Polluted Water
In the recent past, water quality has become a concern for Canadians. The human pollution in urban centres tends to have a negative influence on water quality. There are three types of contaminants that contribute to water pollution:Physical Contaminants
Physical contaminants consists of objects that do not dissolve in water (ex. petroleum products, garbage, floating debris, soil). The removal of physical contaminants is the first step in the water purification process.
Biological Contaminants
Biological contaminants include bacteria and viruses. Many beaches close each summer due to fecal coliform bacteria level. The removal of biological contaminants is the second step in the water purification process.
Seven peopled died and hundreds were seriously ill in Walkerton, ON due to a major aquifer that was polluted with E. coli bacteria, due to agricultural runoff from cow manure. Had the town’s chlorination system worked properly, many lives would have been saved.
Chemical Contaminants
Chemical contaminants consist of substances that are soluble in water (ex. manufactured chemicals, metal ions and compounds, pesticides, fertilizers and soluble petroleum products). The removal of chemical contaminants is the third and final step in the water purification process.
There is an unprecedented amount of chemical waste finding its way to bodies of water – dumping, leaching from landfills, incineration, etc. Some wastes, like fertilizers, are biodegradable to a certain extent. Other wastes, like the pesticide, DDT, are not easily broken down by nature.
Each of the above contaminants is removed in turn to provide clean drinking water.
The Solution
- do not dump harmful chemicals down the drain – at school or at home
- use smaller quantities of toxic, corrosive and/or reactive chemicals
- dispose of chemicals properly – at designated drop offs
- store chemicals properly and safely
The Government’s Role
The province is responsible for setting and enforcing standards to ensure that treatment facilities operate properly and that drinking water is safe to use.
There are federal-provincial water quality guidelines that list the maximum acceptable concentrations (MACs) of chemicals that may be left in drinking water after treatment (see Table 2, p. 283).
Water treatment plant operators are in charge of ensuring that the water meets these standards and plant lab techs are responsible for the testing the quality of samples sent to them.
Homework:
Section Questions,, p. 284 # 1-4, 6a
Read "Water Disinfectation Methods" p. 288-289 and do p. 289 # 1, 2.
Read "Protecting Canada's Great Lake Environment" p. 290-292 and do p. 292 # 1-4.
Here are a few water bottle labels:
Answers:
