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Topic 1 – Organic Molecules and Nutrients:

The process of digestion breaks down the chemicals present in food. The molecules are small and soluble, which can then pass through membranes into your blood. These chemicals (nutrients) are then carried throughout your body to the cells, which need them for energy, growth, body building and cell repair. 

Our body needs about 25 different chemicals for normal growth. There are 4 major types of nutrients which we call organic molecules. The organic nutrients, which come primarily from green plants, are classified into four major groups (see table to the right).

Nutrients, made up of elements and compounds, help living organisms survive. The best way to avoid nutrient deficiencies is to have a healthy and balanced diet to provide your body with the nutrients that it needs.

organic compounds contain carbon, as well as mostly oxygen and hydrogen.inorganic compounds do not contain carbon .macronutrients are need in large quantitiesmicronutrients are needed for growth, but not in large quantities.

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Plants need the proper amount of nutrients as well. Here are some signs of nutrient deficiency in plants. In order to provide plants with all of the nutrients that they need, we often use fertilizer. This happens especially in agriculture.

The three numbers on a bag of fertilizer refer to the percentage of nitrogen, phosphate and potassium that is available to plants from that bag of fertilizer.

Topic 2 – A Growing Concern:

Pesticides: a chemical used to control “pests”Herbicides: a chemical used to control weedsInsecticides: a chemical used to control insectsFungicides: a chemical used to control molds and fungiBioaccumulate: to collect in progressively higher concentrations toward the top of the food chain.Biomagnification: the process whereby chemicals accumulate in the tissues of organisms along the food chain.

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Topic 3 - Acids and Bases:

pH is a measure of the concentration of hydrogen ions in a solution. It means the “power of hydrogen” and refers to the formation of hydrogen atoms that have lost an electron (and become ions).

Acids taste sour, are soluble in water and undergo similar chemical reactions, have a pH of less than 7.

Neutral substances  are neither acidic nor basic, such as water.

Bases taste bitter, are soluble in water, feel slippery, and react with acids, have a pH of more than 7

Indicators: The pH scale is a way of comparing the relative acidity or basicity/alkalinity of a substance. To identify a substance as an acid, a base, or neutral, an indicator is used. It changes color according to the type of substance it is put into. Indicators can be solid or liquid. Some common indicators are litmus paper, universal indicator paper, phenolthalein, phenol red, bromothymol blue or cabbage juice.  

Neutralization: Acids and bases react together when they are mixed. This type of reaction is called neutralization. Both the acid and the base are used up in the is type of reaction. A salt and water are produced.

Acid Precipitation: Sulfur, nitrogen and carbon oxides emitted from industries combine with water vapor in the air to produce sulfuric, nitric and carbonic acid. These pollutants then fall to the ground as acid precipitation (with a pH lower than normal rain - which is about 5.6).

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Some of the effects of acid precipitation are...

… the chemical change reduces soil fertility… it kills organisms in lakes & streams… it leaches toxic chemicals from the soil…it damages or destroys aquatic ecosystems…it slows tree growth…corrodes exposed metal surfaces …breaks down stone and limestone

Topic 4 – Concentration:

pollutant: any material, or form of energy, that will cause harm to a living organism.pollution: any alteration of the environment producing a condition that is harmful to living things.toxicity: the ability of a chemical to cause harm to an organismchronic toxicity: when symptoms appear only after a chemical accumulates to a specific level after many exposures over time.acute toxicity: when serious symptoms appear after only one exposure.

Concentration: The amount of a substance per defined space. We can use concentrations to compare different solutions. Remember that a solution has a solute and a solvent. 

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How do we measure concentrations?

