Environmental Chemistry test 2(#1)

Movement of chemicals

D- dispersion The scattering movement of a chemical in various directions away from its source

• Example: wind blows it

D- deposition the location where a chemical stops moving and begins to accumulate

• Examples: acid precipitation, seepage into ground water, run-off

R- Release of chemicals at the source

• Example: evaporation of chemicals and/or burning of fossil fuels enter the air

Factors that affect travel of airborne pollutants?

• Weight-the heavier the pollutant, the sooner it will be deposited

• Wind Speed-the faster the wind speed, the sooner the pollutant will be deposited

• Precipitation-the more precipitation, the sooner the pollutant will be deposited

• Temperature-the cooler the temperature, the sooner the pollutant will be deposited

Different types of sources for pollutants?

• Point Source Pollutants

  • Any single, identifiable source of pollution from which pollutants are discharged. 

  • (ex: pipes, ship or factory smokestacks, etc.)

• Non-point Source Pollutants

  • The diffuse contamination of water or air that does not originate from a single discrete source

  • (ex: rainfall, snowmelt, urban runoff)

Factors that affect how far away a pollutant travels +its speed in water

How far away the pollutant travels in water is based on 3 main factors:

1. Water Solubility-the more insoluble the pollutant, the sooner it will be deposited

2. Weight-the heavier the chemical pollutant, the sooner it will be deposited

3. Water Speed-the slower the water, the sooner the pollutant will be deposited

Factors that affect the movement of contaminants in groundwater?

• The number and connection of pores (tiny spaces between soil grains) in the soil

• When the pores are packed very tightly and are not connected, the soil is considered impermeable

• If the pores are connected the soil is permeable and water can move through it quite easily

What is toxicity

The ability of a chemical to cause harm to an organism.  It’s the amount of chemical causing the damage that matters.

Types of Toxicity

Acute Toxicity - serious symptoms occur after only one exposure to a chemical Ex. Methyl isocyanate

Chronic Toxicity - symptoms appear only after a chemical accumulates to a specific level after many exposures  Ex. Lead

what does LD50 stand for, do and mean

-a common measurement of the toxicity of a substance

-refers to the dose of a chemical that will kill 50 percent of the population to which it is applied

-the smallest number that kills 50% is the most toxic substance

Waste management 4Rs?

• Reduce: buying/using items that have less packaging, or more environmentally-friendly packaging

• Reuse: finding new uses for items that would otherwise be discarded

• Recycle: having old items broken down to be turned into new products

• Recover: capturing energy from waste products to use as fuel