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主题:【求助】PX的毒性 -- 燕人

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家园 这样的反驳很难认同

MSDS中你所说的section2确实是比较粗略而且容易用来误导不明白的人的。

但是你关于乙醇和醋酸的举例值得斟酌,40-50%的乙醇,和食醋大概1-2%的醋酸含量当然没有什么问题,但是MSDS中的描述针对的是接近100%的乙醇和醋酸,100%的醋酸确实就是Short exposure could cause serious temporary or moderate residual injury。因此这样的例子也许可以用来说明MSDS section2可以用来误导,但是我觉得如果用这样的类比来暗示对PX的描述是耸人听闻的,这样的暗示不一定合适。

日常生活遇到的乙醇和食醋是低浓度的,引用MSDS数据没有太大意义。

但是对于px而言,如果px泄露,px的闪点27摄氏度,燃点AUTOIGNITION TEMPERATURE: 924°F (496°C) (approximate) 外链出处

燃点虽然很高,但是27度闪燃是不可否认的,如果发生泄露,是有可能碰到火焰的,这个可能不能用来说明px有多危险。

爆炸极限1.1-7%,我不否认爆炸极限范围越大越危险,对于px,可以查到下面这些数据

VAPOR PRESSURE: 6.4 mm Hg at 20 °C

VAPOR DENSITY: 3.7

外链出处

饱和蒸汽压(kPa)1.33(32℃)

外链出处

计算一下就可以知道当px泄露扩散到空气中,32度时饱和蒸汽很容易就能到达爆炸极限的下限,考虑到px vapor density比较大,是很有可能在靠近泄露区域高于爆炸极限上限,但是更靠外的区域应该很容易不慎引起爆炸。

另外,关于px的毒性,同样应用MSDS的数据

外链出处

In humans, overexposure to xylene can cause headache, fatigue, dizziness, listlessness, confusion, irritability, gastrointestinal disturbances (nausea and loss of appetite), flushing of the face, and a feeling of increased body heat. Exposure to xylene vapors above recommended exposure limits (100 ppm - TWA) can cause irritation of the eyes, nose and throat as well as tightening of the chest and staggering gait. Severe overexposure to xylene has been reported to cause irregular heartbeat or rapid incoordinate contractions of the heart, tremors, central nervous system depression, and unconsciousness. Lethality has resulted upon exposure to 10,000 ppm . The odor threshold for xylene is reported to be 1 ppm.

Aspiration of this product into the lungs can cause chemical pneumonia and can be fatal. Aspiration into the lung can occur while vomiting after ingestion of this product.

The oral LD50 for xylene is 4300 mg/kg (rat). The inhalation LC50 is 6350 ppm in rats exposed for 4 hours and 3907 ppm in mice exposed for 6 hours.

No significant treatment related effects were seen following inhalation exposure of rats and dogs exposed t0 810 ppm for 13 weeks, whereas liver damage and lung inflammation were reported in guinea pigs exposed to300 ppm for a total of 64 exposures (4 hours der day, 6 days per week).

100ppm只有0.01%, 10,000 ppm是1%,6350 ppm是0.635%,3907 ppm是0.39%,300 ppm是0.03%,这样的数据,再参照饱和蒸汽压1.33kPa(32度)约1.3%,我并不认为不应该引起注意。

以上只是就px本身的讨论。

个人观点,如果我家不是很远的地方建了px化工产,而且这次差点又泄露,我也会抗议,要求工厂搬远一点。

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