Sources, Environmental Impacts and Health Effects of Mercury Mercury is a heavy metal that is widespread and persistent in the environment. Exposure to Mercury can affect foetal neurological development, and high levels of mercury in the blood system have been linked to lowered fertility, brain and nerve damage, and heart disease in adults.In the last 200 years, human activities have significantly altered the global mercury cycle, mainly as a result of the burning of fossil fuels, smelting and mining. Research shows that the amount of mercury in the environment is about four times higher than it was prior to the industrialisation period. Once released into the air, mercury is transported and deposited globally where it can bio-accumulate in, and biomagnify up the food chain, especially in the aquatic food chain where it constitutes a major threat to global food security. Even at low concentrations, mercury poses a risk of causing adverse effects to human health and the environment.Mercury was and is still used in many products and processes. In the mid 1800’s, mercury was used in the felting process to make hats. Exposure to mercury vapours led to widespread cases of mercury poisoning among hatters and gave rise to the expression “mad as a hatter”. Other use of mercury includes electricity materials, such as switches and batteries, artisanal gold and silver mining and industrial processes such as vinyl chloride monomer production (VCM).Mercury has not been used as a primary mineral commodity in Australia for at least 50 years, but it is still obtained as a by-product in other mining activities and in natural gas extraction. Coal combustion, significantly tied to economic growth and industrialisation in Southeast Asia, is the fastest growing source of mercury emissions affecting worldwide air quality and the environment.Through its highly experienced team of researchers, Mercury Australia aims to fill the significant knowledge gap that exists on mercury research in Australia to address the magnitude and extent of human impacts on the biogeochemical cycle of mercury and the implications for human, plant and wildlife populations.