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H2S 硫化氢物理特性和对人体的作用机理
(2006-07-29 13:29:57)| 分类： 学习 |
硫化氢简介：
硫化氢可溶于水和乙醇，与空气混合能形成爆炸性混合物，遇明火、高热能引导起燃烧爆炸。若遇高热，容器内压增大，有开烈和爆炸的危险。
硫化氢是许多工业生产中的副产物。目前，有70多种职业有机会接触硫化氢。这些职业包括采矿、石油开采与提炼、皮革制造、橡胶合成、煤气制取、人造纤维、造纸、染料、印染、制糖、食品加工等。此外，有机物腐败场地也有硫化氢产生，因此清理垃圾、阴沟、粪池、菜窖时，也会接触硫化氢。
一、硫化氢的理化特性
硫化氢：Hydrogen sulfide，CAS：7783-06-4，分子式H2-S，为无色、有“臭皮蛋”气味的有毒气体，分子量34.08，熔点：－82.9℃，沸点：－61.8℃，相对密度（空气=1）：1.19，饱和蒸气压：2026.5kPa（25.5℃），临界温度：100.4℃，临界压力：9.01MPa，爆炸下限：4.3%，爆炸上限45.5%，引燃温度：260℃，最小点火能：0.077mJ，最大爆炸压力：0.490Mpa，与空气混合能形成爆炸性混合物，遇明火、高温能引起燃烧爆炸。与浓硝酸、发烟硝酸或其它强氧化剂剧烈反应，发生爆炸。硫化氢比空气重，能在较底处扩散致相当远的地方，遇明火迅速引着回燃。另外，它易溶于水，易溶于甲醇、乙醇类和石油溶剂以及原油中。
二、硫化氢的毒害特点
硫化氢是强烈的神经毒物，侵入人体的主要途径是吸入，而且经人体的黏膜吸收比皮肤吸收造成的中毒来的更快。硫化氢对黏膜的局部刺激作用是由接触湿润黏膜后分解形成的硫化钠以及本身的酸性所引起。由于人的中枢神经对缺氧最敏感，因而首先受到损害的就是人的中枢神经。人若吸入硫化氢70～150毫克/立方米/1～2小时,出现呼吸道及眼刺激症状：流泪、眼痛、畏光、视物模糊和流涕、咳嗽、咽喉灼热，吸2～5分钟后嗅觉疲劳,不再闻到臭气，变得麻木；若吸入毫克/立方米/1小时，6～8分钟出现眼急性刺激症状，稍长时间接触引起肺水肿。吸入760毫克/立方米/15～60分钟，发生肺水肿、支气管炎、肺炎，出现头晕、头痛、恶心、呕吐、晕倒、乏力、意识模糊等症状；若吸入1000毫克/立方米/数秒之内，很快出现急性中毒，突然昏迷，导致呼吸、心跳骤停，发生闪电型死亡。高浓度接触眼结膜会发生水肿和角膜溃疡。而低浓度长期接触，会引起神经衰弱综合症和植物神经功能紊乱等。
硫化氢对粘膜的局部刺激作用系由接触湿润粘膜后分解形成的硫化钠以及本身的酸性所引起。对机体的全身作用为硫化氢与机体的细胞色素氧化酶及这类酶中的二硫键(-S-S-)作用后，影响细胞色素氧化过程，阻断细胞内呼吸，导致全身性缺氧，由于中枢神经系统对缺氧最敏感，因而首先受到损害。硫化氢作用于血红蛋白，产生硫化血红蛋白而引起化学窒息，是主要的发病机理。急性中毒早期，实验观察脑组织细胞色素氧化酶的活性即受到抑制，谷胱甘肽含量增高。
[color=#ccff33Hydrogen Sulfide[/color] Chemical Information Sheet
Hydrogen sulfide is a colorless gas with a rotten-egg odor. Some people can smell hydrogen sulfide at very low levels, as low as 0.5 parts per billion (ppb) in air. Most hydrogen sulfide in the air comes from natural sources. It is produced when bacteria break down plant and animal material, often in stagnant waters with low oxygen content such as bogs and swamps. Volcanoes, hot springs and underwater thermal vents also release hydrogen sulfide. Industrial sources of hydrogen sulfide include petroleum and natural gas extraction and refining, pulp and paper manufacturing, rayon textile production, chemical manufacturing and waste disposal. Some bacteria change calcium sulfate, the major component of wallboard, into hydrogen sulfide. If construction and demolition debris contain large quantities of wallboard, large amounts of hydrogen sulfide can be formed. Production is greatest when the wallboard is finely crushed and when there is little oxygen, such as when the debris is buried and soaked with water.
Most of the information on human health effects from hydrogen sulfide exposure comes from accidental and industrial exposures to high levels. Exposure to high levels can cause muscle cramps, low blood pressure, slow respiration and loss of consciousness. Short-term exposure to moderate amounts of hydrogen sulfide in the workplace produces eye, nose and throat irritation, nausea, dizziness, breathing difficulties, headaches and loss of appetite and sleep. Continued exposure can irritate the respiratory passages and can lead to a buildup of fluid in the lungs.
