Water Supplies and Their Impurities

Natural fresh water supplies are derived indirectly from the oceans, clouds form by solar evaporation and winds move the moisture over the surface or percolates into the ground excess water flows back to the oceans completing the hydrological cycle.

Water supplies are classified as surface supplies and underground waters. Surface waters are rivers, lakes, creeks, ponds and reservoirs. Wells, Tube wells and springs are the sources of underground water.

Water vapour in clouds is generally pure but gathers dust and gases when it reaches the earth, suspended organic matter and soil turbidity are picked up. Minerals are leached from the soil and rocks and organic matter is added from municipal and industrial wastes and decaying vegetation. Well water usually are free of suspended materials and organic matter due to filtration through the earth. Surface waters are generally low in mineral content but relatively high in suspended and organic materials.

                                                                           * Organic materials may be suspended or dissolved, ionic or nonionic.

COMMON BELIEF ABOUT DRINKING WATER

There is a general assumption that bacteria and virus are the disease causing agents present in the water and the removal of these would make the water safe for drinking. But the scientific and medical community acknowledges that there is more to this.

In general there are three types of contaminants in water:

Physical, Microbiological and Metal/Chemical (both suspended and dissolved)

Most suspended physical contaminants (like dust, sand particles, dried leaves etc.) can be easily removed through simple filtration processes or simply by passing water through a fine cloth. But the real complication arises with Microbiological and Chemical impurities, thus making water undrinkable.

A study from the Centers for Disease Control and Prevention stated the following contaminants commonly found in well water and their adverse effect on human health:

CONTAMINANTS	HEALTH EFFECTS
Bacteria
Campylobacter	Causing diarrhea, abdominal pain and fever
Escherichia coli (E. coli) O157:H7	Bloody or non-bloody diarrhea, fever or even more severe effects like hemolytic uremic syndrome (HUS) and kidney failure in young children
Salmonella	Diarrhea, Typhoid fever and the infection can spread from intestines to blood causing even more serious illness.
Shigella	Watery or bloody diarrhea, fever, vomiting etc.
Viruses
Enterovirus	May cause mild upper respiratory, “Flu-like” symptoms with fever, muscle pain. In rare cases may cause Meningitis
Hepatitis A	Jaundice, tiredness, nausea, fever
Norovirus (Norwalk)	Causes stomach cramps, vomiting, diarrhea
Protozoa
Cryptosporidium and Giardia	Diarrhea, upset stomach and fever

METALS/CHEMICALS	HEALTH EFFECTS
Atrazine	May cause congestion of heart, lungs, kidneys; low blood pressure; muscle spasms; weight loss or even cancer
Arsenic	May cause stomach pain, nausea, vomiting, diarrhea, numbness in hands and feet, partial paralysis, skin damage and increased risk of cancer
Copper	Though an essential nutrient at very low levels, excess of it can cause upset stomach, vomiting, diarrhea and in the long run can also cause liver and kidney problems
Lead	Causes delayed physical and mental development in babies, also causes in shortened attention span, hearing and learning abilities in children. Long term exposure may lead to high blood pressure, stroke, kidney disease or even cancer
Mercury	May cause kidney damage
Nitrate	May cause Methemoglobinemia – a blood disorder that causes shortness of breath and blueness of skin which could even lead to death. Its known to mainly affect infants and pregnant women Also causes of increased urination and bleeding of the spleen
Radium	May cause cancer
Volatile Organic Compounds (VOCs)	May cause drowsiness, skin irritation and if exposed for a long time may even cause cancer

Source: www.cdc.gov/ncidod/healthywater