After 311 earthquake that devastated Japan in 2011, Greenpeace came to Japan (and/or greenpeace japan itself) to mess around. They monitor radiation level and say government's monitoring posts arent accurate, without understanding what monitoring posts are for in the first place.
Also they monitored radioactive level in fishes, by not so accurate and appropriate measures, and without making it clear key things like what eating xx bq/kg means to your body, whether or not the fishes are on the market, etc, they made further mess.
Their aim is just question everything public sectors have done, never send out accurate and balanced info, yet pretending they are objective. What they did here was only to make people who are confused and worried already even more confused and worry. I find their conduct after 311 earthquake (related to nuclear accident), as well as people, esp journos who naively believed and supported them and helped spread their words, unforgivable to say the least.
They just come when and where they can advertise themselves effectively. In Japan there're many local activities to protect and preserve local nature systems but I never see their names. It's mostly local people's effort aided by university study, NGO etc (+pseudo science and frauds like EM, unfortunately).
Those environmental groups in general were relevant and respectable up until 80s but, altho I wouldnt disregard everything they appeal of course (sure i tend to agree with concern regarding Arctic drilling this time), generally I consider them hardly trustworthy now, and there're good enough reasons.