Want to get your students' attention? Direct them to the FDA (Food and Drug Administration) January 12, 2001, advisory that warns pregnant women about eating certain fish. Part of the advisory reads: "The Food and Drug Administration (FDA) is announcing its advice to pregnant women and women of childbearing age who may become pregnant on the hazard of consuming certain kinds of fish that may contain high levels of methyl mercury. The FDA is advising these women not to eat shark, swordfish, king mackerel, and tilefish. As a matter of prudent public health advice, the FDA is also recommending that nursing mothers and young children not eat these fish as well."

On the same day the EPA (Environmental Protection Agency) issued national advice to women who are pregnant or may become pregnant, nursing mothers, and young children on the amount of freshwater fish that can be safely consumed from local waters. Part of the advisory reads: "If you are pregnant or could become pregnant, are nursing a baby, or if you are feeding a young child, limit consumption of freshwater fish caught by family and friends to one meal per week. For adults one meal is six ounces of cooked fish or eight ounces uncooked fish; for a young child one meal is two ounces cooked fish or three ounces uncooked fish. Many states collect data on mercury levels in fish from local waters. Check with your state or local health department for specific advice on waters where your family and friends are fishing."

Go to the Listing of Fish and Wildlife Advisories for the advisories from your home state. Note that you must scroll right to see the map. Be sure to note the year of the various advisories. Go to the table listing 1999 Fish Advisories Issued by Contaminant to learn that there were 2,073 advisories concerning fish consumption focusing on mercury--a 7.5 percent increase above the number of 1998 advisories.

The Clean Water Act, section 303, establishes the water quality standards and TMDL programs. Total Maximum Daily Load (TMDL) is a calculation of the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards, and an allocation of that amount to the pollutant's sources. Water quality standards are set by states, territories, and tribes. Go to the EPA's TMDL program site for Major Pollutants Causing Impairment by State to check for mercury pollution of the waterbodies in your state. Go to the Atlas of America's Polluted Waters and click on your state for a map of its impaired waters.

Now your students surely are wondering what is harmful about mercury. Go to the 1995 FDA site "Mercury in Fish: Cause for Concern?" Go to the EPA consumption advisory to find more information about the dangers of methyl mercury. Read the EPA Fact Sheet, Mercury Update: Impact on Fish Advisories. Also go to the cover story of the June 19, 2000 issue of U.S. News and World Report: Kids at Risk. For detailed information go to the U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry on Mercury. The United States Geological Survey (USGS) has an excellent site on Mercury Contamination of Aquatic Ecosystems. Building Environmental Education Solutions, Inc. (BEES) hosts another inclusive site about mercury. Here is an invitation for your students to participate in Water Quality Monitoring Data Base.

Find general information at the EPA Mercury site. Go to WebElements for Mercury and read about the volatility of mercury. Click here for a wonderful graphic of how complex the impact of mercury is on our environment. This site, which also includes information about analytical procedures for mercury, is sponsored by the Department of Analytical Chemistry, Umeå University, Umeå, Sweden. Analytical methods are part of the review of Methyl Mercury Ingestion by Donald Briscoe, Clinical Toxicology Review, Vol. 18, No. 6, March 1996, published by the Massachusetts Poison Control System. Go to the report by Mark L. Olson and John F. DeWild about Low-Level Collection Techniques and Species-Specific Analytical Methods for Mercury in Water, Sediment, and Biota to read about analytical procedures involved in analyzing samples for mercury. Analytical chemistry is in important part of detecting mercury pollution.

The history of the mercury contamination of Clear Lake in California is interesting reading. An important source of mercury found in this beautiful lake is the mercury mine formerly located on the shores of the lake. The University of California Davis-Clear Lake Environmental Research Center (CLERC) has been researching mercury in Clear Lake since 1992.

The EPA produced a Mercury Study Report to Congress in 1997. Read here for sources of mercury pollution and planned efforts to combat it.

Let's end this exploration with a positive look at mercury. Go to http://www.fordham.edu/halsall/mod/1776priestley.html to read in Modern History Sourcebook: Joseph Priestley: The Discovery of Oxygen: From a Joseph Priestley, Experiments and Observations on Different Kinds of Air, 2nd ed. 1776.

On the 8th of this month I procured a mouse, and put it into a glass vessel, containing two ounce-measures of the air from mercurius calcinatus. Had it been common air, a full-grown mouse, as this was, would have lived in it about a quarter of an hour. In this air, however, my mouse lived a full hour; and though it was taken out seemingly dead, it appeared to have been only exceedingly chilled; for, upon being held to the fire, it presently revived, and appeared not to have received any harm from the experiment.

This transcription by John F. Tinkler is part of the Internet Modern History Sourcebook. The Sourcebook is a collection of public domain and copy-permitted texts for introductory-level classes in modern European and World history.

From visiting these sites, your students will learn a lot--and may live healthier lives.