甲醛慢性吸入暴露致小鼠精子畸形

目的研究甲醛慢性吸入染毒致雄性小鼠生殖细胞遗传毒性。方法 SPF级雄性ICR小鼠40只,随机分为4组:低剂量组、高剂量组、阴性对照组和阳性对照组,每组10只,低、高剂量组染毒剂量分别为1、10 mg/m~3,用静式吸入的方法进行染毒,每天一次,每次2 h,连续染毒20周,阳性对照组给予环磷酰胺。小鼠染毒后继续饲养5周。观察并计算精子畸形率。结果阴性对照组、低剂量组和高剂量组的睾丸脏器系数分别为(0.81±0.13)%、(0.82±0.12)%和(0.78±0.12)%,各组之间差异无统计学意义(P0.05);阴性对照组、阳性对照组、低剂量组和高剂量组的精子畸形率分别为4.1%、6.4%、11.5%和11.3%,与阴性对照组比较,各染毒组精子畸形率明显增加,差异有统计学意义(P0.01);且染毒剂量与精子畸形率之间存在剂量-反应关系(r_s=0.888,P0.01)。结论甲醛慢性吸入染毒可引起小鼠精子畸形率升高,且染毒剂量与精子畸形率之间存在剂量-反应关系。     

Immune activation and autoantibodies in humans with long-term inhalation exposure to formaldehyde

Four groups of patients with long-term inhalation exposure to formaldehyde (HCHO) were compared with controls who had short-term periodic exposure to HCHO. The following were determined for all groups: total white cell, lymphocyte, and T cell counts; T helper/suppressor ratios; total Ta1+, IL2+, and B cell counts; antibodies to formaldehyde-human serum albumin (HCHO-HSA) conjugate and autoantibodies. When compared with the controls, the patients had significantly higher antibody titers to HCHO-HSA. In addition, significant increases in Ta1+, IL2+, and B cells and autoantibodies were observed. Immune activation, autoantibodies, and anti-HCHO-HSA antibodies are associated with long-term formaldehyde inhalation.     

Health risk assessment for inhalation exposure to arsenic

Health risk assessment was used as the formal process to estimate the likelihood and magnitude of the health effects occurring in humans as a result of environmental and occupational exposure to polluting agents. This study was focused at estimating the human health risk of the general and working population living in the region polluted by arsenic for more than 40 years, from combustion of coal with high arsenic content in the power plant. The exposure to arsenic from inhalation was under investigation. A study period of 40 years (1973-1993) was chosen. The study period was defined taking into account, besides the availability of data, the temporal patterns of the technological processes and the trends over time of environmental concentrations. The results from the arsenic risk assessment study were used for the evaluation of the health risk for different population groups in the polluted areas and for different professions of workers exposed to As in a power plant. The results are applicable for the evaluation of risk in real conditions, for health surveillance and for remedial changes and a potential suggestion on technological improvement.     

Classification of occupational activities for assessment of inhalation exposure

There is a large variety of activities in workplaces that can lead to emission of substances. Coding systems based on determinants of emission have so far not been developed. In this paper, a system of Activity Classes and Activity Subclasses is proposed for categorizing activities involving chemical use. Activity Classes share their so-called 'emission generation mechanisms' and physical state of the product handled and the underlying determinants of emission. A number of (industrial) stakeholders actively participated in testing and fine-tuning the system. With the help of these stakeholders, it was found to be relatively easy to allocate a large number of activities to the Activity Classes and Activity Subclasses. The system facilitates a more structured classification of activities in exposure databases, a structured analysis of the analogy of exposure activities, and a transparent quantification of the activity emission potential in (new) exposure assessment models. The first use of the system is in the Advanced REACH Tool.     

