Most of the NPP radionuclide discharge is in the form of highly mobile tritium and noble gas fission products. Since these radionuclides do not accumulate biolo

Most of the NPP radionuclide discharge is in the form of highly mobile tritium and noble gas fission products. Since these radionuclides do not accumulate biologically, they rapidly dilute to levels that translate into very low human exposure. Most of the discharge from coal plants modeled in "Radiological Impact of Airborne Effluents of Coal and Nuclear Plants" was from traces of radium discharged from the smoke stack along with other combustion products. Since radium behaves chemically like calcium, and is taken up into plants and the bones of people who eat those plants, it can have a much greater effect on human radiation exposure even though the coal plant discharging fewer curies of radioactive material to the environment. A modern do-over of the 1978 study would need to take into account a few things: - Smokestack emissions of radionuclides from coal have been incidentally reduced by other anti-pollution measures required on coal power plants in the US. Ash precipitators, SO2 scrubbing, and mercury scrubbing will all cut down somewhat on radium escaping via the smokestack. (None of this helps with coal's CO2 profile, but it does reduce other pollution hazards.) - Operational changes have reduced how much effluent nuclear power plants discharge into the environment -- even if the plant was already built in the 1970s. It should use more recent effluent numbers like those in "Radioactive Effluents From Nuclear Power Plants: Annual Report 2008" rather than 1970s NPP effluent numbers. - Locality of food production/consumption has decreased since 1978. The original study assumed that people ate food grown in the same region they live in, so that radioactive effluents from power plants affected local populations via the agricultural food chain. It will change if people living near a power plant in Maryland are eating foods mostly produced out-of-state.