Environmental Assessment
Volume E-5.4
Tailings Facility
Human and Ecological Health
Ambatovy Project
224
January 2006
As part of the water quality assessment, predicted water quality was estimated
and then simulated water samples were assessed using toxicity tests with aquatic
biota (Daphnia magna) considered to be more sensitive than most aquatic biota.
The results suggest predicted water quality would present no acute toxicity to
aquatic organisms including fish, and based on the actual data unlikely to yield
chronic toxicity as well (see Section 3.10 in this Volume for further details).
Sediment Quality
Copper and nickel were considered chemicals of potential concern in the baseline
health assessment (Section 5.4.3) but they were not further evaluated since
concentrations during operation and post-closure of the facility are expected to be
similar to the baseline conditions.
Predicted levels of lead, mercury and zinc met sediment guidelines. Based on
these observations, the incremental risk to benthic communities posed by the
tailings facility site is considered low to negligible.
5.4.4.5 Mitigation
Mitigations that are applicable to human and aquatic health were addressed
previously in the Water Quality Assessment, (in this Volume). Results of the
health assessment suggest that additional mitigation is not warranted.
5.4.4.6 Residual Impacts
The residual impact classification on health impacts in the tailings facility area is
provided in Table 5.4-2. They have been assessed as negative, low to negligible,
local (limited to the watersheds directly affected by the tailings site), long-term
(lasting after the site closure) and of high frequency (occurring continuously).
All residual impacts are therefore of low to negligible environmental
consequence.
