This is one of the many posters I have designed during my university course.
This poster is on the impacts of Polychlorinated Biphenyls (PCB) on Killer whales (Orcinus orca). I have done a few posters on the same topic now.

Polychlorinated Biphenyls, or PCB’s, are a conglomeration of 209 individual chlorine-based compounds known as congeners. Such compounds are not known to be naturally occurring, and occur as mostly colourless (rarely light yellow in colour), odourless, tasteless oils. PCB’s were extensively used as coolants and lubricants due to their stability, heat-resistant and fire-retardant features. At the same time, their stability and lipophilic nature make elimination of PCB’s from an organism almost impossible8. As a result, PCB’s are easily accumulated in blubber with age (bioaccumulated) and mobilizated at the top of the food chains (biomagnificated). In recent studies, the transference of PCB’s via transplacental transfer and lactation from mothers to calves who concentrate it to their tissues causing high mortality of neonatal calves. PCB’s transport can also be physical: they may volatilize, with atmospheric pathways carrying them to Arctic and Antarctic where they sink into the oceanic surface waters by wet and dry deposition. Migratory movements of fish and other animals can physically translocate PCB’s from one region of the world to another. Because of these complexities and the negative effects that they have on organisms the United States government ceased the manufacture of PCB’s in 1977.

Effects of PBC’s
The presence of soluble Polychlorinated Biphenyls (PCB’s) in the marine environment can be devastating to marine mammals, as well as all other marine species. As a bioaccumulating and biomagnifying agent, the persistent exposure of killer whales and other marine species to PCB’s has the capability of leading to extremely high contamination concentrations found within the blubber stores of the animal. Such high total concentrations of PCB’s in tissues of southern resident killer whales, of Puget Sound, British Columbia, Canada, make them amongst the most contaminated of all cetacean species in the world. Adverse consequences of high contaminant concentrations include the increased susceptibility to diseases, such as the cetacean pox virus (Orthopox virus), as well as other detrimental inflictions including reproductive impairment, skeletal abnormalities, immunotoxicity, neurological and endocrine disruption. The ability of PCB’s to be pass from mother to calf through the processes of reproductive transference, in conjunction with the previously mentioned inflictions, can adversely impact upon a population, with possible repercussions including the decrease in the gene pool or even the eventual extinction of the population.