About Mercury

Number 80 on the Periodic Table, mercury is a dense silvery liquid metal that readily compounds with other metals to extract gold from mines or produce amalgam dental fillings. Mercury is also used in batteries and switches to conduct electricity, and in thermometers and barometers as it responds to change in temperature and atmospheric pressure.

Where does mercury originate? Mercury occurs in several forms. It may arise naturally in the environment, be dissolved in rainwater or appear as a solid mineral.

Most mercury found in the Sacramento River watershed comes from abandoned gold mines worked during the late 1800's and early 1900's. The elemental mercury coming from leaching mines, air deposition and other sources can be converted into methyl mercury when it enters our waterways and absorbed by small aquatic organisms, which are then eaten by small fish.

Ultimately, the small fish are eaten by larger fish, which are consumed by humans. Once ingested, mercury attacks the human nervous system and may disrupt normal brain development in children under six. Loss of sensation in the hands, as well as hearing, speech and vision problems, are examples of the effect mercury can have on adults. Much worse, mercury can bioaccumulate over time and result in death.

Where would I find mercury in my home or business? Mercury is found in several things. It can be found in switches, thermostats, thermometers and fluorescent tubes. Mercury is also used in disinfectants that kill bacteria, like contact lens solution. It can even be found in novelty toys and jewelry.

SRCSD launched "Be Mercury Free", an educational outreach program, to reduce mercury sources found in households, schools and universities, hospitals and dental offices. Additionally, a future offset program may reach out to communities that rely heavily on fish consumption to educate them about the presence of mercury in fish as a result of mercury fallout from past mining activities.