does anybody have any information about seawater contamination?

Iodine activity has always been a factor of two or three higher than caesium. The highest level for iodine 330 metres south of the discharge point was was 180 Bq/l on 30 March and fell to about 18 Bq/l on 5 April Caesium (134 and 137) were almost exactly equal. From a peak of 45 Bq/l the levels fell to 8 Bq/l.

30 metres north from discharge point the levels were slightly lower than to the south although on 5 April the caesium was slightly higher, 12 Bq/, than to the north.

I am looking at levels in seawater trying to work out whether there can be any contamination outside Japan's 200 mile zone and hence affect fish that are not landed and checked at Japanese ports.

Iodine activity has always been a factor of two or three higher than caesium.The highest level for iodine 330 metres south of the discharge point was was 180 Bq/l on 30 March and fell to about 18 Bq/l on 5 April Caesium (134 and 137) were almost exactly equal. From a peak of 45 Bq/l the levels fell to 8 Bq/l. 30 metres north from discharge point the levels were slightly lower than to the south although on 5 April the caesium was slightly higher, 12 Bq/, than to the north.

30 km out the levels are still quite high. Not all instruments can detect radioactivity but levels of 80Bq/l of iodine 131 and 40 of caesium 137 can still be detected. The activity is higher near the surface than at bottom suggesting that the contamination might be from the air rather than from the discharge.

I have set up a facebook group on the issue

http://www.facebook.com/#!/home.php?sk=group_200295596670161&ap=1