![]() Mercury is emitted by natural sources, such as volcanoes, geothermal springs, geologic deposits, and the ocean. This is because mercury emissions generally disperse widely in the atmosphere before being deposited to the earth's surface. Mercury contamination is global and affects many waters that have no obvious mercury source. Numerous chemical forms in air, water, sediment, and biota.Biomagnifies (higher concentrations at increasingly higher levels in the food chain).Bioaccumulates (higher concentrations in tissues of aquatic plants and animals than in water).HIGHLIGHTED PUBLICATION: Mercury in the Nation's Streams-Levels, Trends, and Implications For a deeper dive into the topic, download the USGS Circular 1395, highlighted below. The fact sheet Mercury Contamination of Aquatic Ecosystems answers many of the basic questions about mercury. 2 The geographic extent of mercury advisories covers more than 10 million acres of lakes and more than 400,000 stream miles. Mercury is the leading cause of impairment in the Nation's estuaries and lakes and was cited in nearly 80 percent of all reported fish-consumption advisories. As a result, mercury can bioaccumulate in fish in areas with no obvious source of mercury pollution. Much of the mercury in the environment originates from combustion of coal and can travel long distances in the atmosphere before being deposited on the land surface. Mercury contamination of fish is the primary reason for issuing fish consumption advisories, which exist in every State in the Nation. Mercury is a potent neurotoxin that can accumulate in fish to levels of concern for human health and the health of fish-eating wildlife. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |