define the term water pollution
•Any physical or chemical change in water that adversely affects the health of humans and other organisms
define the term eutrophication
Enrichment of a water body with nutrients, resulting in excessive growth of phytoplankton, algae, or vascular plants, leading to depletion of oxygen.
define DO
disolved oxygen
define BOD
Biological Oxygen Demand…the amount of oxygen consumed by aquatic decomposers
define dead zone
hypoxic (low-oxygen) areas in the world’s oceans and large lakes, caused by “excessive nutrient pollution from human activities coupled with other factors that deplete the oxygen required to support most marine life in bottom and near-bottom water.
oligotrophic
•Unenriched, clear water that supports small populations of aquatic organisms
eutrophic
- Slow-flowing stream, lake or estuary enriched by inorganic plant and algal nutrients such as phosphorus
- Often due to fertilizer or sewage runoff
types of water pollution
- Sewage
- Disease-causing agents
- Sediment pollution
- Inorganic plant and algal nutrients
- Organic compounds
- Inorganic chemicals
- Radioactive substances
- Thermal pollution
Sewage pollution cause
oThe release of wastewater from drains or sewers
•Includes human wastes, soaps, and detergents
Sewage pollution effect
Enrichment
- •Fertilization of a body of water by high levels of plant and algal nutrients (nitrogen and phosphorus)
Increase in Biological Oxygen Demand (BOD)
- •Amount of oxygen needed by microorganisms to decompose biological wastes
- •As BOD increases Dissolve Oxygen (DO) decreases
Disease-causing Agents
oInfectious organisms that cause diseases
•Originate in the wastes of infected individuals
Sediment Pollution cause
oExcessive amounts of suspended soil particles
•Originates from erosion of agricultural lands, forest soils exposed by logging, degraded stream banks, overgrazed rangelands, strip mines, and construction
Sediment Pollution effects
- Limits light penetration
- Covers aquatic animals and plants
- Brings insoluble toxins into waterways
Inorganic Plant and Algal Nutrients cause
Chemicals such as nitrogen and phosphorus that stimulate the growth of plants and algae
•Harmful in large concentrations
Sources:
•Human and animal wastes, plant residues, atmospheric deposition, and fertilizer runoff
Inorganic Plant and Algal Nutrients effects
•Enrichment, bad odors, and a high BOD
Organic Compounds causes
oChemicals that contain carbon atoms
Inorganic Chemicals causes
oContaminants that contain elements other than carbon
Radioactive Substances
Contain atoms of unstable isotopes that spontaneously emit radiation
Sources
- Mining
- Processing radioactive materials
- Nuclear power plants
- Natural sources
Thermal Pollution causes
oOccurs when heated water produced during industrial processes is released into waterways
Thermal Pollution effects
oOrganisms affected
- Temperature affects reproductive cycles, digestion rates, and respiration rates
- Warm water holds less DO than cold water
Types of Water Pollution
- oPoint Source Pollution
- •water pollution that can be traced to a specific origin
- •Discharge via pipes, sewage, and ditches
- o-Non-point Source Pollution
- •Pollutants that enter bodies of water over large areas rather than being concentrated at a single point of entry
- •Diffuse, but its cumulative effect is very large
- •Ex: runoff from agricultural fields or parking lots
How do we measure water quality
- Dissolved Oxygen: BOD Biological Oxygen Demand…the amount of oxygen consumed by aquatic decomposers
- Chemical Analysis: looking for presence of inorganic or organic chemicals
- Suspended Sediment water clarity
Municipal Sewage Treatment
- oPrimary treatment
- •Removing suspended and floating particles by mechanical processes
- oSecondary treatment
- •Treating wastewater biologically to decompose suspended organic material; reduces BOD
- oTertiary treatment
- •Advanced wastewater treatment methods that are sometimes employed after primary and secondary treatments
- •Reduce phosphorus and nitrogen
- oChlorination
- •Particularly effective on viruses and pathogenic bacteria and nitrogen.
