Point source pollution originates from identifiable, localized sources like sewage treatment plants, industrial facilities, and fish farms. It is easier to regulate than non-point source pollution. Major sources release excess nutrients like nitrogen and phosphorus that can cause algal blooms, fish kills, and dead zones in affected water bodies. New technologies aim to further reduce nutrient levels in treated wastewater effluent. Excess nutrients from both point and non-point sources can lead to eutrophication if not properly managed. Wetlands and riparian buffer strips help mitigate non-point source pollution and enhance restoration efforts.

1. Nitrogen and Phosphorus
Point Source Vs. Non Point Source
Pollution
Marek Koloszyc & Stacey Findlater

2. Point Source Pollution
• Point-source pollution
occurs when pollutants
enter a waterway directly.
• Can be tracked back to a
specific source , location
and offender.
• Easier to regulate and
manage compared to Non-
Point Source pollution.

3. Major Sources of Point Source Pollution
Sewage Treatment Plant
Effluent
• Excess nutrients – nitrogen and
phosphorus compounds
• Detergents and personal care products
• as an additive phosphorus softens
water and loosens dirt particles from
fabrics
Industrial Effluent
• Manufacturing and mining end of pipe
pollution
Aquaculture Fish Farms
• large numbers of fish in a small area

4.  Possible Technological
Enhancements:
• Activated carbon filters-to
remove phosphorus and
nitrogen
• Ion exchange filters –remove
charged ions
• Enhanced nutrient removal
(ENR) with can reduce total
nitrogen down to 3 mg/L or
less and total phosphorus to
0.3 mg/L or less
• Effluent filtration in
combination with chemical
precipitation can be used to
remove phosphorous to very
low levels (< 0.1 mg/L)

5. Aquaculture – Fish Farms
• A Special case of agricultural
pollution
• Rapidly growing industry in both
fresh and marine water
• Feed wastes (up to 20%) and fish
wastes - contribute to nutrient
loading and eutrophication
• For every ton of fish, aquaculture
operations produce up to 66
kilograms of nitrogen waste and
between up to 10.5 kilograms of
phosphorus waste
• Greatly impacts Benthic
communities and native fish
Georgian Bay rainbow trout Farm

6. Issues Caused by Excess Nutrients in
water Bodies
•Increase in production and biomass of
algea
•Massive fish kills – due to deoxygenation
•Drinking water odour and taste problems
during algal blooms
•Piles of rotting algae along shore line
•Recreation ,navigation and irrigation are
affected
•Harmful algal blooms – production of toxins
, acutely toxic or cause skin rashes, poison
shellfish
•Dead zones
•Loss of desirable fish ( salmon and trout)
•Economic loss

7. Methods to Control Excess Nutrient Input
Use advanced ( tertiary)
waste treatment to remove
nitrates and phosphates
from effluent
limits on phosphates in
household detergents and
other cleaning agents
Soil conservation and land-
use control to reduce
nutrient runoff
 But Can more be done?

8. Trophic Classification of Aquatic Ecosystems
• Oligotrophic – Low levels of
organic matter – tend to be deep
and clear , oxygen rich bottom
supports cold water fish such as
trout , Phosphorus is limiting
• Mesotrophic – more organic
matter, oxygen level in lake
bottom is low
• Eutrophic- High levels of organic
matter – abundant plant growth ,
poor clarity , stratified with
oxygen poor bottoms
• A dead zone is an area where
oxygen levels fall below 2 ppm

9. The Nitrogen Cycle
• The most common forms of nitrogen in wastewater are: Ammonia (NH3)
Ammonium ion (NH4+) Nitrite (NO2‐)Nitrate (NO3‐) and Organic
nitrogen
• Microorganisms make all chemical forms of nitrogen interchangeable
• Organic forms of nitrogen are broken down and converted to ammonium
in a process called ammonification
• Nitrate and Ammonium are used by primary producers
• Ammonia is oxidized to nitrate by nitrifying bacteria in aerobic zones
and the nitrate is converted to free nitrogen in the anoxic zone by
denitrifying bacteria – removing it from the environment

10. The Phosphorus Cycle
• One of the Slowest nutrient
cycles
• Phosphorus is limiting in Marine
systems – natural phosphorus
comes from the weathering of
rocks
• Anthropogenic sources are
rapidly taken up by primary
producers – resulting in rapid
overproduction
• Phosphates in marine
ecosystems precipitate out as
iron phosphate and form a sink
in the sediment

