Joselene de Oliveira 1111, Elisabete de Santis Braga
Joselene de Oliveira1, Elisabete de Santis Braga2 , Sueli Carvalho de Jesus1, Fernanda Franco Abrahão1, Glorivânia Ferreira dos Santos1 and Vitor Chiozzini2
Activity concentrations of
226Ra and 228Ra determined in surface and groundwater samples studied during the 1st Semester of 2009 are presented in Figure 3. Ra - 226
Natural radionuclides from U and Th series have been widely used as tracers
Ra - 226
25
Ra - 228
Ra - 228 20
[Ra]m Bq/L
40 [ Ra ] mBq/L
for the investigation of open ocean processes and for coastal zone management. These radionuclides are a powerful tool for studying coastal processes and have been used intensively as tracers of groundwater sources that discharge into the ocean.
30 20
15 10 5
10
0
0 St 1
St 2
St 3
St 6A
St 4
Cananéia Outlet
St 6B
St 7A
St 7B
St 8A
St 8B
St 9A
St St St St St 9B 10A 10B 11A 11B
Iguape Outlet
50 40
were determined to trace water exchange and SGD in Cananéia-Iguape estuarine complex, a shallow coastal plain estuary in southern São Paulo area.
[Ra] mBq/L
222Rn
[Ra] mBq/L
30 20 10
30 20 10
0
0 Rib 1 Rib 2 Rib 3 Rib 4 Rib 5 Rib 6 Rib 7 Rib 8 Ribeira de Iguape River
The research work was carried out in Cananéia-Iguape estuary during the 1st semester of 2009. This is a complex, mangrove-surrounded estuary system covering a total area of 110 km2.
Ra - 228
40
Ra - 228
In this paper, naturally ocurring Ra isotopes and
Ra - 226
Ra - 226
W1 W2 W3 W4 W5 W6 W7 W8 W9 W 10
W 11
W 12
W 13
Groundwater
In Ribeira of Iguape river the highest value of 228Ra/ 226Ra activity ratio of 20.6 was observed in station Ribeira 02 (salinity 1.0). In groundwater, the 228Ra/226Ra activity ratios varied from 3.3 to 31.7. 222Rn activities in groundwater up to 747 Bq L-1 were observed, the highest value found in Cananéia well 03. In Cananéia outlet activity ratio of228Ra/ 226Ra up to 11.8 was observed in Station 01 (salinity 31.6). Activities of Ra were slightly higher in samples collected at 5 m depth than at the surface water level.
Water circulation in the estuary channels is brought about by tidal flow and inflow of fresh water from continental drainage of several small rivers. The average tidal amplitude in this system is 0.82 m. The annual average temperature of the region is 21.2°C and the annual average precipitation 2200 mm.
In northeast of the system Ribeira de Iguape River mouth is found. This largest drainage system of the southeastern Brazilian seashore, drains all the crystalline coastal montainous complex behind the coastal plain.
Radium isotopes and nutrient data showed scattered distributions with salinity and distance offshore. This indicates that in this estuarine system the area is influenced by tidal oscillation and groundwater-seawater mixing. Sources of nitrate observed in visited stations are both due to transport of pollutants by local currents and do to possible contributions of SGD. Increased nitrate levels in wells sampled in Cananéia and Comprida Island indicates that nitrogen is fed by coastal contaminated groundwater and recirculated estuarine water (with different proportions of groundwater in the mixture), which gives rise to potential environmental concern with implications for management of freshwater resources in the region.
Acknowledgments – Science support was provided by Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq, Project n˚ 552437/2007-7 and 573601/2008-9.
Activity concentrations of
226Ra and 228Ra determined in surface and groundwater samples studied during the 1st Semester of 2009 are presented in Figure 3. Ra - 226
Natural radionuclides from U and Th series have been widely used as tracers
Ra - 226
25
Ra - 228
Ra - 228 20
[Ra]m Bq/L
40 [ Ra ] mBq/L
for the investigation of open ocean processes and for coastal zone management. These radionuclides are a powerful tool for studying coastal processes and have been used intensively as tracers of groundwater sources that discharge into the ocean.
30 20
15 10 5
10
0
0 St 1
St 2
St 3
St 6A
St 4
Cananéia Outlet
St 6B
St 7A
St 7B
St 8A
St 8B
St 9A
St St St St St 9B 10A 10B 11A 11B
Iguape Outlet
50 40
were determined to trace water exchange and SGD in Cananéia-Iguape estuarine complex, a shallow coastal plain estuary in southern São Paulo area.
[Ra] mBq/L
222Rn
[Ra] mBq/L
30 20 10
30 20 10
0
0 Rib 1 Rib 2 Rib 3 Rib 4 Rib 5 Rib 6 Rib 7 Rib 8 Ribeira de Iguape River
The research work was carried out in Cananéia-Iguape estuary during the 1st semester of 2009. This is a complex, mangrove-surrounded estuary system covering a total area of 110 km2.
Ra - 228
40
Ra - 228
In this paper, naturally ocurring Ra isotopes and
Ra - 226
Ra - 226
W1 W2 W3 W4 W5 W6 W7 W8 W9 W 10
W 11
W 12
W 13
Groundwater
In Ribeira of Iguape river the highest value of 228Ra/ 226Ra activity ratio of 20.6 was observed in station Ribeira 02 (salinity 1.0). In groundwater, the 228Ra/226Ra activity ratios varied from 3.3 to 31.7. 222Rn activities in groundwater up to 747 Bq L-1 were observed, the highest value found in Cananéia well 03. In Cananéia outlet activity ratio of228Ra/ 226Ra up to 11.8 was observed in Station 01 (salinity 31.6). Activities of Ra were slightly higher in samples collected at 5 m depth than at the surface water level.
Water circulation in the estuary channels is brought about by tidal flow and inflow of fresh water from continental drainage of several small rivers. The average tidal amplitude in this system is 0.82 m. The annual average temperature of the region is 21.2°C and the annual average precipitation 2200 mm.
In northeast of the system Ribeira de Iguape River mouth is found. This largest drainage system of the southeastern Brazilian seashore, drains all the crystalline coastal montainous complex behind the coastal plain.
Radium isotopes and nutrient data showed scattered distributions with salinity and distance offshore. This indicates that in this estuarine system the area is influenced by tidal oscillation and groundwater-seawater mixing. Sources of nitrate observed in visited stations are both due to transport of pollutants by local currents and do to possible contributions of SGD. Increased nitrate levels in wells sampled in Cananéia and Comprida Island indicates that nitrogen is fed by coastal contaminated groundwater and recirculated estuarine water (with different proportions of groundwater in the mixture), which gives rise to potential environmental concern with implications for management of freshwater resources in the region.
Acknowledgments – Science support was provided by Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq, Project n˚ 552437/2007-7 and 573601/2008-9.
