As of 7pm today (March 29), the prefecture is continuing to monitor the sites that had iodine readings of more than 100 Bq/kg in the past. The highest reading now is 47.6 Bq/kg in Hitachi City. Hitachi also had the highest cesium level at 3.28 Bq/kg. Neither is high enough for concern.
They are also monitoring various water sources around the prefecture. The one that probably concerns many of us the most is Kasumigaura. The readings there as of today (March 29) were 14.9 Bq/kg of iodine and 1.06 Bq/kg of cesium. Neither is high enough for concern.
Source: http://www.pref.ibaraki.jp/20110311eq/pdf/0249.pdf (Ibaraki Prefectural Government)
Levels at which we need to start getting concerned
iodine 300 Bq/kg for drinking water (adults) and iodine 100 Bq/kg for drinking water (babies)
cesium 200 Bq/kg for drinking water
Today’s verdict: Safe to drink the water in Tsukuba