Environmental Engineering Reference
In-Depth Information
1.4 Ingestion
Microplastics present in both pelagic and benthic ecosystems are ingested by marine
biota because it is mistaken for prey [12]. Most of the ingested material includes
plastic bags, fragments of plastics and plastic pellets. This blocks the digestive tract,
or stomach resulting in starvation, malnutrition and potentially death. Of the sea
turtles that are found dead, 80% are known to have ingested debris, which can directly
have a negative impact on their population. In the case of seabirds, up to 80% are
known to ingest marine debris, which affects the larger population (111 out of 312
species). Marine debris ingested by the marine organisms can accumulate in the gut
and results in a false sense of fullness, that stops the animals from eating and which
causes them to slowly starve to death. Sometimes ingestion of sharp material could
damage the gut and results in pain and infection, and even possibly death.
Chemicals leaching out from the plastics can be absorbed by the animal's body, which
could be toxic. Hazardous pollutants such as polychlorinated biphenyls (PCB) and
dichlorodiphenyldichloroethylene (DDE) are absorbed and concentrated onto the
surface of the plastic pellets. The contamination of ocean water by plastic or scrubbers
from hand washes, cosmetics and airblast cleaning media have an impact on sea surface
microlayer ecosystem which is the most important place for numerous marine species.
Tiny plastic particles that are used in air blasting affects marine species because they
contain heavy metals. The heavy metals present in the contaminants together with
the debris are taken in the ilter feeding organisms and ultimately passed onto other
organisms in the food chain [13].
Sea turtles are more prone to death by ingestion of marine debris, if the debris is
predominantly plastics. Studies conducted on dead turtles reported that among the
total number of sea turtles examined, 79.6% were dead because of the ingestion of
marine debris. Many researchers describe that the primary side effect caused by the
ingestion of marine debris was the weight loss. Research on seabirds collected in the
tropical Paciic Ocean indicated that the ingested plastics had a negative impact on
their body weight. It is proposed that the weight loss may be because of the blockage
of the digestive tract, physical damage, and introduction of toxic chemicals into the
bird's body. Organisms present in the lower tropical level are more susceptible to
ingestion of microplastics because most of them are indiscriminate feeders with an
inadequate ability to distinguish between food and plastic debris. Most of the plastic
materials that are used include low-density polymers such as polyester and PE which
loat. The availability of microplastics near the sea surface are abundant, so they are
widely available to the host of planktonic organisms, including the larval stage of
many species that are living in the euphotic zone.
