Only about 2 percent of the women were exposed to the highest risk levels, meaning they consumed five or more glasses with at least 75 micrograms per liter. As THM's levels are directly linked to levels of organic contaminants and nitrate levels are connected to fertiliser use and organic wastes, we suppose that THM levels and nitrate levels are positively correlated. In 1977 concern about that risk led the federal government to set a standard for city water systems of no more than ten milligrams of nitrate per liter of water. Those regulations, though, don't cover private wells. And when LaGrange County health officials realized that three women who had suffered repeated miscarriages all drank well water, and all lived downstream from a hog farm's leaky septic system, they began to suspect that nitrate might endanger a developing fetus as well as an infant.
Excessive nitrate can result in restriction of oxygen transport in the bloodstream.
Infants under the age of 4 months lack the enzyme necessary to correct this condition. The source of this water is the Raccoon River. Much of the land upstream is planted in corn, soybeans, or other row crops, and fertilizer is heavily used. The State also reports that trace inorganic elements, flow alterations, and nitrates degrade over 1,000 square miles of ground water aquifers. In spite of the recognition of potentially toxic chemicals in chlorinated drinking water, few studies have evaluated reproductive health consequences of such exposure.