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Traditional Aboriginal Knowledge


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Persistant Pollutants
Water Pollution and How it Occurs
Flow of Pollutants
Selected Water Pollutants

adapted to HTML from lecture notes of Prof. Stephen A. Nelson Tulane University
image from:  http://compoundchem.com  with thanks

Atmospheric Pollutants

Persistant Pollutants

Accumulates in our bodies over long periods of time. The US EPA, has set maximum standards, or limits, for many of these.
Lead -- Less than .05 ppm in water.
Arsenic -- Less than .05 ppm in water.
Mercury -- Less than .002 ppm in water.
Nitrates -- Less than 10 ppm in water.
Main sources are fertilizers and sewage.
Inhibits blood ability to carry oxygen.
Can not boil water to remove, like you can with bacteria and virii -- boiling only concentrates nitrates, making them more toxic.   Epidimiology - Study of disease rates and what causes them. Often provide a very valuable source of information on how deaths are related to other factors.

Area Cardiovascular Disease Other Causes Total
Hard Water 
642 556 1198
Soft Water
1255 216 1971 

It was found that taking into account all possible causes for the differences in death that:
The hard water regions have the lower death rates.
The soft-water regions, which are the areas in the coastal plains, have the higher death rates.

Water Pollution and How it Occurs

Point Source Pollutants

Pollutants that enter into the system at one single point.

Non-Point Source Pollutants

Flow of Pollutants

Ground water - flows along the gradient in the water table, taking a path that is perpendicular to the contours. Pollutants in the groundwater will flow in plumes along the same path. When a pollution source is introduced into the groundwater, the resulting plume will only affect areas downgradient from the source. Areas upgradient of the source, to the sides of the plume or below the plume will not be contaminated. Groundwater flows relatively slowly. On Long Island a typical rate of flow is about one foot per day near the water table. As the contaminant plume travels it becomes somewhat broader and more dilute as it slowly mixes with the surrounding cleaner water. Depending upon the original concentration of the plume and the distance the plume travels the contaminants may become so diluted that eventually the concentrations are lower than drinking water standards.

Selected Water Pollutants

Overabundance of Nutrients -- can cause Eutrophication.


Hazardous Chemicals (Toxic organic and Inorganic compounds). Heavy Metals -- Lead, Mercury, Zinc, Cadmium
Radioactive Chemicals Thermal Pollution Many industries use water to cool their factory machines. They then dump this warm water back into it's source. This is pretty harmful to the native life of the region, as it has generally evolved to survive in a particular range of temperatures.