Noise exposures of rail workers at a North American chemical facility

BACKGROUND: Both continuous and impact noise exposures of rail yards and railways have been historically understudied. We summarize noise exposures to rail workers at a large chemical facility in North America. METHODS: Rail workers were surveyed over the course of three 12-hr shifts. Personal noise dosimeters were used to derive a 12-hr time-weighted average (L(AVG)), an 8-hr time-weighted average (L(TWA)), and a percent dose. Peak and maximum sound levels were also recorded during each sampling period. Six workers were sampled on three separate days for a total of 18 full-shift noise samples. RESULTS: Full-shift noise exposures were all below the Occupational Safety and Health Administration's (OSHA) permissible exposure limit (PEL) and action level for a 12-hr workday. Peak impact sound levels exceeded 140 dB in 17 of 18 samples (94%) with a mean peak sound level of 143.9 dB. Maximum continuous sound levels were greater than 115 dBA in 4 of 18 samples (22%) with a mean maximum sound level of 113.1 dBA. The source of peak impact sound levels was a daily exposure to a concussion caused by a sudden break in a freight airline. CONCLUSIONS: Rail workers at this facility are at risk of noise induced hearing loss from high impact noise exposures. Peak impact and maximum continuous sound levels can be attenuated through the use of hearing protection or by increasing distances from railroad noise sources.     

飞机噪声引起的永久性听力变化

本文报告了在飞机噪声100～130dB(A)条件下工作的410名不同工龄机务人员的听力损伤。结果表明,机务人员的听力损伤严重,且随着工龄的延长而加重。其中高频听力损失占46.1％,噪声性耳聋占6.1％,与对照组相比,各频率的听力均值显著提高。值得提出的是机务人员高频听力损失的“V”形凹点不是在4kHz,而是在6kHz,由此我们认为,以前关于4kHz凹陷形成的理论有待商榷。     

Predictors of hearing loss in New York farmers.

BACKGROUND: Data from the telephone interview portion of the New York Farm Family Health and Hazard Surveillance were used to study self-reported hearing loss in New York farmers. METHODS: One thousand six hundred and twenty-two persons completed the hearing loss and noise exposure interview. Hearing loss was defined as at least some trouble hearing in one or both ears. Predictors of hearing loss were determined using logistic regression. RESULTS: Twenty-two percent of participants reported hearing loss. From the logistic regression, significant confounders are age (P = 0.0001), gender (P = 0.0001), being from a livestock farm (P = 0.012), and loss of consciousness due to head trauma (P = 0.04). Significant noise exposures are more hours of lifetime exposure to noisy farm equipment (P = 0.001) and having had a noisy non-farm job (with some hearing protection P = 0.002, without any hearing protection P = 0.0001). CONCLUSIONS: Farm noise exposure is a serious risk to the hearing of this population. Although use of hearing protection should be encouraged, replacing and modifying farm equipment to decrease noise at the source should be the first priority.     

职业噪声暴露与吸烟联合作用对听力影响的研究进展

职业噪声暴露所导致的职业性听力损伤是世界范围内的主要职业性疾病，但噪声并不是引起职业性听力损伤的惟一因素。研究发现吸烟也是听力损伤的重要危险因子之一，吸烟可能通过损伤内耳毛细胞及导致内耳组织缺氧加重噪声暴露所导致的听力损伤。     

噪声所致工人听力损失与高血压的关系

目的研究某钢铁企业工人噪声暴露与高血压的关系。方法选择2014年1~7月底参加职业体检单纯接触噪声工人2061例,按照高频听力损失严重程度分组,即在4000 Hz或者6000 Hz,低听力损失组平均听力损失值(HLVs)15 d B(A)660例,噪声40 h等效声级为(74.69±11.97)d B(A);中听力损失组,15 d B(A)≤HLVs30 d B(A)741例,噪声40 h等效声级为(84.38±11.57)d B(A);高听力损失组,HLVs≥30 d B(A)660例,噪声40 h等效声级为(88.03±14.08)d B(A)。比较三组高血压患病率的差异。结果工人4000 Hz和6000 Hz时,左、右和两耳平均的HLVs值与平均噪声暴露水平显著相关(P0.05)。高血压患病率中听力损失组(29.5%)和高听力损失组(36.1%)明显高于低听力损失组(23.8%)(P0.05)。多因素Logistic回归分析显示,在调整了年龄、心率(HR)、甘油三酯(TG)、噪声40 h等效声级、糖尿病、吸烟、饮酒、体育锻炼等影响因素后,中听力损失组和高听力损失组患高血压的风险较高,其OR值分别为2.14(1.21~3.79)、2.58(1.44~4.62)。结论钢铁企业工人高频噪声引起的听力损失与患高血压的风险有关。     

