Formaldehyde Exposure in a Gross Anatomy Laboratory. Personal Exposure Level Is Higher Than Indoor Concentration (5 pp)

Goal, Scope and Background Cadavers for gross anatomy laboratories are usually prepared by using embalming fluid which contains formaldehyde (FA) as a principal component. During the process of dissection, FA vapors are emitted from the cadavers, resulting in the exposure of medical students and their instructors to elevated levels of FA in the laboratory. The American Conference of Governmental Industrial Hygienists (ACGIH) has set a ceiling limit for FA at 0.3 ppm. In Japan, the Ministry of Health, Labour and Welfare has set an air quality guideline defining two limit values for environmental exposure to FA: 0.08 ppm as an average for general workplaces and 0.25 ppm for specific workplaces such as an FA factory. Although there are many reports on indoor FA concentrations in gross anatomy laboratories, only a few reports have described personal FA exposure levels. The purpose of the present study was to clarify personal exposure levels as well as indoor FA concentrations in our laboratory in order to investigate the relationship between them. Methods The gross anatomy laboratory was evaluated in the 4th, 10th and 18th sessions of 20 laboratory sessions in total over a period of 10 weeks. Air samples were collected using a diffusive sampling device for organic carbonyl compounds. Area samples were taken in the center and four corners of the laboratory during the entire time of each session (4-6 hours). Personal samples were collected from instructors and students using a sampling device pinned on each person's lapel, and they were 1.1 to 6 hours in duration. Analysis was carried out using high performance liquid chromatography. Results and Discussion Room averages of FA concentrations were 0.45, 0.38 and 0.68 ppm for the 4th, 10th and 18th sessions, respectively, ranging from 0.23 to 1.03 ppm. These levels were comparable to or relatively lower than the levels reported previously, but were still higher than the guideline limit for specific workplaces in Japan and the ACGIH ceiling limit. The indoor FA concentrations varied depending on the contents of laboratory sessions and seemed to increase when body cavity or deep structures were being dissected. In all sessions but the 4th, FA levels at the center of the room were higher than those in the corners. This might be related to the arrangement of air supply diffusers and return grills. However, it cannot be ruled out that FA levels in the corners were lowered by leakage of FA through the doors and windows. Average personal exposure levels were 0.80, 0.45 and 0.51 ppm for instructors and 1.02, 1.08 and 0.89 ppm for students for the 4th, 10th and 18th session, respectively. The exposure levels of students were significantly higher than the mean indoor FA concentrations in the 4th and 10th sessions, and the same tendency was also observed in the 18th session. The personal exposure level of instructors was also significantly higher than the indoor FA level in the 4th session, while they were almost the same in the 10th and 18th sessions. Differences in behavior during the sessions might reflect the differential personal exposure levels between students and instructors. Conclusion The present study revealed that, if a person is close to the cadavers during the gross anatomy laboratory, his/her personal exposure level is possibly 2 to 3-fold higher than the mean indoor FA concentration. This should be considered in the risk assessment of FA in gross anatomy laboratories. Recommendation and Outlook If the risk of FA in gross anatomy laboratories is assessed based on the indoor FA levels, the possibility that personal exposure levels are 2 to 3-fold higher than the mean indoor FA level should be taken into account. Otherwise, the risk should be assessed based on the personal exposure levels. However, it is hard to measure everyone's exposure level. Therefore, further studies are necessary to develop a method of personal exposure assessment from the indoor FA concentration.     

Influence of secondary formation on atmospheric occurrences of oxygenated polycyclic aromatic hydrocarbons in airborne particles

Temporal and spatial variations in concentrations of particle-associated polycyclic aromatic hydrocarbons (PAHs) and their nitrated and oxygenated derivatives (nitro-PAHs and oxy-PAHs) were investigated to assess the influence of secondary formation on atmospheric occurrences of oxy-PAHs associated with particulate matter in downtown Tokyo, Japan. The daily variation in concentration of 1,8-naphthalic anhydride (1,8-NA) in summer 2007 was similar to that for 2-nitrofluoranthene (2-NF), a representative secondary formed nitro-PAH, while the variation for benzanthrone (BA) was similar to PAHs. In addition, the concentrations of polycyclic aromatic compounds (PACs) associated with airborne particulate matter decreased in the order of PAHs > BA > 9-fluorenone (9-FO) or 9,10-anthraquinone (9,10-AQ) > 1,8-NA with an increase in distance from the roadside, whereas 2-NF was constant. These results suggest that a considerable fraction of some oxy-PAHs such as 1,8-NA associated with airborne particulate matter in downtown Tokyo originates from atmospheric secondary formation.     

Mechanochemical degradation of chlorinated contaminants in fly ash with a calcium-based degradation reagent

This report presents our results in a low-temperature mechanochemical hydrodechlorination process applied to fly ash coming from a municipal waste incinerator in order to efficiently remove all traces of PCDDs, PCDFs and PCBs. We found that the most suitable degradation agent is a mixture of metallic calcium and calcium oxide. A sample of fly ash presenting a TEQ of 5200 pg g⁻¹ was completely detoxified (no traces of PCDDs, PCDFs and PCBs detected) after ball-milling at 400 rpm over night.     

