Effects of Long-Term Low Level Hydrogen Sulfide Exposure

描述（由申请人提供）：硫化氢（H2S）气体具有高急性毒性，但对长期低水平暴露的影响知之甚少。目前的证据表明，神经系统、呼吸系统和眼睛是对H2S影响最敏感的器官。在美国，职业和社区长期暴露于H2S。来源包括集中的动物饲养操作，纸浆米尔斯厂，天然气精炼厂。然而，暴露人群规模小，H2S的“臭鸡蛋”气味引起的恐惧，来自诉讼和赔偿问题的潜在报告偏差，以及其他暴露的潜在混淆，使得对慢性H2S暴露是否造成健康影响的调查非常困难。罗托鲁瓦市（人口> 50，000）位于新西兰的地热田上，提供了一个独特的机会来调查慢性H2S暴露是否会导致健康影响。在没有其他潜在有毒气体的情况下，没有其他大规模的人群长期低水平暴露于H2S，同时接受气味作为日常生活的事实（避免恐惧引起的症状或未决诉讼的可能偏见）。这项对罗托鲁瓦人口样本的横断面研究遵循了早期的研究，该研究表明，该市的H2S暴露可能对健康产生影响。研究样本将包括1，800名年龄在18至65岁之间的成年人，他们居住在罗托鲁瓦地区，暴露于H2S的程度为高、中、低。我们将获得：（1）对调查表的回答，包括关于人口统计学因素、疾病学以及居住和职业史的问题;（2）神经行为功能的一系列测试的结果;（3）周围神经功能的检查结果;（4）通过肺量计进行的肺功能测试的结果;及（5）视力及视力测试的结果，包括白内障及色觉障碍的检查。暴露数据将基于罗托鲁瓦广泛的硫化氢监测数据，并对整个城市的暴露进行空间建模。对于每一位参与者，将从调查问卷中获得的关于居住和工作历史以及日常活动模式的信息与H2S建模结果相结合，以构建个人累积暴露指数。为了验证暴露估计值，参与者样本将佩戴个人H2S采样器三周。统计分析将寻求暴露指数与每项健康影响指标-神经行为、周围神经病变、呼吸和眼功能/视力-之间的关联。研究结果将证实美国现行的H2S职业和环境暴露标准的充分性，或提供证据证明这些标准不足以保护健康。

DESCRIPTION (provided by applicant): Hydrogen sulfide (H2S) gas has high acute toxicity, but little is known about the effects of long-term, low-level exposures. Current evidence indicates the nervous system, the respiratory system and the eye are the most sensitive organs to effects of H2S. Substantial chronic occupational and community exposures to H2S occur in the United States. Sources include concentrated animal feeding operations, pulp mills, and gas refineries. However, small exposed population sizes, fears caused by the "rotten eggs" odor of H2S, potential reporting biases from litigation and compensation issues, and potential confounding by other exposures have made very difficult investigations into whether health effects are caused by chronic H2S exposures. Rotorua city (population >50,000), situated on a geothermal field in New Zealand, presents a unique opportunity to investigate whether chronic H2S exposure causes health effects. No other large population exists where chronic low-level exposures to H2S, in the absence of other potentially toxic gases, coincide with acceptance of the odor as a fact of daily life (avoiding possible biases from fear-induced symptoms or pending litigation). This cross-sectional study of a sample of the Rotorua population follows earlier research suggesting possible health effects associated with H2S exposure in the city. The study sample will consist of 1,800 adults, aged 18 to 65, living in Rotorua areas with high, medium and low exposures to H2S. We will obtain: (1) responses to a questionnaire, including questions on demographic factors, symptomatology, and residential and occupational histories; (2) the results of a battery of tests of neurobehavioral function; (3) the results of an examination of peripheral nerve function; (4) the results of lung function testing by spirometry; and (5) the results of ocular and vision testing including examination for cataract and color vision impairment. Exposure data will be based on extensive Rotorua monitoring data for H2S, with spatial modeling of exposures across the city. For each participant, the information from the questionnaire on residential and work histories and daily movement patterns will be combined with the H2S modeling results to construct individual cumulative exposure indices. To validate exposure estimates, a sample of participants will wear personal H2S samplers for three weeks. Statistical analysis will seek associations between the exposure indices and each of the measures of health effect - neurobehavioral, peripheral neuropathy, respiratory and ocular function/vision. Study results will either confirm the adequacy of current U.S. occupational and environmental exposure standards for H2S or provide evidence that they are insufficiently health protective.