Ballast Water Sampling and Sample Analysis for Compliance Control - Global Maritime Transport and Ballast Water Management: Issues and Solutions - page 177

Because of all limitation as stated above, biological sampling is not recommended
for D-1 standard compliance control. The non-biological methods also seem to gen-
erate results with low confi dence levels so that only the measurement of ballast
water salinity seems to be a pragmatic option to check the compliance with the D-1
standard. However, as explained above, all vessel which load ballast in a marine
port would always be in compliance when using this method. Therefore, salinity
D-1 standard compliance checks should be done together with checking the vessels
logbook and the salinity in the ballast water uptake port(s).

In-Tank D-1 Standard Sampling

Selection of Ballast Water Sampling Equipment and Methods
for In-Tank D-1 Standard Sampling

As suggested here, the in-tank D-1 standard compliance control should be limited
to a non-biological analysis of the water and salinity measurements seem to be a
good parameter for this analysis. Already a very small volume of water is suffi cient
for this measurement.
The water used for salinity measurements may be collected by a water column
sampler or a pump. Alternatively the sensor of a salinity meter may also be low-
ered into the tank or sounding pipe to enable direct measurements (see Table 1 ).
A detailed description of the sampling equipment and sampling arrangements is
given in section “ Sampling Equipment and Sampling Point Arrangements ”.
Measuring the water salinity from ballast tanks is not as trivial one may assume.
Experiments have shown that salinity measurements via sounding pipes, with sepa-
rate readings in different heights, resulted in different salinity values over the length
of the sounding pipe. The deeper the salinity meter was lowered down the sounding
pipe the higher was the salinity value (Gollasch et al. 2012 ). This is a reasoning for
our recommendation that more than one sample should be taken to cover potentially
varying water salinities in the same ballast tank. This may either be done by lower-
ing the salinity sensor to different water depths or by operating a water column
sampler to sample different water depths.

Table 1 Sampling access points, equipment and other details recommended for compliance
control sampling with the D-1 standard (Modifi ed after David 2013 )

Water
volume Sampling point Equipment Number of samples

Sounding pipe,
manhole or air vent

Water column
sampler or pump

ca. 50 ml 1 integrated sample from possibly

whole water column

Sounding pipe,
manhole or air vent

Point-source sampler
or pump

ca. 50 ml 1 integrated sample from 3

different depths