Ballast Water Sampling and Sample Analysis for Compliance Control - Global Maritime Transport and Ballast Water Management: Issues and Solutions - page 176

and David, own observation), they may reproduce inside the tanks and release their
larvae into the ballast water. The presence of barnacle larvae originating from in-tank
reproduction may then wrongly be assumed as originating from a ballast water
exchange in coastal areas. Although this scenario may be of very low probability, but
it cannot be completely excluded. The other organism group mentioned here, adult
harpacticoid copepods, are benthic species and their presence in ballast water may
therefore indicate coastal water origin . However, adult harpacticoids were also fre-
quently found in ballast tank sediments. In addition, a ballast water sampling study
with daily sampling events of the identical ballast tank showed that the harpacticoid
copepod numbers in that ballast tank increased during the voyage which indicated
that an in-tank reproduction may have occurred (Gollasch et al. 2000 ).
The presence of human faecal bacteria, such as Escherichia coli , Enterococci or
Vibrio cholerae may also be used for D-1 standard compliance checks. Their pres-
ence in water indicates improper waste water management along the coasts in or
close to urban areas. Most of these indicator microbes cannot survive for longer
times free living in marine waters. Therefore, their occurrence in a ballast water
sample indicates ballast water exchange had occurred close to land without meeting
the depth and distance requirement of the D-1 standard. These indicator microbes
are unlikely to survive a (longer) vessel voyage in a ballast tank outside their human
(or other) “hosts” and therefore this method seems less reliable for longer voyages.
As shown above, the analysis of the biota for D-1 standard compliance control
delivers results only with a limited level of certainty. Therefore, in cases when non-
compliance is indicated by these methods, we believe that these data are not robust
enough to justify a non-compliance action with all its logistical, costs and legal
implications.
Another option for D-1 standard compliance control may be to document tracers
of human infl uence on the sea. It seems to be logical that human infl uence is greater
in near shore regions compared to the high seas. Candidate methods include to
document Nitrogen or Phosphorous levels of which high concentrations may result
from river run-offs in areas with human settlements, but this method may deliver
regionally very different results. In several oceanic regions, especially in oceanic
island states or in coastal environments with low human populations, the Nitrogen
or Phosphorous levels may be very low even close to shore. Although these short-
comings are known, it was concluded that the absence of trace elements may be
used to identify the oceanic origin of ballast water thereby evaluating whether or not
ballast water was exchanged at sea (Murphy et al. 2002 , 2004 ; Hunt et al. 2007 ).
Consequently a tracer detection tool was developed for compliance control (Murphy
et al. 2008 ).
Murphy et al. ( 2006 ) suggested also that fl uorescence may be used to verify bal-
last water exchange for most samples of high salinity ballast water, but water
contamination with, e.g., fuel oil, may infl uence the measurements.
Other instruments may be used to measure the characteristics and concentration
of chromophoric dissolved organic matter (CDOM) in water (Murphy et al. 2008 ).
CDOM is a result of the decay process of (terrestrial) plants and it is believed that
higher CDOM concentrations indicate near shore ballast water exchanges.