Environmental Engineering Reference
In-Depth Information
Chloride (Cl), total CO
2
(TCO
2
), glucose, hematocrit, pH, partial pressure CO
2
(pCO
2
) and bicarbonate (HCO
3
−
).
The second right gill arch and a part of the liver were dissected for analysis of
accumulated metals (ICP-MS): Cd, Cu, Zn, Ni, Pb, Fe and Al.
A second part of the liver was snap frozen in liquid nitrogen and stored at −80°C
prior to enzymatic response analysis of superoxide dismutase (SOD, Fluka kit) and
catalase (CAT, Cayman kit). SOD and CAT are known to be important enzymes
detoxifying free radical induction
[11]
. In addition, analyses of metallothionein
(MT) and total protein content were performed. MT, a cystein rich protein complex
able to bind various heavy metals, was analyzed by the Cd-/Zn chelex method
[12,
13]
and the protein concentration was analyzed by the Bradford assay
[14]
.
Results and Discussion
Water Quality
The accumulated precipitation of 8.6 mm was registered over a period of 6 days
prior the exposure experiment. However, the pollutant loadings were rather low
compared to earlier studies
[15]
. As expected the highest concentrations of most of
the pollutants were observed in the PI and only minor differences were observed
between the pond outlet water (PO) and the stream water (SW) (Table
1
). The dis-
solved fraction appeared to be dominating for Ni, Cu, and Zn and to some extent
for Cd, while Pb, Al and Fe were more associated with particles.
The high chloride levels indicated that the runoff water was considerably affected
by road salting, being almost 37 times higher in the PI compared to the SW (Table
1
).
The elevated salt concentrations might explain the higher fraction (%) of dissolved
metals species in the untreated runoff compared to the stream water, as increased ion
strength can aggregated particles and sedimentation can occur. Furthermore, high
levels of salt can mobilize colloidal- or organically bound metals
[3]
.
Metal Accumulation in Gill Tissue
No mortality occurred during the 24 h exposure experiment. Despite the small
differences between the various treatment tanks regarding Pb and Al concentrations
in the water, the concentration of these two elements appeared significantly higher
in trout gills from PI compared to the other groups (gill Pb in SW not significant
different from PI, however four values were <LOD, n = 2) (Fig.
1
).
The high salt concentrations in the untreated inlet water (PI) led to a substantial
and immediate increase in ionic strength in the mixed water of PI + SW and PO +
SW. Since both Al and Pb in gills were strongly and significant correlated with the
