Strontium 90 detected in 10 municipalities in Ibaraki Prefecture, Japan
According to an article dated February 17, 2012 in the Ibaraki Shimbun newspaper, a survey conducted of soil samples taken between August and October 2011 from 16 municipalities in Ibaraki Prefecture, on the southern border with Fukushima Prefecture, showed Strontium 90 readings that ranged from 54 to 290 becquerels per square meter. In addition, low levels of Plutonium 239 and 240 (1.3 to 15 becquerels per square meter) were detected in soil samples from 11 of the 16 municipalities.
According to the prefecture’s Nuclear Safety Department, the fact that Strontium 89 was not detected in any of the samples indicates that these readings are not the result of the accident at the Fukushima Da-iichi nuclear complex, but rather are commensurate with the results of nationwide surveys conducted by the Ministry of Education, Culture, Sports, Science and Technology from FY 1999 to 2008, which showed Strontium 90 levels in the prefecture of 72-950 becquerels per square meter and Plutonium 239 and 240 levels ranging from 20 to 90 becquerels per square meter. According to the Nuclear Safety Department, these radiation levels may be the result of “nuclear tests, etc.” and “do not pose a health risk”.
http://ibarakinews.jp/news/news.php?f_jun=13294014152654
One comment: The article does not mention it, but in September 1999 there was a “critical mass” nuclear accident at the Tokai Mura nuclear fuel processing facility on the Ibaraki coast that resulted in the deaths of two workers and serious injury to a third, with an additional 667 people in the surrounding area being affected as well.
http://ja.wikipedia.org/wiki/東海村JCO臨界事故
= new reply since forum marked as read
It's interesting that Tsuchiura (yeah, my neighborhood) had by far the highest readings for Strontium 90. 
That would be pretty close to your relatives' area as well.
