低浓度1-溴丙烷对接触者神经系统的影响

[目的]观察低浓度1-溴丙烷(1-BP)接触对人外周神经系统和中枢神经系统功能的影响。[方法]以25名1-BP接触工人为接触组(其中男性17人)和25名非接触工人为对照组(其中男性17人),使用问卷调查收集研究对象的年龄、性别和吸烟、饮酒状况及教育程度等信息,测定1-BP接触的时间加权平均浓度(TWA),进行神经传导速度和神经行为学检查。[结果]接触组女性和暴露组女性相比,一般情况中除年龄(接触组女性年龄低于对照组,P<0．05)外,其他方面差别均无显著性;接触组男性和暴露组男性一般情况差别均无显著性。1-BP接触浓度的TWA平均值80．4(2．0-384．9)mg/m3;男性接触组与其对照组相比,运动神经传导速度减慢,末端潜伏期延长,简明情绪量表(profile of mood states,PMOS)表中紧张焦虑项得分增高,视觉记忆项得分降低,差异有显著性(P<0．05);女性接触组与其对照组各项比较差别均未见统计学意义(P>0．05)。[结论]低浓度1-BP暴露能对男性接触者外周神经传导速度和神经行为产生影响。     

Neuro-reproductive toxicities of 1-bromopropane and 2-bromopropane

2-Bromopropane was used as an alternative to chlorofluorocarbons in a Korean electronics factory and caused reproductive and hematopoietic disorders in male and female workers. This causality was revealed by animal studies, and target cells were identified in subsequent studies. After identification of 2-bromopropane toxicity, 1-bromopropane was introduced to the workplace as a new alternative to ozone-depleting solvents. 1-Bromopropane was considered less mutagenic than 2-bromopropane, but, in contrast, animal experiments revealed that 1-bromopropane is a potent neurotoxic compound compared with 2-bromopropane. It was also revealed that 1-bromopropane has reproductive toxicity, but the target cells are different from those of 2-bromopropane. Exposure to 1-bromopropane inhibits spermiation in male rats and disrupts the development of follicles in female rats, in contrast to 2-bromopropane, which targets spermatogonia and oocytes in primordial follicles. After the first animal study describing the neurotoxicity of 1-bromopropane, human cases were reported. Those cases showed decreased sensation of vibration and perception, paresthesia in the lower extremities, decreased sensation in the ventral aspects of the thighs and gluteal regions, stumbling and headache, as well as mucosal irritation, as the initial symptoms. The dose–response of bromopropanes in humans and mechanism(s) underlying the differences in the toxic effects of the two bromopropanes remain to be determined.     

Investigation of toxicity through human cases and animal experiments--study of bromopropanes

In 1995, workers in a Korean electronic factory exhibited oligospermia or amenorrhea. We investigated the toxicity of 2-bromopropane used as an alternative to chlorofluorocarbons in the factory in animal experiments, and clarified that exposure to 2-bromopropane depletes spermatogenic cells in male rats and oocytes in female rats. Subsequently, we investigated the neurotoxicity of 2-bromopropane on the basis of the reported neuropathy in the Korean workers exposed to 2-bromopropane. For comparison, we employed 1-bromopropane, which is now used as a new alternative to chlorofluorocarbons. The results showed that 1-bromopropane is more neurotoxic than 2-bromopropane, causing harm to reproductive organs by inhibiting spermiation in the testis and impairing follicular development in the ovary. Shortly after the initial investigation of 1-bromopropane in animals, human cases were reported in the United States. Neurologic abnormalities in Chinese workers exposed to 1-bromopropane were also reported, such as the elongation of distal latency and lowered sense of vibration in the lower limbs. Thus, these serial studies revealed that 1-bromopropane is neurotoxic, but its dose-response relationship in humans remains unknown. In the investigation of 2-bromopropane toxicity, initial animal studies were designed on the basis of human studies, while in research on 1-bromopropane, animal studies preceded human studies and contributed to the prediction of toxicity in humans. However, the use of animal model is limited in its ability to predict the toxicity of chemicals introduced depending on species differences. Further studies should focus more on the differences and commonality between animals and humans in response to toxic agents.     

