Environmental Assessment
Volume B-3.9
Mine
Water Quality
Ambatovy Project
129
January 2006
of cadmium and lead that are above the South African guideline values. The
biological receptor effects of the predicted increase in substance concentrations
are further assessed as described in Section 3.9.5.2 (Assessment Criteria).
Table 3.9-4 Comparison of Maximum Predicted Concentrations with Baseline
Levels and South African Guideline Values
Basin
Antsahalava
Sahaviara
Sahamarirana
Torotorofotsy
Sakalava
Ankaja
Season
Wet Dry
Wet Dry
Wet
Dry
Wet
Dry
Wet Dry
Wet Dry
nitrate (NO
3
)
3
-
-
-
-
-
-
-
-
-
-
-
nitrite (NO
2
)
-
3
-
3
-
-
-
3
-
-
-
-
fluoride (F)
3
3
-
-
-
-
-
-
-
-
-
-
sodium (Na)
3
3
3
-
-
-
-
-
-
-
-
-
sulphate (SO
4
)
3
3
3
3
3
3
3
3
3
3
3
3
antimony (Sb)
-
3
-
3
-
3
-
3
-
3
-
3
arsenic (As)
-
3
-
3
-
3
-
3
-
3
-
3
barium (Ba)
3
3
3
3
3
3
3
3
3
3
3
3
cadmium (Cd)
-
y
-
-
-
-
-
y
-
y
-
y
chromium (Cr)
1
y
y
y
y
y
y
y
y
y
y
y
y
chromium (Cr)
2
3
y
3
3
y
y
y
y
y
y
y
y
lead (Pb)
-
-
-
-
-
-
-
y
-
y
-
y
molybdenum (Mo)
n/a
3
n/a
3
n/a
3
n/a
3
n/a
3
n/a
3
selenium (Se)
-
3
-
3
-
3
-
3
-
3
-
3
thallium (Tl)
n/a
3
n/a
3
n/a
3
n/a
3
n/a
3
n/a
3
uranium (U)
-
3
-
3
-
3
-
3
-
3
-
3
zinc (Zn)
-
y
-
y
-
y
-
3
-
3
-
3
-
Not above baseline (less than 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.
y
Above baseline and South Africa Ecosystems Guidelines (Department of Water Affairs and Forestry 1996).
n/a
Baseline data for this substance was not available for the wet season.
Notes:
1
Compared to hexavalent South African Ecosystems Guidelines for chromium.
2
Compared to trivalent South African Ecosystems Guidelines for chromium.
Chromium had the greatest increase in predicted concentrations due to
project-related activities. The source of the higher chromium is the runoff from
the mine and waste areas. Predicted concentrations of chromium in the receiving
waters were greater for basins in the Analamay area than for the Ambatovy
basins. Predicted chromium concentrations in the runoff from the Analamay area
range between 0.36 and 0.41 mg/L compared to concentrations from the
Ambatovy area, which are between 0.02 and 0.11 mg/L (Volume B, Section 3.2).