某拉链制造企业甲醛职业接触致癌风险评估

目的 评估某拉链制造企业接触甲醛作业人员致癌风险。
方法 通过对某拉链制造企业塑料拉链车间甲醛浓度的测定, 运用美国环境保护署吸入风险模型, 估算作业人员接触甲醛所增加的致癌风险。
结果 该企业塑料拉链车间树脂切片、注塑、组装岗位均存在甲醛危害, 其中树脂切片岗位甲醛超标率为75%, 岗位最高检测浓度为3.10 mg/m3, 致癌风险为7.97×10-4; 注塑、组装岗位甲醛浓度符合职业接触限值的要求, 致癌风险分别为5.14×10-5和7.07×10-5。
结论 该拉链制造企业甲醛接触人员致癌风险较大, 尤其树脂切片岗位致癌风险高, 应采取更多措施以减少甲醛接触。
     

Italian survey on human behaviour for inhalation exposure assessment

In order to support risk management in identifying effective mitigation measures, exposure assessment related to environmental pollution needs to integrate monitoring of pollution levels and control data with information on population behaviour and lifestyle. With this aim, a sample population survey was carried out in a Northern Italian city, collecting data on human behavioural factors influencing inhalation exposure. Questionnaires gathering data on dwelling characteristics, and weekly individual diaries on personal behaviour, such as places frequented and daily activities, were used. Data collection was carried out in two different seasons, spring-summer and fall-winter. A sample of 270 families, randomly selected from the municipal registry, was enrolled for each seasonal observation. The study allowed quantification of variability in human behaviour revealing seasonal variation and differences due to age and gender. Daily activity patterns were described and probability distributions of inhalation rates were obtained for all observed population groups. A probabilistic exposure model was developed and the resulting exposure distributions for the two seasonal periods were compared. Results confirm that exposure estimates are strongly biased if variability in human behaviour is not taken into account.     

Methodology to reduce formaldehyde exposure during laboratory fumigation

Laboratory fumigations achieve disinfection and are performed following the non-contained release of infectious agents. Gaseous formaldehyde remains the most commonly used fumigant but evidence relates formaldehyde exposure to the development of nasopharyngeal cancer. Laboratory personnel must be confident and competent in the procedure to protect themselves, others and the environment. The present study outlines methodology to reduce worker exposure to formaldehyde during essential fumigation training. A simulation fumigation protocol significantly shorter than a genuine fumigation was devised using aromatic cajuput oil to train staff in the fumigation technique without potentially harmful exposure to formaldehyde. Personnel reported increased confidence and compliance of the fumigation procedure after the simulation suggesting that this model protocol would be a valuable training tool for any individual that may be required to undertake genuine formaldehyde fumigations.     

Conceptual model for assessment of inhalation exposure to manufactured nanoparticles

As workplace air measurements of manufactured nanoparticles are relatively expensive to conduct, models can be helpful for a first tier assessment of exposure. A conceptual model was developed to give a framework for such models. The basis for the model is an analysis of the fate and underlying mechanisms of nanoparticles emitted by a source during transport to a receptor. Four source domains are distinguished; that is, production, handling of bulk product, dispersion of ready-to-use nanoproducts, fracturing and abrasion of end products. These domains represent different generation mechanisms that determine particle emission characteristics; for example, emission rate, particle size distribution, and source location. During transport, homogeneous coagulation, scavenging, and surface deposition will determine the fate of the particles and cause changes in both particle size distributions and number concentrations. The degree of impact of these processes will be determined by a variety of factors including the concentration and size mode of the emitted nanoparticles and background aerosols, source to receptor distance, and ventilation characteristics. The second part of the paper focuses on to what extent the conceptual model could be fit into an existing mechanistic predictive model for 'conventional' exposures. The model should be seen as a framework for characterization of exposure to (manufactured) nanoparticles and future exposure modeling.     

Conceptual model for assessment of inhalation exposure: defining modifying factors

The present paper proposes a source-receptor model to schematically describe inhalation exposure to help understand the complex processes leading to inhalation of hazardous substances. The model considers a stepwise transfer of a contaminant from the source to the receptor. The conceptual model is constructed using three components, i.e. (i) the source, (ii) various transmission compartments and (iii) the receptor, and describes the contaminant's emission and its pattern of transport. Based on this conceptual model, a list of nine mutually independent principal modifying factors (MFs) is proposed: activity emission potential, substance emission potential, localized control, separation, segregation, dilution, worker behavior, surface contamination and respiratory protection. These MFs describe the exposure process at a high level of abstraction so that the model can be generically applicable. A list of exposure determinants underlying each of these principal MFs is proposed to describe the exposure process at a more detailed level. The presented conceptual model is developed in conjunction with an activity taxonomy as described in a separate paper. The proposed conceptual model and MFs should be seen as 'building blocks' for development of higher tier exposure models.     