A survey on exposure level, health status, and biomarkers in workers exposed to 1-bromopropane

BACKGROUND: The aim of this study was to evaluate the health effects of exposure mainly to 1-bromopropane, which is an alternative to ozone-depleting solvents, and to establish biomarkers for assessing 1-bromopropane exposure. METHODS: Twenty-four female and 13 male workers of a 1-bromopropane-factory were interviewed, and their urine and blood samples were collected. Measured parameters included 1-bromopropane levels in the factory, as well as individual exposure levels, urinary 1-bromopropane levels, enzymatic activity and M subunit's concentration of serum creatine kinase (CK). RESULTS: Frequent symptoms reported by workers exposed to 1-bromopropane were nose, throat, and eyes irritation or malaise and/or headache. Urinary 1-bromopropane levels correlated significantly with individual exposure levels, but enzymatic activity or CK-M subunit did not. CONCLUSIONS: The symptoms suggested irritation of the mucous membrane and possible adverse effects on the central nervous system. There were no severe chronic symptoms suggestive of neurological damage in workers exposed to less than 170 ppm. Urinary 1-bromopropane level may be a good indicator of exposure. Am. J. Ind. Med. 45:63-75, 2004.     

Risk of chronic effects on the central nervous system at low toluene exposure

This study evaluates the chronic effects on the central nervous system of exposure to low concentrations of toluene (TWA < 20 ppm) on workers in a rotogravure plant. Ninety-eight male workers from a selection pool of 107 (92%) were examined neuropsychologically using a Cognitive Function Scanner, and neurologically by computerized methods measuring co-ordination ability, tremor and position stability. In addition measures of symptoms and former exposure were obtained by questionnaire. The workers were divided into three groups: Group 0 with no exposure to organic solvents (n = 19); Group 1 with exposure to TWA < 20 ppm of toluene for less than 13 years (n = 30) and Group 2 with exposure for more than 12 years (n = 49). Within Group 2, 37 (75%) had been exposed at levels exceeding 100 ppm for 10+ years before 1983. No significant differences were found between Group 0 and Group 1 regarding symptoms and results of the applied tests. Group 2 differed significantly from the two other groups in scoring higher on a symptom index (p = 0.04), particularly regarding concentration ability, reduced memory and fatigue. Group 2 scored significantly poorer on tests for visuospatial function, number learning and word recognition, while no differences regarding neurological functions were observed. The study showed no differences regarding neuropsychological and neurological functions between a non-exposed group of male workers and workers exposed to toluene less than 13 years at TWA < 20 ppm. However, long-term exposure to TWA (time weighted average) of toluene exceeding 100 ppm was associated with impaired neuropsychological function.     

Four-year follow-up of effects of toluene diisocyanate exposure on the respiratory system in polyurethane foam manufacturing workers

Fifty-seven polyurethane foam manufacturing workers (PF workers) and 24 reference workers were followed for 4 years to clarify the effects on pulmonary function of working in PF factories with exposure to toluene diisocyanate (TDI). No significant differences in the average annual losses (AALs) of pulmonary function for 4 years were observed among the 28PF workers whose TDI exposure levels were very low (mean = 0.1 ppb, group L), the remaining 29 PF workers with mean TDI exposure of 5.7 ppb (group H), and the reference workers. However, 15 PF workers in group H who had experienced peak exposure excursions to 30 ppb or above with a mean concentration of 8.2 ppb showed significantly larger AALs in percentage maximal mid-expiratory flow, forced expiratory volume in 1 s ratio to vital capacity (FVC), and forced expiratory flow at 25% of FVC than expected, and significantly larger AALs in some obstructive pulmonary function indices than those of the 14 remaining PF workers in group H whose peak exposure excursion levels were 3-14 ppb with a mean time-weighted average (TWA) of 1.7 ppb, group L, and the reference workers. These findings suggest that the peak exposure excursion level of TDI might be important in inducing obstructive pulmonary function changes in the PF workers rather than the TWA exposure levels, though further comparative studies of the AAL in those who are exposed to different peak exposure excursion levels but the same mean exposure levels are necessary. From the standpoint of prevention, the proposition that peak exposure excursion levels exceeding 20 ppb should be avoided is reasonable.     

