The Number One Menace - The Ripple Effect: The Fate of Freshwater in the Twenty-First Century - page 32

CHAPTER 4
The Number One Menace
POINT / NONPOINT
The nature of water pollutants has changed in recent decades, but regulators have not
kept pace, and the public and the environment are vulnerable to new kinds of contamin-
ation.
In contrast to the obvious “point-source” pollutants of last century—the classic in-
dustrial pipe spewing brown filth into pristine waterways such as Newtown Creek or
the Housatonic River—the greatest source of water pollution today is the more diffuse
“nonpoint-source” pollution known as storm-waterrunof.his term describes pollut-
ants of many kinds, from many sources—motor oil, paint, sewage, fertilizers, insect-
icides, pharmaceuticals, and other contaminants—that are washed off the land by rain,
snow, or mist and into water supplies.
This represents a reversal. In 1970, the EPA estimated that 85 percent of water pollu-
tion came from obvious point sources, such as factories or wastewater treatment plants;
only 15 percent came from nonpoint sources, such as poultry farms, suburban lawns,
or city streets. By 2010, point-source pollution had been significantly reduced, thanks
largely to the Clean Water Act (CWA). Now point-source pollution accounts for only 15
percent of water contamination, while nonpoint sources account for 85 percent.
But EPA regulations have not adapted to this shift. The traditional top-down regula-
tions of the CWA are not well suited to control runoff across a watershed. Storm-water
runoff is especially difficult to identify and remediate because it is so diffuse, washes
across wide swaths of landscape, and pollutes water in myriad ways. This holds as true
for rural citizens who draw water from a single well as it does for urban dwellers who rely
on vast systems of pipes, pumps, and reservoirs.
It was long assumed that well water was better protected from contamination than
surface water. But that is not always the case. Ninety-six percent of all health violations
occur at small water systems, according to the EPA, and those who use private wells are
most vulnerable to contamination.
While wells are relatively cheap to build, they can be polluted by impurities, such as
bacteria, viruses, parasites, fungi, fertilizers, volatile organic compounds (such as meth-
ane or formaldehyde), and naturally occurring arsenic or uranium. Frequently they are
polluted by agricultural runoff, such as manure, pesticides, and nutrients.