3-EPA
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                                   ,   '  *  *
                          Chlorination first beganlntheeariy 1900s-
                          As a result, diseases tuchw cholera and
                          typhoid have been nearly eliminated.


                          In 1974, diloftrfdnn was found to occur in
                          water following tWorinatioru Additional
                          byproducts have linoe been identified as
                          byproducts of the reaction between chlorine
                          and organic material found in water.

                          Chlorofojin^atrihaloniethaneCrHMs^isan
                          animal carcinogen.  Some of the other by-
                          products have abo been shown to cause
                          cancer or other advene health effects in
                          EPA ertablished a relation In 1979 that
                          limited the amount of THMsto 0.1 mg/L for
                          water supplies serving 10^00 people or
                          more      »• "  -
                          In the 1980§, several epidemiology studies
                          rejected an increased risk of Uaddery colon
                          and rectal cancer ** Individuals drinking
                          
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