Acid rain and pollutionAcid rain and pollution

Acid rainAcid rain

• Rain is naturally acidic (pH 5.6) because it Rain is naturally acidic (pH 5.6) because it mixes with COmixes with CO2 2 making water acidicmaking water acidic

• Precipitation with pH lower than 5.6 is acid rainPrecipitation with pH lower than 5.6 is acid rain

• Aquatic life prefer pH 6-8- excessive amounts Aquatic life prefer pH 6-8- excessive amounts of acid rain leads to trouble with reproduction of acid rain leads to trouble with reproduction and lack of plant growthand lack of plant growth

• Acid rain dissolves calcium, eventually leading Acid rain dissolves calcium, eventually leading to snail-eating birds having eggs with thinner to snail-eating birds having eggs with thinner shellsshells

Causes of Acid rainCauses of Acid rain

• SOSO22, SO, SO33, NO, NO, NO, NO22- created by industrial - created by industrial process and fuel combustionprocess and fuel combustion– Aside from acid rain, these compounds cause Aside from acid rain, these compounds cause

airway constrictionairway constriction

• Once these compounds mix with oxygen-Once these compounds mix with oxygen-containing compounds, form sulfuric and containing compounds, form sulfuric and nitric acidsnitric acids

• These acids fall with precipitation- both These acids fall with precipitation- both are strong acidsare strong acids

What can be done about acid What can be done about acid rain?rain?

• catalytic converters in cars- converts catalytic converters in cars- converts nitrogen oxide to Nnitrogen oxide to N22 and O and O22 to be to be emitted emitted

• Scrubbing- exposing sulfur dioxide to Scrubbing- exposing sulfur dioxide to lime solution to form calcium sulfite- lime solution to form calcium sulfite- non-toxic, but is disposed of in a landfillnon-toxic, but is disposed of in a landfill

• Draw your version of the picture on Draw your version of the picture on page 439 (about how acid rain forms)page 439 (about how acid rain forms)

OceansOceans

• How they were formedHow they were formed– Hot planet cooled downHot planet cooled down

• In cooling process, water vapor released, then In cooling process, water vapor released, then condensed to form bodies of watercondensed to form bodies of water

– Amount of water the same as the age of the Amount of water the same as the age of the dinosaursdinosaurs

– Hydrosphere- water layer of Earth- 97% of Hydrosphere- water layer of Earth- 97% of water in form of oceanswater in form of oceans

– Lithosphere is solid layer that covers EarthLithosphere is solid layer that covers Earth– Oceans “fed” by rivers, groundwater, rain,Oceans “fed” by rivers, groundwater, rain,

Sources of “salt”Sources of “salt”

• Weathering of rocks on landWeathering of rocks on land– Contribute silica, sodium, calcium, Contribute silica, sodium, calcium,

potassium, and magnesium ionspotassium, and magnesium ions

– Bicarbonate (HCOBicarbonate (HCO33) added by rivers from ) added by rivers from dissolved limestonedissolved limestone

• Chemical reactions b/t seawater and Chemical reactions b/t seawater and volcanic eruptions on ocean floorvolcanic eruptions on ocean floor

• Volcanic eruptions on landVolcanic eruptions on land

Composition of seawaterComposition of seawater

• 99% ions- Cl, Na, SO99% ions- Cl, Na, SO44, Mg, Ca, K and more than , Mg, Ca, K and more than 70 small amounts of trace elements (like iron)70 small amounts of trace elements (like iron)

• Salinity- refers to amount of salt dissolved in Salinity- refers to amount of salt dissolved in 1kg of water1kg of water

• Misc. components of seawater:Misc. components of seawater:– Organic materials from living organismsOrganic materials from living organisms– Dissolved gases (NDissolved gases (N22 , O , O22, CO, CO22, H, H22, and others, and others

• Salinity constant over the years b/c of balanceSalinity constant over the years b/c of balance– Ex: rivers provide salts and minerals, organisms use Ex: rivers provide salts and minerals, organisms use

ions to build shells and skeletons, excess substances ions to build shells and skeletons, excess substances deposit on rocks, etc.deposit on rocks, etc.

Excess of carbon dioxide Excess of carbon dioxide revisitedrevisited

• Photosynthesis and respiration of Photosynthesis and respiration of organisms release oxygen and organisms release oxygen and carbon dioxide in the water- normalcarbon dioxide in the water- normal

• Excess Carbon dioxide- would make Excess Carbon dioxide- would make pH lower, but calcium carbonate pH lower, but calcium carbonate buffer neutralizes it to keep pH about buffer neutralizes it to keep pH about 8- but what if buffer fails?8- but what if buffer fails?

Pollution and ocean food Pollution and ocean food chainchain

• Pollution enters oceans via dumping Pollution enters oceans via dumping and flow from rivers and streamsand flow from rivers and streams– Raw sewage, toxic chemicals, heavy Raw sewage, toxic chemicals, heavy

metals, petroleum metals, petroleum – Once enter ocean- diffuses Once enter ocean- diffuses

• Pollutants are passed through the Pollutants are passed through the food chain and concentrate in tissues food chain and concentrate in tissues of marine organismsof marine organisms

Pollution passed up the Pollution passed up the food chainfood chain

• Producers absorb pollutants in process of Producers absorb pollutants in process of making energymaking energy

• Herbivores eat producers, and acquire Herbivores eat producers, and acquire energy and pollutants absorb in fatty energy and pollutants absorb in fatty tissuetissue

• Carnivores eat herbivores, acquire energy Carnivores eat herbivores, acquire energy and higher concentrations of pollutantsand higher concentrations of pollutants– Toxins can sometimes be passed along to Toxins can sometimes be passed along to

youngyoung