Table 4-2. Speciation of Trace Metals in Aquil with 
EDTA Concentration Reduced to 10' 8 M. 
Major Species 
Percent of Total Metal 
Iron 
FE(OH) 3 (S) 
100 % 
Manganese 
MnO^(S) 
100 % 
Copper 
Cu2+ 
1 % 
CuEDTA 
87% 
CuCOo 
12 % 
Cadmium 
Cd2+ 
3% 
CdCI 3 + 
39% 
CdCI 2 
42% 
CdEDTA 
6% 
Zinc 
Nz2+ 
60% 
ZnSO^ 
8% 
ZnCI 
3% 
ZnCI 3 ' 
1 % 
ZnEDTA 
27% 
ZnOH+ 
1 % 
Nickel 
NiEDTA 
99% 
Mercury 
HgCI 4 2- 
87% 
HgCI 3 
13% 
Lead 
PbC0 3 
21 % 
PbCI 3 
50% 
PbCI 2 
5% 
PbCI+ 
3% 
PbEDTA 
20 % 
PbOH+ 
1 % 
Cobalt 
Co2+ 
51% 
C 0 SO 4 
11 % 
CoCI+ 
21 % 
CoEDTA 
15% 
CoOH 
2 % 
Chromium 
CrEDTA 
57% 
Cr(OH) 4 - 
40% 
Cr(OH) 2 + 
3 % 
copper on some fishes (31), and for cadmium on a grass shrimp (45). Although 
there has been no experiment reported to date that provides direct evidence for 
the importance of inorganic complexation in controlling metal toxicity to 
phytoplankton, this result can be inferred from data with these other 
organisms, and from the general demonstration that metal ion activities are the 
important parameters of toxicity to algae. 
43 
