water pollution a selective demonstration

1. WATER POLLUTION
APES
Moberg

2. A water pollutant is any
substance that decreases the
quality of water

3. Only 3% of all water on earth is
freshwater
• As pollution of
freshwater increases,
the amount of usable
freshwater decreases.
• The primary water
pollution problem in
the world is the lack of
disease free drinking
water

4. Many types of pollutants can
enter our waterways
• Common pollutants
include
– Acid mine drainage
– Agricultural and urban
runoff (animal waste,
nutrients, pesticides and
herbicides)
– Sewage
– sediments
– Heat (thermal pollution)
– Heavy metals
– Oil and gasoline
– Leachate from landfills

5. Two major classes of pollutants
• POINT SOURCE
– Can be traced to their
single, stationary source
such as a pipe
– Sewage spills from a
treatment plant, dumping
from cruise ship or septic
tank are point sources
• NON POINT SOURCE
– Cannot be traced to a
specific stationary source;
but is diffuse and mobile
– Urban and agricultural
Runoff are non-point
sources

6. Practice question
• Of the following which is the best
example of a point source of water
pollution?
a) Factory effluent
b) Storm water
c) Acid precipitation
d) Agricultural run off
e) Residential pesticide runoff

7. Water pollutant: RAW
SEWAGE
• Sewage is the waste (used)
water from residential and
commercial buildings. It is a
mixture of various substances
• Sewage can enter
groundwater via leaks from
underground septic tanks in
rural areas
• Untreated sewage can enter
surface water with storm
water runoff during heavy
rains in urban areas when
treatment plants become
overwhelmed
• Sewage carries
pathogens such as
viruses and bacteria;
excessive nutrients such
as NITRATES and
PHOSPHATES; fats, oils
and grease; prescription
drugs to stream water
• Sewage pollution also
increases total dissolved
solids (sediments), fecal
coliform bacteria and
heavy metals

8. Table 12.1

9. SEWAGE REGULATIONS (Clean Water
Act)
Laws typically have limits of intestinal bacteria
that can be in surface waters. These pathogens
get into aquatic systems through untreated
sewage or overwhelmed systems in storm water
runoff.
US EPA regulations for swimming waters:
Geometric mean <200 fecal coliforms/100ml
US EPA regulations for drinking water:
Maximum contaminant level: 1 fecal coliform
cell/100mL

10. WHY IS SEWAGE A PROBLEM?
HEALTH consequence (social impact of sewage
pollution)
Bacteria and viruses present in sewage effluent
→ bathers are at increased risk of contracting
illnesses spread through feces such as cholera,
Hepatitis A, typhoid fever, diarrhea and intestinal
distress (cramps, vomiting), ear infections
Shellfish grown in sewage contaminated waters
may cause food poisoning
→ mussels and oysters can accumulate
human pathogens through their filter feeding
apparatus.

11. WHY IS SEWAGE A PROBLEM?
ECONOMIC consequence
Sewage debris (e.g. condoms, diapers, tampons,
rags) accumulate on beaches
• → loss of tourism dollars due to beach closure
and lowered aesthetic appeal
• → expense of cleaning up beaches
• → ALSO closure of shellfish beds due to
sewage contamination or sewage induced
HABs (harmful algal bloom)/ hypoxia can lead
to high loss of income and closure of
businesses.

12. WHY IS SEWAGE A PROBLEM?
ENVIRONMENTAL consequence
Sewage is primarily organic in nature and subject
to bacterial decay. It increases BOD and nutrients
in the water, ultimately leading to HYPOXIA and
lower biodiversity
Bacterial decay also involves the breakdown of
proteins and other nitrogenous compounds
releasing ammonia and hydrogen sulfide gas
Even low concentrations result in massive fish kills
ALSO suspended solids in sewage may smother
river and sea beds, preventing respiration of
benthic (bottom dwelling) flora and fauna, again
lowering biodiversity

13. Preventing sewage pollution is
more effective than trying to
remove it
1. Using separate storm water
and sewage sewer systems
help to prevent overflow
during a storm.
2. Maintaining sewer lines by
routinely checking and
replacing aging infrastructure
prevents leaks into
groundwater
3. Though not sewage, Picking up pet
waste and providing baggies for
waste in public areas prevent animal
waste from entering surface water
through storm drains. Pet waste carries
many of the same pathogens as
human feces

14. Animal waste is a huge problem
with industrial-sized livestock
farms called CAFO: Concentrated
Animal Feeding Operations
4. Farms with hundreds of animals
should dispose of the manure
in waste lagoons (retention
ponds) FAR from surface water
bodies, such as rivers. Lining
the ponds with plastic and
impermeable clay will prevent
pollution of groundwater
5. Manure could also be
harvested and sold for use as
biofuel or soil fertilizer

