Tissue distribution of lead in the neonatal rat exposed to multiple doses of lead acetate.

The tissue distribution of lead (Pb) was examined in the neonatal rat intragastrically administered lead acetate (50 mg/kg, containing 210Pb) beginning on d 6 postpartum and thereafter at 3-d intervals to d 18. A time-dependent pattern of uptake was observed in bone, kidney, liver, and brain, while stomach, lung, heart, and spleen had no accumulation of Pb. The highest concentration of Pb at d 21 was detected in bone, and the least amount was found in blood and brain. Body weight was not significantly affected by the level of Pb exposure employed.

Evaluation of radiation monitor effectiveness for the detection of 85Kr.

As part of the preparations for the purging of TMI Unit-2, the 85Kr sensitivity of 12 radiation detector systems or system combinations was determined. Eleven of these were evaluated using a cube-shaped polyethylene-walled room containing a volume of 5.6 m3 (200 ft3). Krypton-85 gas was added to produce a concentration of 6.7 x 10(-6) muCi/ml in the test room. It was found that none of the ion chambers and scintillation detector systems were able to detect this concentration of 85Kr. Detectors employing thin window GM pancake probes were found to be sensitive enough to monitor this gas down to the unrestrictive area maximum permissible concentration level (MPC) of 3 x 10(-5) muCi/ml, while a large window gas flow proportional counter was found to be sensitive enough to monitor down to about 09.1 MPC. At the end of this experiment, 2.3 m3 (80 ft3) of the gas in the test room was pumped into a compressed air cylinder (scuba bottle) and was used to calibrate The Pennsylvania State University (PSU) Noble Gas Monitor. The sensitivity of this system, which employs gas compression and Ge(Li) spectroscopy, was demonstrated to be between 0.1 and 0.03 times MPC, depending on the counting time employed.