Water Pollution and Eutrophication Pathogens Organic wastes Sediment Chemical pollutants Nutrients
Dec 18, 2015
In past ~ 40 yrs, reduction in:
toxic dischargespoint sources of Phosphorus
Still largely uncontrolled:sewage inputs of Nitrogennon-point source N & P
Eutrophication = nutrient over enrichment
Phosphorus freshwater
Nitrogen salt & brackish
Limiting nutrient: The one in shortest supply relative to demand. If you add more of that nutrient the plants/algae will grow
Gulf coast dead zone
Fish and large animals swim away from poor water, small things die
May be responsible for sharks coming inshore near TX, shark bites high this summer
ice
winter springwind
mixing, all same temp
heating faster than mixing
summerwarm water less dense, floats, need lots of wind to mix
Summer stratification
thermocline
dep
th (
m)
temperature (C)0 10 3020
0
10
30
20
region of rapid temp change
But…… point source controls of Phosphorus are in place.
Why would the central basin of Lake Erie be getting “over fertilized”?
What other conditions might contribute to the formation of a dead zone (it doesn’t happen every year)?
What might help stop dead zone formation?
What will happen if it isn’t stopped?
Harmful algal blooms in Oceans: Pfiesteria
Coast of Carolinas
Floating microrganisms that thrives in nutrient conditions
Highly toxic to fish and humans
Coral Reef overgrowth
Nutrients stimulate algae that cover coral\
Loose habitat and biodiversity
Loose economic benefits
PathogensDisease causing bacteria, viruses and other parasites
Waste from an infected person or animal deposited in water that contacts another person
Cholera: common in US in 1800s, present in places with poor sewage treatment, can also be in food
Current outbreak in Senegal:
The first case diagnosed on October 11, 400 dead
Emergency water treatment now in place
Street merchants banned from selling water, fruit juice and other foods
It is the first cholera epidemic in Senegal since 1997.
Typhoid fever: common in developing world, vaccine available, contact with water, person or food
Giardia: common in US, carried by many animals (beaver fever), water (while swimming or drinking untreated, touching surface with microbe)
E. coli: common in US, water or food born, may not be toxic but indicates recent fecal contamination, causes beach closing locally (Maumee Bay and Put-in-Bay), can come from farms or people
Avoid Disease
Don’t drink untreated water: -camping, boil or treat w/ iodine or bleach-don’t drink lake water while swimming-traveling in developing world, bottled H2O, boil, or treat
Wash hands frequently, don’t put them in your mouth after touching public surfaces of any kind