Pollution Science 9 PDF

Pollution Science 9  What is Pollution? “any alteration to the environment producing a condition that is harmful to living things” Let’s brainstorm some sources of pollution that you have heard about either in school or in the media: Sources There are two main categories...

Pollution Science 9  What is Pollution? “any alteration to the environment producing a condition that is harmful to living things” Let’s brainstorm some sources of pollution that you have heard about either in school or in the media: Sources There are two main categories of pollution sources Point source: small, defined area causing pollution Non-point source: wide area, not easily defined where pollution is coming from or what its effects may be Dilution and Concentration Dilution means pollution is becoming less concentrated. What could help dilute pollution in a stream? In the air? What factors could concentrate pollution?  Water Quality Water quality in Canadian rivers, national and by land use category, 2016 to 2018 period  Aquatic Environments ** As pH increases the diversity of all organisms will decrease Chemical Factors Affecting Organisms ∙Pure Water (H2O) is made up of SOLELY water molecules ∙Water in the environment is never completely pure Examples: dissolved oxygen, pH, heavy metals, plant nutrients (nitrogen/phosphorus), pesticides, salts (sodium chloride/ magnesium sulfate) 30  Water quality is set by the provincial and federal government in five categories : ∙ Human Drinking Water ∙ Recreation (ex. Swimming) ∙ Livestock Drinking Water ∙ Irrigation 8 ∙ Protection of Aquatic Life  How We Can Tell If Water Is Good- Biological Indicators Scientists∙ use organisms living within the water to determine water quality ∙ Examples: fish, plants, worms, insects, plankton, protozoa, and viruses ∙ 9 Microbiological Indicators ∙ microscopic organisms (bacteria) which can cause health problems, which is why samples of water are taken to maintain the levels of harmful bacteria build up These are organisms that tell us about the quality of the environment by their presence or absence in water Macroinvertebrates 10 Good quality water will have a large variety of organisms but a higher occurrence of organisms that need lots of oxygen: Stonefly, mayfly, caddisfly, beetle  Dissolved Oxygen ∙ This is essential for the health of aquatic life , insects and microorganisms Levels of DISSOLVED OXYGEN depend on several factors: ∙ Temperature ∙ Amount of photosynthesis ∙ Turbulence due to produced by plants/algae in the wind or speed of the water water ∙ Number of organisms that are using the oxygen 11  Quantifying Pollution Most times concentration of pollutants is reported as a “parts per” value – usually parts per million (ppm) or parts per billion (ppb) But what does this mean? \ Measuring Chemicals in the Environment Parts per Million (ppm) – chemical concentration in the environment Meaning: ONE UNIT OF THE ELEMENT CAN BE FOUND IN ONE MILLION UNITS OF THE SOLUTION 13 When one substance dissolves into another, a solution is formed. The solute is the substance that is being dissolved, while the solvent is the dissolving medium.  What is the concentration of a solution, in parts per million, if 0.02 gram of salt is dissolved in 1000. grams of solution? An aqueous solution has 0.0070 gram of oxygen dissolved in 1000. grams of water. PPM Practice A 50 L drum filled with concentrated sulfuric acid fell of a truck during an accident. It rolled into the lake and burst open. The entire contents of the drum spilled into the lake. The lake has 30 000 L of water in it. What is the concentration of sulfuric acid in the lake? PPM Practice A 50 L drum filled with concentrated sulfuric acid fell of a truck during an accident. It rolled into the lake and burst open. The entire contents of the drum spilled into the lake. The lake has 30 000 L of water in it. What is the concentration of sulfuric acid in the lake? 50 L X 1 000 000 = 1663 ppm 50 L + 30 000 L PPM Practice A student added 70 mL of pee into a pool to make 1000 L of solution. Calculate the concentration of pee in parts per million PPM Practice A student added 70 mL of pee into a pool to make 1000 L of solution. Calculate the concentration of pee in parts per million 0.070 L X 1 000 000 = 70 ppm 1000 L PPM Practice The water in a swimming pool was analyzed for its chlorine content. It was found that 20 mL of a water sample contains 0.5 mL of free chlorine. What is the concentration of chlorine in ppm? PPM Practice The water in a swimming pool was analyzed for its chlorine content. It was found that 20 mL of a water sample contains 0.5 mL of free chlorine. What is the concentration of chlorine in ppm? 0.5 mL X 1 000 000 = 25 000 ppm 20 mL Toxicity: how poisonous a substance is ** The mixing of different pesticides within our water systems can develop into a very deadly combination of chemicals Some pesticides have long term effects, due to remaining in the environment without being broken down. Most modern pesticides are broken down after one growing season due to bacteria. 23  Measuring Toxicity Toxins: (poisons) substances which can cause serious health problems or death LD50 – lethal dose at 50% (meaning: the amount of a substance that causes 50% of test animals to die if they are given a specific dose of that substance at once) 24 The LD50 for rat poison is 0.27mg/kg. If a rat named Dwane with a mass of 0.85 kg ingested 0.50 mg of rat poison will it possibly die? The LD50 for rat poison is 0.27mg/kg. If a rat named Dwane with a mass of 0.85 kg ingested 0.50 mg of rat poison will it likely die? Mass = 0.85 kg Dosage = 0.50 mg LD50 = 0.27 mg/kg Max Dosage = Mass x LD50 = 0.85 kg x 0.27 mg/kg = 0.2295 mg = 0.23mg 0.50 mg > 0.23 mg - The dosage given (0.5 mg) is larger than the max dosage (0.23mg), therefore the rat will possibly die. (Note that the LD50 really only tells us how much poison is needed to kill half of the population) Find the amount of arsenic needed to reach the LD50 amount for a 1.75 kg duck. Arsenic LD50 = 13 mg/kg Find the amount of arsenic needed to reach the LD50 amount for a 1.75 kg duck. Arsenic LD50 = 13 mg/kg Mass = 1.75 kg Dosage LD50 = 13 mg/kg Max dosage = ? Max Dosage = Mass x LD50 = 1.75 kg x 13 mg/kg = 22.75 mg The maximum dosage that can be given to a 1.75 kg duck to reach its LD50 for arsenic is 22.75 mg  Caffeine LD50 The LD50 of caffeine is 150–200 milligrams per kilogram of body mass. Let’s say 175 mg/kg Let’s take a 55 kg person. So 175 mg/kg x 55 kg = a lethal dose = 9625 mg One Can of Monster Energy Drink has 160-300 mg of Caffeine So 9625 mg / 300 mg per can = 32 cans. At this dosage, half of the 55kg people will die. Going above 400 mg daily, the recommended dose for adults, can cause unpleasant side effects that are probably familiar to you: jitteriness, insomnia, irritability. (The American Academy of Pediatrics recommends kids 12 to 18 years old stay below 100 mg of caffeine a day, or one cup of coffee.) That’s because caffeine can speed up the heart beat and disturb the body’s blood flow — which, in extreme cases, can be fatal. Risk Management Many substances will have different effects in animals vs humans Tests on animals can be misleading Sometimes known risks are acceptable depending on the situation Every chemical has the potential to cause harm depending on type, duration and quantity of exposure. Check and Reflect pg. 224 Questions: 1, 6, 7, 8, 9 & 10 33