1. Ecosystem Services
ALCOS #9

2. How do we purify our drinking water?

3. Why do we purify our drinking water?
The removal of contaminants from raw water to produce drinking water that is pure enough for human consumption or for industrial use.
Substances that are removed during the process include parasites, bacteria, algae, viruses, fungi, minerals (including toxic metals such as Lead, Copper etc.), and man-made chemical pollutants.
Many environmental and cost considerations affect the location and design of water purification plants.
Groundwater is cheaper to treat, but aquifers usually have limited output and can take thousands of years to recharge
It is not possible to tell whether water is safe to drink just by looking at it.

4. Coagulation and flocculation are often the first steps in water treatment. Chemicals with a positive charge are added to the water. The positive charge of these chemicals neutralizes the negative charge of dirt and other dissolved particles in the water. When this occurs, the particles bind with the chemicals and form larger particles, called floc.
Sedimentation During sedimentation, floc settles to the bottom of the water supply, due to its weight. This settling process is called sedimentation.
Filtration Once the floc has settled to the bottom of the water supply, the clear water on top will pass through filters of varying compositions (sand, gravel, and charcoal) and pore sizes, in order to remove dissolved particles, such as dust, parasites, bacteria, viruses, and chemicals.
Disinfection After the water has been filtered, a disinfectant (for example, chlorine, chloramine) may be added in order to kill any remaining parasites, bacteria, and viruses, and to protect the water from germs when it is piped to homes and businesses.

5. How does the environment recycle nutrients?
The nutrient cycle describes how nutrients move from the physical environment into living organisms, and subsequently are recycled back to the physical environment. This movement of nutrients, essential for life, from the environment into plants and animals and back again, is a vital function of the ecology of any region
large parts of humankind influence the nutrient cycle in such a way that we remove nutrients from the land and discharge them into aquatic environments.

7. How Humans Influence Nutrient Cycles?
With harvesting crops, nutrients are removed from the soil.
Agriculture speeds up land erosion, because disking and tilling disturb and expose the soil — so more nutrients drain away with runoff
One problem with human alterations to natural nutrient cycle is that we are extracting nutrients from the soil, and discharging them essentially in aquatic environment – this leads to a huge biological imbalance with severe consequences.

8. Soil Erosion

9. How do humans affect soil erosion?
Soil is a non-renewable resource that once it is eroded it is not renewed. 
Soil erosion is the permanent change of the main characteristics of soil that could see it lose its fertility, pH, color, humus content or structure. 
Soil erosion occurs naturally by wind or harsh climatic conditions but human activities include overgrazing, overcropping and deforestation.

10. How do humans affect soil erosion?
Soil is a non-renewable resource that once it is eroded it is not renewed.  Soil erosion is the permanent change of the main characteristics of soil that could see it lose its fertility, pH, color, humus content or structure.  Soil erosion occurs naturally by wind or harsh climatic conditions but human activities include overgrazing, overcropping and deforestation.
Overgrazing occurs when farmers stock too many animals such as sheep, cattle or goats on their land.  The animals damage the soil surface by eating the vegetation and either digging into wet soil or compacting dry soil with their hooves.  This can prevent grass growing and slow down the percolation of water through the soil.
Overcropping is when the land is being continuously under cultivation and is not allowed to lie fallow between crops.  This constant farming of the land reduces the soils ability to produce valuable humus for soil fertility as it is constantly being ploughed or stripped for crop growth. 
Deforestation is the cutting down of large areas of forests leaving an open, exposed landscape.  Deforestation occurs for many reasons such as the sale of wood, charcoal or as a source of fuel, while cleared land is used as pasture for livestock, plantations of commodities, and settlements.

11. How do humans prevent soil erosion?
Silt fencing and wattle (hay inside mesh netting) during construction.

12. Retaining walls

13. Planting grass, vegetation, trees.
Hydro seeding

14. Toxic waste’s affect our environment
Acid rain can kill trees, vegetation, and organisms.
Health effects on humans such as asthma and lung damage.
Dead zones in lakes and oceans where nutrients and oxygen are depleted.
Harm drinking water for all organisms on the Earth, including humans.
Damage wildlife and the ecosystems in which they live.

15. How do we prevent toxic wastes in our environment?
Do not pour chemicals down the drain, outside on the ground, nor in rivers/ bodies of water.
Be conservative of water, gas, and electricity usage.

16. Oil Spills
Our increasing reliance on oil and petroleum products has resulted in multiple marine oil spills at offshore drilling sites and from transport vessels.
Oil spills are detrimental to the health of marine environments and marine organisms.

17. Have we had a major toxic spill in the South?
BP Oil Spill

18. In the BP Oil Spill, more than 200 million gallons of crude oil was pumped into the Gulf of Mexico for a total of 87 days, making it the biggest oil spill in U.S. history.
16,000 total miles of coastline have been affected, including the coasts of Texas, Louisiana, Mississippi, Alabama, and Florida.
Even though the gushing well was capped in July 2010, oil is still washing up on shores, which might cause long-term damages to people living in the area.
The initial oil rig explosion killed 11 people and injured 17 others.

19. Responders used 5.5 million feet of boom, a barrier placed in water, to collect and absorb oil.
Of the 400 miles of Louisiana coast, approximately 125 miles have been polluted by the oil spill.
A method of treating the oil spill is "in-situ burning" or burning oil in a contained area on the surface of the water, which has negative effects on the environment.
Over 8,000 animals (birds, turtles, mammals) were reported dead just 6 months after the spill, including many that were already on the endangered species list.
BP is responsible for close to $40 billion in fines, cleanup costs, and settlements as a result of the oil spill in 2010, with an additional $16 billion due to the Clean Water Act.
Over 30,000 people responded to the spill in the Gulf Coast working to collect oil, clean up beaches, take care of animals and perform various other duties. As of 2012, the Gulf was still polluted with oil.