Adsorption of 2,4-dichlorophenoxyacetic acid by an Andosol

To identify the important soil components involved in 2,4-dichlorophenoxyacetic acid (2,4-D) adsorption on Andosols, 2,4-D adsorption on a surface horizon of an Andosol was compared with that on hydrogen peroxide (H2O2)-treated (soil organic matter [SOM] was removed), acid-oxalate (OX)-treated (active metal hydroxides and SOM were removed), and dithionite-citrate-bicarbonate (DCB)-treated (free and active metal [hydr]oxides and SOM were removed) soil samples at equilibrium pHs ranging from 4 to 8. Although the untreated soil contained a large amount of organic C (71.9 g kg-1), removal of SOM had little effect on 2,4-D adsorption. Active surface hydroxyls, which were attached to the active and free metal (hydr)oxides and metal SOM complexes, were identified as the most important soil functional group for 2,4-D adsorption. The dominant mechanism of the 2,4-D adsorption was a ligand exchange reaction in which the carboxylic group of 2,4-D displaced the active surface hydroxyl associated with metals and formed a strong coordination bond between the 2,4-D molecule and soil solid phase. The ligand exchange reaction reasonably accounted for the selective adsorption of 2,4-D over Cl-, competitive adsorption of phosphate over 2,4-D, reduction in plant-growth-inhibitory activity of soil-adsorbed 2,4-D, and the high 2,4-D adsorption ability of Andosols. Although a humic acid purified from the soil did not adsorb 2,4-D, the presence of the humic acid increased 2,4-D adsorption on Al and Fe, probably by inhibiting the hydrolysis and polymerization of Al and Fe resulting in the preservation of available adsorption sites on these metals. The adsorption behavior of 2,4-D on soils could be a good index for predicting the adsorption behavior of other organic acids in soils.     

Production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from various carbon sources by batch-fed cultures ofAlcaligenes eutrophus

Copolyesters of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) were produced at 30°C from various carbon sources byAlcaligenes eutrophus under batch-fed growth conditions. The production of P(3HB-co-3HV) from butyric and pentanoic acids was effective under nitrogenlimited conditions, and the conversion of carbon sources into copolyester was as high as 56 wt% at a C/N molar ratio of 40. In contrast, under excess-nitrogen conditions (C/N<10), cell growth was good, while P(3HB-co-3HV) production was partially inhibited. The production of P(3HB-co-3HV) from fructose and propionic acid was almost completely inhibited under excess-nitrogen conditions.     

Detection and average content levels of carcinogenic and mutagenic compounds from the particulates on diesel and gasoline engine mufflers

Carcinogenic and mutagenic compounds, which were extracted from the particulates that adhered to inner surfaces of diesel and gasoline engine mufflers, were quantified by the series method of Soxhlet extraction, liquid-liquid partition, thin-layer chromatography, and spectrofluorometry. Mutagenic activity of their neutral and acidic fractions was tested in the improved Ames assay by the preincubation method with Salmonella typhimurium TA98 in the presence and absence of metabolic activation system (S-9 mix). The average content levels (μg/g tar) of polycyclic aromatic hydrocarbons from gasoline engine cars were greater than those from diesel engine vehicles. However, the levels of nitro derivatives of PAHs and polycyclic quinones from the diesel engines were greater than from the gasoline engines. Mutagenic activity of the diesel acidic fraction was the highest among the diesel and gasoline fractions, and was significantly higher in the absence of the S-9 mix. Furthermore, the relative value (R_{c = 0}) of infrared absorption of carbonyl stretching vibration to that of methylene asymmetric stretching vibration of the diesel acidic fraction was the highest among the diesel and gasoline fractions. These results strongly suggest that highly direct-acting mutagens in the acidic fraction are at higher levels in diesel emission particulates than those from gasoline, and that these mutagens are carboxylic acid, aldehyde, and alcohol derivatives of PAHs and NPAHs.     

Polychlorinated biphenyl levels in the blood of Japanese individuals ranging from infants to over 80 years of age

Individuals’ exposure to various persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs), and its adverse health effects have been a cause of concern. We measured blood PCB concentrations from samples taken from 507 Japanese individuals ranging from infants to those over 80 years of age. The blood PCB levels increased with age for both male (Spearman’s r?=?0.69, p?<?0.001) and female (Spearman’s r?=?0.70, p?<?0.001) participants. Adult men and nulliparous women showed similar increases with age. However, the PCB levels of multiparous women were lower than those of nulliparous women in their thirties (p?=?0.005), probably because the PCBs were transferred from the mothers to their children during pregnancy and lactation. Among infants (<2 years of age), some had as high levels of accumulated PCB levels as those in adults >30 years of age. In some cases, the PCB levels were over 0.8 ng/g wet weight, similar to levels observed in adults over 50 years of age. In the future, it will be necessary to do research on the health of the children who are exposed by high concentration level of POPs.