Major Kinds and Sources of Pollution
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Bernard Nebel.
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Guide kids in discussion to expand their minds as to the multitude of kinds and sources of pollution (see text, outline below). Give kids a historical perspective: polluting the environment is not a new “sin”. It is that both number of people (population) and use of materials per person have grown many-fold so that there is no longer a place to dispose that is “out of sight, out of mind”.
Major Kinds and Sources of Pollution
Trash and garbage from homes and businesses:
Disposal pre 1960s. open burning dumps (Type into your browser: open burning municipal dumps images) Problem: intolerable pollution
Current disposal–landfills. (Type into your browser: landfill operation images) Problem: Limited space near cities
Burning trash in modern incinerators with pollution controls to produce electrical power. See video at: https://www.youtube.com/watch?v=lmtOuAed5nM
Exhaust from vehicles and industry
Lack of controls prior to the 1970s resulted in cities being cloaked in “smog”. Type into your browser: smog images
Legislation (the Cleat Air Act of 1970) was passed, targets were set, and technologies were developed and implemented. See:
Sediment in streams and rivers–soil particles from erosion
Type into your browser: sediment pollution images
Consider impacts on aquatic life
Controls. see video: https://www.youtube.com/watch?v=Kdm-Z-_AGnU
Sewage
From early times through the 1960s, raw sewage was commonly discharged directly into waterways. Type into your browser:
raw sewage discharge into waterway images
Since that time sewage treatment plants have been constructed. The following video describes the multistep process of cleaning wastewater (sewage) before it is discharged.
Toxic chemicals
The discharge of industrial wastes containing toxic chemicals, e.g., mercury, have been identified and are now regulated and largely controlled, albeit inspectors must remain vigilant.
Remaining problematic are pesticides and herbicides, that are used in massive quantities to protect agricultural crops, lawns and gardens from being devoured by insects and other pests or being crowed out by weeds. The story of DDT, given in following video, is illustrative of the problem. See: https://www.youtube.com/watch?v=fVI0QhJnT_c
Be sure students understand the phenomenon of and problems posed by the phenomenon of bioaccumulation/biomagnification.
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