1) % of volume or weight (actually parts per hundred or pph)2) ppm – parts per million: ppm is measured in mg/kg – it tells us how many milligrams (mg) of solute are present in a kilogram (kg) of solvent.

example: 1 ppm of salt water means there is 1 part NaCl and 999 999 parts H2O3) ppb – parts per billion: ppb is measured in g/kg – it tells us how many micrograms ( g) μ μof solute are present in a kilogram (kg) of solvent. 1 g is 0.000001 g.μ  

Lethal Dose 50: Lethal Dose 50 (LD50) is a common measurement used when examining the toxicity of a substance. LD stands for 'Lethal Dose'. '50' represents 50% of the subject group that will die, if they are given the specified dose, all at once. 

Topic 5 – Environmental Monitoring:

non-persistant vs. persistent waste: persistent accumulates in the environments, where non-persistent can be broken down by chemical reactions or bacterial action.bioindicator/biological indicators: organisms that are found in either clean or polluted environments. Their presence (or absence) can tell us about water quality.point source of pollution: pollution comes from a specific location (ie. sewer pipe)non-point source of pollution: pollution not from a specific point and not released regularly (ie. construction site).

Water Quality: There are many factors that can affect our water quality. This diagram shows just a few of them. When we assess water quality, we test a number of different factors such as temperature, pH, turbidity and dissolved nutrients. Water that supports healthy ecosystems has expected values for these factors.

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Topic 6 –Pollution

Pollution used to be a local issue, but not anymore. Increased globalization and production has resulted in more waste that can move around the world. Solid wastes are relatively immobile, but waste that enters our air and water can travel vast distances. This means that more and more waste is entering our 'backyard'. 

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How do wastes and pollution travel?

The source of a pollutant may be in one place, but it can show up in many other places around the world. There are three stages of transport of substances in the environment:.

1) Release of chemicals at the source2) Dispersion of the chemical into the atmosphere3) Deposition of the chemical in soil or water

The direction and distance that airborne chemicals travel are determined by various factors, including:-        The properties of the chemical pollutant-        The wind speed-        The direction of the prevailing winds-        The distribution of particles may also be limited by lack of wind or precipitation.

Ozone and CFCs:ozone(O3(g)): A molecule that exists naturally in the stratosphere and provides essential protection from ultraviolet (UV) radiation for life on Earth. chlorofluorocarbons (CFCs): Organic molecules containing carbon, fluorine and chlorine that are released by some refrigerators and aerosols. When CFCs react with sunlight in the stratosphere, they break down ozone and deplete the ozone layer. CFCs are no longer widely used but they will continue to persist in

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the atmosphere for many years.

Water Pollution:

Surface Water Pollution: Most surface water pollution occurs because of human everyday activities such as washing clothes or going to the bathroom. Wastewater is channeled through storm sewers (for surface runoff) or sanitary sewers (for sewage). Before the wastewater can be returned into a water system, it is required by law that it is treated to remove

nitrates/phosphates (from detergents) and organic material/bacteria (from sewage).

Groundwater Pollution: Groundwater pollution can occur because of use of herbicides, pesticides and the use of chemicals in industry and agriculture. Groundwater pollution is extremely difficult (if not impossible) to clean up.  

groundwater: water that filters down through soil and fills the spaces between particles of rock and soil.  aquifers: an underwater reserve of water.

Biodegradation: Biodegradation occurs in the environment because living things (earthworms, bacteria and fungi) are actively breaking down organic substances, including many pollutants. Micro-organisms are especially important in the biodegradation of pollutants. During the winter, biodegradation is slow, because temperature is one factor that affects the rate of biodegradation. Other factors include soil moisture, pH, oxygen supply and nutrient availability.

aerobic biodegradation – occurs in environments where oxygen is present.anaerobic biodegradation – occurs in environments where oxygen is not present.

Hazardous Waste: A hazardous waste is any discarded material that contains substances that can be poisonous, toxic, corrosive, flammable, or explosive. Chemicals used in the home and garden can be classified as hazardous wastes. Hazardous wastes need to be stored and disposed of properly in order to ensure that they do not contaminate our groundwater. 

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