Chemicals making their way into the Great Barrier Reef are threatening the health and survival of animals including the rare snub fin dolphin.
According to new research published in Ecological Indicators, 68% of the dolphins sampled contained levels of PCBs that could impact the health of the marine mammal. PCB chemicals were banned in Australia in 1975 but are still present in the Great Barrier Reef along with DDTs and HCBS. PCB was widely used in building materials such as coolants and additives in paint till it became aware of the potential hazard to our health.
In one of the samples taken in 2015 from the Fitzroy River estuary, a female Australian humpback dolphin had PCB concentrations “among the highest found in published literature and exceeded all available threshold levels for PCBs including those associated with carcinoma in California sea lions.
Samples were taken from humpback and snubfin dolphins in the Fitzroy River and Port Curtis region of Queensland from 2014 to 2016 and were then compared to samples taken between 2009 and 2010. The results showed that all three chemicals were higher in concentration by between two and seven times.
PCBs and DDTs are stored in the mammals blubber and can be 100 times higher than what would be found in their prey. Female dolphins can also transfer up to 80% of the contaminates to their first-born calf.
Extensive flooding in the early 2010s is most likely responsible for increased distribution of the chemical in waters which led directly to the mammals being contaminated. Land-based pollution running into waterways in an ongoing threat to coastal systems and particularly for apex predators where the concentration of the chemicals increase.
The study recommends that reduction of land-based pollutants into coastal waters of the GBR will be critical for the health and survival of the dolphin species in the region.