How does mercury get into our environment?
The environment is host to three types of mercury: Elemental, Inorganic and Organic. Toxicity of mercury in relation to humans depends on its form, exposure pathway and concentration.
Emissions of mercury into the environment result from man-made and natural sources. Natural sources range from volcanic activity, forest fires, the off-gassing of soils, rocks and the oceans. Although no direct evidence quantifies the total amount of naturally-release mercury, estimates range from 13 million pounds per year to 36 million pounds per year.
Estimations put man-made emissions at less than half the total mercury emissions in the environment. While estimates vary, approximately 5 million pounds per year are believed to come from man-made sources.
Sources of man-made emissions consist of chemical and industrial processes, home heating oil, coal-fired utility boilers, metal smelting, solid waste disposal facilities and agricultural operations.
Due to reduced mercury content in consumer products and advanced pollution control devices, municipal solid waste combustion facilities are no longer one of the largest known sources of mercury emissions and are regarded as insignificant sources of mercury emissions.
Over the past several years health risk assessments for new and existing waste-to-energy plants consistently reveal that levels of mercury emissions produce exposures which are 100 times less than the threshold health effects standard established by federal and state regulatory agencies.
How does mercury exposure affect us?
The three main types of exposure are: skin contact, inhalation and ingestion. Mercury can travel a far way from the point of release and easily settle in soil and grain into surface water bodies. Upon entry in water, mercury is converted to methylmercury by bacteria. This toxin is passed up the food chain by water borne creatures and its concentration increases the higher it goes.
Even low exposure levels to mercury can cause muscle tremors, irritability and immune system dysfunction. High exposure can cause speech and hearing issues, respiratory problems and sometimes death. Due to the ongoing development of their nervous systems, fetuses and young children are at the greatest risk. There is potential they could suffer from developmental problems in learning, walking, talking and birth defects.