Audiometric notch as a sign of noise induced hearing loss

OBJECTIVES—To investigate the relation between different types of exposure to noise and a classic sign of noise induced hearing loss (NIHL), the audiometric notch.METHODS—The study sample had exposure to both continuous and impulse noise and was drawn from a population of electrical transmission workers. Audiograms, taken as part of a hearing conservation programme, were read by three clinicians experienced in the assessment of NIHL. Working independently and using their clinical judgment, they were asked to identify localised increases in the threshold of hearing (audiometric notches) which they would attribute to noise, had a suitable history of exposure been elicited. Prevalent cases of NIHL were identified by the presence of a notch in either ear. Risk factors for NIHL were assessed by a questionnaire which sought information about exposure to air blast circuit breaker noise; firearms; explosions, and continuous noise. The odds of exposure to these factors in those with and without hearing loss were calculated, and odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated by logistic regression.RESULTS—Of the 648 questionnaires sent out 357 were returned, a response rate of 55%. Of these, at least two out of the three assessors identified 175 (49%) people with a notch at any audiometric frequency. There was no association between these cases and the NIHL risk factors identified by the questionnaire, but a further frequency specific analysis showed a small proportion of people (15 (4%)) with notches at 4 kHz who had the expected associations with exposure to noise and a significant OR for firearms of 4.25 (95% CI 1.28 to 14.1). The much larger proportion of people with 6 kHz notches (110 (31%)) did not show these associations.CONCLUSIONS—To diagnose NIHL it is important to elicit a detailed and accurate history of exposure to noise: although the notch at 4 kHz is a well established clinical sign and may be valuable in confirming the diagnosis, the 6 kHz notch is variable and of limited importance.     

The LD50 and Chronic Toxicity of Reactor Terphenyls

Acute ingestion of reactor coolant terphenyls (HB-40) revealed LD₅₀ values of 17,500 mg/kg rat and 12,500 mg/kg mouse for nonirradiated coolant and 6,000 mg/kg mouse or rat for irradiated coolant. Chronic ingestion of the mixtures by mice produced mitochondrial changes in epithelial cells of proximal tubules, and at high doses these cells became necrotic as interstitial nephritis and scarring developed. The nephritis was irreversible and followed 16 weeks’ ingestion of 1,200 mg/kg nonirradiated HB-40 or 600 mg/kg irradiated coolant. Hepatic changes were observed only at the ultrastructural level where abundant smooth endoplasmic reticulum was seen. It appears that organic terphenyl coolants are potentially toxic when ingested in high doses. This could only occur as a result of chronic exposure at a level greatly in excess of that currently observed in the reactor working environment.     

高温作业与噪声对人耳听力的联合影响

目的为探讨高温与噪声联合作用对作业工人听力的影响。方法联合作用组(A组)67名,单纯噪声组(B组)56名,对照组54名(C组)进行听力损伤的调查。结果噪声强度A组LAeq87．4dB(A),B组LAeq87．0dB(A);各组听损发生率A组＞B组＞C组,组间比较(P＜0．01);各组间不同频率的听阈均值对比中,2、3、4、6kHz以A组＞B组＞C组,各组间比较(P＜0．01)。结论提示高温与噪声对工人高频听阈有协同作用。     

