Environmental Chemistry (1-3)

• Acid rain is corrosive to buildings and plants


  Adding calcium hydroxide (liming) can help neutralize the effects
• Diffusion


  Passive transport, goes from high to low concentration, does not require energy
• Commercial Fertilizers


  Fertilizers can be used to increase the nutrient content of the soil, thereby allowing plants to grow better
• Fertilizer label


  1. 32-10-10

  2. Nitrogen: growth of leaves and stem

  3. Phosphorous: growth of roots and flowers

  4. Potassium: protects against disease, early development
• Dangers of fertilizers


  • Can run off and affect bodies of water
  • Raise pollution levels
  • Pose health risks in water due to algae levels
• Biological


  Indicator of water quality
• Indicators


  Used to determine water quality
• Biomagnification


  Increase of concentration of a chemical or element as you move up the food chain
• Bioaccumulation


  Build-up of a chemical over the span of an organism's life
• LD 50


  The amount of a substance that causes 50% of the group of test animals to die
• Taxic


  Substances that cause serious health problems or death when introduced to an organism
• Spring acid shock


  Acid deposits from acidic precipitation can build up in ice and snow. During the spring when everything starts to melt, this can increase the acid concentration and dramatically lower the pH in a pond, lake or river
• Pollutants


  • Heavy metals
  • Sulfur dioxide
  • Nitrogen oxides
  • Carbon monoxide
  • Ozone
• Invertebrates


  Indicator of the effects of pollution in the water
• Parts per million (ppm)

  Concentration of pollutants is often reported as parts per million
• Water quality is determined according to what the water is used for
• Categories of guidelines for water use

  • Drinking water
  • Recreation (swimming)
  • Livestock drinking water
  • Irrigation
  • Aquatic life
• Using microorganisms to determine water quality

  1. Take samples of a water source and test for harmful bacteria

  2. If levels of harmful bacteria are high, the water has to be treated
• Using aquatic invertebrates to determine water quality

  1. Indicator of the effects of pollution in the water

  2. Sensitive species indicate safe water, less sensitive species indicate unsafe water
• Important chemical indicators to test for

  • Dissolved oxygen
  • Lead
  • Mercury
  • Copper
  • Heavy metals
  • Acidity
  • Plant nutrients
  • Pesticides
  • Salts
• Diversity of organisms decreases as acidity increases and dissolved oxygen decreases
• Dissolved oxygen


  The level of dissolved oxygen in the water can be affected by temperature, turbulence, algae/plant levels, and the number of organisms using it up
• Pesticides can remain in environments after no longer being needed
• The mixing of pesticides can lead to toxic or poisonous substances
• Aquatic environments most affected by pesticide use
• LD50


  Lethal dose - the amount of a substance that causes 50% of the test animals to die
• Acute toxicity


  Causes serious harm after a single exposure
• Chronic toxicity


  Effects are not evident until the toxin has accumulated to a certain level, usually over many exposures
• Transport of chemicals in the environment

  1. Release at the source

  2. Dispersion in the atmosphere

  3. Deposition in soil/water
• Factors that help track down the source of harmful airborne chemicals include pollutant properties, wind speed, wind direction, and precipitation
• Deposition of airborne pollutants is an international problem as chemicals travel across borders
• Groundwater


  Water that soaks into the soil and fills the spaces between soil grains
• Factors affecting groundwater movement include number and connection of pores in the soil
• Leachate


  Liquid that dissolves and carries substances as it passes through soil
• Dispersion


  Scattering of a substance away from its source
• Dilution


  Reducing the concentration of a pollutant by mixing it with larger quantities of air or water
• Biodegradation


  Substances being broken down by bacteria, worms, fungi (living things)
• Phytoremediation


  Technique to reduce the amount of harmful chemicals in soil using plants
• Photolysis


  Breakdown of compounds using the energy released by sunlight
• Persistent pollutant


  Chemicals that stay in the environment for a long time, e.g. lead, CFCs, DDT, mercury