How to Assess Pollution

Notes Jan. 18 (cont. from yesterday)

Direct Methods
-In situ (field work)

• It is reliable
• It gives straightforward data.
• Measures directly in the source.
  
• Can have technical difficulties (Instruments: costly or not portable)

- Ex Situ (lab work)

• Use a wider variety of methods and instruments
• More flexible (Test more variables, have more repetitions)
• Samples are not fresh. The time after the sample was extracted may affect it and alter the results.

Direct measurements can assess
*Concentration of gases
*Particulate matter
*pH
*Dissolved oxygen in water
*Biomass content
*Salts
*Conductivity
*Turbidity
*Temperature
*Density

Indirect measurement is done through
*BOD
*Indicator species
*Biodiversity
*Spectroscopy
*Chromatography