Environmental Engineering Reference
In-Depth Information
Lake Mälaren
Lake Mälaren
Lake Trekanten
Lake Trekanten
Pt concentration
0-5 ng g
-1
5-15 ng g
-1
15-20 ng g
-1
>20 ng g
-1
Lake Björnsjön
(reference)
Lambarfjärden
(upstream)
Archiepelago
(downstream)
Rh concentration
0-1 ng g
-1
1-3 ng g
-1
4-5 ng g
-1
>5 ng g
-1
Lake Björnsjön
(reference)
Lambarfjärden
(upstream)
Archiepelago
(downstream)
Lake Drevviken
Lake Drevviken
Fig. 3
Distribution of Pt and Rh in Stockholm sediments
Table 1
Sediment quality guidelines values
Probable
effect
concentration
[9]
High/very high
content
[7]
Apparent effect
threshold
[8]
Metal
mg/g
Cd
>7
7.6
4.98
Cu
>100
840
149
Pb
>400
260
128
Zn
>1,000
520
459
Ag
−
4.5
−
Sb
−
3.0
−
Assessment of Potential Risks
Potential risks from the occurrence of metals in sediments were assessed by com-
parison of concentrations with Swedish EPA sediment quality guideline values
[7]
,
as well as reported apparent effect threshold concentrations (AET, concentration of
a selected chemical above which statistically significant biological effects always
occur
[8]
) and probable effect concentrations (PEC, concentration above which
adverse effects are expected
[9]
) (Table
1
).
Guideline concentrations are exceeded at most sites for Cu, with the exception
of background sites (Lake Bornsjon and Lambarfjarden) and one site at Lake
Drevviken. Zn and Pb concentrations are only high at Lake Trekanten and Cd is not
found at high concentrations. In contrast, measured concentrations exceeded PEC
at nine sites for Cu, at five sites for Zn and at nine sites for Pb. PEC concentrations
were not exceeded for Cd.
