The history and source of particulate 137Cs and 239,240Pu deposition in sediments of the Ob River Delta, Siberia

Natural background and anthropogenic inputs of polycyclic aromatic hydrocarbons (PAH) in sediments of South-Western Barents Sea

“…3). The peak may be mostly due to atmospheric nuclear tests, conducted at Novaya Zemlya in 1950-s and the beginning of 1960-s and resulting in similar peaks in 137 Cs levels in sediments from other locations in the Arctic (Sayles et al, 1997). The top of the observed peak is dated by 210 Pb to ca.…”

A depositional history of particulate organic carbon in a floodplain lake from the lower Ob’ River, Siberia

“…Kenna and Sayles (2002) found sedimentation rates in this lake to be 0.41-0.53 cm/year using several approaches, with three of four approaches yielding estimates of 0.51-0.53 cm/year. Lakes in this region freeze to depths of 1-1.5 m, which approaches the water depth of this lake, however Sayles et al (1997) examined the top 24 cm of the core and found no evidence that the sediment record had been disturbed by lake ice freezing to the sediment. This sediment profile also shows very little bioturbation or other mixing of sediments (Panteleyev, 1995;Sayles et al, 1997).…”

“…The sediment core used in this study (94-7b) was collected in 1994 and analyzed for natural and anthropogenic radionuclides as part of an earlier study (Sayles et al, 1997;Kenna and Sayles, 2002). Sediments were collected from a shallow (1.5 m deep) lake within the lower Ob' River floodplain downstream of Salekhard and about 20 km upstream of the delta crown (66°40.035 0 N, 68°32.521 0 E; Sayles et al, 1997).…”

“…Sediments were collected from a shallow (1.5 m deep) lake within the lower Ob' River floodplain downstream of Salekhard and about 20 km upstream of the delta crown (66°40.035 0 N, 68°32.521 0 E; Sayles et al, 1997). Kenna and Sayles (2002) found sedimentation rates in this lake to be 0.41-0.53 cm/year using several approaches, with three of four approaches yielding estimates of 0.51-0.53 cm/year.…”

The 7Be/210Pbxs ratio as an indicator of suspended sediment age or fraction new sediment in suspension

“…Applying the same technique of Cushing et al (1993) to the data set of Graf (1996) yields a mean transport distance of 6 km. Sayles et al (1997) reported that 137 Cs and 239,240 Pu contaminated sediments of the Ob River (Siberia) have been transported approximately 1700 km over many years. Although these other studies encompass a wide variety of hydrologic conditions and transit times, the results indicate that fine particles, once they enter the stream system, tend to travel long distances (many kilometres) in a short time period (days to years).…”