You can read all the posts about groundwater contamination discovery of June-July 2013, at this link. The link is also in the right column of the blog.
The entire Japan is too obsessed with the Upper House Election and not many are paying attention enough to appreciate the clever spin that TEPCO's PR puts in the press release.
TEPCO dug up a new observation hole, No.1-3, after No.1-2 started to show high tritium and all-beta and No.1 was about to be plugged. The first sample from the new hole was drawn on July 12, 2013, and TEPCO announced the result on July 12.
From TEPCO's email notice for the press, 7/12/2013:
The result of all-beta measurement of the sample from the groundwater observation hole No.1-3 showed about one-tenths of radioactivity compared to the result of the sample from the nearby observation hole No.1-2 (south of the observation hole No.1) from the previous day.
＜地下水観測孔№1-3（新規）＞Groundwater observation hole No.1-3 (New)
・７月12日採取分： Sample collected on July 12
セシウム134 Cs-134 ＮＤ（0.66 Bq/L）
セシウム137 Cs-137 1.4 Bq/L
全ベータ all-beta 92,000 Bq/L
WHY DOES TEPCO COMPARE IT TO THE HOLE NO.1-2, whose sample was found with 890,000 Bq/L of all-beta on July 11, 2013?
Because the company can then claim the hole No.1-3 had only about one-tenths of all-beta compared to the hole No.1-2. One-tenths, nothing to worry about.
What TEPCO does not say and does not show in the email notice is this (from TEPCO's earlier email notice on July 12, 2013):
All-beta from the observation hole No.1 on July 11: 1,600 Bq/L
All-beta in the sample from the hole No.1-3 is thus 57.5 times as much as that from the hole No.1.
TEPCO's PR wouldn't want to emphasize that, would it?
And speaking of spin, the title of the series of email notices regarding the groundwater contamination along the seawall, east of the turbine buildings, is:
Result of measuring tritium in seawater inside the harbor at Fukushima I Nuclear Power Plant
It is outright false, as the email notices are about groundwater samples from the observation holes dug in the space between the turbine buildings and seawall, and NOT the seawater, and the measurements are on gamma nuclides, all-beta including strontium, and tritium.
TEPCO's English notice title is just as deceptive:
Tritium Density Result of Water Quality Survey inside the Port of Fukushima Daiichi NPS
Just by looking at the titles, I didn't realize these notices were about groundwater samples along the turbine buildings until one day I followed the link in the TEPCO Nuclear's tweet about groundwater samples.