Water is our most needed resource. There is a vast amount of water that covers most of the Earth’s surface. There is often either too much water or too little water. But what water there is, whether fresh or saline, is subject to many forms of pollution, either anthropogenic (caused by humans) or natural.
The waters of the world are biomes, or habitats that support life. That life exists in a food chain of life forms that depend upon certain temperatures, certain salinity or freshness and certain substances being either present or absent. A few degrees of change in water temperature, for example, can decimate the chances of fish eggs making it though their process or can cause life forms to migrate to other areas that might not be able to sustain the increased population.
Water pollution in it’s simplest form is the introduction of large amounts of any substance that makes the water unclean or that otherwise causes a negative effect on the water system. There are two classifications for water pollution: point source and non point source.
Point source water pollution involves those substances that are directly put into the water.
Non point source water pollution is the major source of stream and lake pollution. This form involves indirectly putting substances into the water through changes in the environment or due to anthropogenic causes. Automotive oil, for example, is thrown down a storm drain. The rains come and wash the oil through the drainage system, where it ends up in rivers and streams. When the drains for a city block meet up with the drains for a section of a city, then meet up with larger drains, a large amount of automotive oil can end up in the river, bay or stream where the drains dump all that has been collected directly into the waterway. Farm pesticides, fungicides and fertilizers do the same, via irrigation ditches and natural paths of water runoff.
Even the habit of washing unused prescription medications down the drains has been publicized as affecting the life forms that end up ingesting the stuff!
Natural non point source water pollution occurs mostly when, rain washes silt, animal feces and decomposition and other material from the higher levels into the waterway, causing light blockage that kills aquatic plants and cloudy conditions that the living creatures cannot tolerate. In addition, recreational areas might have to be closed do to E-Coli contamination from the animal feces.
In the Western US and in other arid or semi-arid places, it is of great concern when the water becomes compromised from damage to the environment. Overgrazing and building logging roads, for example decimates the plant and tree population. Rain washes the bare silt and debris into the water. With no plants to shade the water in hot times, living organisms cannot tolerate the heat. The concept of managing the environment of waterways is called “Riparian Restoration”. This is a combination of programs to repair the results of both natural and man made environmental causes.
Dissolved oxygen levels are a consequence of much of the water pollution. Life forms use dissolved oxygen in order to survive. Some pollutants lead directly or indirectly to reductions in the DO levels that are needed for some life to go on.
Fertilizers and sewage that contain nitrates and phosphates will overstimulate aquatic plant and algae production. Overproduction of these life forms will clog waterways and will use up the dissolved oxygen that other life forms need for survival.
Soil, silt and other solids will cause Eutrophication, which is the process where stream and river beds fill up and the water cannot flow as normal. This lowers the allowable depth of the water and life forms that require a certain depth and amount of dissolved oxygen will be challenged.
Dissolved oxygen levels are compromised when excessive amounts of organic material are put in the water to decompose. The organisms that cause the decomposition can hog up the DO! Thus, the decomposition process can use up the dissolved oxygen.
Pathogens are the next category of pollutants and are quite destructive when they want to be. The main categories are bacteria, protozoa and viruses. There are plenty of tales of Cholera, Typhus, E-Coli and other illnesses that come from raw sewage, animal farm runoff, boat toilet emptying and which can cause closure of recreational areas. Again, these pathogens can be washed into waterways naturally, as animals interact with the water or die.
Radioactive material from mining, petroleum waste and heat or cold are the final source of water pollution. Dams and reservoirs that release colder water that disrupts life from the bottom; industrial processes that release warmer water than is tolerable, and a host of processes that release chemical or petroleum residue are major problems.
Finally, the major sources of water pollution have classifications: municipal, industrial and agricultural. In the treatment of municipal and industrial waste water, there have been improvements in reducing the amount of grit and other solids, pathogens and dissolved oxygen hogs.The sludge is managed to allow the biological actions to complete outside of the waterways.
Agricultural operations can now use containment ponds, anaerobic lagoons, and other methods to allow natural decomposition and filtering of problem materials.
Globally, over a billion people are said to have insufficient drinking water quality, with millions dying from water pollution issues annually. Oil spills are in danger of exceeding the ocean’s capacity to dilute the material. Beaches, rivers, streams and other waterways are too polluted for safe fishing and recreation and must often close.
As a result, it is a global imperative to no longer consider water as an unlimited resource that can take on and dissipate the waste of over 6.6 billion humans and their activities.
David Krantz and Brad Kifferstein, “Water Pollution And Society”, University of Michigan