Generation of constant formaldehyde levels for inhalation studies

Development of the described formaldehyde generator was undertaken to provide researchers engaged in inhalation studies with the capability to produce constant and controllable levels of formaldehyde in air. Depolymerization of purified paraformaldehyde under rigorously controlled conditions in a modified Freeland calibration manifold is employed. The desired formaldehyde concentration in the exposure chamber is achieved by adding an appropriate fraction of the generator effluent to the normal air supply to the chamber. Variation in generator formaldehyde concentration is less than +/- 11% over a three-day period and less than +/- 2% over short periods (36 seconds).     

Dose assessment to inhalation exposure of indoor 222Rn daughters in Korea.

Long-term, average indoor 222Rn concentrations were measured in 12 residential areas by passive CR-39 radon cups. Corresponding equilibrium-equivalent concentration of radon daughters were derived. The resulting effective dose equivalent for the Korean population due to inhalation exposure of this equilibrium-equivalent concentration of radon daughters was then evaluated.     

孕期甲醛暴露与女性自然流产关系的Meta分析

目的综合分析孕期甲醛暴露与孕妇发生自然流产之间的关系。方法检索并收集2014年以前国内外发表的关于孕期甲醛暴露与自然流产关系的文献。使用Rev Man 5.1软件对相关文献进行统计分析。结果共纳入6篇文献(暴露组666例,对照组3087例),森林图显示纳入文献是同质的(I2=37%,P=0.16),采用固定效应模型计算得到孕期甲醛暴露与孕妇发生自然流产相关(OR=1.64,95%CI1.20~2.24,P=0.002)。结论孕期甲醛暴露可能会增加自然流产的发生风险。     

Airway response to formaldehyde inhalation in asthmatic subjects with suspected respiratory formaldehyde sensitization

The aim of the study was to characterize the mechanism of formaldehyde (FM)-induced nasal and bronchial response in asthmatic subjects with suspected FM allergy. Ten subjects purported to have FM rhinitis and asthma and 10 healthy subjects submitted to an inhalation provocation in an exposure chamber with FM at a dose of 0.5 mg/m³ over 2 hr. Spirometry at rest and following bronchial provocation with histamine (PC₂₀) were recorded before and after FM inhalation. In addition, FM-specific serum IgE antibodies were measured and cellular, biochemical, and mediator changes were assessed in nasal lavage before, and immediately after, provocation and at 4 hr and 24 hr later. Provocation with FM caused only transient symptoms of rhinitis in both groups. None of the subjects supposed to have occupational asthma developed clinical symptoms of bronchial irritation. No specific IgE antibodies to FM were detected in persons with occupational exposure to FM. No differences in the nasal response to FM were found between subjects reporting to have occupational allergic respiratory diseases and healthy subjects (P > 0.05). In summary, inhaled formaldehyde at a level as low as 0.5 mg/m³ did not induce a specific allergic response either in the upper or in the lower part of the respiratory tract. Moreover, there is no difference in nasal response to FM in asthmatic subjects occupationally exposed to FM and healthy subjects. Am. J. Ind. Med. 33:274–281, 1998. © 1998 Wiley-Liss, Inc.     

