I noticed you didn't address my first question about the lack of adequacy of the measurement network. BTW I noted no direct advice in the reports on this topic, but may be now the measurement network is more appropriate? (I hope so...).

<rant>Laurent, can't you do some digging by yourself?</rant>

Réseau national de mesures de la radioactivité de l'environnement.

You have also a lot of continuous detectors at nuclear facilities and things like measure wells for water table monitoring , etc. On top of that, you have the military network but those detectors are not meant for long term public health monitoring but for sustaining military operations under nuclear warfare. The goals, the measures and the thresholds are very different.

One important note: for public health, the monitored levels are extremely low and continuous detectors are not doing a very good job. The measures must done off-line in laboratories. So the network is more a matter of trained personnel, capable of performing samplings - properly controlled and recorded - and sending them to analysis.

Lots of work has been done on pesticide concentration in the food chain and effects on water, this superficially look similar to me.

For radioactive elements, the mechanisms are actually quite different and depend on the specific elements. See the ANL fact sheets. One important nuance is that contrary to pesticides, dioxins and heavy metals, most radioactive contaminants from nuclear accidents like Chernobyl have short to medium life and actually disappear by decay. So there is a big difference between one-time exposure and constant exposure. The numbers for cancer risk in the ANL data are for constant life-time exposure. Assessing the risk for one-time releases is much more complex and for most scenario yield much more lower risks unless the doses are acute. But some elements, like Sr-90, have wildly different effects depending on the age and health of the subjects.