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Environmental Chemistry. The environment is made up of chemicals that can support or harm living things. Learning Objective For Today:. Students will describe processes by which chemicals are introduced into the environment.
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Environmental Chemistry The environment is made up of chemicals that can support or harm living things.
Learning Objective For Today: • Students will describe processes by which chemicals are introduced into the environment.
But First An Inspirational New Year’s Speech and Review of Class Rules:
As I was correcting your exams over Christmas break and weeping…
I decided that unfortunately you do need a mommy to teach you Science.
Routine, Routine, Routine • Every Monday I will post a Check & Reflect assignment on the class website. • It will be due on the following Monday. • You will hand it in THAT DAY with your NAME ON IT (emailing is fine). • I will record your mark and hand it back to be corrected on Tuesday.
Vocabulary words and study resources are posted for the new unit. • Try to review for 10/15 per day.
When will an interior decorator/designer every use Chemistry? • Why don’t you use chemistry to create some new amazing, beautiful, desirable, tres cool colour and gain a propriety patent miss fancy pants? Then every crazy rich client will want what you exclusively control, and you will be queen of the world. • So there.
I don’t think my job as a teacher is to teach you the “stuff” in the curriculum. • Life is not a little box • You can create • You should care • What makes life good is a passion for learning, empathy, wonder.
Excellence is a habit of the mind… • Do it because if feels good!
And Now, back to our regularly scheduled learning… • The environment is made up of chemicals that support or harm living things. • Interesting fact: an estimated 80 to 90 per cent of cancers can be attributed to environmental factors. • What makes chemicals unique is that there's only so much we can do as individuals to reduce our exposure to chemicals in the environment.
Chemicals can linger in our environment and eventually make their way into our bodies. • Without even knowing it, and despite our best efforts, we come in contact with these pollutants everyday — in our water, soil, air, food, and manufactured products. • Many industrial contaminants can be measured in our tissues and blood. • Traces of these chemicals have even been found in the blood of Inuit in northern Canada, although they live thousands of kilometers away from the original sources.
Water is one of the chemicals that is essential for life. • Can only live a few days without it. • Life-supporting substances dissolve in water and are transported to all parts of your body. • Water carries waste materials to your kidneys for removal. • Is it possible to die from drinking too much water?
“Hold Your Wee for a Wii” • In January 2007, hours after competing in a radio station contest to win a Nintendo Wii, 28 Jennifer Strange was found dead in her home. • She died from drinking too much water too quickly, resulting in a condition called water intoxication. • Water intoxication causes an electrolyte imbalance that affects concentrations of the ion sodium, and it leads to a condition called hyponatremia.
The exact amount of water intake that can lead to water intoxication is unknown and varies with each individual. • Symptoms of water intoxication actually look a lot like the symptoms of alcohol intoxication, including nausea, altered mental state, and vomiting. • Other symptoms include severe headaches, muscle weakness and convulsions. In severe cases of water intoxication, coma and death come fairly quickly as a result of brain swelling.
Medicine from the environment • When you look at a willow tree, you probably just see a tree… a pharmaceutical chemist sees an important chemical- salicylic acid. • Some environmental chemicals can interact to cure sickness and improve health in organisms. • First Nations people made use of chemicals in their environment for food and medicine.
Willow bark tea • Used by First Nations, and in Europe at least as far back as 400 B.C. • Hippocrates- Known as the Father of Medicine- recommended it to treat pain and fever. • Active ingredient in willow bark was identified in the 1800s as salicylic acid.
Bayer Company • 1898, German company used a synthetic version of this chemical, acetylsalicylic acid, to develop a new medicine under the brand name Aspirin.
Racism • There was a period of time in history (ethnocentrism/colonialism) when Europeans rejected knowledge coming from societies they considered inferior… from First Nations, Asians, even other Europeans.
Aspirin is just one example of the many medicines we use today that were originally derived from naturally occurring chemicals in the environment. • E.g. Many people use an extract made from the purple coneflower (Echinaciap.) to help stimulate their immune systems. • Plants can be made up of hundreds of different chemicals. When a potentially useful chemical is found, it must be tested for safety and effectiveness.
Thanks Bill! • Thanks to the science guy… we now know that the trees, mountains, the air we breathe- everything that makes up the environment is made up of chemicals. • Not all chemicals in the environment support living things. Naturally produced substances can be harmful. • Forest fires and volcanoes (or as we learned from Kuwait- burning oil) release large amounts of chemicals such as carbon dioxide, sulfur dioxide, and ash.
Human activities can also cause chemical changes in the environment. • We benefit from using products such as gas, electricity, and pesticides, but by using them we may be harming both the living and non-living environment. • Right now, we don't have a very good relation with creation. (Pope Francis)
The Nitrogen Cycle • P.S. I hate the nitrogen cycle.
Elements are pure substances that cannot be broken down into other substances. • All chemical compounds are made up of elements. • Some elements, such as oxygen & carbon are always moving through ecosystems. • They form chemical compounds that are used and reused by living things.
The chemical compound water changes state as it moves through ecosystems • The repeating changes of these elements and water as they move through ecosystems is called a cycle. • The element nitrogen cycles this way.
