Environmental Impact
In open fields, forests, and wetlands, most rain is absorbed
by the soil or is taken up by plants and trees. In developed
areas, rain that falls on impermeable roofs, parking lots,
streets, and lawns is not absorbed. Instead, it travels down
roadways, settles in gutters and ditches, and flows through
storm drains to finally end up in rivers, lakes, and wetlands.
Rainwater that enters a surface water body, by flowing either
overland or through a storm sewer system, is called storm
water or storm water runoff.
Storm water runoff is one of the leading causes of pollution
in rivers and lakes. In both urban and agricultural settings,
it can dissolve and transport a variety of chemicals, fertilizers,
pesticides, and litter picked up while traveling overland.
Identifying sources of storm water pollution and keeping
them from coming in contact with runoff is the best and most
economical way to protect the quality of the nation's waters.
Tests conducted by EPA on fluid samples from service station
floor drains indicate that improper disposal of waste generated
during vehicle servicing poses the threat of surface water
contamination. Waste oil, antifreeze, and solvents are washed
into floor drains which are improperly disposed into separate
storm drains. EPA prohibits the discharge of wastewaters
into separate storm sewers and permits certain storm water
discharges under the authority of the Clean Water Act.
In most cases, typical fluid samples exceed EPA's criteria
for identifying properties or characteristics that define
a waste as hazardous under the Resource Conservation and
Recovery Act (RCRA). Benzene and a number of chlorinated
solvents are among the 25 chemicals that have been added
to EPA's Toxicity Characteristics list under RCRA.
In addition, any facility that generates more than 27 gallons
of wastewater per month containing any of the listed chemicals
in amounts exceeding EPA's regulatory levels needs either
to recycle the material or to dispose of it as hazardous
waste. Facilities that generate less than 27 gallons of wastewater
per month are conditionally exempt.
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