Chapter 19

Land Pollution

Solid Wastes- Solid waste is defined as garbage, refuse, and sludge products

from agriculture, forestry, mining, and municipalities.- First garbage dumps were in Athens Greece, around 500 BC- BUT for the most part, the world just dumped their garbage in

the streets- In 1892, New York began better sanitary changes, but wasn’t

until 1900 that garbage began to be collected.- Typically it was loaded onto barges and dumped into the ocean- Ironically it wasn’t until, after many years, swimmers observed

mattresses and dead animals floating past them.- Landfills were the solution (a site where wastes are disposed of

by burying them).

Landfills- As populations grew, more and more garbage is produced…where do we put

it all?- Open dumping landfills was the first step (not very pretty)

- Supported large populations of rats, insects, and other unwanted organisms

- Smelled- Rain washed pollutants into the soil and rivers or leached underground- And basically a huge eye sore

- “sanitary landfills” became the solution- The idea: wastes are spread in layers about 3 meters deep, compacted by

bulldozers, about 15 cm of soil is spread on top, and compacted again.- This continues until a maximum height is reached where a last layer of soil

is placed, grass and trees are planted.

“sanitary”, not so “sanitary”- Methane gas is produced by the decay of the materials

(can be harnessed and used if built correctly)- Leaching is still an issue, even with the best designs.

Hazardous Waste- Solids, liquids, or gaseous wastes that ae potentially

harmful to humans and the environment, even in low concentrations.

- Examples of effects….(see page 309 for more)

190 million in relief (in 1970)

3600 died, 200,000 injured

Classifications of Hazardous Materials- Reactive Waste: waste that can explode- Corrosive waste: waste that can eat through steel and other

materials.- Ignitable waste: can burst into flames at relatively low

temperatures- Toxic waste: poisonous to people- Radioactive waste: radiation givin off by mining these materials,

medical, and nuclear- Medical waste: old medicines, medicine containers, lab

equipment, and lab specimens.- Hazardous home waste: stuff in your home that is hazardous

- Ammonia, bleaches, toilet cleaners, oven cleaners, disinfectants, furniture polish….just to name a few.

Top soil erosion- Soil can become unsuitable for planting if:

- Overgrazing, deforestation, poor irrigation, and cultivation are practiced or mis-managed

- Desertification: type of land degradation in which a relatively dry land region becomes increasingly arid, typically losing its bodies of water as well as vegetation and wildlife. It is caused by a variety of factors, such as climate change and human activities.- It is estimated that 30 percent of the earth’s land is or has undergone

desertification- 1/3 of all farmland in the US is threatened by erosion- 2.5 billion metric tons of topsoil is washed away by water each year- 1.5 billion metric tons loss to wind erosion- Largest concern around the world is soil loss due to water

Effective, but costly and time consuming, less destructive methods:- Strip-cropping: plowed so that plowed strips are separated

by planted strips. Always having at least part of the land covered by planted crops.

- Contour farming: plowing along a slope, instead of across it. This prevents water from eroding, and aids in collecting excess.

- Terracing: platforms are built into the slope or hill. Each is separated by a vertical step.

- Shelter Beds: rows or trees are planted on outside edge, providing wind breaks.

Controlling pollution on the land- The best way to eliminate wastes is not to produce them, however,

since this seems to be impossible, we need to rely on the three R’s\

- Biodegradable: substances decompose easily and enrich the soil. Example: compost pile

- Hazardous waste- most believe there is no safe way to dispose of this.

- Waste exchange: taking one person’s/company’s waste and moving it to another who can use it in the production of their goods.

- Deep-Well injection: liquid wastes are pumped into deep porous rocks through lined pipes, located well beneath the drinking-water aquifers…nothing bad can happen with this one huh?

- Secure chemical landfill: made in areas with non-porous bedrock, to prevent leaching, covered with clay to keep water out.

- Controlled incineration: burning of wastes at extremely high temps. 540-1600 degrees Celsius. Very expensive.

- Chemical and biological treatment plants: hazardous to non hazardous by using treatment plants, neutralizing the hazardous parts and then disposed of.

- Radioactive waste: placed in water, sealed in stainless steel tanks, encased in concrete, then buried deep underground.

Legislation- CERCLA : Comprehensive Environmental Response,

Compensation, and Liability Act of 1980. Nicknamed “superfund”

- Obligations:- Cleaning up hazardous waste dumps- Make polluters pay for it- Develop a national priorities list (most threat)- Take emergency actions where spills or releases have

occurred- Encourage the use of the three R’s