苯及其同系物对职业女工生殖机能的影响

目的 :研究苯及其同系物对职业接触者月经及生殖机能的影响。方法 :对化工行业 2 6 8名苯作业女工月经及生殖机能进行回顾性调查 ,探讨职业接触对女工的影响。结果 :月经周期延长、经量增多、经期腰痛明显高于对照组 (χ2 =9.90 ,P<0 .0 0 5 ) ,且妊娠后自然流产、早产、胎儿失天缺陷等均高于对照组。结论 :苯职业接触可引起女工月经及生殖机能障碍。     

Diffusive Sampling and Biological Monitoring of 2-Bromopropane

The possibilities to apply personal ambient air monitoring by diffusive sampling and biological exposure monitoring by urinalysis for 2-bromopropane or its metabolites were explored. The abilities of carbon cloth to adsorb 2-bromopropane was examined by experimental vapor exposure followed by solvent extraction and FID-GC. Urine from factory workers and rats exposed to 2-bromopropane were analyzed for 2-bromopropane, acetone and isopropyl alcohol by FID-GC, and for bromide ion by ECD-GC after chemical methylation. Carbon cloth adsorbed 2-bromopropane in a manner linearly related to exposures up to 1500 mg/m³ and to 8 h. The adsorption could quantitatively detect a 15 min peak exposure at 3,000 mg/m³. In rat experiments, analyses of urine samples collected over a 4-h period after termination of a 4-h exposure to 2-bromopropane at 500, 1,000 or 1,500 mg/m³ showed that acetone and bromide ion were excreted dose-dependently. Essentially, no 2-bromopropane or isopropyl alcohol was detected. When the analytical methods were applied to urine samples from 5 male workers exposed to 2-bromopropane at a low level (3 mg/m³ as a geometric mean), acetone and bromide ion levels were within respective normal ranges in four cases, but were higher than the upper limits of the normal ranges in the fifth case of a foreman who probably had the highest exposure. Thus, diffusive sampling is applicable to monitor exposure to 2-bromopropane. Urinalysis for acetone and bromide ion in combination appears to be a promising selective tool for biological monitoring of occupational exposure to 2-bromopropane. Received: 26 February 1996/Revised: 29 May 1996     

Occupational exposure to 50 Hz magnetic fields in workers employed in various jobs

BACKGROUND: Information on occupational exposure to ELF magnetic fields (MF) in workers is largely insufficient, and is mostly based on results obtained in Scandinavian countries and North America. Accordingly, the collection of further data is needed, especially in workers exposed in other countries, including in Italy. METHODS: One hundred and fifty workers (84 males and 66 females) employed in 28 different jobs in the Emilia-Romagna Region of Italy were examined. Individual exposure was measured using personal monitors worn on the hip in a belted pouch during three whole work-shifts (8 hours each) of a normal working week. A sampling interval of 10 seconds was adopted, resulting in the collection of more than 8600 measurements for each worker. The individual Time-Weighted Average (TWA) occupational exposure of workers was calculated as the arithmetic mean of all measurements during each work-shift. Environmental non-occupational exposure was also measured. RESULTS: The 50 degrees percentile of individual TWA in the whole group was 0.15 microT, and the 5 degrees - 95 degrees percentile was respectively 0.02-1.45 microT. Job-related exposure (expressed as the mean of the TWA measured in all workers engaged in that job) was highest in substation electric power plant workers (1.12 microT) and in sewing machine workers (0.84 microT), but was lower than 0.2 microT in more than the 70% of the examined jobs. Considering the geometric mean of individual TWA are 27 out of 28 the jobs inducing an exposure lower than 0.2 microT. The lowest exposure was observed in infant school teachers. A high variability was observed among different workers engaged in the same occupation, mainly in substation electric power plant workers, machine testers and grinders in the engineering industry and in sewing machine workers and quality control in garment production. A marked variability of the pattern of exposure during the work-shift was also observed The overall environmental (non-occupational) exposure was 0.044 microT, and individual exposure was lower than 0.2 microT in about 97% of the examined subjects. Occupational exposure was usually higher and was not correlated with environmental exposure. CONCLUSIONS: The results show that the occupational component of overall exposure must be considered in studies on the biological effects of ELF-MF in populations. The high variability observed among workers engaged in the same occupation and the variability of the pattern of exposure certainly constitute major problems and could be a cause of the scarce coherence of the results of epidemiological studies on biological effects of ELF-MF to date. An improvement in protocols for the evaluation of exposure in workers, including the use of personal monitoring, is certainly needed.     

