Chemicals in the Environment PDF

Chemicals in the Environment Unit C- Section 1.1  Remember: The term chemical doesn’t mean “bad”. All things are made of chemicals. However, in this unit we will be talking mostly about chemicals that are harmful to the environment and living things.  Harmful Chem...

Chemicals in the Environment Unit C- Section 1.1  Remember: The term chemical doesn’t mean “bad”. All things are made of chemicals. However, in this unit we will be talking mostly about chemicals that are harmful to the environment and living things.  Harmful Chemicals Living things need chemicals to survive. Sometimes, harmful chemicals end up in the environment. This can happen in many ways. What sorts of chemicals might be bad for our environment?  The Nitrogen Cycle Nitrogen is critical for living organisms, especially plants. However, plants cannot use “free-floating” nitrogen. It needs to be attached to another element. This is why nitrogen fixation is important. It is the process of combining nitrogen with another element(s) to make it usable for plants. Nitrogen fixation is often done by bacteria in soil. The Nitrogen Cycle | Environmental Chemistry | Chemistry | FuseSchool  Nitrogen Cycle in Steps Steps in the Cycle Step One: Free Nitrogen in the air is converted by lightning Step Two: Animal/Plant waste are broken down and Nitrogen compounds are released into the soil Step Three: Bacteria in root nodules converts Nitrogen into useable compounds Step Four: Plants uptake useful Nitrogen Step Five: Bacteria will release some free nitrogen back into the air Processes That Affect Environmental Chemicals The nitrogen cycle is an example of how the level of chemicals in the environment can change over time. The nitrogen cycle is a natural process. However, humans contribute to changes in chemical levels in unnatural ways. What sorts of things do we do that might impact the level of environmental chemicals?  Pollution Pollution is any change in the environment that is harmful to living things. Pollution is not only caused by human activities.  Agricultural Practices that Cause Pollution Pesticides Fertilizer Herbicides: kill weeds Fertilizer improves the amount of nutrients in soil to promote crop growth. Insecticides: kill insects Generally they contain: Fungicides: kill fungi -Nitrogen (N) -Potassium (K) Phosphorus (P) Excess amounts of fertilizer can be very harmful.  Reading Fertilizer Labels  Solid Wastes We dispose of solid waste (garbage) in landfills. This waste can get into our groundwater and air. Sanitary landfills are landfills with plastic liners and clay. They prevent waste from leaking into groundwater and soil. This is called leachate.  WasteWater Waste Water Waste water that contains undissolved materials from human Sewage treatment plants treat use is called sewage. sewage from homes and industry. A septic tank is an underground Treated waste water (effluent) is tank that stores sewage sent to our rivers and lakes. → bacteria break down sewage material. Would you drink this water?  Fuel Combustion Coal, oil, and natural gas (fossil fuels) are formed from plants and animals that died millions of years ago. Burning them releases carbon dioxide and water vapour. Combustion of fossil fuels may also release pollutants like sulfur dioxide, nitrogen oxides, and lead (Pb) into the air. What is combustion?  Industrial Processes Industrial processes like generating power release chemicals into the air. Processing natural gas releases specific substances. If natural gas contains hydrogen sulfide it is called “sour gas”. If it does not it is called “sweet gas”. Air Pollution 101 | National Geographic