Changes in Work Practices for Safe Use of Formaldehyde in a University-Based Anatomy Teaching and Research Facility

Comparison of real-time instrument use and absorbent tube method for measuring formaldehyde in working environments: A health risk assessment for gross anatomy staff

Formaldehyde is widely used for the preservation of cadavers, exposing workers to potential risks of formaldehyde exposure in the workplace. This study compared the performance of real-time instruments (Gasmet) and absorbent tube methods in controlling formaldehyde levels in gross anatomy dissections with four working process areas. The concentrations of formaldehyde were determined over working periods ranging from 2 to 5 h. For the Gasmet results, a Monte Carlo simulation was applied in the uncertainty analysis to predict the formaldehyde concentration. Data collection involved questionnaires that included personal and work-related information. The Wilcoxon matched-pairs signed-rank test and intraclass correlation coefficients (ICC) were used to test-retest reliability between the two instruments. The results showed that the Gasmet direct reading and absorbent tube concentrations were not significantly different (p > 0.05) in all working areas and ICC was 0.939 indicating a highly reliable test result between the two measurements. The health-risk estimation indicated the hazard quotient and carcinogenic risk of formaldehyde. The carcinogenic risk was found to be unacceptable for all staff and processes, while the hazard quotient was found to be acceptable only in the body injection process. Future studies should employ a larger sample size and a greater number of sampling points to enhance the statistical power and precision of the results. The findings of this study can be used to improve work environments and develop strategies to reduce the risks for staff who work in gross anatomy dissections.

The effects of enhanced formaldehyde clearance in a gross anatomy laboratory by floor plan redesign and dissection table adjustment

Formaldehyde has carcinogenic properties. It is associated with nasopharyngeal cancer and causes irritation of the eyes, nose, throat, and respiratory system. Formaldehyde exposure is a significant health concern for those participating in the gross anatomy laboratory, but no learning method can substitute cadaver dissection. We performed a formaldehyde level study in 2018, which found that most of the breathing zone (S-level) and environment (R-level) formaldehyde levels during laboratory sessions at the Faculty of Medicine Siriraj Hospital exceeded international ceiling standards. In the academic year 2019, we adapted the engineering rationale of the NIOSH hierarchy of controls to facilitate formaldehyde clearance by opening the dissection table covers and increasing the area per dissection table, then measured formaldehyde ceiling levels by formaldehyde detector tube with a gas-piston hand pump during (1) body wall, (2) upper limb, (3) head-neck, (4) thorax, (5) spinal cord removal, (6) lower limb, (7) abdomen, and (8) organs of special senses dissection sessions and comparing the results with the 2018 study. The perineum region data were excluded from analyses due to the laboratory closure in 2019 from the COVID-19 outbreak. There were statistically significant differences between the 2018 and 2019 S-levels (p < 0.001) and R-levels (p < 0.001). The mean S-level decreased by 64.18% from 1.34 ± 0.71 to 0.48 ± 0.26 ppm, and the mean R-level decreased by 70.18% from 0.57 ± 0.27 to 0.17 ± 0.09 ppm. The highest formaldehyde level in 2019 was the S-level in the body wall region (1.04 ± 0.3 ppm), followed by the S-level in the abdomen region (0.56 ± 0.08 ppm) and the spinal cord removal region (0.51 ± 0.29 ppm). All 2019 formaldehyde levels passed the OSHA 15-min STEL standard (2 ppm). The R-level in the special sense region (0.06 ± 0.02 ppm) passed the NIOSH 15-min ceiling limit (0.1 ppm). Three levels for 2019 were very close: the R-level in the head-neck region (0.11 ± 0.08 ppm), the abdomen region (0.11 ± 0.08), the body wall region (0.14 ± 0.12 ppm), and the S-level in the special sense region (0.12 ± 0.04 ppm). In summary, extensive analysis and removal of factors impeding formaldehyde clearance can improve the general ventilation system and achieve the OSHA 15-min STEL standard.

Real-time Raman analysis of the hydrolysis of formaldehyde oligomers for enhanced collagen fixation

Formaldehyde (FA) is widely applied as a fixative for proteins such as collagen. Current studies have confirmed that the reversible oligomer-to-monomer equilibrium of FA in aqueous solution and the proportion of FA monomer is a significant factor affecting tissue fixation. Since the hydrolysis of FA oligomers is a dynamic process affected jointly by different factors, its real time monitoring has proved to be challenging. In this work, by utilizing the well-established Raman technique as an analytical platform, we identified the factors affecting the hydrolysis of FA oligomers by rationally examining the ν_s (OCO) and ν_as (OCO) modes with varying conditions, such as time, pH, temperature, and FA concentration. The optimized conditions of the highest hydrolysis rate of oligomers into monomers for fixation on collagen and tissues have been found to be relatively low FA concentration (≤5%) in phosphate-buffered saline at pH 9.0 in room temperature. In order to compare the fixation quality of the optimized conditions to that of the conventional conditions used by current medical practices (4% FA concentration in tap water under room temperature), Raman spectroscopy and chemical derivatization methods with o-phthalaldehyde and fluorescent probe FAP-1 have been investigated, and our results revealed that the FA molecules under our optimized conditions have reacted with at least 15% more amino groups within collagen compared to those under the conventional conditions mentioned above. This study provides direct evidence of the FA equilibrium in solution by Raman spectroscopy, which could be applied for the optimal use of FA in medicine, even at an industrial scale.

