By the numbers, the effects of the Clean Water Act on the Mississippi River have been staggering. Now, a new survey looking at more than a century of river chemistry reports shows the full value of the act like never before.
As early as 1909, people were testing the Mississippi, the largest river in the United States, for bacteria, sulfate, lead, and oxygen content. The great waterway was shown to get dirtier and dirtier until 1980, when the effects of the Clean Water Act (CWA) of 1972 began to show.
Eugene Turner, author of Louisiana State University Study, examined water quality reports at four sites near the end of the Mississippi River where it empties into the gulf: St. Francisville, the eerily named “Plaquemine,” New Orleans, and Belle Chasse.
Following the implementation of the CWA, wastewater treatment infrastructure became mandatory and more advanced, resulting in a huge drop in the density of fecal coliform bacteria from wastewater discharge over the past 50 years. “They are 1% of what they were before the 80”, says Eugene to How.
Oxygen concentrations, necessary for the survival of aquatic life, increased at three of the four sites during the same period, although the site furthest from the sea changed little over the past 50 years.
Lead contamination could almost be described as non-existent, such was the effect of the CWA’s industrial runoff restrictions. They are 1000 times lower than in 1979. In some places, they are 2000 times lower.
In 2011, environmental agencies stopped inspecting the Mississippi for lead because minute amounts in the water remained the same over a period of about 10 years.
In 1950 there were about 50 milligrams of sulfur dioxide per liter of water. Thanks to the reduction in sulfate emissions as a result of the Clean Air Act, the river now averages 18 micrograms per liter. This sulfate reduction has also led to the restoration of a much more normal pH level in the water of about 8.4.
“All of these changes happened over decades; they were achieved not quickly after some masterful reconfigurations of technology or rules, but by sustained attention in many places, one chimney or one sewer plant at a time, ”writes Eugene in his study.
“The Clean Water Act has been tremendously effective in reducing the amount of industrial and urban pollution, as this study shows,” said Olivia Dorothy, an American Rivers Mississippi River Management Expert. How. “We need to protect the act and all its authorities, [and] we also have to start thinking about expanding it to cover emerging threats to public safety when it comes to water. “
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