98
A variety of physicochemical parameters of the water chemistry influence the U
toxicity and bioavailability for aquatic organisms (Jha et al. 2016). These parameters can influence the toxicity of U by decreasing or increasing the concentration
required to generate a biological response (Chapman 2008). It has been related a
decrease in the toxicity caused by waterborne U in response to water hardness
(caused possibly by the competition between the U and the Ca and/or Mg for the
membrane ligands) (Riethmuller et al. 2001; Charles et al. 2002). The increase of
pH was also demonstrated to decrease the biological effects caused by the U
Fig. 4 The dissolved
uranium content in
groundwater from Morro
do Ferro area collected in
September 1983 plotted
against the total clay layer
thickness
Table 1 Uranium concentration in surface waters at Morro do Ferro and vicinity sampled from
June 1980 through July 1981
Parameter
Unit
Site
Number of samples
Average value
238 U in filtrate
μg L
−1
All locations
67
0.23 ± 0.12
South Stream
43
0.32 ± 0.18
238 U on filter
μg L
−1
All locations
68
0.10 ± 0.01
South Stream
39
0.10 ± 0.02
234 U/
238 U in filtrate
–
All locations
67
1.33 ± 0.04
South Stream
43
1.26 ± 0.05
234 U/
238 U on filter
–
All locations
68
1.07 ± 0.03
South Stream
39
1.07 ± 0.03
All analytical uncertainties correspond to 1σ standard deviation. According to Grimaldi (1981)
J. A. Galhardi et al.
A variety of physicochemical parameters of the water chemistry influence the U
toxicity and bioavailability for aquatic organisms (Jha et al. 2016). These parameters can influence the toxicity of U by decreasing or increasing the concentration
required to generate a biological response (Chapman 2008). It has been related a
decrease in the toxicity caused by waterborne U in response to water hardness
(caused possibly by the competition between the U and the Ca and/or Mg for the
membrane ligands) (Riethmuller et al. 2001; Charles et al. 2002). The increase of
pH was also demonstrated to decrease the biological effects caused by the U
Fig. 4 The dissolved
uranium content in
groundwater from Morro
do Ferro area collected in
September 1983 plotted
against the total clay layer
thickness
Table 1 Uranium concentration in surface waters at Morro do Ferro and vicinity sampled from
June 1980 through July 1981
Parameter
Unit
Site
Number of samples
Average value
238 U in filtrate
μg L
−1
All locations
67
0.23 ± 0.12
South Stream
43
0.32 ± 0.18
238 U on filter
μg L
−1
All locations
68
0.10 ± 0.01
South Stream
39
0.10 ± 0.02
234 U/
238 U in filtrate
–
All locations
67
1.33 ± 0.04
South Stream
43
1.26 ± 0.05
234 U/
238 U on filter
–
All locations
68
1.07 ± 0.03
South Stream
39
1.07 ± 0.03
All analytical uncertainties correspond to 1σ standard deviation. According to Grimaldi (1981)
J. A. Galhardi et al.