15. Water pollutant: nutrients
• Nutrients, such as N and P, enter
waterways through non-point
source runoff from manure,
fertilizers and septic tanks
(sewage) or treated wastewater
• STEPS TO EUTROPHICATION:
– Nutrients cause an immediate
increase in algal growth; plants grow,
die and are decomposed by bacteria.
This is called eutrophication
– Bacteria consume a lot of
dissolved oxygen in
decomposing dead plant
material causing HYPOXIA,
– Low oxygen levels cause
macroinvertebrate and fish kills
because they cannot respire

16. Eutrophication causes DEAD
ZONES in the Gulf of Mexico

17. PRACTICE QUESTION
• Which of the following will result in
accelerated eutrophication when
introduced into streams, lakes and
bays?
a) Bacteria and viruses
b) Pesticides
c) Herbicides
d) Phosphates
e) Acid wastes and salts

18. Oxygen sag curve shows the effect
of eutrophication in a stream
• THE CAUSE: Sewage
(immediately) and nutrient
pollution (after the algae die
) which increase the BOD
• THE EFFECT:
Decomposing bacteria then
decrease the DO levels in
the stream (hypoxia)
• THE CONSEQUENCE:
lower biodiversity since
many organisms cannot
respire, increased odors and
even coral bleaching

19. Other impacts of nutrient
pollution
REDUCED LIGHT PENETRATION
High concentrations of algae in
surface water increase the
turbidity, reducing the amount of
light reaching bottom dwellers,
reducing photosynthesis and
productivity
Particularly a problem for coral
which are typically found in
Oligotrophic water with good
light penetration.
Eutrophication reduces amount of
photosynthesis of the algae living
in coral and causes coral
bleaching

20. Other impacts of nutrient
pollution
• CHANGE IN SPECIES
COMPOSITION
As nutrient tolerant plants and
algal species proliferate, they
displace more sensitive species
and change the composition of
the community. A survey of the
macroinvertebrates in the
stream can indicate pollution if
only the most tolerant species
are found there. Mayflies,
stoneflies and caddisflies can
only survive in clean water

21. More impacts of nutrient loading
• HEALTH IMPACT
Drinking groundwater or
surface water with nitrate
contamination results in
BLUE BABY syndrome
which is potentially fatal to
infants under 6 months old.
Nitrates are converted to
nitrites in the stomach and
lead to methemoglobin, a
blood disorder aka blue
baby syndrome
The Clean Water Act does not allow
Nitrate levels above 10ppm for
drinking water

22. Cultural eutrophication is also
caused by phosphates, from
sources shown below.

23. PRACTICE QUESTION
• Identify TWO ways
agriculture adds
nitrogen to waterways
today.
– A) pesticides and manure
– B) fertilizers and manure
– C) sediments and
herbicides
– D) eutrophication and
animal waste

24. Preventing nutrient pollution
1. Wetland and riparian plant communities can filter
nutrients from farms or urban runoff (carrying fertilizer
or pet waste). Plants, algae, denitrifying bacteria
directly uptake nutrients. Some can be adsorbed by
wetland soils, then used by plants or bacteria.
2. Building more wastewater treatment plants or
composting toilets for individual buildings also reduces
sewage load in waterways. Small centralized plants
reduce the need for many septic tanks in rural areas,
each with the potential to leak and contaminate the
groundwater supply.

25. Water pollutant: sediment
1. Construction, road building, logging, mining and soil
erosion from agriculture can cause large quantities of
sediment (sand, clay, silt) to enter the water. Removing
trees cause an increase in erosion since roots are not
there to anchor soil. More sediment washes into streams.
EFFECTS:
• Sediment buildup reduces the ability of waterways to
control floods by lowering the capacity to store water and
additional sediments from runoff
• Stream turbidity increases, blocking sunlight, lowering
primary productivity (especially true for coral reefs!)
• Sediments are darker colored than the water and so
cause heating by absorbing additional sunlight
• Sediments can lower biodiversity by blocking fish gills
and burying benthic organisms, suffocating them

26. Preventing sediment pollution
• Wetlands and
sediment
fences can
trap about 80
to 90% of
sediment from
runoff and
construction.
The roots of
plants can
prevent
erosion or trap
sediments
from land
sources.