Neurotoxicity of 2-bromopropane and 1-bromopropane, alternative solvents for chlorofluorocarbons

To clarify the neurotoxicity of 2-bromopropane (2-BP) in comparison with 1-bromopropane (1-BP), 36 Wistar strain male rats were divided into 4 groups of 9 and exposed daily to 100-ppm 2-BP, 1000-ppm 2-BP, 1000-ppm 1-BP, or fresh air for 8 h a day. Exposure to 1000 ppm of 1-BP was discontinued after 5 or 7 weeks' exposure because of the unexpected appearance of incomplete hindlimb paralysis followed by serious emaciation. The other groups were sacrificed at the end of 12 weeks' exposure. Exposure to 1000 ppm of 2-BP resulted in significant decreases in body weight and motor nerve conduction velocity (MCV) and elongation in distal latency (DL). A ball-like enlargement of myelin sheaths was observed. Significant reductions in the number of erythrocytes, platelets, and leukocytes, testicular germ cell loss, and seminiferous atrophy were also observed in this group, but not in 100-ppm 2-BP group. Exposure to 1000 ppm of 1-BP for 5 or 7 weeks caused a significant decrease in body weight and MCV and elongation in DL. Linearly arranged ovoid- or bubble-like debris of the axons and myelin sheaths in the teased tibial nerves and axonal swelling in gracilis nucleus were found in this group. No significant changes in hematological indices or histopathological findings of the testis were found in this group. In conclusion, 2-BP is neurotoxic to the peripheral nerves in addition to its toxic effects on the reproductive and hematopoietic systems at 1000 ppm. No noticeable changes were found in the rats exposed to 100 ppm of 2-BP. 1-BP is a potent neurotoxicant at 1000 ppm for 5 or 7 weeks, while testicular and hematopoietic toxicity was not found.     

Markers of cadmium exposure in workers in a cadmium pigment factory after changes in the exposure conditions

The objective of this study was to assess changes in concentrations of cadmium in the blood (Cd-B), cadmium in the urine (Cd-U), beta2-microglobulin in the serum (beta2-mG-S) and beta2-microglobulin in the urine (beta2-mG-U) of workers at a cadmium (Cd) pigment factory in Japan in which exposure conditions improved. We evaluated reversibility of these markers in continuously employed workers in relation to changes in exposure levels resulting from improvements in the workplace and the reduced production of Cd. Our study involved both environmental and biological monitoring. Data were collected for four years. We measured the Cd concentration in the air of each work area, using the time-weighted average (TWA). Cd-B and Cd-U were measured in workers as direct indices of Cd exposure. beta2-mG-S and beta2-mG-U were measured as markers of renal tubular function. Exposure levels were high in all work areas, according to the criteria set by the American Conference of Governmental Industrial Hygienists (ACGIH). Workers' Cd-B and Cd-U concentrations reflected high levels of exposure. Correlation was found between these direct indices and beta2-mG-S concentrations. Since the second year, ambient Cd concentrations decreased and reacted markers have been improved. Our results suggest that Cd-B, Cd-U, beta2-mG-S and beta2-mG-U are appropriate markers for monitoring both the level of Cd exposure and the tubular function of workers. Reversibility of urinary low molecular weight protein was observed in the workers over the four years.     

