Behavior of 60Co and 134Cs in a Canadian Shield lake over 5 years

Investigation of the radiological impact on the coastal environment surrounding a fertilizer plant

This investigation was carried out in order to assess the marine environmental radioactive pollution and the radiological impact caused by a large production plant of phosphate fertilizer, located in the Lebanese coastal zone. Natural radionuclides ((238)U, (235)U, (232)Th, (226)Ra, (210)Po, (210)Pb, (40)K) and anthropogenic (137)Cs were measured by alpha and gamma spectrometry in seawater, sediment, biota and coastal soil samples collected from the area impacted by this industry. The limited environmental monitoring program within 2 km of the plant indicates localized contamination with radionuclides of the uranium decay chain mainly due to the transport, the storage of raw materials and the free release of phosphogypsum waste.

Distribution of gamma-ray emitting radionuclides in the marine environment of the Burullus Lake: II. Bottom sediments

The sediment compartment has the ability to trap large amounts of radionuclides and to indicate the radiological impact of pollution. The present work shows the results obtained related to the concentrations of 137Cs and natural radionuclides in sediment in the Burullus Lake, Egypt. The average values of 226Ra, 232Th, and 40K in the bottom sediments collected from the east of the Burullus Lake ranged from 10.3 to 21.8 Bq/kg, from 11.9 to 34.4 Bq/kg, and from 268 to 401 Bq/kg, respectively. The study has shown that 40K concentration is nearly uniform throughout the studied area while 226Ra and 232Th are more concentrated in the northeastern shore. Lake sediments showed contamination with 137Cs (2.7-15.9 Bq/kg). The 137Cs sediment activities indicated higher concentrations in the off-shore sites. Concentrations of all γ -ray emitting radionuclides except 40K in water samples were below the detection limits. The 40K sediment-water distribution coefficients of the near-shore samples were higher than the off-shore samples.

The changes in the contents of 137Cs in bottom sediments of some Masurian lakes during 10-15 y observation (Poland)

The measurements of radioactive caesium contents in bottom sediments were carried out in four lakes. First samples (47) were taken in 1992-95. The repeat sampling (109) was performed from the same places in 2005. We examined eight chosen areas in these lakes. In six of them, we observed statistically significant differences in the level of radioactive caesium. It indicates the permanent decrease in the level of 137Cs. The mean annual decrease in the level of radioactive caesium, taking into consideration the radioactive decay, was from 4.2 to 7.8%. In two areas of the profundal zone, we did not observe statistically significant differences in the level of radioactive caesium (lakes Garbas and Rogale Wielkie). Taking into consideration the radioactive decay of caesium, it means about the appearance of the process of accumulation of 137Cs in these areas.