Chapter 4 Water Quality
Fundamental Concepts
Physical Parameters
Chemical Parameters
Biological Parameters
Water Sampling
Significance and contents
The topic of water quality focuses on the presence of foreign substances in water and their effects on people or the aquatic environment.
What substances are in the water and in what concentrations they are present.
Effects of those substances
Yardsticks or standards are needed.
Pure water? Rarely
Water in nature: contains some natural impurities in solution and in suspension.
as rain falls through the atmosphere: dust particles and gases----acid rain
Runoff: silt particles, bacteria, organic material and dissolved minerals.
Human activities: land use and direct discharge of municipal or industrial wastewaters to the environment.
How to determine and describe the condition of the water?
Quantitative measures
Parameters: physical, chemical, biological
Standards Methods for the Examination of Water and Wastewater (by Chinese EPA)
Portable field test kits
Fundamental Concepts
Chemistry: composition and properties of substances
Elements pounds
Solutions
Suspensions and Colloids
Expressing Concentrations
Acids, Bases, and anic Substances
Mass Balance
Elements pounds
Table +Table
Atom, compounds, molecule, chemical anic, anic
Nucleus, protons, neutrons, electrons
Positively/negatively charged particles, uncharged or neutral particles
Outmost shell or orbital
atomic number, atomic weight
Formation of molecules
Ionic bonding: transfer of electrons
Covalent bonding: share electrons
Polar molecule
Hydrogen bond
Solutions
Aqueous solution: solutions in water
Solvent/solute
Saturated solution; solid, liquid, gas
Factors: temperature, altitudes, salinity
Ionization: positive sodium ion, negative chloride plex Ions: hydroxyl ion, sulfate ion, nitrate, phosphate, ammonium, hypochlorite
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