VCE Environmental Science

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Between September and March, up to 23,000 dolphins will be harvested in Japan, and most sold as ‘whale meat’ for human consumption. Ric O’Barry, an environmental activist, has recently premiered a documentary, “The Cove”,  he filmed about the annual slaughter of dolphins in the Japanese fishing port of Taiji. He hopes to raise awareness about the plight of these marine mammals and sever the sister-city relationship between Taiji and Broome. The Age produced an article here. However, it may not be economic or environmental debate that saves the dolphins from slaughter – it may be human health and safety. The documentary reveals that some of the dolphin meat tested had mercury contamination of up to 2000 ppm. Mercury poisoning causes serious birth defects, brain and kidney damage, sensory impariment and lack of co-ordination. Mercury contamination may prevent the consumption of dolphin meat – will it prevent the slaughter of these animals? And how does mercury effect the health of these intelligent creatures?

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What is the difference between bioaccumulation and biomagnification? Read an interesting article from the Scientific American – “Bald eagles succumb to poisin in rat eradication on Alaskan island” . Is this an example of bioaccumulation or biomagnification?

Local examples of bioaccumulation from the Australian government department of environment, water, heritage and the arts – uranium in freshwater mussles and fish in the Northern Territory. Bioaccumulation of copper and tungsten in northern Queensland. What types of toxins are most likely to bioaccumulate and biomagnify?

“Almost all mercury compounds are toxic and can be dangerous at very low levels in both aquatic and terrestrial ecosystems. Because mercury is a persistent substance, it can build up, or bioaccumulate, in living organisms, inflicting increasing levels of harm on higher order species such as predatory fish and fish eating birds and mammals through a process known as “biomagnification”. Although the long-term effects of mercury on whole ecosystems are unclear, the survival of some affected populations and overall biodiversity are at risk.” from Mercury and the Environment. Another resource about mercury in our environment here: “Methylmercury Contamination in Fish and Shellfish.” Health effects of mercury here: “Mercury in the body and health effects“.