PX toxicity, carcinogenicity and danger Discussion
From the above explanation we can see the name, toxicity, carcinogenicity and hazardous chemicals are different concepts in different areas, can not be confused, not out of context, to confuse the public. Bigger is not necessarily toxic carcinogenic strong, such as salt and caffeine; carcinogenicity is not necessarily strong toxicity, such as electromagnetic waves and X-rays, because they can not measure their toxicity; hazardous chemicals are not necessarily highly toxic carcinogens, such as alcohol and acetic acid.
3.1 Question 1: 'Coffee' and the PX belong to the third category of carcinogens it?
As noted above, on the third level of carcinogens have caffeine, but not coffee. Coffee, caffeine, but the two are different substances. One is the world's three drinks, which contain the excitement of caffeine, but for most people drink is non-toxic and harmless to normal. Caffeine is a central nervous system stimulant, are psychotropic drugs, is addictive and dangerous drugs, LD50 (rat oral) of 192mg / kg, belong to very toxic class. Therefore, the report should be mistaken for the caffeine of coffee, and the media are baseless assertion.
3.2 Problem 2: PX with salt and alcohol toxicity close to it?
LD50 values ??if only to see if toxicity closer. But it depends on how the LD50 value is obtained, which is alien to many rat oral compound a certain amount, then half of the rats death statistics to determine, in units of mg / kg, and the smaller the value, the greater the toxicity LD50 . A person's weight to 70kg meter, then eat 210g of salt (not allowed to drink) have risks, I do not think it was right to eat half a pack of salt, that is actually very dangerous, this is just to illustrate the LD50 value only as research and does not have practical significance in life. Some media said the PX (5000mg / kg) less toxic than alcohol (7060mg / kg), which is completely understand nonsense, irresponsible, only to see the value of the LD50 value PX is small, but the value is less toxic but big . In this case even the television media was also cited reports, can only say that some media practitioners quality to be improved.
The media can not write articles out of context, to rigorous scientific analysis for the job, you can not mislead the public. Take PX with salt and alcohol can not just compare the toxicity, carcinogenicity depends, obviously PX carcinogenic than salt and alcohol to be much stronger; even take the PX and caffeine comparison, not only the carcinogenicity, toxicity depends on coffee due to much higher than the PX toxicity.
3.3 Problem 3: PX is a flammable toxic class of dangerous chemicals, and belong to the same grade of gasoline.
This is obviously taken out of context, even by other media directly into the "PX toxicity with gasoline equivalent." The body of the interviewed experts say the risk of chemicals through to illustrate its flammability risk, obviously gasoline, natural gas and liquefied petroleum gas are our common fuel flammability and PX quite sure even more burning, only flammable compare them really PX relatively safe. But not that PX flammable safer, it's dangerous and toxic, no problem. The article also pointed out that "both dangerous mark, health dangers, toxicology information, or in the occupational hazard protection and other standards, PX highly toxic products are not high-risk." But experts did not say PX nontoxic, can and gasoline Like usual, after PX carcinogenicity still there, but nothing to be confirmed.
3.4 Problem 4: PX and OX and MX isomers are toxic chemicals, carcinogens do not belong to it?
PX for paraxylene, OX for o-xylene, MX for m-xylene, can be regarded as toxic chemicals, but they belong to the third category of carcinogens. Although yet to be confirmed that the carcinogenicity data, but there is no evidence to deny its carcinogenicity, how you can say it belongs to carcinogens?
3.5 Problem 5: PX environmental problems - and from the city is not a controlling factor, strict implementation of the EIA is most important, how strictly enforced?
We can not just "every PX device and neighborhoods all the way only to Yokohama, Japan; Busan, South Korea PX device four kilometers from the city center; Singapore's Jurong petrochemical area also has PX device, about 10 km away from the city." More depends Why local residents agree PX built in their home side, the local government is how to conduct environmental assessments of how the people in the exercise of bargaining PX project, the project beneficiary of the decision and compensation. How can blinders, look at the economic benefits, but only residents of other countries agreed to build PX project, without looking at how the interaction between his government and the people, how to ensure that the interests of the environment and the residents do?