ENSC after midterm 2

About how much of U.S groundwater is contaminated

25%

water pollution

any physical or chemical change in water that adversely affects the health of humans and other organisms

what are the types of water pollution and its subcategories?

physical:

• sediment

• trash

• thermal pollution

chemical:

• sewage

• fertilizers

• chemicals

• metals

• radioactive materials

biological

• disease-causing pathogens

sediment pollution

sediments in water are suspended particles carried along by moving water, particles accumulate at the bottom of the lake

what is the most polluted river in the US

the new river, imperial county, CA

As BOD ( biological oxygen demand) increases

dissolved oxygen decreases

what are the three major environmental problems from sewage

1. contamination by pathogens like bacteria or viruses

2. enrichment: fertilization of a body of water by high levels nitrogen and phosphorus

3. increase in BOD

cryptosporidium

“hidden spore” transmitted readily by water systems the organism is named after the ease which it can escape detection. it is a serious threat to public health

rotavirus

the leading single cause of severe diarrhea among infants and young children, and is one of the several viruses that cause infections like the stomach flu

BOD

the oxygen-depleting potential of a contaminated water

explain BOD

water containing a lot of organic matter (sewage) can lower the oxygen level of a lake or stream

1. microorganisms feed on the organic matter, consuming oxygen in the process

2. as the microbial population builds up, oxygen levels can fall enough to harm other aquatic organisms ( fish)

eutrophication

the enrichment of a surface water body with nutrients ( nitrogen and phosphorus)

fertilizer pollution

fertilizer in runoff or drainage can contain high levels of nitrogen and phosphorus

• these nutrients can cause rapid growth of algae and plants, high BOD and loss of oxygen

oligiotrophic

low nutrients

• good light penetration

• high dissolved oxygen

• deep waters

• low algal growth

organic compounds

chemicals that contain carbon atoms (sugars, amino acids, pesticides)

inorganic chemicals

contaminants that contain elements other than carbon, they don’t degrade easily ( lead, mercury- which can cause mental impairments)

Mercury is coming out of smoke regions due to burning coal and into water areas

And accumulating on the top predators of the sea (bio accumulating)

thermal pollution

occurs when heated water produced during industrial processes is released into waterways

warm water holds…

less dissolved oxygen than cold water

point source pollution

water pollution that can be traced to a specific origin

• if there is a pipe, you can find specifically that is the origin of pollution

non-point source pollution

pollutants that enter bodies of water over large areas rather than being concentrated at a single point of entry

ex: agricultural fields running throughout the whole soil area

what is the leading source of water pollution in the US

agriculture!!

municipal sewage treatment

primary treatment- removing suspended and floating particles by mechanical processes

secondary treatment- treating wastewater biologically to decompose suspended organic material, reduces BOD

sewage sludge

solids remaining after primary and secondary municipal sewage treatment has been completed

tertiary treatment

advanced wastewater treatment methods that are sometimes employed after primary and secondary municipal treatments (reduces phosphorus and nitrogen)

which municipal sewage treatment method is the most effective

secondary

• removes 95% of the suspended solids and BOD

• removes most of the pathogens

• doesn’t remove plant nutrients, metals, or salts

what are important water pollution regulations

clean water act: established standards for wastewater that is to be discharged into the environment

safe drinking water act: established standards for maximum contaminant levels, gives EPA enforcement power to guarantee safe public water supplies