某纺织厂噪声作业工人听力损失调查

目的:通过对某纺织厂噪声强度监测和对作业人员的听力检测,掌握噪声强度及听力损失的发生情况,为采取积极有效的防护措施提供依据。方法:用HS6288系列噪声分析仪监测作业场所噪声强度,并进行频谱分析,计算累积噪声暴露量(CNE);对某纺织厂接触噪声作业的无耳疾患的931人进行听力检测;用EpiData建立数据库,SAS软件8.0统计包进行统计分析。结果:该厂噪声车间的连续等效A声级均超过了85db(A),主要为中高频噪声;噪声作业人员有高频听力损失264人,检出率为28.36%,语频听力损失9人,检出率为0.97%;高频和语频听力损失的发生率均随累积接触噪声剂量的增加而升高;听力损失发生率及程度与工龄密切相关;织一车间和织二车间噪声平均>100dB(A),高频听损率分别为43.68%和42.62%,在强噪声车间作业戴耳塞者高频听损检出率低于不戴耳塞者,但高频听力损失的检出率仍然明显高于其他车间;听力损失曲线以高频凹陷谷点为3kHz及4 kHz的“V”字型为主,占高频听力损失的73.0%。结论:该厂噪声污染较严重,对作业人员听力已经产生了明显影响,应采取积极的综合预防性措施来控制噪声对作业人员健康的影响。     

噪声对听力损伤与对心功能影响之间的关系探讨

本文对69名接触相同水平工业噪声的工人,进行了听力损伤和心功能变化的比较研究。结果显示,噪声聋组与非耳聋组相比,等容收缩时间(ICT)、射血前期时间(PEP)延长,ICT/LVET和PEP/LVET比值增高,心脏射血分数降低,两组间有显著差异,提示噪声对听力与心功能的影响吴平行关系。     

Evaluation of noise-induced hearing loss by reference to the upper limit of hearing

We have defined the upper limit of hearing as the maximum audible frequency measured with fixed intensity and changing frequency. We have previously established the standard upper limit ageing curves from the normal age variation in the upper limit of hearing. In the present study, we sought to clarify the effects of occupational noise on the upper limit of hearing. We measured the upper limit of hearing in 239 healthy male workers (478 ears) exposed to intensive occupational noise. Their age variation in the upper limit of hearing was compared with the standard upper limit ageing curves in males. There were statistically significant deteriorations. Even if the ears that had normal hearing levels (35 dB or less) were selected, deterioration in the upper limit of hearing was noticeable. The upper limit of hearing may serve as clinically useful information on the hearing impairment that precedes noticeable hearing impairment in conventional audiometry for workers exposed to intensive occupational noise.     

两种测量方法评价稳态噪声暴露与高频听力损伤的剂量-反应关系

目的 比较环境噪声水平、个体噪声暴露和累积噪声暴露量评价稳 态噪声所致听力损伤剂量－反应关系的优劣。方法 用个体计量仪采集8小时工作期间挡车工的噪声暴露数据,并将数据传输至微机存储和分析。选择细砂、布机车间使用不同类型机器的4组工人作为观察对象,每组选择3－5人,分别在早、中、晚班各测量1个班次的个体噪声暴露数据;用网格法和普通声级计测量每组工人工作环境的噪声水平,同时对该纺织厂接触稳态噪声的163名工人进行了问卷和听力检查。结果 经年龄、性别校正后的高频听力损伤患病率为64．4％;语频听力损伤患病率为2．5％,其中高频听力损伤患病率随噪声暴露的剂量增大而升高,呈现典型的剂量－反应关系。经趋势卡方检验和和Logistic回归模型拟合,累积噪声暴露量评价剂量－反应关系的效果优于噪声级,个体噪声暴露的效果优于环境噪声水平。结论 个体噪声暴露和累积噪声暴露量是评价稳态噪声暴露与高频听力损伤剂量－反应关系最好的暴露评价指标。     

Is occupational noise exposure during pregnancy a risk factor of damage to the auditory system of the fetus?

In the Province of Quebec, the regulated daily noise exposure limit is 90 dBA-8h. This limit value also applies to pregnant women. Experimental studies suggest however, that this standard is not sufficiently stringent to protect the auditory system of the fetus, particularly in cases of low-frequency noise exposure. An exploratory study was undertaken to assess this possibility. A total of 131 children were examined. Their mothers had worked, while pregnant with that child, in noise conditions ranging from 65 to 95 dBA-8h. Results show a three-fold increase in the risk of having a high-frequency hearing loss in the children whose mothers were exposed to noise in the range between a LAeq,9 m of 85 to 95 dB, and a significant increase in the risk of hearing loss at a frequency of 4000 Hz when these exposures involved a strong component of low-frequency noise.     

