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Alternative medicine

Certain dietary supplements and alternative remedies are claimed to be beneficial in the treatment of herpes. There is however insufficient evidence to support use of many of these compounds including echinacea, eleuthero, L-lysine, zinc, bee products and aloe vera. While there are a number of small studies showing possible benefit from L-lysine, aspirin, lemon balm, topical zinc or licorice root cream in treatment, these are preliminary studies that have not been confirmed by higher quality randomized controlled studies.

Air pollution

Air pollution is the introduction into the atmosphere of chemicals, particulate matter, or biological materials that cause discomfort, disease, or death to humans, damage other living organisms such as food crops, or damage the natural environment or built environment.

fukushima

The plant comprises six separate boiling water reactors originally designed by General Electric (GE), and maintained by the Tokyo Electric Power Company (TEPCO). At the time of the quake, Reactor 4 had been de-fueled while 5 and 6 were in cold shutdown for planned maintenance. Immediately after the earthquake, the remaining reactors 1-3 shut down automatically, and emergency generators came online to control electronics and coolant systems. However the tsunami following the earthquake quickly flooded the low-lying rooms in which the emergency generators were housed. The flooded generators failed, cutting power to the critical pumps that must continuously circulate coolant water through a nuclear reactor to keep it from melting down. As the pumps stopped, the reactors overheated due to the high radioactive decay heat that normally continues for hours or days after a nuclear reactor shuts down.

At this point, only prompt flooding of the reactors with seawater could have cooled the reactors quickly enough to prevent meltdown. Salt water flooding was delayed because it would ruin the costly reactors permanently. Flooding with seawater was finally commenced only after the government ordered that seawater be used, and at this point it was already too late to prevent meltdown.

As the water boiled away and levels in the fuel rods pools dropped, they began to overheat severely, and to melt down. In the hours and days that followed, Reactors 1, 2 and 3 experienced full meltdown.

In the intense heat and pressure of the melting reactors, a reaction between the nuclear fuel metal cladding and the remaining water surrounding them produced explosive hydrogen gas. As workers struggled to cool and shut down the reactors, several hydrogen-air chemical explosions occurred. The flooding and earthquake damage hindered external assistance.

Concerns about the repeated small explosions, the atmospheric venting of radioactive gasses, and the possibility of larger explosions led to a 20 km (12 mi)-radius evacuation around the plant. During the early days of the accident workers were temporarily evacuated at various times for radiation safety reasons. At the same time, sea water that had been exposed to the melting rods was returned to the sea heated and radioactive in large volumes for several months until recirculating units could be put in place to repeatedly cool and re-use a limited quantity of water for cooling. Electrical power was slowly restored for some of the reactors, allowing for automated cooling.