1—溴丙烷工厂工人健康状况调查及接触生物标记物的研究

目的 分析1-溴丙烷毒性并评价其危险度，探讨适宜的接触生物标记物，方法 对37名工人进行问卷调查。血液学指标和血生化指标的测定。包括垂体激素和性激素测定。以该工厂工人为接触组，食品厂工人为对照组，比较两组间的血浆，脶酸激酶（CK）活性和血浆肌酸激酶M亚基（CK-M）。尿中1-溴丙烷用气相色谱仪检测，个体暴露蓄积水平用个体采样器估测。结果 接触组工人出现眼，鼻，口腔，喉的粘膜刺激症状。部分工人出现眩晕，可能是神经系统的反应。结论 接触1-溴丙烷引起的主诉症状提示它能刺激上呼吸道粘膜，在约100mg/m^3浓度水平可影响中枢神经系统，尿1-溴丙烷浓度有望成为接触的生物标记物。     

Sister chromatid exchange (SCE)and high-frequency cells in workers professionally exposed to extremely low-frequency magnetic fields (ELF)

BACKGROUND: Up now no firm conclusions can be drawn on the genotoxicity of Extremely Low Frequency (ELF) Magnetic Fields (MF) in exposed workers: both an increase in chromosomal aberrations (CA) and micronuclei (MN) or no effects were observed in substation workers, while a slight increase in CA, but not in sister chromatid exchanges (SCE) or MN was reported in linesman; an increase in CA was observed in cable splicers and, more recently, in train engine drivers, but results have not been replicated. OBJECTIVES: Objective of the study was an evaluation of possible genotoxicity of occupational exposure to ELF-MF. METHODS: SCE, high-frequency cells (HFC) and SCE in HFC were measured in peripheral blood lymphocytes from 70 workers exposed to various levels of ELF-MF in different occupations, not involving exposure to known mutagens or carcinogens. In all participants, individual ELF-MF exposure was measured throughout the whole work-shift for 3 consecutive days by personal monitoring. RESULTS: Time Weighted Average (TWA) values of ELF-MF in the whole group ranged from 0.01 to 3.48 microT; the geometric mean was 0.19 mT, and only 3 subjects exceeded 2 microT. According to the individual TWA exposure, subjects were divided into two groups: low exposed (< or = 0.2 microT) and highly exposed (> 0.2 microT). The mean values of SCE, HFC and SCE in HFC were compared between low and highly exposed: no significant differences were observed. The result was further tested by selection and comparison of workers exposed up to 0.1 microT vs. exposed > 0.4 microT only, i.e. excluding intermediate exposures: again no difference in genotoxicity indices was observed. Also multivariate analysis did not show any correlation between individual ELF-MF exposure and genotoxicity indices. CONCLUSIONS: The results of our study do not give any support to the hypothesis that occupational exposure to ELF-MF up to about 2 microT, i.e. at the levels currently found in most workplaces, can exert a genotoxic effect in workers.     

An assessment of the exposure of water reclamation workers to hydrogen sulphide

The paper describes a 4-month study of water reclamation workers in a rural area. Workers were chosen randomly from each of three groups: permanent site workers, mobile workers and tanker drivers. The exposure to H2S of each of these workers was monitored with pumped long-term colorimetric tubes over 4 days. The reclamation sites were visited over the period of the study and monitored with a hand-held H2S-measuring instrument to identify sources of possible exposure. Data on the weather conditions were also collected. Routine exposure to H2S was found to be low; only 14% of exposures were above the minimum detection limit of 0.1 ppm 8-h time-weighted average (TWA). None of the 190 valid samples were above the 8-h TWA occupational exposure standard (OES) of 10 ppm. If all the exposure had occurred in a 10 min period, 6% of exposures would have been above the 10 min TWA limit. The hand-held readings and knowledge of the work pattern suggest that this was unlikely to have been the case. Most of the positive personal exposure measurements were associated with tanker drivers who were not dealing with treated sludge only. There was a statistically significant difference between the likelihood of exposure to H2S occurring in warmer, drier weather and in cooler, wetter weather. Sites and jobs which can result in transient exposure to H2S are identified.     

