“Marine plastic
pollution is one of the most serious emerging threats to the health of oceans
and is now considered a major hazard to marine biodiversity. Plastics may
fragment but do not biodegrade and so persist indefinitely, leading to a
progressive rise in quantities found in the marine environment.” (Environmental
Investigation Agency, 2016)
Nowadays, the knowledge about the pollution of the
environment by humans is well-established and widespread. Nevertheless, many
people do not act according to this knowledge. Taking littering as an example,
it is publicly known that littering harms the environment. Despite this, many
people drop their waste just where they are – in the streets, in the woods or
even into the water when they are near a lake or ocean. A big part of this
waste is plastics (Plastic Europe, 2015), mostly light-weight material which
floats on water and thus often ends up in the ocean. Here begins the area of
interest for this study which will review the characteristics and impacts of
marine plastic debris to introduce the topic. So one of the research questions
to be answered is where the debris found in the oceans comes from and where it
goes. This is to be visualised in Sankey diagrams, which will show the
different plastic flows in order to form a global picture of the problem. As
the most remarkable part of marine litter are different kinds of plastic
fractions, the attention here is focused on plastics only. Additionally, the
impacts of marine debris on wildlife and the ocean ecosystem in general as well
as on human beings are summarised.
This review is used as the background for the
second part, where an analysis regarding problem mitigation strategies will be
conducted. So the description of the problem in the first part delivers the
motivation for why mitigation actions against marine littering are of essential
importance. Different mitigation actions will be presented and assessed for
their utility in the given context. Then next, different environmental
evaluation methods will be presented and applied onto the described mitigation
efforts with the goal to get an idea about their effectiveness. A specific
section of the second part is the environmental evaluation of an arctic
clean-up operation as an example for mitigation actions, which will be
conducted in terms of a life cycle assessment (LCA).
The more general aim of this exploratory
study is to collect and organise the growing knowledge about plastics in marine
environments and to review the debris flows and their related problems. The
analytical aim is to appraise the effectiveness of the analysed mitigation
project Clean Up Svalbard; that is if
the benefits for the ecosystem weight out the costs of the operation for the
environment (greenhouse gas emissions). The study will be done in the context
of Industrial Ecology, as it explores the impact of industrial systems
(industries, human settlements) onto the ocean environment. The relevance of
the topic of marine plastic debris for environmental sciences is based on the
importance of the ocean ecosystem for life on earth and the growing attention
for the topic from environmental researchers just now.
9 Conclusion
The research questions about where the plastic debris comes from, where
it goes and what impact it has on the oceans and on us humans have been covered
throughout this report. Still, the knowledge about the severe impacts of marine
plastic debris and its widespread distribution into even the most pristine
environments is growing steadily. It has been documented in literature that
numerous seabirds, turtles, fish and whale species suffer and die from
ingestion of plastic particles mistaken for food and from entanglement in
plastic items. Further, floating debris acts as a vector for the spread of
alien species and can hinder gas exchange on the seafloor when sedimented.
Additionally, plastic particles concentrate endocrine disrupting toxics and
other persistent chemicals on their surface which are then accumulated in the
food chain across trophic levels.
As researchers find out more and more alarming characteristics of the
problem, people also get creative and think about problem mitigation
strategies. While The Ocean Cleanup probably is one of the most remarkable
projects at the moment, also numberless smaller and more locally focused beach
cleaning actions around the world contribute essentially to the urgently
required change. In the conducted life-cycle assessment of the arctic
beach-cleaning operation Clean Up
Svalbard it was calculated that 268 t of carbon were emitted in total, with
roughly 500 kg of plastic debris collected on about 12 km of coastline. The
carbon emissions equal 2.37 ton per person which is about a third of annual
Swedish emissions per capita. Though not quantifiable properly, the various
benefits arising from the project seem to outweigh the caused negative effect
of greenhouse gas emissions. One resulting benefit is an increased awareness of
marine litter for all participants and their nearest acquaintances, however not
measurable, which contributes to reduced littering behaviour in the long term.
General awareness raising and to attain a positive impact for the local
environment through participation in clean-up projects etc. could also be
promoted as a new strategy for ecotourism. In addition, an ecological benefit
is assumed to arise from the clean-up, although it could neither be detected in
local wildlife observation nor in the amount of plastics ingested by an
indicator species.
The study identified a lack of operational assessment methods for
positive environmental impacts. Therefore own approaches to describe the
achieved effects are set up as evaluation methods for the positive impact here.
For a better quantification of the positive impact of planned or conducted
mitigation projects in the future, observation efforts should to be reinforced
and the harmful impacts of debris documented more systematically. Besides,
standardised methods for sampling would ensure the comparability of results, so
that a more consistent picture of marine pollution around the globe could be
formed.
Finally, we will only manage to tackle this pervasive problem if the
input of new plastic debris into the oceans will be stopped eventually or at
least reduced drastically in the near future. As in the IUCN Net Positive
Impact approach where the aim is to make a positive impact in order to ensure
the achievement of at least No Net Loss, the goal should be to stop new
pollution altogether and to remove as much of the litter that already is in the
oceans as possible. Thereby, we should be able to safeguard the health of
marine ecosystems and to most likely not cross any essential ecological
thresholds. The oceans provide food, medicine and various vital ecosystem
services that many communities rely on. Life on earth depends on the ocean, let
us not jeopardise its soundness.