27. Water pollutant: salt, sand,
petrochemicals and heavy metals
from roads
Zinc and copper are released
from cars: brakes release
copper, while tire wear
releases zinc. Motor oil
leaks, salt used to de-ice
roads in winter also
contribute to water pollution
through urban runoff into
a storm drain.
Petrochemicals like benzene,
are known carcinogens and
enter the water from
storage tank leaks

28. Water pollutant: leachate
• Formed when waste in
a landfill mixes with
water percolating down
from the surface or with
groundwater moving
through the site.
Leachate enters the
groundwater under
the landfill
• Leachate is a mixture
including heavy metals
(such as lead,
cadmium, iron, mercury
from batteries and
electronics) bacteria,
nitrates, sulfates and
hazardous chemicals
including paints,
solvents, pesticides

29. leachate
• Leachate pollution can
be prevented in a
SANITARY LANDFILL,
lined with multiple
barriers such as
impermeable clay and
plastic; drainage pipes
to collect leachate at he
bottom of the liner; plus
monitoring wells to test
soil and water table for
leakages

30. SUPERFUND SITES –hazardous
chemical waste that threatens
water
• Superfund is EPA’s
program to prevent,
identify, investigate and
clean up hazardous
waste sites throughout
the USA. Groundwater
can be pumped and
treated, then returned
• Known as the
CERCLA policy

31. Water pollutant: heat (Thermal)
pollution
• Thermal pollution can occur when
shade trees are removed from along
waterways or
• when water is heated as it runs over
hot impervious surfaces such as roads
and parking lots.
• Also from warm water discharges from
cooling towers or power generating
equipment.
• Dark colored sediments entering
through urban or agricultural runoff
absorbs more sunlight and creates
heat in the water
• If the temperature
exceeds the range
of tolerance for
aquatic organisms
they become
stressed and may
die as enzymes
denature. Also,
warm water holds
less oxygen so
hypoxia may
occur

32. Water pollutant: ACID MINE
DRAINAGE (AMD)
• AMD is a nonpoint source pollutant
which can occur during or after mining
has ended
• Coal and gold mines contain sulfur
bearing rocks that when mixed with
rainwater and air, creates sulfuric acid.
This acid leaches heavy metals such
as Fe, Al, Pb, Hg, arsenic and
cadmium from the surrounding soil,
after which it enters the groundwater or
surface waters.
• Heavy metals are neurotoxins. They
can lead to lower mental abilities.
Metals such as Hg can bioaccumulate
and biomagnify up the food chain

33. Acid mine drainage increases the
acidity, turbidity and conductivity of
the stream

34. Decreasing pH causes more
metals to leach from soil and enter
the stream
• pH is a measure of the
concentration of H+ ions in the
stream. Each whole pH value
below 7 is ten times more acidic
than the next higher value
• The acid is often sulfuric acid
formed in coal and metal mines
when air, water and sulfur
bearing rocks combine.
• Even good metals such as
Calcium and Magnesium will
leach from the soil, depriving
plants of these nutrients, lowering
photosynthesis.

35. A pH around neutral is optimum
for most organisms. Lower than 5
decreases biodiversity

36. Preventing acid mine drainage or
at least, mitigating the acidity
1. Adding limestone
(carbonate) to
contaminated water
can increase the pH,
neutralizing the acid.
2. Keeping the mine
tailings covered with
plastic can prevent
exposure to water and
avoids creating an
acid in the first place

37. LEAD and other heavy metals
SOURCES:
• unlined landfills
containing batteries
or coal ash;
• household chemicals
such as paint;
• plumbing;
• mining refuse/tailings
• industrial discharges
• IMPACTS:
– Can cause cancer
– Disrupts learning
and memory
– Is bioaccumulated
and biomagnified up
the food chain
Lead levels can be lowered
by using bacterial
bioremediation or chelating
with chemical polymers

38. Pollution: PESTICIDES
Pesticide pollution come from
agricultural and urban areas,
especially golf courses and
farms. Pesticides drift or
enter water through run off
They include insecticides (for
bugs), herbicides (weeds) and
fungicides (mold, spores) and
rodenticides (mice)
However, 1/4th of all pesticides
in the US is for use in homes,
gardens, lawns, parks,
swimming pools and golf
courses.

39. How pesticides become non point
pollutants
Pesticides may drift on the
wind, enter surface or
groundwater in runoff. Many
chemical pesticides are
persistent, meaning they
take a long time to
decompose. Meanwhile,
they are still toxic.
Many pesticides kill by
interfering with the
production of ATP and some
by preventing Ach
neurotransmitter reuptake

40. Water pollutant: Pesticides and
Herbicides
• Pesticides and herbicides can kill or deform (cause lesions
and tumors) fish directly and are linked to cancer and birth
defects in humans, if ingested in contaminated fish or
shellfish
• Ecological effects of pesticides extend to entire
ecosystems, threatening biodiversity:
– Pesticides can bioaccumulate and biomagnify in the fatty tissue of
fish, affecting the entire food chain and threatening fisheries.
– Insecticides can also cause a disruption in predator-prey
relationships when macro invertebrates are targeted. This results in
lower biodiversity in the stream and can threaten top predators such
as eagles

