Unit C: Environmental Chemistry P Science in Action 9

The environment is made up of chemicals that can support or harm living things. Chemicals in the environment go through cycles. water cycle (hydrolytic), carbon cycle, Nitrogen cycle

Nitrogen Fixation Bacteria in the soil convert free nitrogen (N 2 ) to a compounds that can be used by plants. Nitrogen fixers are found in root nodules of certain plants (legumes: clover, alfalfa, beans, etc)

If soil lacks nutrients farmers (gardeners) can : add fertilizers to enrich the soil plant crops such as clover, alfalfa and peas to increase nitrogen

Fertilizers are labeled with a number that indicates the percentage of nitrogen, phosphorus and potassium -We use different ratios to achieve different goals - Sometimes a fourth number with an S indicates the amount of Sulfur 10 % K 10 % N 10 % P

Pesticide- Chemicals used to kill pests. Organic Foods- are grown in an environment free of pesticides

Problems with Pesticides Some are non- selective (round-up) pests may become resistant to them some stay in the environment for a long time and may be passed on to other organisms

an estimated 20,000 cancer deaths each year in the U.S. are caused by pesticide residues on food. an estimated 3.5 million cases of acute pesticide poisoning are caused each year in developing nations due to lack of protection during pesticide application. an estimated 900 plant and insect species have built up resistances to pesticides PESKY PESTICIDES

4.1 billion pounds of pesticides are used throughout the world each year 30 times more pesticides are used today than were used in percent of insecticides are believed to be carcinogenic 60 percent of herbicides are believed to cause cancer 90 percent of fungicides are believed to be carcinogenic (cause cancer ) 23 of the 28 most commonly used pesticides are believed to be carcinogenic

Pollution = Changes in the environment that produce conditions harmful to living things.

There are many kinds of pollution Noise Thermal (Lake Wabamum) Chemical

Landfills Use plastic liners and/ or compacted clay to prevent leaching LEACHING- when chemicals enter the waterways and soil

Waste Water Sewage (all waste water from your home) enters here!

What can YOU DO? Use phosphate free laundry detergent biological controls instead of pesticides walk or ride your bike instead of consuming fossil fuels and creating pollution reduce your solid wastes

Copy the nitrogen cycle from p 185 Do questions 1-11 on page 190