The fallout from the crisis at the Fukushima Daiichi nuclear power plant continues to spread, with excessive radiation levels measured in Tokyo's water supply and many countries now blocking imports of some produce from Japan.
The Tokyo Water Bureau last night confirmed levels radioactive iodine in some city tap water is two times the recommended limit for infants.
The United States have restricted dairy and vegetable imports from four prefectures - Fukushima, Ibaraki, Tochigi and Gunma - and Hong Kong is now banning imports of Japanese farm produce, meat and seafood from five prefectures - Fukushima, Ibaraki, Tochigi, Gunma and Chiba - while France is calling on the European Union to do the same.
Tokyo Water Bureau officials told reporters a water treatment centre in downtown Tokyo that supplies much of the city's tap water found that some water contained 210 becquerels per litre of iodine 131.
The limit for consumption of iodine 131 for infants is 100 becquerels per litre.
While it is recommended that babies not be given tap water, Chief Cabinet Secretary Yukio Edano said it is safe for adults to drink and urged people not to buy more than necessary bottled water as supplies are still required in tsunami-ravaged towns.
The government's safety limit for people other than infants is 300 becquerels per kilogram.
Japan has ordered the halt of consumption and shipments of a range of farm products grown near the quake and tsunami-hit facility after health ministry tests found vastly elevated levels of iodine and caesium.
Prime Minister Naoto Kan ordered a stop of shipments of untreated milk and vegetables including broccoli, cabbage and parsley from areas near the Pacific coast plant, 250km northeast of Tokyo.
The health ministry said radioactivity drastically exceeding legal limits had been found in 11 kinds of vegetable grown in Fukushima prefecture.
Radioactive caesium at 82,000 becquerels - 164 times the legal limit - was detected in one type of leaf vegetable, along with 15,000 becquerels of radioactive iodine, more than seven times the limit.
The ministry said if people eat 100 grams a day of the vegetable for about 10 days, they would ingest half the amount of radiation typically received from the natural environment in a year. Even if the short-term risk is limited for now, scientists pointing to the 1986 Chernobyl disaster warn that some radioactive particles concentrate as they travel up the food chain and stay in the environment for decades.
The fear of nuclear radiation from Japan has spread to China and Hong Kong as people have resorted to panic buying of iodized salt over rumours that it can prevent radiation, Kyodo News reports.
Around Asia, many Japanese restaurants and shops are reporting a decline in business and governments have stepped up radiation checks on the country's goods. Tainted fava beans from Japan have already cropped up in Taiwan.
Japan - a highly industrialised and mostly mountainous island nation - is a net food importer. According to the European Commission, the EU imported 9,000 tonnes of fruits and vegetables from Japan in 2010.
Power back at three reactors
Meanwhile black smoke was seen billowing from the unit 3 three reactor at the Fukushima Daiichi plant at 4.20pm Japan time last night (8.20pm NZT).
After the smoke was reported Tokyo Electric Power Company evacuated workers from the control room of the reactor, as well as firefighters from Tokyo and Yokohama preparing for a water-spraying operation. The water spraying operation was cancelled for the day.
No fire was seen at the site and the smoke had cleared within an hour.
Radiation levels did not change around the reactor, Tepco reported.
The International Atomic Energy Agency said AC power is now at units 1, 2 and 4. At unit 3, the main control room has lighting, but no power to its equipment or instruments.
Yesterday morning 35 tonnes of water was pumped into water cooling pipes at the unit 3 reactor, and plan to do the same at the unit 4 reactor today and unit 1 reactor tomorrow.
Meanwhile, the Nuclear and Industrial Safety Agency revealed workers in the unit 2 reactor's turbine building were exposed to radiation totalling 50 to 60 microsieverts when they stayed there for about five minutes on Friday, Jiji Press reported. Radiation levels there are estimated to have been 500 millisieverts per hour, the agency said.
Death toll continues to rise
Japan's police agency said more than 9,300 people are dead and almost 13,800 are missing.
Those tallies are likely to overlap, but police officials estimate the final figure will likely exceed 18,000 deaths.
A police spokesman from the hard-hit Miyagi Prefecture, said the deaths will top 15,000 in that region alone. Police in other devastated areas declined to estimate eventual tolls, but said the confirmed deaths in their areas already number nearly 3,700.
The National Police Agency said the overall number of bodies collected so far stood at 9,301, while 13,786 people have been listed as missing.
The Japanese Government estimates the cost of the disaster to be up to 25 trillion Yen (NZ$416 billion), however the actual figure could be even higher, Kyodo News reports, as this projection does not account for the effects of power supply shortages caused by the nuclear crisis.