Soil and Land Pollution RAD Guide (Ch.18-19)

April 19, 2023

What are 2 ways that exposed rock can be weathered?

1. Mechanically

• Example: waves on a cliff

2. Chemical

• Example: rusting

What is bedrock? Why is it important to soil formation?• Bedrock: igneous, metamorphic, and

sedimentary rock of lithosphere that may exist as mountains, cliffs, or low-lying plains

• Supplies material needed to build soil

Describe what soil is and how is formed. • Soil: mixture of mineral particles, air,

H2O, & living and decaying organisms

1. Outer layer of bedrock weathers (cracks and holes)

2. Cracks reach deeper & outer layer becomes broken into small particles

– Burrowing animals & plant roots break down bedrock & aerate soil

VOCAB: parent

rock

Describe what a soil profile is and what 4 distinct layers form. • Soil profile: a vertical cross section of soil

from the ground surface down to the bedrock

• A Horizon: topsoil

• B Horizon: subsoil

• C Horizon: parent rock

• R Horizon: bedrock

Describe the 3 major soil textures.

1. Sandy: enables soil to drain well but dries out quickly; largest mineral size

2. Clay: flat and traps H2O, preventing H2O drainage; smallest mineral size

3. Loam: mixture of sizes for good drainage and moisture for plants; medium mineral size

Describe the interaction of soil & climate.

• Desert: small soil profile; large particles

• Grasslands: thicker soil profile; faster weathering of rock

• Tropical: very thick soil profile; very fragile soil because of so much rain; a lot of clay in the subsoil

What are the major causes of erosion?

• Wind and running water

What causes soil loss & desertification? What % has undergone desertification?

• Overgrazing, deforestation, & poor irrigation and cultivation

• 30%

How much topsoil is lost to water & wind erosion?

• 2.5 billion tons lost to water

• 1.5 billion tons lost to wind

• TOTAL=4 billion metric tons!

Describe the 4 types of soil conservation & land management.1. Strip-cropping: farmland plowed so

plowed strips separated by planted strips

2. Contour Farming: plowing along a slope instead of across it; furrows collect H2O which reduces erosion

3. Terracing: series of platforms (terraces) are built into the slope; separated by vertical steps

4. Shelter belts: rows of trees planted along outer edges of field

How do we define solid wastes?

• All garbage, refuse, & sludge products from agriculture, forestry, mining, and municipalities–Examples: garbage trash

junk sewage scrap refuse

Describe how garbage disposal has changed over the years. • Hunter-gatherers: left it and moved on

• Athens, Greece 500BCE: trashed dumped outside of city walls– Rest of Europe dumped in the streets

• NYC/NJ 1892-1900CE: garbage loaded onto ships and dumped in Atlantic Ocean

• Now we use landfills

What is a landfill? How much garbage is dumped there?

• Site where wastes are disposed of by burying them

• 70%

Why are open landfills no longer allowed in the US?

• It supported large populations of rats, insects, etc.

• Foul odor and disease

Describe what a sanitary landfill is & identify 2 problems.• Wastes are spread in layers ~3m deep &

compacted by bulldozers

• Soil spread on top of refuse & compacted

• Repeated until garbage reaches certain heights

1. Methane produced

2. Leaching of toxic substances

What are hazardous wastes?

• Solid, liquid, or gaseous wastes that are potentially harmful to humans and environment

• Love Canal, NY: Town built next to old chemical plant– Steel containers holding waste leaked– Birth defects and cancer affected the people– Government relocated them ($190 million)

Name 6 types of hazardous waste.

1. Reactive Waste: can explode 2. Corrosive Waste: can eat through steel,

clothing, and burn skin3. Ignitable Waste: can burn at low temp;

toxic fumes when lit4. Toxic Waste: chemicals that are poisonous

to people5. Radioactive Waste: gives off radiation

(given off when mining Uranium)6. Medical Waste: old medicine, medicine

containers, lab equipment and specimens

Identify & explain 4 methods for reducing volume of waste.

1. Recycle: paper, plastic, aluminum, glass, etc.

2. Reuse: cloth diapers

3. Biodegradable: leaves, grass clippings, food waste*, composting

4. Repair: old appliances, shoes, cars

Name 6 ways of disposing of hazardous waste.1. Waste exchange: use haz. waste in

production of other materials

2. Deep Well Injection: inject waste into porous rock under water table; LIQUID

3. Secure Chem. Landfill: waste is stored on nonporous bedrock

• pipes to monitor and collect leaks; cover with clay

4. Controlled Incineration: burn waste at high temp

• Expensive

5. Biological and Chemical Treatment Plants: turn harmful things into harmless

6. Radioactive Waste Disposal: put in H2O or bury underground

What does EPA stand for?

• EPA = Environmental Protection Agency

• Established in 1970

Briefly describe Superfund.

• Law designed to protect communities from dangers of hazardous wastes

• CERCLA (1980): got $9 billion dollars to implement

What are some countries doing to combat high cost of disposal?

• Ship waste to developing nations and leave it there

–Examples: West Africa and Zimbabwe