41. Bioaccumulation and
biomagnification and dispersal
• DDT and other organochlorines
are broad spectrum and persistent,
remaining toxic for a long time
• In the environment, they adhere to
soil particles, are stored in fatty
tissue of plants and animals and
magnify up the food chain.
Organisms that travel great
distances can spread pesticides to
far-flung areas. Global trade
between countries where pesticide
use is still permitted can also
spread pesticide coated products

42. CASE STUDY: DDT and
Palos Verdes, CA
• DDT is present in the
Palos Verdes Shelf
sediments about 2km
offshore largely as a
result of wastewater
discharges to local
sewers from the
Montrose Chemical
plant in Torrance from
1947 to 1983.
• High levels of DDT
are found in bottom
feeding fish (such as
the White croaker)
from the area and
fish-eating birds
such as eagles. The
DDT levels do not
pose a risk for
swimming at the
surface.

43. Herbicides like ATRAZINE
cause intersexuality in fish
• This herbicide, as well as,
birth control pills flushed
down the toilet or excreted
in urine, act as estrogen
hormones in fish.
• They are termed HAAs or
hormonally active agents,
also known as
ENDOCRINE
DISRUPTORS. They are
known to feminize fish and
frogs

44. Sample question

45. Preventing pesticide pollution
1. Farms should be placed
farther away from surface
water bodies to limit the
amount of agricultural runoff
and drift from aerial spraying
that enters streams.
2. Many pesticides dissipate
rapidly in soil as microbes
consume the pesticide as a
source of carbon, breaking
down the pesticide before it
can enter the water
(bioremediation). The natural
riparian zone between
farmland and stream could
act as buffer zone.
3. Reduce the amount
of pesticide used,
turning to IPM
(biological and
physical control)
instead
4. Promote organic
farming which, by
definition, does not
use pesticides
5. Require training and
licensing in the
proper use of
pesticides

46. EXAMPLES OF BIOLOGICAL
CONTROL AGENTS
• Parasitoid wasps, flies or
weevils
• Bacterial toxin for
caterpillars and some fly
larvae, such as that
produced by BT (Bacillus
thuringiensis) a soil
bacterium
Biological controls reduce
pests via a feeding
relationship

47. PRACTICE QUESTION
• An APES class was doing a field study of effluent
water entering a river through a large drainage
pipe from a large building. Which of the following
would be a logical conclusion based on their
observations?
• A) the students observed algae covering a small
area of the river a mile away and concluded that
the factory was dumping hot water into the river as
algae grow profusely in warm water
• B) the students detected measurable amounts of
coliform bacteria in the river near the pipe and
concluded that the building could be a meat
packing plant

48. Methylmercury
• Natural sources of
mercury occur in rocks
and from volcanic
eruptions.
• Human input of mercury
is from coal burning,
waste incineration and
processing metals like
gold. Deposition from
the atmosphere into
surface water occurs
during precipitation.
• Inorganic mercury enters
water where bacteria
then turns it into methyl
mercury, an organic form
that readily passes
through cell membranes
into plants, animals and
biomagnifies up the food
chain.
• Mercury is a neurotoxin-
it damages brain cells,
lowering IQ and
increased learning
disability

49. PCBs
• Polychlorinated
biphenols are oils used
in electric insulation on
transformer poles.
• Damage by weather
caused PCBs to leak
into soil, drift on the
wind or runoff into
surface water
• PCB biomagnifies
up the food chain
and are endocrine
disruptors, leading
to lower
reproductive rates
and low population
of fish and
amphibian species

50. PLASTIC
• Storm water runoff from land
brings trash, including plastic to
the ocean where they break
into smaller fragments but do
not biodegrade.
• Tiny plastic particles are
mistaken for food by fish,
marine mammals and birds
who swallow them and die from
blockages in the stomach,
starvation or choking or
poisoning from chemicals
adhered to the plastic

51. Water quality testing: an
indication of pollution
• Some tests, such as DO, can indicate
the presence of a pollutant. They may
not necessarily indicate the specific
nature of the pollutant but they are a
good start.
• The significance of each variable is
described on the left of the following
slides

52. WATER QUALITY
MITIGATION: AGRICULTURE
Buffer strips can be hay bales,
silt fences or riparian
vegetation along the river
banks
Conservation tillage or no tilling
or plowing of soil reduces
amount of loose sediment
Creating runoff RETENTION
ponds to divert water from the
fields to one spot where
specific wetland plants can
remove nutrients and
sediments

53. WATER QUALITY MITIGATION:
URBAN