Lethal inhalation exposure during maintenance operation of a hydrogen fluoride liquefying tank

Calcium sulfate adheres to the inside of liquefying pipes during the production of liquefied hydrogen fluoride. It is regularly washed away with water jets every six months. Two days before the operation, the pipes were experimentally washed down with water and the safety of the operation was confirmed with acidic washing fluid (pH 5). A 65-year-old man was severely sprayed on his face just after the start of the operation. He died half an hour later from acute respiratory failure. High serum concentrations of ionized fluoride indicated massive exposure to hydrofluoric acid (HFA). Pathological findings revealed severe bilateral pulmonary congestion and edema. It was hypothesized that calcium sulfate hardened with the water during the experimental washing and caused some blockages in the pipes. Consequently, choking of the pipes caused the HFA to collect and the washing fluid ran back. Weak HFA is not pungent to skin and mucous membranes. Therefore, it was suggested that a low concentration of HFA was inhaled directly into the peripheral respiratory tracts. No risk management against HFA exposure was in place during the operation. It is especially important to take thorough safety measures against inhalation of HFA. It is also essential that there are no stoppages of the pipes before the operation.     

Measurement of the physical properties of aerosols in a fullerene factory for inhalation exposure assessment

Assessment of human exposure is important for the elucidation of potential health risks. However, there is little information available on particle number concentrations and number size distributions, including those of nanoparticles, in the working environments of factories producing engineered nanomaterials. The authors used a scanning mobility particle sizer and an optical particle counter to measure the particle number size distributions of particles ranging in diameter (D(p)) from 10 nm to >5000 nm in a fullerene factory and used scanning electron microscopy to examine the morphology of the particles. Comparisons of particle size distributions and morphology during non-work periods, during work periods, during an agitation process, and in the nearby outdoor air were conducted to identify the sources of the particles and to determine their physical properties. A modal diameter of 25 nm was found in the working area during the non-work period; this result was probably influenced by ingress of outdoor air. During the removal of fullerenes from a storage tank for bagging and/or weighing, the particle number concentration at D(p)<50 nm was no greater than that in the non-work period, but the concentration at D(p)>1000 nm was greater during the non-work period. When a vacuum cleaner was in use, the particle number concentration at D(p)<50 nm was greater than that during the non-work period, but the concentration at D(p)>1000 nm was no greater. Scanning electron microscopy revealed that the coarse particles emitted during bagging and/or weighing were aggregates/agglomerates of fullerenes; although origin of particles with D(p)<50 nm is unclear.     

Changes in nasal lavage fluid due to formaldehyde inhalation

Summary The aim of the study was to characterize the nature of the formaldehyde-induced nasal response consisting in symptoms of rhinitis and changes in nasal lavage fluid. Eleven healthy subjects and nine patients with specific skin sensitization were provoked in a toxicological chamber with formaldehyde at a dose of 0.5 mg/m³ over 2 h. Nasal lavage was performed prior to and immediately after provocation and 4 and 18 h later. Provocation with formaldehyde caused transient symptoms of rhinitis and prolonged changes in nasal washings. There were increases in the number and proportion of eosinophils and elevated albumin and total protein levels in nasal lavage fluid 4 and 18 h after provocation. No difference in the nasal response to formaldehyde was found between patients with skin sensitization and healthy subjects. These data confirm the irritative effects of formaldehyde and are also suggestive of nonspecific proinflammatory properties when formaldehyde is inhaled at a low (0.5 mg/m³) dose.     

甲醛吸入对小鼠某些血液成分的影响

目的 观察甲醛吸入对小鼠某些血液成分的影响.方法 80只成年雌、雄各半昆明种小鼠随机分成4组,每组20只,每天2 h吸入不同浓度气态甲醛(0、2.5、10.0、30.0 mg/m3)持续2周,测定小鼠外周血某些成分.结果 甲醛染毒低、中、高组小鼠外周血白细胞数分别为(2.4±1.2)、(1.9±0.4)、(1.5±0.2)×109/L,均显著低于对照组(4.0±1.1)×109/L,差异均有统计学意义(P<0.05),并且雄性或雌性单独统计差异亦有显著性(P<0.05);血小板计数中、高浓度染毒组分别为(53.1±20.6)、(49.6±18.0)×109/L.显著低于对照组(73.1±19.8)×109/L,差异均有统计学意义(P<0.05).结论 吸入一定浓度甲醛能引起小鼠白细胞和血小板数降低.