standardization of environmental data and information - International ...

ecological comparisons. Several other general recommendations are
possible:
i. An environmental baseline should be established in the testmining
area for at least two years before the tests. This will
allow evaluation of pre-disturbance spatial and temporal
variability.
ii. The monitoring of test mining should include deployment of
current meters, transmissometers and sediment traps to
evaluate the size and behaviour over time of the sediment
plume both within the benthic boundary layer and at the level of
tailings discharge.
iii. Resedimentation thicknesses must be measured using multiple
techniques and mapped to allow evaluation of dose-response
patterns of various components of the benthic biota. The
frequency and intensity of individual deposition events should
also be evaluated.
iv. The sampling design for biological communities should include
(a) sample collection from at least five points along the
redeposition gradient and (b) sampling in at least two control
(i.e., unimpacted) areas for the duration of the impact study.
v. Seafloor communities along the deposition gradient, as well as
in control areas, should be sampled at least at the following
approximate intervals after disturbance: