Environmental Assessment
Volume B-5.4
Mine
Human and Ecological Health
Ambatovy Project
383
January 2006
Table 5.4-7 Hazard Quotients (HQs) for the Aquatic Fauna in the Mine Area - Outlet
Annual Average
HQ Aquatic Plant
HQ Invertebrates
HQ Fish
Magnitude of the Risk
Measured Values -
Baseline
(a)
(mg/L)
Average Operation -
Predicted Values
(b)
(mg/L) Baseline
Average
Operation
Baseline
Average
Operation Baseline
Average
Operation
Average Operation
Antsahalava River Outlet
sodium (Na)
2.3
2.7
nd
nd
0.00
0.00
nd
nd
chromium (Cr)
0.007
0.023
0.02
0.06
0.17
0.53
0.01
0.03
molybdenum (Mo)
0.00
0.01
nd
nd
0.00
0.01
nd
nd
selenium (Se)
0.002
0.003
0.02
0.03
0.02
0.03
0.02
0.03
thallium (Tl)
0.0045
(d)
0.01
0.05
0.07
0.03
0.05
0.08
0.12
zinc (Zn)
0.006
0.008
0.21
0.26
0.13
0.17
0.17
0.21
negligible
Sahaviara River Outlet
sodium (Na)
2.3
2.4
nd
nd
0.00
0.00
nd
nd
chromium (Cr)
0.007
0.019
0.02
0.05
0.17
0.42
0.01
0.02
molybdenum (Mo)
0.00
0.01
nd
nd
0.00
0.01
nd
nd
selenium (Se)
0.002
0.002
0.02
0.02
0.02
0.03
0.02
0.03
thallium (Tl)
0.0045
(d)
0.01
0.05
0.06
0.35
0.47
0.08
0.11
zinc (Zn)
0.006
0.007
0.21
0.23
0.13
0.15
0.17
0.19
negligible
Sahamarirana River Outlet
chromium (Cr)
0.007
0.018
0.02
0.05
0.17
0.41
0.01
0.02
molybdenum (Mo)
0.00
0.00
nd
nd
0.00
0.00
nd
nd
selenium (Se)
0.002
0.002
0.02
0.02
0.02
0.02
0.02
0.02
thallium (Tl)
0.0045
(d)
0.01
0.05
0.06
0.03
0.04
0.08
0.10
negligible
Torotorofotsy River Outlet
chromium (Cr)
0.007
0.030
0.02
0.07
0.17
0.68
0.01
0.03
molybdenum (Mo)
0.00
0.00
nd
nd
0.00
0.00
nd
nd
thallium (Tl)
0.0045
(d)
0.01
0.05
0.06
0.03
0.04
0.08
0.10
negligible
Sakalava River Outlet
chromium (Cr)
0.007
0.021
0.02
0.05
0.17
0.47
0.01
0.02
molybdenum (Mo)
0.00
0.00
nd
nd
0.00
0.00
nd
nd
thallium (Tl)
0.0045
(d)
0.01
0.05
0.05
0.03
0.04
0.08
0.09
negligible
Ankaja River Outlet
chromium (Cr)
0.007
0.038
0.02
0.10
0.17
0.87
0.01
0.04
molybdenum (Mo)
0.00
0.002
nd
nd
0.00
0.00
nd
nd
thallium (Tl)
0.0045
(d)
0.006
0.05
0.06
0.03
0.05
0.08
0.10
negligible
(a)
Measured average concentration (dry and wet seasons) (See Water Quality Session in this volume).
(b)
Predicted average annual concentration (operation average years 4, 10, 15 and 20, dry and wet seasons).
(c)
Only chemicals of potential concern for aquatic life are listed (For further details refer to Water Quality Assessment, this volume).
(d)
Baseline values <0.009 mg/L (detection limit): 0.5x detection limit used in calculations.
Toxicological Benchmarks based on the Lowest Chronic Values (Suter 1996) (mg/L) (See Human and Ecological Risk Assessment Methodology, Volume K, Appendix 4.2).
nd = Not determined.
HQ>10 in bold.
