOL, depending on the model tested.

CONCLUSIONS

Both descriptive approaches and deterministic models accurately reproduced the patterns of measured concentration peaks. However, only deterministic models provided an understanding of the relations between pollutant releases, air movements, and the resulting concentrations and may thus be recommended for exposure variability assessment purposes.

Formaldehyde and leukemia: an updated meta-analysis and evaluation of bias

OBJECTIVE

Formaldehyde exposures are common, and data linking these exposures to leukemia have been mixed and controversial. The objective of this analysis is to review the current epidemiologic literature on formaldehyde and leukemia.

METHODS

We performed an updated meta-analysis focusing on high-exposure groups and myeloid leukemia and included two large recent studies: one involving >25,000 workers in US formaldehyde industries and the other involving a cohort of >13,000 funeral directors and embalmers.

RESULTS

Formaldehyde was associated with increased risks of leukemia (relative risk = 1.53; 95% confidence interval = 1.11 to 2.21; P = 0.005; 14 studies), specifically myeloid leukemia (relative risk = 2.47; 95% confidence interval = 1.42 to 4.27; P = 0.001; 4 studies).

CONCLUSION

These findings provide evidence of increased myeloid leukemia risk with exposure to formaldehyde.

Occupational exposure to formaldehyde: genotoxic risk evaluation by comet assay and micronucleus test using human peripheral lymphocytes

Formaldehyde (FA) is a world high-production compound with numerous applications ranging from production of resins to medicines. Due to its sensitizing properties, irritating effects and potential cancer hazard FA is of great environmental health concern. Numerous studies in humans and experimental animals demonstrated that inhaled FA produced toxicity, genotoxicity, and cancer at distal sites. IARC, based on sufficient data, reclassified FA as a human carcinogen. The highest level of human exposure to this aldehyde occurs in occupational settings, namely, in pathology and anatomy laboratories, where FA is commonly used as a fixative and tissue preservative. Several studies consistently showed that the levels of airborne FA in anatomy laboratories exceeded recommended exposure criteria. In order to assess the genotoxic effects of chronic occupational exposure to FA, a group of pathology/anatomy workers was assessed using a micronucleus (MN) test and comet assay. The level of exposure to FA was also determined and the time-weighted average (TWA) of exposure was calculated for each subject. The TWA mean value for FA exposed workers was 0.43 ± 0.06 ppm, exceeding national and international recommended limit levels of 0.3 ppm. Both MN frequency and comet assay parameters were significantly higher in exposed subjects. Data obtained confirm a correlation between genetic damage and occupational exposure to FA. These data, along with recent implications of human carcinogenicity, point out the need for close monitoring of occupational exposure to FA. Implementation of security and hygiene measures as well as good practices campaigns may be crucial to decrease risk.

Genotoxic effects in occupational exposure to formaldehyde: A study in anatomy and pathology laboratories and formaldehyde-resins production

BACKGROUND

According to the Report on Carcinogens, formaldehyde ranks 25th in the overall U.S. chemical production, with more than 5 million tons produced each year. Given its economic importance and widespread use, many people are exposed to formaldehyde environmentally and/or occupationally. Presently, the International Agency for Research on Cancer classifies formaldehyde as carcinogenic to humans (Group 1), based on sufficient evidence in humans and in experimental animals. Manyfold in vitro studies clearly indicated that formaldehyde can induce genotoxic effects in proliferating cultured mammalian cells. Furthermore, some in vivo studies have found changes in epithelial cells and in peripheral blood lymphocytes related to formaldehyde exposure.

METHODS

A study was carried out in Portugal, using 80 workers occupationally exposed to formaldehyde vapours: 30 workers from formaldehyde and formaldehyde-based resins production factory and 50 from 10 pathology and anatomy laboratories. A control group of 85 non-exposed subjects was considered. Exposure assessment was performed by applying simultaneously two techniques of air monitoring: NIOSH Method 2541 and Photo Ionization Detection equipment with simultaneously video recording. Evaluation of genotoxic effects was performed by application of micronucleus test in exfoliated epithelial cells from buccal mucosa and peripheral blood lymphocytes.

RESULTS

Time-weighted average concentrations not exceeded the reference value (0.75 ppm) in the two occupational settings studied. Ceiling concentrations, on the other hand, were higher than reference value (0.3 ppm) in both. The frequency of micronucleus in peripheral blood lymphocytes and in epithelial cells was significantly higher in both exposed groups than in the control group (p<0.001). Moreover, the frequency of micronucleus in peripheral blood lymphocytes was significantly higher in the laboratories group than in the factory workers (p < 0.05). A moderate positive correlation was found between duration of occupational exposure to formaldehyde (years of exposure) and micronucleus frequency in peripheral blood lymphocytes (r=0.401; p<0.001) and in epithelial cells (r=0.209; p < 0.01).

CONCLUSIONS

The population studied is exposed to high peak concentrations of formaldehyde with a long-term exposure. These two aspects, cumulatively, can be the cause of the observed genotoxic endpoint effects. The association of these cytogenetic effects with formaldehyde exposure gives important information to risk assessment process and may also be used to assess health risks for exposed workers.

Cancer effects of formaldehyde: a proposal for an indoor air guideline value

Formaldehyde is a ubiquitous indoor air pollutant that is classified as "Carcinogenic to humans (Group 1)" (IARC, Formaldehyde, 2-butoxyethanol and 1-tert-butoxypropanol-2-ol. IARC monographs on the evaluation of carcinogenic risks to humans, vol 88. World Health Organization, Lyon, pp 39-325, 2006). For nasal cancer in rats, the exposure-response relationship is highly non-linear, supporting a no-observed-adverse-effect level (NOAEL) that allows setting a guideline value. Epidemiological studies reported no increased incidence of nasopharyngeal cancer in humans below a mean level of 1 ppm and peak levels below 4 ppm, consistent with results from rat studies. Rat studies indicate that cytotoxicity-induced cell proliferation (NOAEL at 1 ppm) is a key mechanism in development of nasal cancer. However, the linear unit risk approach that is based on conservative ("worst-case") considerations is also used for risk characterization of formaldehyde exposures. Lymphohematopoietic malignancies are not observed consistently in animal studies and if caused by formaldehyde in humans, they are high-dose phenomenons with non-linear exposure-response relationships. Apparently, these diseases are not reported in epidemiological studies at peak exposures below 2 ppm and average exposures below 0.5 ppm. At the similar airborne exposure levels in rodents, the nasal cancer effect is much more prominent than lymphohematopoietic malignancies. Thus, prevention of nasal cancer is considered to prevent lymphohematopoietic malignancies. Departing from the rat studies, the guideline value of the WHO (Air quality guidelines for Europe, 2nd edn. World Health Organization, Regional Office for Europe, Copenhagen, pp 87-91, 2000), 0.08 ppm (0.1 mg m(-3)) formaldehyde, is considered preventive of carcinogenic effects in compliance with epidemiological findings.