Routine surveillance of environmental radioactivity in the influence area of the institute during 1998

The radioactivity measurements were performed according to the Monitoring Concept for nuclear units in IFIN-HH, which provides the type, the locations and sampling frequency of the environmental factors that were analyzed. Samples of water, sediment, soil, vegetation and aerosols have been analyzed for both gross beta and gamma activity, as follows: 1030 samples of potential radioactive water, surface, drinking and underground water; 21 sediment and 90 soil samples; 27 samples of spontaneous vegetation and 9 samples of milk, cereals and vegetables. Aerosol samples have been monitored twice a month. We analyzed for gross beta and gamma activity 119 samples of radioactive liquid effluents from the two nuclear units CPR and STDR. The maximum values of gross beta activity for drinking water was; 0.71 Bq/l (absolute error: 0.14 Bq/l) for the sample collected from the village well near to the reactor canal and 0.71 Bq/l (absolute error: 0.15 Bq/l) for the water collected from the village well near to the IFA-canal. For all the results reported in this paper the confidence level is 95 %. Gross beta values measured daily for sewage and surface water varied generally between 0.3 and 0.9 Bq/l. The maximum value of the gross beta activity recorded for the river water downstream to the sewage spill flow was 1.32 (absolute error: 0.20 Bq/l), that was situated below the maximum allowed level (1.8 Bq/l). Gamma spectroscopy analyses and radiochemical separations performed on annual composite samples of sewage water showed an average activity concentration for Cs-137 of 5 mBq/l (absolute error: 1 mBq/l) and 35 mBq/l (absolute error: 12 mBq/l) for Sr-90, values similar to those determined for the surface water samples. Co-60 was also detected in the sewage water and sediment collected at the sewage spill flow, with an activity concentration of 8 mBq/l (absolute error: 2 mBq/l) and 31 Bq/kg (absolute error: 5 Bq/kg), respectively. For the surface water and sediment samples collected upstream and downstream the discharge site, the Co-60 concentration was bellow the detection limit. Monthly determinations of H-3 in daily composite sewage water samples indicate a low level of this radionuclide, with a concentration that has not exceed 10 Bq/l. The major contributor to the radioactive content of the soil and sediment is K-40, with an average level of 330 Bq/kg (absolute error: 80 Bq/kg) for sediment and 530 Bq/kg (absolute error 120 Bq/kg) for soil samples. The concentration of Cs-137 in soil ranged from 28 Bq/kg (absolute error: 6 Bq/kg) for the samples collected from the living area, up to 123 Bq/kg (absolute error: 13 Bq/kg) for samples collected from the wood site. Gross beta values for cultivated vegetation and milk samples collected from the living area followed the activity of K-40. The concentration level recorded for this radionuclide level was: 30 Bq/l (absolute error: 5 Bq/l) for milk samples, 145 Bq/kg (absolute error: 25 Bq/kg) for maize and wheat, 62 Bq/kg (absolute error: 8 Bq/kg) for tomatoes and 41 Bq/kg (absolute error: 5 Bq/kg) for cabbage. No significant difference between the radioactive content of soil and vegetation samples collected from the influence area and those from the reference site (Bucharest) was observed. (authors)