1. The Bioaccumulation of Mercury Cloze reading notes

2. Mercury is a naturally occurring element found in the Earth’s crust

3. Mercury is commonly used in thermometers and compact fluorescent light bulbs

4. Mercury is also present in coal and when coal is burned it is released into the air. This is the largest source of anthropogenic mercury in the environment in the US. Other sources are manufacturing and industry. A natural release of mercury is from volcanoes.

5. Mercury from the air settles in water or onto land where it can be washed into water. It is then transformed into methylmercury by certain organisms. This form is highly toxic and builds up in shellfish and fish.

6. Methylmercury is a neurotoxin, meaning it effects the brain. In children methylmercury impairs neurological development and impacts cognitive thinking ability, memory, attention, language, fine motor skills, and visual spatial skills. It can slow neurological processes in adults

7. Methylmercury is taken up by tiny aquatic plants called phytoplankton and tiny animals called zooplankton. These organisms are eaten by larger organisms such as fish, and the concentration of methylmercury increases at each level of the food chain. The larger and older the fish the more accumulation of mercury in their system.

8. The process of taking in the contaminant, such as methylmercury and storing it in the body is called bioaccumulation. As the concentrations increase with each level of the food chain, this process is called biomagnification. Bioaccumulation occurs within the organism and biomagnification occurs within the food chain.