Science 9

Science 9Aim: How do we determine water and air quality

AgendaScience SizzlerWater Quality notesHomework worksheetsNext class

Dissolved OxygenEssential for the health of aquatic lifeThe level of dissolved oxygen in water depends on:TemperatureTurbulence due to wind, or speed of moving waterAmount of photosynthesis by plants and algae in waterThe number of organisms using up the oxygen.5 milligrams per litre (5ppm) of dissolved oxygen will support most organisms that live in lakes and streams.Phosphorous and NitrogenAn increase in P and N can lead to a decrease in dissolved oxygen.High concentrations of P and N can lead to some problems.Cause increased growth of algae and green plants.Bacteria increase, using up O in the water.

PesticidesMixing of different pesticides in bodies of water may form a much more toxic or poisonous substance.Toxicity describes how poisonous a substance is.Most pesticides used today are designed to break down after a certain time passes.

Measuring ToxinsToxins are substances that produce serious health problems or death when introduced into an organism.Measurement used to compare toxins is called LD50, where LD stands for lethal dose, and 50 stands for 50%.LD50 is the amount of substance that causes 50% of a group of test animals to die.Heavy MetalsHeavy metals have a density of 5 g/cm2or more.This means that they are five or more times heavier or denser than water. (Cu, Pb, Zn, Hg, Cd, and Ni)These metals occur naturally.Found in a lot of everyday items. (batteries, tires, gas, paints, pipes, thermometers, and fertilizer.)

Monitoring Air QualityWhat is our air made of?

Nitrogen (78%), Oxygen (21%), Argon (less than 1%) Trace amounts of CO2, Hydrogen, and Neon

Monitoring Air QualityIrritated throat and stinging eyes may indicate poor air quality

Monitoring Air QualityDetermining Air Quality:1) Measuring the level of pollutants in the air2) Estimating the amount of emissions from potential pollution sources

Monitoring Air QualityMajor Air Pollutants SO2 = Sulpher dioxide NOx = nitrogen oxides CO = Carbon Monoxide O3 = ozone (ground level)

Monitoring Air QualitySULFUR DIOXIDE (SO2)

forms when sulfur combines with oxygen major source = industrial processes (ex. Oil & Gas) forms smog and acid rain can result in throat and lung problems and irritated eyes

Monitoring Air QualityDEALING WITH SULFUR DIOXIDE (SO2)Many industrial plants use scrubbers to reduce SO2 emissions

These scrubbers use LIMESTONE (calcium carbonate) to convert the pollutant to produce GYPSUM a useful material in manufacturing (GypRock or drywall)

Monitoring Air QualityNITROGEN OXIDES (NOX) NOX = Means mixture of NO and NO2 Form from the combustion in vehicles and industrial processes Can affect respiratory system and eyes

Monitoring Air QualityCARBON MONOXIDE (CO)

The Silent Killer = colourless and odorless

If there isnt enough oxygen available during combustion, carbon monoxide forms instead of carbon dioxide

Sources can include: vehicles, natural gas, burning wood, industrial processes

Can cause headaches, sleepiness, brain damage and death

Monitoring Air QualityOZONE (O3)

Ozone in the upper atmosphere protects the Earths surface from harmful ultraviolet light

BUT on ground level, ozone is a harmful pollutant

Monitoring Air QualityGROUND-LEVEL OZONE (O3)

Odorless and colorless gas

Forms from reactions between oxygen, nitrogen oxides and compounds called volatile organic compounds (VOCs) in the presence of sunlight

Sources: fuel combustion and industrial processes

Monitoring Air QualityGROUND-LEVEL OZONE (O3)

A major issues in the summertime in large citiesVery harmful to lungs, especially for at-risk people (elderly, children, people with lung diseases)

Is Carbon Dioxide a Pollutant??No, because it is naturally present in the air (many organisms exhale CO2 into the air)

BUTThe amount of CO2 is increasing in our atmosphere, which is cause for great concern

Why are CO2 levels increasing?Since the Industrial Revolution, CO2 levels in the atmosphere have been rising

burning of fossil fuels exhaust from vehicles any combustion reactionThe Increase of CO2 and the GREENHOUSE EFFECTThe Earth is like a Greenhouse:

The atmospherelets the sunlightin and traps someof the energy inside while lettingsome energy back out

GREENHOUSE EFFECTSome gases in our atmosphere act like the glass of a greenhouse trapping the suns energy in.

This keeps the Earth at temperatures that allow life to exist.

These gases are called GREENHOUSE GASES and include: Water Vapour, CO2, Methane and NOx

Human activities, such as burning of fossil fuels, contribute to an enhanced greenhouse effect

Keeps more of suns energy(and warmth)in the atmosphere

Impacts of a Warming EarthIncreased TemperaturesMore Violent StormsFlooding of Coastal AreasMelting of Glaciers and Ice CapsPotential Increase of Disease Spread

26The Ozone LayerAlthough ground-level ozone (O3) is considered a pollutant and can be very harmful, ozone in our atmosphere is essential

This ozone is found 15-50km above the Earths surface

The Ozone LayerThe ozone layer, high up in our atmosphere, absorbs dangerous Ultraviolet light from the sun

The Ozone LayerOver the years, the ozone layer has become thinner allowing more UV light in.

