Nonpoint source pollution comes from diffuse sources rather than a specific point of discharge. It includes pollutants such as oil and grease from roads, fertilizers from agricultural fields, and bacteria from livestock waste that are carried into waterways by rainfall runoff. States are required under the Clean Water Act to develop lists of impaired waters that do not meet water quality standards and to establish total maximum daily loads of pollutants that waterbodies can receive without exceeding standards. Nonpoint source pollution has negative impacts on aquatic life, recreation, fishing, and drinking water supplies.

1. Water Pollution

2. Definitions

Impaired Waters
Section 303(d) of the Clean Water Act requires states to
develop lists of impaired waters, those that do not meet
water quality standards that states have set for them .

Total Maximum Daily Load
The law requires that states establish priority rankings for
impaired waters and develop total maximum daily loads
(TMDLs) for them. A TMDL specifies the maximum
amount of a pollutant that a body of water can receive
and still meet water quality standards.
http://www.epa.gov/owow/tmdl/overviewfs.html

3. Point Source Pollution
vs.
Nonpoint Source Pollution
What’s the difference?
Slides by Christopher C. Obropta, Rutgers University

4. Point Source Pollution

comes from a specific
source, like a pipe

factories, industry,
municipal treatment
plants

can be monitored and
controlled by a permit
system

5. What is nonpoint source pollution?

Nonpoint Source
(NPS) Pollution is
pollution associated
with stormwater or
runoff

NPS pollution cannot
be traced to a direct
discharge point such
as a wastewater
treatment facility

6. Examples of NPS





oil & grease from cars
fertilizers
animal waste
grass clippings
septic systems



sewage & cleaners from
boats
household cleaning
products
litter

7. Pollutant Transport Mechanisms
•
NPS pollutants build up on land surfaces during dry
weather
Atmospheric deposition
Fertilizer applications
Animal waste
Automotive exhaust/fluid leaks
•
Pollutants are washed off land surfaces during precipitation
events (stormwater runoff)
•
Stormwater runoff will flow to lakes and streams

8. Pollutant build-up and wash off are affected by
land use.

Imperviousness increases runoff

Land use changes impact build up

9. Linking Land Use to Water Quality
More Imperviousness = More Water

10. What is impervious cover?

roads, rooftops, parking lots, and other hard
surfaces that do not allow stormwater to soak
into the ground

“predominant American vegetation”

11. Impervious Cover
• provides a surface for
accumulation of
pollutants
• leads to increased
polluted runoff and
flooding
• inhibits recharge of
groundwater

12. Impact of Nonpoint Source Pollution
fish and wildlife
 recreational water
activities
 commercial fishing
 tourism
 drinking water quality


13. Pollutants Found in Runoff
S e dime nt
Soil particles
transported from
their source
Bioc he mic al Oxyge n De mand (BOD)
● Oxygen depleting material
Leaves
Organic material
Nutrie nts
Toxic s
● Various types of materials that
● Pesticides
 Herbicides
become
dissolved and
 Fungicides
suspended in water (commonly
 Insecticides
found in fertilizer and plant material):
 Nitrogen (N)
● Metals (naturally occurring
 Phosphorus (P)
in soil, automotive
emissions/ tires)
 Lead
 Zinc
Bacteria/ Pathogens
The rmal
 Mercury
S tre s s
Originating from:
● Petroleum Hydrocarbons
Heated runoff,
● Pets
(automotive exhaust and
removal of
● Waterfowl
fuel/oil)
streamside
● Failing septic systems
vegetation
De bris
Litter and illegal dumping

14. Potential Sources of Pollutants
Found in Residential Areas






Nutrients: Fertilizers
and septic systems
Pathogens: Pet waste
and septic systems
Sediment:
Construction, road
sand, soil erosion
Toxic: Pesticides,
household products
Debris: Litter and illegal
dumping
Thermal: heated runoff,
removal of streamside
vegetation

15. Pollutants from Agriculture
Sediment
 Nutrients
 Pathogens
 Pesticides


16. Why are these pollutants important?




Sediment reduces light penetration
in stream, clogs gills of fish and
aquatic invertebrates.
Nutrients act as fertilizer for algae &
aquatic plants which can cause
highly varying dissolved oxygen
levels. At low DO levels, the
aquatic life has the potential to be
harmed.
Toxics can impact life and
contaminate drinking water
supplies.
Bacteria/Pathogens are an indicator
of possible viruses present in the
system.