Nitrogen Fixation • Plants require nitrogen to make substances necessary for life. • However, plants can use nitrogen only when it is combined with other elements, such as hydrogen and oxygen. • Air is about 78% nitrogen in the form of Nitrogen gas (N2(g)) but plants can’t survive using this “free” nitrogen directly.
Nitrogen Fixation • It has to be “fixed” in compounds with other elements. • Nitrogen fixation is the process of changing free nitrogen so that the nitrogen atoms can combine with other elements to form compounds that organisms can use.
Certain types of bacteria do most of the nitrogen fixation in the soil. • Some of these bacteria are located in the root nodules of specific types of plants, such as beans, clover, and alfalfa.
The bacteria are able to separate the two atoms that form nitrogen gas (free nitrogen). • Once separated, the nitrogen atoms can form compounds with other elements, such as hydrogen and oxygen. • Lightening also converts nitrogen in the air to nitrogen compounds that plants can use.
Steps in the cycle • After nitrogen fixation occurs, plants use the nitrogen-containing compounds. • Animals then eat the plants. • Their bodies need to use the nitrogen to make more complex substances, like proteins.
Decomposers break down large nitrogen-containing molecules in the soil in dead animals and animal waste. • This nitrogen is released back into the air as free nitrogen, and the cycle begins again. • The concentration of nitrogen is not the same everywhere- similar to water- the amount on Earth does not change, but there is too much in some places (like a flood) and too little in others (drought).
Amount of usable nitrogen varies… • Because it can be removed from the local environment in 3 different ways.
1. Conversion to free nitrogen by bacteria is one way. • 2. Water carrying dissolved nitrogen compounds away or deep into the soil so that they are unavailable to plants. • Nitrogen is also lost to an area when plants are harvested. If soil lacks nitrogen, farmers plant nitrogen-fixing plants such as clover or alfalfa, or add fertilizers to increase the amount of nitrogen.
Processes and activities that affect environmental chemicals • The nitrogen cycle is one example of how environmental chemicals change. • Humans also use and change chemicals; we release carbon dioxide into the environment through breathing, for example. • When we travel in vehicles, oxygen is required in the combustion reaction that happens when a vehicle burns fuel. • Gases such as water vapour, carbon dioxide, carbon monoxide, and nitrogen oxides are released into the atmosphere.
Both natural processes (cellular respiration & the nitrogen cycle) and human activities (driving a car) may change chemicals in the environment.
The chemicals formed by human activities cause concern about pollution • Pollution: any change in the environment that is harmful to living things. • For example, smog caused by vehicle exhaust emissions (or industrial emissions) is pollution because it makes it hard for people and other animals to breathe. • Smog • Forest fires (or oil fires such as the ones in Kuwait) produce similar chemical pollution.
Human Activities • Release chemicals into the air, water, and soil everyday through growing crops, disposing of solid waste, treating wastewater, manufacturing products, driving vehicles, etc.
Agriculture Activities • Farmers have to have a good understanding of chemistry to produce good crops; need to know what chemicals to add to the soil to improve plant growth. • Fertilizer: substance that enriches the soil so plants will grow better; for example, potassium is essential for plant growth. If soil is low in potassium, growers can add a potassium fertilizer.
15-30-15 • Fertilizers are described by the major nutrient elements they contain. • Nitrogen-Phosphorus-Potassium • 15% Nitrogen, 30% Phosphorus, 15% Potassium • Some fertilizers have a fourth number and the letter “S” which indicates they contain sulfur as a major ingredient.
Too much fertilizer can damage organisms • Fertilizer can come from natural sources or synthetic chemicals. • From either source, too much can damage crop it’s supposed to help, ponds, lakes, streams, rivers and ecosystems. • When I was in university, I completed a research project which examined how windshield wiper fluid is damaging the environment (methanol), but can lead to increased plant growth (phosphorus).
Farmers use their understanding of Chemicals to apply Pesticides Safely • Pesticides: are chemicals used to kill pests. • A pest is an organism that harms people, crops, or structures. • Pesticides are grouped according to the pest they kill. • Herbicides: kill or control weeds; Insecticides: kill or control insects; Fungicides: kill or control fungi.
It is estimated that 50% of world’s food production would be lost to pests without pesticide. • But pesticides can cause problems, and pests can grow resistant to them (like bacteria to antibiotics) • Some kill both pest and non-pest species. • For example, spraying for armyworms (canola pest) may kill bees, which are important for pollinating other crops. • Some pesticides, like DDT can stay in the environment for long periods (2 to 15 years)
Solid Wastes • Chemicals are introduced into the environment when we dispose of solid waste or wastewater. • Solid waste: includes garbage that is collected from households, industrial plants, commercial buildings, institutions, constructions and demolition sites. • Includes large items such as machinery, and small items, like caps on plastic drink bottles.
Some solid waste can be reused or recycled • But most ends up in landfill sites; hazardous wastes which are burned in incinerators at very high heats contribute to air pollution through emissions released into the atmosphere. • Sanitary landfill sites are specially built to prevent waste chemicals from leaching/moving into the soil (by using plastic liners and compacted clay), but are not foolproof.
Wastewater • Sewage: wastewater containing dissolved and undissolved materials from your kitchen, bathroom, and laundry.
