The Davis Strait - DCE - Nationalt Center for Miljø og Energi

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effects found in the blue mussels reflect exposure gradients and that the
mussels were affected by components in the produced water.
Atlantic cod was also used to assess possible impacts of alkylphenols, also
present in produced water and suspected to belong to those substances that
cause endocrine disruptive effects in fish (Lie et al. 2009). In another study
the genotoxic potential of water-soluble oil components on Atlantic cod has
been documented (Holth et al. 2009).
Finally, the release of produced water under the ice gives reason for concern,
because there is a risk of accumulation just below the ice, where degradation,
evaporation, etc are slow and the sensitive under-ice ecosystem, including
the eggs and larvae of the key species polar cod may be exposed
(Skjoldal et al. 2007).
10.3.2 Other discharged substances
Besides produced water, discharges of oil components and various chemicals
occur in connection with deck drainage, cooling water, ballast water,
bilge water, cement slurry and testing of blowout preventers. Such releases
are regulated by the OSPAR convention, and these standards should be applied
as a minimum in order to minimise impacts. Sanitary wastewater is
usually also released to the sea. The environmental impacts of these discharges
are generally small from a single drilling rig or production facility,
but releases from many facilities and/or over long periods of time may be of
concern. BAT (Best Available Technology), BEP (Best Environmental Practice),
applying international standards (OSPAR and MARPOL) and introduction
of less environmentally damaging chemicals or reduction in volume
of the releases all represent ways in which the effects can be reduced. It
should be mentioned that release of environmentally hazardous substances
from the oil industry to the marine environment in Norwegian areas has
been reduced by 99% over 20 years by applying these measures (SFT 2008).
Ballast water from ships poses a special biological problem, i.e. the risk that
non-native and invasive species (also termed as Aquatic Nuisance Species –
ANS) are introduced to the local ecosystem (Anon 2003a). This is generally
considered a severe threat to marine biodiversity and, for example, blooms
of toxic algae in Norway have been ascribed to release of ballast water from
ships. There are also many examples of introduced species which have impacted
fisheries in a negative way (e.g. the comb jelly Mnemiopsis in the
Black Sea (Kideys 2002).
Presently, the Arctic seas are the least severely affected areas by non-native
invasive species as shown by Molnar et al. (2008). However, many tankers
releasing ballast water near an oil terminal and the increasing water temperatures,
particularly in the Arctic, may increase the risk of successful introduction
of alien, invasive species in future.
There are methods to minimise the risk from releasing ballast water, e.g. in
applying the international ballast water management convention, which restricts
and regulates the exchange of ballast water. The International Maritime
Organization (IMO) has adopted this convention and requires that
ships follow a strict ballast water management plan and in future install ballast
water management systems to treat the ballast water before its release
into the environment (IMO 1998). All vessels and drilling units involved in