Topic 4.0 – Transport of Materials in the Environment

I. Transport of MaterialsA. Transport in Air

Chemical is released

Dispersion (particles scatter in air)Deposition of

chemical in soil or water

I. Transport of MaterialsA. Transport in AirFactors affecting

distribution:Wind – direction and

distance of travelPrecipitation – will

deposit chemical where rain/snow occurs

Where is the healthiest place to live around:

Fort McMurray?

Sherwood Park?

Grande Prairie?

Calgary?

INFO : Particulates can land 30 – 300 miles away from the source!

Does this change your answer?

Does this information change your answer?

I. Transport of MaterialsB. Transport in Surface WaterSurface water – fast moving water (streams, rivers) or

standing water (sloughs, lakes)Solutions that dissolve easy travel far in surface water

Which will carry a toxin further? Where will it be more concentrated?

I. Transport of MaterialsC. Transport in GroundwaterGroundwater – water beneath the surface layer

of soil Slower movement of water than surface How packed the soil is dictates how fast

water flows through this region (usually downwards)

Packed soil = pores which are not connected = slow water movement

Permeable soil – has pores which are connected and allows quick water movement

I. Transport of MaterialsC. Transport in GroundwaterGravel – high porosity (permeability) - allows

water to flow through quicklySandy soil – has med-high porosity-Clay – low porosity – little water movement

I. Transport of MaterialsD. Transport in SoilLeachate – water which has dissolved

chemicals in the soil and carries to the groundwaterThis can contaminate our ground water and

drinking water sourcesAquifier – a source of ground water that has

been naturally filtered but can contain toxins due to leaching

I. Transport of MaterialsD. Transport in SoilCommon Sources and Contaminants

Sources ContaminantsLandfills Heavy metals (lead, mercury,

cadmium)Pipelines Gasoline, oil

Highways Salt, oil

Septic tanks, sewers, livestock wastes

Bacteria, viruses,

Farmer fields Fertilizers – phosphorus, nitrates,

II. Changing Chemical ConcentrationsFive mains ways of reducing chemical

concentrations:1) Dispersion – particles spread out from

where they were released2) Dilution – adding water or air to a

chemical/toxin to reduce the concentration

3) Biodegredation – using living organisms to break down substances Ex. Bacteria, fungi, earthworms>anaerobic – when bacteria degrade without oxygen-in landfill sites>aerobic – when bacteria require oxygen to break down toxins

To speed up biodegredation:Warm temperaturesPlanting plantsUse bioreactorsLots of oxygen

II. Changing Chemical Concentrations4) Phytoremediation

“phyto” means plants“remediation” means cure

Using plants to clean the soil of metals or toxins (they absorb the toxins)

5) Photolysis“photo” means light; “lysis” means break Using the sun to break down compounds

Ex. PlasticsEx. NO2 can form O3

Introduction Qs. What are the 5 methods of reducing toxin

concentration?Why do we want to reduce the concentration

of toxins?How can we dilute a toxin?What is phytoremediation?Would clay or gravel-soil remove more

toxins? Why?What are the conditions that affect how far

an emission is deposited on the ground?

Which is a better method of garbage disposal? Why?

Sanitary landfill or incinerator?

Waste and Toxin managementSanitary landfill – landfill with a clay base

and plastic liner to prevent leachate from entering our water tableIs covered daily with dirt to avoid scavengers

and litter movementIs “flared off” – the anaerobic biodegradation

produces methane, so it is piped to surface and burned off

Incinerator – burning of waste to break down toxic compounds ; can contribute to air pollution

Waste and Toxin managementWastewater managementSewage – waste water from homeSeptic tank – underground container where

bacteria break down materials before released to soil

Sewage treatment plant – treats wastes before re-entering environment

Effluent – treated wastewater which is released to river or lakes

Storm sewers – leads directly to river when sewers are overfilledContain gas, oil, etc from street

Wrap-Up Notespersistent vs. non-persistent

Persistent – toxins that remain in the environment for long periods of time

Point source vs. non-point sourcePoint source – source of pollution is from one

identifiable source Ex. Sewage effluent pipeNon-point source – exact location of source of

pollution is not identifiable Ex. Smokestacks release air pollutants that travel 100’s of km in any direction

Wrap-Up NotesNIMBY – not in my back yard

Where citizens do not support development due to it being too close to their community.

Examples: Electrical powerlines Landfills Chemical plants