Transcript Ground Water Pollutants - Effingham County Schools

Resources, Use, and Pollution
Essential Question: What is the
current and future status of our
clean water supply?
1
Water Resources
● Humans use water for:
● Drinking
● Agriculture
● Sanitation
● Travel
● Entertainment
● Essential for life – can go
3 weeks without food,
but only 3 days without
water
● Need freshwater! (not
salt water)
2
Water Resources: Distribution
● Water covers 2/3 of earth
● 97% of water on Earth is
salt water in ocean & seas
● 2.5% is Frozen freshwater
in glaciers
●
77% of all freshwater is
frozen
● 0.5% is available
freshwater
● on surface or in ground
3
Surface Water
● Surface H2O = lakes,
rivers, streams, wetlands
● Rivers especially important
for human civilizations
● River system: flowing
network of water that
forms from streams
● Amazon*, Mississippi, Nile
● Watershed: area of land
drained by a river
● Ex: Amazon River Basin
4
Water Cycle
● Water is a Renewable Resource - circulated in
the water (hydrologic) cycle:
● Evaporation (liquid → vapor in clouds)
● Condensation (vapor → liquid; in atmosphere)
● Precipitation
(rain, sleet, snow)
● Surface Runoff
(back to oceans)
● Note: can still deplete
or ruin it
5
Groundwater
● Most available
freshwater
exists
underground
● Groundwater:
water beneath
Earth’s surface
in soil & rock
Groundwater
● Aquifer: underground
formation that contains
lots of groundwater
● H2O is between rock,
sand, & gravel
● Upper boundary of
aquifer = water table
● Getting H2O depends on:
● Porosity: amount of space
b/w rock & soil (H2O is
stored in pores)
● Permeability: ability of
rock or soil to allow H2O
to flow
6
Groundwater
● How does water get to
aquifer?:
● Recharge zone: area
where H2O percolates
down
●
H2O must travel through
permeable layers of soil
●
Where aquifers are
sensitive to pollution!
● Well: hole that is dug or
drilled to reach
groundwater in aquifer
● Must be below water table, or
can dry up
7
Groundwater
● Groundwater
Problems:
● Overdrawing –
wells runs dry
● Pollution: oil,
chemicals, salt
water
● Pavement
prevents recharge
● Video:
http://www.youtube.com/watch?v=
uQRvN6MUajE
7
Different Types of Wells: Unconfined vs.
Confined (artesian)
Assignment: Draw On Paper & Color– Include All Words!
Water Use & Management
● Three major uses of H2O:
1. Agriculture: irrigation
2. Industries
3. Residential – drinking &
washing
Average person in US
uses 300 L (80 gallons) /
day
Water Use: Industrial
● Accounts for 19% of water
used in world
● Used to
● manufacture goods
● dispose of waste
● Generate power
● Cool power plants
●
Use & return water from
lake or river → Thermal
pollution??
Water Use: Residential Use
● Water from toilet,
dishwasher, bath, etc.
enters sewers & must be
treated
● Why Treat Water?
● Sewage: human
wastes, paper, soap,
detergent, food,
bacteria, etc.
● Three-step process
2.
3.
5.
Water Treatment:
1. Primary Treatment:
● Removes large solid objects (trash,
diapers) & sand/grit
2. Secondary Treatment:
● Removes organic matter & kills
microorganisms
● Oxygen is added for
decomposition
● Is disinfected with chlorine to kill
bacteria & viruses
3. Tertiary Treatment:
● = chemical or physical reactions to
remove pollutants (phosphates,
nitrates, salts, pesticides)
● Fluoride is added to drinking water
2.
3.
5.
Water Management
● Dam = structure built to
control river flow; creates a
reservoir = artificial lake
● Provides:
●
●
●
Drinking water
Irrigation water
Recreation
● Hydroelectric dam: uses
power of flowing water to
turn turbine to generate
electricity
● Problems with dams:
flooding; prevents animal
migration; pollution
Ways to Conserve Water:
● In Agriculture:
● Drip irrigation = water crops
directly & little at a time
● In Industry:
● Recycle & reuse wastewater
● In Residential:
● Shorter & cooler showers
● Low-flow toilets
● Aerators in faucets
● Wash only full loads
Ways to Conserve Water:
● Future Solutions to Water
Availability Issues:
1. Desalination = process of removing salt from
ocean water
● Expensive b/c of power requirements
2. Towing Icebergs? - research says too costly
3. Cloud Seeding - silver iodide crystals makes
water droplets form if cloud is present
● Used in China
Water Pollution
Water Pollution = when chemical, physical, or biological
agents get into water and lowers quality &
negatively affects organisms
Two Types:
1. Point-source Pollution = single source of pollution
is known (one factory, one sewage treatment plant)
2. Nonpoint-source Pollution = many different sources
over a wide area
-road chemicals
-agricultural
chemicals
Water Pollution
● Pollutants Include:
● Pathogens (bacteria, viruses, worms)
● Organic matter (feces, food waste, bodies)
● Chemicals (pesticides, oil, plastics, etc.)
● Heavy metals (lead, mercury, arsenic)
● Thermal pollution: Lowered water quality due to
change in water temperature (influx of hot water)
● lowers levels of dissolved oxygen & can cause large fish kills
● Occurs next to power plants & factories
Water Pollution cont.
● Eutrophication: accumulation of nutrients in a lake or
pond – natural process happens over time
● Artificial Eutrophication: increased amounts of
nitrogen & phosphorus due to fertilizers
● speeds up plant growth and eventually choke the water of
all of its animal life
Ground Water & Ocean Pollution
● Ground Water
Pollutants:
● Surface water pollution
● Leaky storage tanks
(gas, septic, chemicals)
● Landfills
● Difficult/ impossible to
clean up
● Ocean Pollutants:
● Land runoff
● Oil spills
● Beach trash
Water Pollution & Ecosystems
• Biomagnification = build up of
pollutants at higher levels of
the food chain
• Examples: DDT enters body of
zooplankton, a hundred of
these organisms are eaten by a
small fish, a hundred of these
fish are eaten by a bigger fish,
an eagle eats ten of these big
fish, the concentration of DDT
is magnified in the eagle
• Enters food chain → humans
Water Regulation
●
Clean Water Act (1972)
●
●
Set goals for clean water; required metals to be
removed from wastewater
Other laws:
●
●
●
Marine Protection, Research, & Sanctuaries Act
(1972; 1988) – controlled dumping of sewage & toxic
waste into water
Safe Drinking Water Act (1975, 1996) – protects
groundwater; standards for water quality
Oil Pollution Act (1990) – all oil tankers must be
double-hulled by 2015