The Ozone LayerScientists have discovered that the thinning of Ozone is due to our use of chemicals calledCHLOROFLUOROCARBONS (CFCs)

The Ozone LayerWhat are CHLOROFLUOROCARBONS (CFCs)?

Chemicals used in many applications, including: refrigerators and aerosol cans

The UV light breaks down CFCs into chlorine molecules, which destroy ozone

Many countries have recognized the danger of CFC use and have reduced their usageTransport of Chemicals in our EnvironmentMany pollutants end up far from where they are produced how do they spread?

Transport of Chemicals in our EnvironmentTransport of Substances in the Air: 3 Stages:1) Release of the Chemical at the Source2) Dispersion of the Chemical in the atmosphere3) Deposition of the Chemical in Soil or Water

Transport of Chemicals in our EnvironmentFactors that Impact Air Transport of Chemicals

Presence of Wind Wind Speed Rain (chemical will be brought down to soil/water closer to where they originated)Transport of Materials in GroundwaterChemicals soak into Soil (zone near the surface) the spaces between soil grains contain water and air

As chemicals move deeper, it enters Groundwater the spaces between soil grains contain water only

SOILGROUNDWATERThe highest point of groundwater is called the WATERTABLE

SOILGROUNDWATERFigure 3.3 (Pg 239)Transport of Materials in GroundwaterOnce chemicals reach the groundwater, they have the potential to become quickly concentrated and disperse but relatively slowly.

Groundwater can move 1 metre per year to 1 metre per day (much slower than rivers/streams)Transport of Materials in GroundwaterMovement of Groundwater:Pores = tiny spaces between soil grains

Movement of Groundwater:Pores = tiny spaces between soil grains

Tightly Packed Soil = the pores arent connected and water cannot move easilyPermeable Soil = pores are interconnected, water can flow and pollutants can travel more

Transport of Chemicals in Surface WaterSubstances that enter surface water can either: Dissolve and disperse quickly may be carried a long way Not Dissolve and attach to soil grains and sink to the bottom become concentrated near the source

Transport of Chemicals in SoilWhat does water do when it hits the soil? some evaporates some runs onto the street or into a stream some soaks into soil and is taken up by plants some soaks into soil and moves downward = dissolving chemicals and bringing them down with it (LEACHATE)

Transport of Chemicals in SoilChemicals in the soil can be absorbed by organic materials slowing the chemicals movement. & Hazardous Materials can a be changed in the soil by chemical reactions (ex. acids being neutralized)

Techniques that Affect Chemical Concentrations in our EnvironmentDispersionScattering of a substance away from its source

DilutionReduces the concentration of a pollutant by mixing the substance with large quantities of air or water

Fast-Flowing Water Can Do Both Of These (but not always a good enough job)How does nature use living organisms to help clean the environment?BIODEGRADATIONBreakdown of materials by organisms such as earthworms, bacteria, and fungi

By breaking up organic substances, including many pollutants, decomposers help return usable nutrients to the soil

Bioplastics, designed to degrade into an ecofriendly mix of water, carbon dioxide, and biomass.BIODEGRADATIONMany micro-organisms (ex. bacteria) use existing organic compounds for food

Some bacteria can do this only in environments with oxygen = this is referred to as AEROBIC BIODEGRADATIONfunction in environments without oxygen this is referred to as ANAEROBIC BIODEGRADATION

Factors affecting BiodegradationTemperature, moisture, pH, oxygen supply, and available nutrients.PhytoremediationA technique used to reduce harmeful chemicals in soil or groundwater using green plants.PhotolysisThe breakdown of substances from exposure to sunlight.Hazardous chemicals affect living thingsBiomagnification: The increase in concentration of a chemical or element as it moves up the food chainEx. MercuryBacteria Algae Invertebrates Fish Humans or other meat eating organisms.If you collect enough mercury in your system it could make you sick.Oil Spills impact on environmentCrude oil is a mixture of many chemicals.Floating algae killedDecrease in dissolved oxygen killing some organisms.Loss of foods, and toxic effects.Physical deformations in some organisms if not killed outright.Oily feathers and fur made organisms susceptible to cold weather.Reduced commercial fishing done by companies.Hazardous Household ChemicalsMany products we use to maintain our houses, cars, and yards have the potential to harm our environment.

These Include:CleanersHygiene ProductsPet-Care ProductsPaintPesticidesAutomotive Fluids

Hazardous Household ChemicalsImproper transport, storage and disposal could contribute to a variety of health problems

so government regulations are designed to protect consumers and reduce any risks

New Product RegulationsNeed to include detailed information on the following:Intended use, physical and chemical properties, active ingredient(s)Instructions for use, safety precautions.Health effects, environmental effects, toxicity to humans, and first aid instructions in case of poisoning.

Transportation of consumer goodsHousehold hazardous materials are transported usually only twiceOn the way home when first boughtUnused portion or waste product are taken to disposal site.Things you should not doDo not mix waste chemicals in a single container.Chemicals should be left in original containers with labels intact.Disposal of Hazardous chemicalsDo not pour down drainDo not pour on soil, or solid waste garbage can

Deliver materials to hazardous waste collection sites.