Human volunteers have been exposed to hydrogen sulfide for up to thirty minutes during moderate exercise at levels equal to or half the Occupational Safety and Health Administration (OSHA) 8-hour standard (10,000 ppb). Chemical changes in blood and muscle were observed, but no volunteer experienced adverse symptoms and no changes were seen in lung function measurements.
There is limited information on the effects of long-term exposure to low levels of hydrogen sulfide. People working in industries where hydrogen sulfide exposure is common, but is usually below the OSHA 8-hour standard (10,000 ppb), may have decreased lung function and increased risk of spontaneous abortion and impaired neurological functions (including reaction time, balance, color discrimination, short-term memory and mood) compared to unexposed workers. People living near industries that emit hydrogen sulfide have an increased risk of eye irritation, cough, headache, nasal blockage and impaired neurological function (same measures as above) compared to unexposed residents. Limited information is available about exposure levels in studies of people working in or living near industries emitting hydrogen sulfide. Hydrogen sulfide exposure is assumed in these studies based on job title, work history or living near facilities emitting hydrogen sulfide. In all cases, the people with presumed hydrogen sulfide exposure had or likely had exposures to other chemicals that could have contributed to some health effects.
Foul odors and health effects were investigated in an Indiana community near a waste disposal lagoon and in five New York State communities near landfills containing construction and demolition debris. Hydrogen sulfide levels in the Indiana community ranged up to 300 ppb during a two-month period. Levels in two of the New York communities ranged up to 4000 ppb for periods of several months. During these episodes there were frequent health complaints including eye, throat and lung irritation, nausea, headache, nasal blockage, sleeping difficulties, weight loss, chest pain, and asthma attacks. Although other chemicals may have been present in the air, these effects are consistent with those of hydrogen sulfide.
The main effects of short-term and long-term hydrogen sulfide exposure in laboratory animals are nasal and lung irritation and damage and effects on the brain. These effects are consistent with effects seen in people exposed to hydrogen sulfide.
The effects of exposure to any chemical depend on the amount of the chemical to which a person is exposed and the length of exposure. The effects may also be influenced by a person's age, sex and general health. The figures (Portable Document Format (PDF) file - help for PDF) summarize the relationship between exposure to hydrogen sulfide and known health effects, including those at very high levels of exposure. The information comes from exposure of people as well as laboratory animals. Effects in humans are shown on the right side and effects in animals on the left side of each line in the diagrams. Federal workplace standards and state ambient air standards are also shown on the diagrams.
硫化氢可溶于水和乙醇，与空气混合能形成爆炸性混合物，遇明火、高热能引导起燃烧爆炸。若遇高热，容器内压增大，有开烈和爆炸的危险。
硫化氢是许多工业生产中的副产物。目前，有70多种职业有机会接触硫化氢。这些职业包括采矿、石油开采与提炼、皮革制造、橡胶合成、煤气制取、人造纤维、造纸、染料、印染、制糖、食品加工等。此外，有机物腐败场地也有硫化氢产生，因此清理垃圾、阴沟、粪池、菜窖时，也会接触硫化氢。
一、硫化氢的理化特性
硫化氢：Hydrogen sulfide，CAS：7783-06-4，分子式H2-S，为无色、有“臭皮蛋”气味的有毒气体，分子量34.08，熔点：－82.9℃，沸点：－61.8℃，相对密度（空气=1）：1.19，饱和蒸气压：2026.5kPa（25.5℃），临界温度：100.4℃，临界压力：9.01MPa，爆炸下限：4.3%，爆炸上限45.5%，引燃温度：260℃，最小点火能：0.077mJ，最大爆炸压力：0.490Mpa，与空气混合能形成爆炸性混合物，遇明火、高温能引起燃烧爆炸。与浓硝酸、发烟硝酸或其它强氧化剂剧烈反应，发生爆炸。硫化氢比空气重，能在较底处扩散致相当远的地方，遇明火迅速引着回燃。另外，它易溶于水，易溶于甲醇、乙醇类和石油溶剂以及原油中。
二、硫化氢的毒害特点
硫化氢是强烈的神经毒物，侵入人体的主要途径是吸入，而且经人体的黏膜吸收比皮肤吸收造成的中毒来的更快。硫化氢对黏膜的局部刺激作用是由接触湿润黏膜后分解形成的硫化钠以及本身的酸性所引起。由于人的中枢神经对缺氧最敏感，因而首先受到损害的就是人的中枢神经。人若吸入硫化氢70～150毫克/立方米/1～2小时,出现呼吸道及眼刺激症状：流泪、眼痛、畏光、视物模糊和流涕、咳嗽、咽喉灼热，吸2～5分钟后嗅觉疲劳,不再闻到臭气，变得麻木；若吸入毫克/立方米/1小时，6～8分钟出现眼急性刺激症状，稍长时间接触引起肺水肿。吸入760毫克/立方米/15～60分钟，发生肺水肿、支气管炎、肺炎，出现头晕、头痛、恶心、呕吐、晕倒、乏力、意识模糊等症状；若吸入1000毫克/立方米/数秒之内，很快出现急性中毒，突然昏迷，导致呼吸、心跳骤停，发生闪电型死亡。高浓度接触眼结膜会发生水肿和角膜溃疡。而低浓度长期接触，会引起神经衰弱综合症和植物神经功能紊乱等。
硫化氢对粘膜的局部刺激作用系由接触湿润粘膜后分解形成的硫化钠以及本身的酸性所引起。对机体的全身作用为硫化氢与机体的细胞色素氧化酶及这类酶中的二硫键(-S-S-)作用后，影响细胞色素氧化过程，阻断细胞内呼吸，导致全身性缺氧，由于中枢神经系统对缺氧最敏感，因而首先受到损害。硫化氢作用于血红蛋白，产生硫化血红蛋白而引起化学窒息，是主要的发病机理。急性中毒早期，实验观察脑组织细胞色素氧化酶的活性即受到抑制，谷胱甘肽含量增高。
[color=#ccff33Hydrogen Sulfide[/color] Chemical Information Sheet
