Minimum level Maximum level Year Up to 1995: 1999: Up to 1995: 1999: Children (> 2y) 0.51 (86)a 1.3 (93)b 0.15 (91) 3.0 (93)a 7.8 (96)b 0.78 (94) Muslyumovo Teenagers (12-17) 2.3 (92) 0.17 (82) 14.5 (96) 65 (95) 1.1 (92) a children 2-7 years; b children 7-12 years Adults (18-48) 11 (90) 0.15 (75) 0.67 (84) Children (> 2y) 0.20 (84)a 0.52 (91)b 1.2 (92)a 3.1 (96)b 0.32 (94) Brodokalmak Teenagers (12-17) 0.92 (91) 5.9 (96) 0.42 (91) 0.0061 (90) 0.068 (81) Int. J. Environ. Res. Public Health 2009, 6 190 Table 8. Total individual external and internal dose to the population in Muslyumovo and Brodokalmak in 1999 and accumulated up to 1995 (mSv). Minimum Levels indicate no use of the sanitary zone; Maximum levels indicate unlimited use of the sanitary zone. Numbers in brackets indicate the contribution of the external dose to the total dose in percent (adapted from [25]). A more recent study that estimated the current external doses to the population in the Techa area was completed in 1998 [24]. Here, doses received in Muslyumovo and Brodokalmak were also investigated. It was found that residents who frequently use the Techa River and riverside areas receive the highest external doses. Despite official restrictions on economic and domestic use of the riverbank area, the local population still uses the riverside to some extent. Activities performed in the riverbank area included the grazing of cattle and sheep, hunting of waterfowl, fishing, collecting fodder, gathering wood and other materials needed domestically and recreation. To make an initial assessment of external dose, gamma dose rates from man-made radionuclides were measured on the floodplains, in the settlements themselves, and outside the floodplain [24]: mean dose rates were 1520 nGy h-1, 15 nGy h-1, 22 nGy h-1; and 440 nGy h-1, 8 nGy h-1, 14 nGy h-1 for Muslyumovo and Brodokalmak, respectively. Occupancy factor values for floodplains were assessed on the basis of observation data for different age groups during field visits within the settlements. Occupancy factors for other locations (e.g. inside and outside of houses) were based on similar investigations in the Bryansk region with conversion factors of 0.7 Sv Gy-1, 0.75 Sv Gy-1 and 0.85 Sv Gy-1 for adults, school children and pre-school children, respectively. Total doses calculated in this study are presented in Table 9. Here, the total effective dose is defined as the sum of the committed effective dose due to the ingestion of radionuclides in a year and external effective dose received in that year. Doses assessments were made for three hypothetical groups in the adult population [24]: • Group 1. People, who do not visit the river floodplain, do not consume milk from cows pastured on the floodplain or fish from the river Techa. This population group’s exposure doses are therefore not connected with contamination of the floodplain. Adults (18-48) 7.0 (93) 0.13 (87) 28 (95) 0.27 (82)