Within-day variability of magnetic fields among electric utility workers: consequences for measurement strategies

Occupational exposure to 50-Hz magnetic fields was surveyed among electric utility workers to investigate (1) components of exposure variability, (2) patterns of autocorrelation between short-term measurements, and (3) imprecision and misclassification due to short-term measurements. Spot measurements every 10 seconds during 81 working days were analyzed for 42 electric utility workers from 10 occupational subgroups and during 8 working days for 4 office workers from the same company. For the 8-hour time-weighted average (TWA) magnetic fields, the variability was partitioned into its components: within workers, between workers, and between groups. For spot measurements of magnetic fields, the within-day variance component also was examined. Autocorrelation functions were determined and numbers of short-term measurements necessary for reliable estimates of 8-hour TWA magnetic fields were assessed. Spot measurements of magnetic fields, as well as 8-hour TWA magnetic fields, were approximately log normally distributed among workers. The mean exposure to magnetic fields was 0.47 microT (n = 81 days) in electric utility workers and 0.12 microT (n = 8 days) in office workers. A large fraction, 76% of the spot measurements total variance, could be attributed to variability within days. For the 8-hour TWA magnetic fields, between-group variability was small and of the same magnitude as between-worker variability. Significant autocorrelations between short-term averages of 7.5, 15, and 30 minutes were present, when taken within periods of 30 minutes. One-hour averages showed no autocorrelation. Simulations showed that, due to high within-day variability and autocorrelation, a limited number of short-term measurements of magnetic fields in electric utility workers are likely to result in imprecise estimates of 8-hour TWA magnetic fields. Measurement strategies relying on short-term (spot) measurements are therefore likely to result in misclassification of exposure and consequently absent or spurious exposure-response relations.     

1-溴丙烷对接触工人神经毒性的剂量-效应关系

目的 探索1-溴丙烷(1-BP)对接触工人神经毒性的剂量-效应关系.方法 对国内1-BP生产工厂进行职业卫生现场调查.按1:1比例选取年龄配对的接触组和对照组女工各71人.作业环境中1-BP的浓度用直读式检气管测定,工人的8 h时间加权平均(TWA)浓度用个体采样器测定.对工人进行问卷调查、神经内科检查、神经传导速度检查、振动觉检查、血常规和血液生化检查.根据TWA值和TWA×工龄值将接触工人分为3个剂量组,进行剂量-效应关系分析.使用USEPA BMDS 2.1软件计算1-BP毒作用基准剂量(BMD)和基准剂量下限值(BMDL).结果 TWA-8 h浓度范围为0.35～535.19 mg/m3,(均值14.08 mg/m3).剂量-效应关系分析表明,1-BP接触工人在运动神经远端潜伏期(DL,线性回归系数为0.0666)、双足振动觉(线性回归系数分别为0.157 2和0.193 9)、肌酸激酶水平(线性回归系数为-1.0464)和促甲状腺激素水平(线性回归系数为0.102 4)等指标与1-BP有剂量依赖关系(P<0.05).依据DL资料计算TWA-8 h的BMD值和BMDL值分别为55.55和30.78 mg/m3.结论 1-BP对接触工人具有神经毒性,可引起胫神经DL延长、振动觉下降的剂量依赖性改变.     

Visual and ocular changes associated with exposure to two tertiary amines

Aims: To determine if exposure to dimethylisopropanolamine (DMIPA) and dimethylaminoethanol (DMAE) in a label printing plant was associated with visual disturbances and/or ocular changes.

Methods: Questionnaires, eye examinations (visual acuity, contrast sensitivity at 2.5% and 1.25% contrast, slit lamp biomicroscopy, and pachymetry), and industrial hygiene monitoring for DMIPA and DMAE were performed over a two week period.