Hydrogen sulfide is a colorless gas with a rotten-egg odor. Some people can smell hydrogen sulfide at very low levels, as low as 0.5 parts per billion (ppb) in air. Most hydrogen sulfide in the air comes from natural sources. It is produced when bacteria break down plant and animal material, often in stagnant waters with low oxygen content such as bogs and swamps. Volcanoes, hot springs and underwater thermal vents also release hydrogen sulfide. Industrial sources of hydrogen sulfide include petroleum and natural gas extraction and refining, pulp and paper manufacturing, rayon textile production, chemical manufacturing and waste disposal. Some bacteria change calcium sulfate, the major component of wallboard, into hydrogen sulfide. If construction and demolition debris contain large quantities of wallboard, large amounts of hydrogen sulfide can be formed. Production is greatest when the wallboard is finely crushed and when there is little oxygen, such as when the debris is buried and soaked with water.
Most of the information on human health effects from hydrogen sulfide exposure comes from accidental and industrial exposures to high levels. Exposure to high levels can cause muscle cramps, low blood pressure, slow respiration and loss of consciousness. Short-term exposure to moderate amounts of hydrogen sulfide in the workplace produces eye, nose and throat irritation, nausea, dizziness, breathing difficulties, headaches and loss of appetite and sleep. Continued exposure can irritate the respiratory passages and can lead to a buildup of fluid in the lungs.
Human volunteers have been exposed to hydrogen sulfide for up to thirty minutes during moderate exercise at levels equal to or half the Occupational Safety and Health Administration (OSHA) 8-hour standard (10,000 ppb). Chemical changes in blood and muscle were observed, but no volunteer experienced adverse symptoms and no changes were seen in lung function measurements.
There is limited information on the effects of long-term exposure to low levels of hydrogen sulfide. People working in industries where hydrogen sulfide exposure is common, but is usually below the OSHA 8-hour standard (10,000 ppb), may have decreased lung function and increased risk of spontaneous abortion and impaired neurological functions (including reaction time, balance, color discrimination, short-term memory and mood) compared to unexposed workers. People living near industries that emit hydrogen sulfide have an increased risk of eye irritation, cough, headache, nasal blockage and impaired neurological function (same measures as above) compared to unexposed residents. Limited information is available about exposure levels in studies of people working in or living near industries emitting hydrogen sulfide. Hydrogen sulfide exposure is assumed in these studies based on job title, work history or living near facilities emitting hydrogen sulfide. In all cases, the people with presumed hydrogen sulfide exposure had or likely had exposures to other chemicals that could have contributed to some health effects.
Foul odors and health effects were investigated in an Indiana community near a waste disposal lagoon and in five New York State communities near landfills containing construction and demolition debris. Hydrogen sulfide levels in the Indiana community ranged up to 300 ppb during a two-month period. Levels in two of the New York communities ranged up to 4000 ppb for periods of several months. During these episodes there were frequent health complaints including eye, throat and lung irritation, nausea, headache, nasal blockage, sleeping difficulties, weight loss, chest pain, and asthma attacks. Although other chemicals may have been present in the air, these effects are consistent with those of hydrogen sulfide.
The main effects of short-term and long-term hydrogen sulfide exposure in laboratory animals are nasal and lung irritation and damage and effects on the brain. These effects are consistent with effects seen in people exposed to hydrogen sulfide.
The effects of exposure to any chemical depend on the amount of the chemical to which a person is exposed and the length of exposure. The effects may also be influenced by a person's age, sex and general health. The figures (Portable Document Format (PDF) file - help for PDF) summarize the relationship between exposure to hydrogen sulfide and known health effects, including those at very high levels of exposure. The information comes from exposure of people as well as laboratory animals. Effects in humans are shown on the right side and effects in animals on the left side of each line in the diagrams. Federal workplace standards and state ambient air standards are also shown on the diagrams.
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