Hearing loss as a risk factor for agricultural injuries

BACKGROUND: Previous studies suggested that hearing impairment based on self-report might increase the risk of agricultural injuries. However, self-reported hearing measures may be subject to inaccuracy and subjective perception. We assessed the association of agricultural injuries with hearing loss and other hearing characteristics using measured hearing. METHODS: Study subjects were 150 farmers who participated in the Iowa Certified Safe Farm study. Injury information was collected by telephone interviews at 2-5 month intervals from September 1999 to October 2002. Hearing levels were measured annually using the pure tone audiometry from 1998 to 2002. Adjusted rate ratios of injuries were calculated using the multivariate Poisson regression model. RESULTS: Hearing loss in the better ear (RR = 1.62), hearing asymmetry (RR = 1.67), and fair/poor self-reported hearing (RR = 1.96) were significantly associated with the risk of agricultural injuries. It is notable that self-reported hearing might be a stronger predictor of injuries than pure tone audiometry (PTA). Exposure to noise elevated the risk of injuries in those farmers with hearing loss or hearing asymmetry. The occasional use of hearing protection was significantly associated with agricultural injuries. CONCLUSIONS: This study adds substantial evidence that hearing loss acts as a risk for agricultural injuries. Prevention of hearing loss and noise exposure may be important in reducing the burden of agricultural injuries.     

中低频噪声下护耳器防护效果的测试与评价

用本作者研究的人体客观测试法对国际上几种典型护耳器在佩戴情况下进行的实验室和现场测试表明，耳塞、耳罩在低频段(125Hz，250Hz)的声衰减均不超过23dB。证实了传统主观测试法在低频段存在4～5dB的生理噪声误差。耳塞在低频段的降噪能力高于耳罩。大容积耳罩的声衰减高于小容积耳罩。耳塞和耳罩同时佩戴所收到的降噪效果比单独使用高6-18dB。该结果表明，低频噪声比高频噪声更难以防护。该结果为进一步防治耳聋和改进护耳器显供依据。     

528名接触非稳态噪声听力损失调查及预测方法的探讨

本文报道了528名接触非稳态噪声的冷作工、锻工听力损失的调查,以接触噪声在70dB(A)以下的机关干部95名作对照。调查结果,作业场所噪声等效连续A声级强度在85～115 dB,语言听力损失率为23.0%,高频听力损失率为83.7%。高频听损和语言听损的发生率与噪声强度和工龄密切相关,与对照组比有极显著性差异(P<0.005)。应用调查结果,采用线性回归方程式y=14.395(ДΓ_(00)-0.735)%计算,其听力损失值与本次调查实测位及ISO公布有关听觉丧失危险性的资料十分接近。故认为,该方程式可作为预测非稳态噪声作业人员听损发生率的预测方法。此方法符合实际,简单易行,具有实用价值。     

船舶工业企业噪声危害调查

目的分析船舶工业企业噪声危害特性、分布、危害程度和劳动者听力损失情况,为企业开展噪声治理及指导劳动者进行听力保护提供科学依据。方法选取3家规模以上船舶工业企业,采用与技术人员和职业卫生管理人员座谈的方式,了解生产工艺和基本情况,并对作业场所开展现场调查和个体噪声暴露剂量检测、频谱分析,对主要接触噪声的岗位工人进行纯音听力测试。结果船舶工业企业接噪岗位多,在检测的17个岗位中,除轮机检验工外,其余岗位个体噪声暴露剂量均超过85 d B(A),其中打磨工和冲砂工最为严重,其个体噪声暴露剂量达100 d B(A)左右,类型主要是高频噪声;主要接噪岗位工人的听力损失比例较高,达26.96%,其中打磨工和冲砂工的听力异常比例分别达37.88%和38.42%,且随着接噪工龄的增加,听力异常者比例不断增加,呈现明显的剂量-反应关系。结论船舶工业企业的噪声危害分布广、程度重,应及时采取工程控制措施和听力保护措施。