Results: Eighty nine per cent of line workers reported having experienced blurry vision while at work in the past 12 months, compared to 12.5% of prime workers. A total of 108 full shift personal breathing zone (PBZ) air samples for the amines were collected. The mean time weighted average (TWA) concentration of DMIPA was significantly higher in the line division than in the prime division, as was the mean TWA concentration for total amines. The mean TWA concentration of DMAE was higher in the prime division than the line division. Higher levels of total amines were associated with increased risk of reporting blurry vision, halo vision, and blue-grey vision. The risk of corneal opacity rose with increasing exposure to total amines. The prevalence of corneal opacity also increased with increasing concentration of total amines. Median corneal thickness increased with increasing grades of corneal opacity. There was a statistically significant relation between total amine concentration and increased risk of reduced bilateral visual acuity and 2.5% contrast sensitivity.

Conclusions: Exposure to tertiary amines was associated with blurry, halo, and blue-grey vision, corneal opacity, and decrements in visual acuity and contrast sensitivity at 2.5% contrast.

     

Relation between airborne arsenic trioxide and urinary excretion of inorganic arsenic and its methylated metabolites.

The relation between exposure to As2O3 fumes and dust, and the urinary excretion of inorganic arsenic metabolites (monomethylarsonic acid, dimethylarsinic acid, unchanged inorganic arsenic) has been studied in 18 workers from a sulphuric acid producing plant. The concentration of arsenic in the breathing zone of each worker was measured during five consecutive days and urine samples were obtained after one shift and before the next. The collection efficiency of the air sampling system exceeded 95%. The time weighted average exposure (TWA) concentrations of As2O3 ranged from 6 to 502 micrograms As/m3 and were log normally distributed. Although exposure probably occurred by ingestion as well as inhalation, statistically significant correlations (log scales) were found between airborne TWA of As2O3 and the inorganic arsenic metabolites in urine collected immediately after the shift, or just before the next shift. For a TWA of 50 micrograms As/m3, the mean concentration of the sum of the three inorganic arsenic metabolites in a postshift urine sample amounted to about 55 micrograms arsenic/g creatinine (95% confidence interval (95% CI) 47-62). Higher estimates of urinary arsenic reported by other authors are probably due either to the influence of dietary organoarsenicals when total arsenic is measured in urine or to a low retention efficiency of the air sampling system for As2O3 in the vapour phase.     

Relation between airborne arsenic trioxide and urinary excretion of inorganic arsenic and its methylated metabolites.

The relation between exposure to As2O3 fumes and dust, and the urinary excretion of inorganic arsenic metabolites (monomethylarsonic acid, dimethylarsinic acid, unchanged inorganic arsenic) has been studied in 18 workers from a sulphuric acid producing plant. The concentration of arsenic in the breathing zone of each worker was measured during five consecutive days and urine samples were obtained after one shift and before the next. The collection efficiency of the air sampling system exceeded 95%. The time weighted average exposure (TWA) concentrations of As2O3 ranged from 6 to 502 micrograms As/m3 and were log normally distributed. Although exposure probably occurred by ingestion as well as inhalation, statistically significant correlations (log scales) were found between airborne TWA of As2O3 and the inorganic arsenic metabolites in urine collected immediately after the shift, or just before the next shift. For a TWA of 50 micrograms As/m3, the mean concentration of the sum of the three inorganic arsenic metabolites in a postshift urine sample amounted to about 55 micrograms arsenic/g creatinine (95% confidence interval (95% CI) 47-62). Higher estimates of urinary arsenic reported by other authors are probably due either to the influence of dietary organoarsenicals when total arsenic is measured in urine or to a low retention efficiency of the air sampling system for As2O3 in the vapour phase.     

1-溴丙烷吸入暴露对雄性大鼠生殖系统的影响

目的研究1-溴丙烷亚急性暴露对雄性大鼠的生殖毒性.方法将48只雄性大鼠分为对照组、1-溴丙烷1 000、2000、4000 mg/m3暴露组.暴露组给予7 d,每天8 h的吸入暴露.结果1-溴丙烷高浓度暴露组大鼠的体重、前列腺和精囊质量显著下降,附睾精子运动率降低,形态异常精子增多.血浆肌酸激酶活力和肌型肌酸激酶含量降低.睾丸病理切片观察到曲细精管的精子释放延迟.结论1-溴丙烷亚急性暴露对雄性大鼠的生殖系统产生毒性影响,附睾精子运动率的下降是本次实验的最敏感指标.