12. Marek this is a good place for you to
start maybe ? 

13. Some Types of Algal Blooms
 Green Algae
• Cladophora sericea - filamentous
,covers rocky areas and shorelines ,
can carry pathogens
 Blue –Green Algae (cyanobacteria)
• Microcystis aeruginosa colonial , float
on water surface – blooms is warm
fresh nutrient enriched water –
produces the toxin microcystin – kills
dogs ,fish and shellfish, toxic or
harmful to humans
• Aphanizomenon flos-aquae – can
produce endotoxins that are released
when the algae dies
• Ananaena sp. – filamentous , fix
nitrogen , can produce neurotoxins

14. Lake Erie 1960 – 2011 Case study
• 1960’s – Scientists recognize that Lake Erie was suffering from
eutrophication – and it was caused by human activities
• Algal blooms covered large areas of the lake during summer
months , decomposing algae on bathing beaches was
removed by bulldozers
• “Newspaper headlines announce Lake Erie is Dead”
• 1972 The Great Lakes Water Quality Agreement led to a
coordinated effort to reduce phosphorus – a 60% reduction in
loading to lake Erie
• Algal blooms of Aphanisomenon reported as decreasing in intensity
and number
• 1980’s – Arrival of Zebra Muscles - several years of improved
water clarity – species changes
• 1990’s – large summer blooms of Microcystis reappear
• 2003-2006- Algal blooms each summer of Microcystis
Lake Erie Oct 5 2011
The Big Question - Why is eutrophication of Lake Erie Microcystis Areuginosa
continuing to get worse since the 1972 Agreement?

15. Restoration of Eutrophic Lakes
• Chemical treatments – Copper
sulfate , calcium hydroxide or
calcium carbonate (lime) –
reduces chlorophyll a levels in
water but may be toxic to non
target organisms
• Oxygenation – oxygen helps fish
survive warm months and reduces
algae
• Dredging – effective but expensive
Restored wetlands in watersheds
Riparian Buffer Strips along
streams and estuaries

16. Restoration of Eutrophic Lakes ‐ Setbacks
• Eutrophic lakes tend to be
shallow and suffer from nutrient
loadings from point / non point
source pollution
• Lake sediments are polluted
with nutrient enriched soil
particles from shore erosion
• Phosphorus enriched particles
sink to the bottom and form a
pool of nutrients for rooted
plants – internal load

17. Riparian Buffer Strips
A well defined Riparian Buffer along a lake
Erie tributary
• May be Natural or engineered for restoration
• Represent both wetland and forest habitats for wildlife
• Herbaceous , shrubby plants and trees with strong roots
• Prevent Nutrients and Sediment from entering watershed
• Useful in intensively used agricultural areas with channeled water

18. Nitrogen and Phosphorus removal in Wetlands
• Wetlands act as a sponge , plants take up some nutrients
• Phosphorus complexes to soil
• Nitrogen is most effectively removed by denitrification
• Restored wetlands provide habitat for wildlife and attract
hundreds of birds
• Provide a space for naturalists and birdwatchers
St. Clair River Restoration

19. Mineral Fertilizers – Possible Solutions
• Fertilizer Plans for land owners –
soil testing and active planning
• Increased autumn/winter green
cover – to reduce leaching of
nutrients from bare soil
• Subsidize smart application
methods
• Develop new environmentally
sound fertilizers
• Tax mineral fertilizers , and lawn
fertilizers containing phosphate
• Funding for Wetland restoration
and Riparian strips

20. Success And On To The Next!
• In the 1970’s detergents contained 40%
phosphorus by weight
• The Great Lakes Water Quality Agreement
in 1972 banned phosphates in laundry
detergents
• July 1, 2010 New federal regulations on
dishwasher detergents and household
cleaners ban phosphates (0.5%) by weight
• This is expected to reduce anthropogenic
phosphorus loads by 10%
• This should be considered a success as we
move on to the next set of Issues

21. Phosphate Free Detergents Receive Bad Press
• News- National Post –
“Phosphate Bans Means
Streaky Dishes” – Jan 6,2011
• Complaints about dishwasher
detergents on online blogs –
short sighted and selfish
• Public needs to be educated
to think greener!
• Tip! – white vinegar or lemon
juice can be used in
dishwashers as a natural rinse
agent