Occupational Exposure to Formaldehyde and Cancer Risk Assessment in an Anatomy Laboratory

Dissecting a human cadaver is an irreplaceable practice in general training of medical students. Cadavers in anatomy laboratories are usually preserved in formalin, an embalming fluid whose basic component is formaldehyde (FA). The aim of this study is to assess the cancer risk of employees and students that are exposed to FA based on the results of three monitoring campaigns, as well as to suggest permanent solutions to the problem of FA exposure based on the results obtained. Three sampling campaigns of formaldehyde concentration in indoor environments were conducted at five different locations at the Anatomy Department of the Faculty of Medicine with the purpose of assessing permanent employees’ and medical faculty first year students’ exposure to FA. Indoor air was continuously sampled during 8 h of laboratory work and analyzed in accordance with the NIOSH Method 3500. Exceeding of the 8 h time-weighted average (8 h TWA) values recommended by Occupational Safety and Health Administration (OSHA) of 0.75 ppm was recorded in 37% of the samples during the three-month monitoring campaign. Cancer risk assessment levels for permanent employees were in the range from 6.43 × 10⁻³ to 8.77 × 10⁻⁴, while the cancer risk assessment levels for students ranged from 8.94 × 10⁻⁷ to 1.83 × 10⁻⁶. The results of the research show that cancer risk assessment for employees is several thousand times higher than the limit recommended by the EPA (10⁻⁶) and point to the importance of reducing exposure to formaldehyde through the reconstruction of the existing ventilation system, continual monitoring, the use of formaldehyde-free products, and plastination of anatomical specimens.

Peak Inhalation Exposure Metrics Used in Occupational Epidemiologic and Exposure Studies

Peak exposures are of concern because they can potentially overwhelm normal defense mechanisms and induce adverse health effects. Metrics of peak exposure have been used in epidemiologic and exposure studies, but consensus is lacking on its definition. The relevant characteristics of peak exposure are dependent upon exposure patterns, biokinetics of exposure, and disease mechanisms. The objective of this review was to summarize the use of peak metrics in epidemiologic and exposure studies. A comprehensive search of Medline, Embase, Web of Science, and NIOSHTIC-2 databases was conducted using keywords related to peak exposures. The retrieved references were reviewed and selected for indexing if they included a peak metric and met additional criteria. Information on health outcomes and peak exposure metrics was extracted from each reference. A total of 1,215 epidemiologic or exposure references were identified, of which 182 were indexed and summarized. For the 72 epidemiologic studies, the health outcomes most frequently evaluated were: chronic respiratory effects, cancer and acute respiratory symptoms. Exposures were frequently assessed using task-based and full-shift time-integrated methods, qualitative methods, and real-time instruments. Peak exposure summary metrics included the presence or absence of a peak event, highest exposure intensity and frequency greater than a target. Peak metrics in the 110 exposure studies most frequently included highest exposure intensity, average short-duration intensity, and graphical presentation of the real-time data (plots). This review provides a framework for considering biologically relevant peak exposure metrics for epidemiologic and exposure studies to help inform risk assessment and exposure mitigation.

Toward safer thanatopraxy cares: formaldehyde-releasers use

Human cadavers constitute very useful educational tools to teach anatomy in medical scholarship and related disciplines such as physiology, for example. However, as biological material, human body is subjected to decay. Thanatopraxy cares such as embalming have been developed to slow down and inhibit this decay, but the formula used for the preservation fluids are mainly formaldehyde (FA)-based. Very recently, other formulas were developed in order to replace FA, and to avoid its toxicity leading to important environmental and professional exposure concerns. However, these alternative FA-free fluids are still not validated or commercialized, and their efficiency is still under discussion. In this context, the use of FA-releasing substances, already used in the cosmetics industry, may offer interesting alternatives in order to reduce professional exposures to FA. Simultaneously, the preservation of the body is still guaranteed by FA generated over time from FA-releasers. The aim of this review is to revaluate the use of FA in thanatopraxy cares, to present its benefits and disadvantages, and finally to propose an alternative to reduce FA professional exposure during thanatopraxy cares thanks to FA-releasers use.

Monitoring of Air-Dispersed Formaldehyde and Carbonyl Compounds as Vapors and Adsorbed on Particulate Matter by Denuder-Filter Sampling and Gas Chromatographic Analysis

Carbonyl compounds (CCs) are products present both as vapors and as condensed species adsorbed on the carbonaceous particle matter dispersed in the air of urban areas, due to vehicular traffic and human activities. Chronic exposure to CCs is a potential health risk given the toxicity of these chemicals. The present study reports on the measurement of the concentrations of 14 CCs in air as vapors and 2.5 µm fraction PM by the ENVINT GAS08/16 gas/aerosol sampler, a serial sampler that uses annular denuder, as sampling device. The 14 CCs were derivatized during sampling prior to gas-chromatographic separation and multiple detection by mass spectrometry, nitrogen-phosphorus thermionic, electron capture detection. Outdoor air multiple samples were collected in four locations in the urban area of Florence. The results evidenced that formaldehyde, acetaldehyde, and acetone were the more abundant CCs in the studied areas. The data collected was discussed considering the particle to vapor ratio of each CC found. The CCs pollution picture obtained was tentatively related to the nature and intensity of the traffic transiting by the sampling sites. This approach allowed to determine 14 CCs in both concentrated and diluted samples and is proposed as a tool for investigating outdoor and indoor pollution.