Environmental Assessment
Volume B-3.9
Mine
Water Quality
Ambatovy Project
133
January 2006
because no baseline data was available. However, a predicted increase in
concentration of 1 mg/kg is considered to be small relative to the CCME ISQG of
37.3 mg/kg.
Table 3.9-6 Comparison of Predicted Maximum Sediment Quality Concentrations
During Operations With Guideline Values
Results Above Canadian Sediment
Guidelines
Substance
Results Above
Baseline Sediment
Concentration
ISQG
1
PEL
2
aluminum
-
antimony
-
arsenic
3
x
x
barium
-
boron
-
cadmium
-
chromium
3
*
x*
x*
cobalt
-
copper
-
lead
-
manganese
-
mercury
-
nickel
-
selenium
3
NG
NG
thallium
3
NG
NG
vanadium
-
zinc
-
iron
-
Notes:
1
Probable Effect Level (CCME 2003);
2
Interim Sediment Quality Guideline (CCME 2003);
- = not above baseline (less 10% difference between baseline and maximum predicted
concentration) or guideline;
3
= project-related changes in water quality concentrations are above baseline by 10% or
greater;
* = because baseline concentrations were not available for chromium, it was assumed that
predicted maximum concentrations were above baseline concentrations. If a 1 mg/kg
increase would have caused concentrations to increase above the ISQG, than this would
have resulted in an increase of less than 10% from baseline;
blank cell = not compared to guidelines when project-related activities results in less than
10% difference in maximum predicted concentration compared to baseline; and
NG = no applicable guideline.
Changes in sediment concentrations in the Torotorofotsy Wetlands are expected
to be less than the maximum predicted changes described above. The predicted
increase in sediment concentrations decreases downstream of the clarification
