Environmental Engineering Reference
In-Depth Information
Another issue to consider are the consequences which may arise from an indicative
sample analysis. Does an indicative D-2 standard test result trigger the need for
further tests, i.e., a detailed D-2 standard compliance test? Or should a vessel be
banned from discharging ballast water solely based on the indicative test result?
Based upon paragraph 6.3 of the G2 Guidelines, it is understood that an indicative
analysis was included to give a Party an opportunity to identify potential non-
compliant ballast water in an early stage, i.e., the detailed compliance test may show
results only after all ballast water was already discharged, the indicative analysis
was implemented to avoid any impact from a possibly non-compliant ballast water
discharges from a ship.
Indicative In-Tank Sampling for Compliance Control
with the D-2 Standard
Sampling will likely be conducted on a number of different ship types in a port.
After ship selection according to the sampling program, i.e., targeting of vessels
based on PSC, the ballast tanks for sampling are to be selected. Hereby the sampling
access plays a crucial role and determines if the ballast water is available for sam-
pling at all. Therefore, a fl exible approach with sampling equipment suitable to be
used via various sampling points, is in most cases crucial to obtain a sample.
Another aspect is the need for in-tank sampling. On certain occasions it may be
appropriate to avoid taking a sample from the ballast water discharge line as G2
recommends, i.e., during the discharge overboard. This refers to cases when it is
known that a vessel carries ballast water from areas with documented outbreaks,
infestations, or populations of HAOP, e.g., toxic algal blooms. Here the sampling
during the overboard discharge should be avoided and a risk assessment should be
used to identify high risk ballast water. Such ballast water discharges overboard
would pose a risk to the environment, human health, property or resources. Instead
it is recommended that in these cases it is preferred to take an indicative ballast
water sample directly from the tank prior any ballast water discharge. Although
such a sampling event may not be representative of the whole discharge, it enables
an indicative compliance control test without taking the risk to discharge this high
risk ballast water into the environment.
Selection of Ballast Water Sampling Equipment and Methods
for Indicative In-Tank D-2 Sampling
Studies have shown that sampling for zooplankton via the sounding pipes does not
result in a representative sample. Comparisons of sounding pipe and manholes sam-
ples taken simultaneously from the same tank found that net samples contained a
higher biological diversity. Sounding pipe samples contained only 0-60 % of the
organisms of a net sample, which indicates the need to sample ballast tanks via
opened manholes. It was an interesting observation that pumps operated via open
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