Water Contamination and Human Health

Water Contamination

• Contamination is caused by pollution from foreign matter such as microorganisms, chemicals, industrial or other wastes, or sewage.

• Many forms of water contamination can be harmful to human health.

• Contamination can occur naturally, but it is mostly due to human activity.

Common Causes of Contamination

• Human and animal sewage• Leakage from underground storage tanks• Urban run-off• Mines• Landfills and waste dumps• Industrial emissions and waste disposal• Pesticides• Agricultural run-off from crops

Types of Contaminants

Water contaminants can be broken into the following categories:– Microorganisms– Disinfectants– Disinfection byproducts– Inorganic chemicals– Organic chemicals– Radionuclides

Example Contaminants

Microbial contaminants include bacteria, viruses, and parasites such as:– Cytosporidium– Giardia lambia– Legionella– E. coli– Enteroviruses

Example Contaminants

Disinfectants and Disinfection Byproducts

Examples include:– Chlorine– Bromate– Chlorite

Inorganic Chemicals

Examples include:– Arsenic– Barium– Cadmium– Chromium– Copper– Cyanide– Mercury– Nitrates/Nitrites

Example Contaminants

Organic Chemicals

Examples include:– Acrylamide– Benzene– Carbon tetrachloride– PCBs– Styrene– Vinyl chloride

Radionuclides

Examples include:– Radium– Radon– Uranium

Drinking Water Standards

• Public water supplies are legally required to meet national standards meant to protect public health by limiting the levels of contaminants in drinking water.

• Private water supplies from wells are not regulated. It is up to well owners to have their water tested.

Drinking water is often tested for the following:• Total coliforms• Fecal coliforms• Ammonium• pH• Chlorine• Chromium• Copper• Cyanide• Iron• Manganese

• Phosphates• Silica• Sulfates• Nitrates• Nitrites• Radon• Lead• Mercury• Turbidity• Hardness

Drinking Water Testing

Source: http://water.epa.gov/drink/info/well/faq.cfm

Conditions Requiring Testing

• Mercury• Lead• Radon• Ammonium nitrogen• pH• Chlorine• Chromium

• Copper• Cyanide• Iron• Nitrates• Phosphates• Silica• Sulfide

You will test both the Williams’ well water as well as the water you collected from a local source for the following contaminants:

Water Test

• Mercury is a naturally occurring element found in many rocks including coal. When coal is burned, mercury is released into the environment.

• Mercury in the air eventually settles into water or onto land where it can be washed into water.

• Once deposited, certain microorganisms can change mercury into methylmercury, a highly toxic form that builds up in fish, shellfish, and animals that eat fish.

Mercury

• Lead is a naturally occurring bluish-gray metal found in small amounts in the earth's crust.

• Lead can be found in all parts of our environment. Much of it comes from human activities including burning fossil fuels, mining, and manufacturing.

Lead

• Radon is a cancer causing, radioactive gas.

• Radon comes from the natural breakdown of uranium in soil, rock, and water and gets into the air.

• Radon can get into any type of building and result in a high indoor radon level.

• The greatest exposure occurs at home, where you spend most of your time.

Radon

• Ammonium is produced when microorganisms break down organic nitrogen products such as urea and proteins in manure.

• Ammonia can lead to eutrophication, or nutrient over-enrichment, of surface waters. – The overabundance of nutrients (particularly nitrogen

and phosphorus) can lead to the over-growth of algae and the resulting “blooms” can cause taste and odor problem and sometimes involve toxin-producing species.

Ammonium

• pH is an expression of hydrogen ion concentration in water.

• pH indicates the degree of basicity or acidity of a solution ranked on a scale of 0 to 14, with pH 7 being neutral.– Low pH indicates acidity and high pH indicates

basicity

• Water should be neutral with a pH close to 7.– Chemical contamination tends to make water acidic or

basic

pH

• The gaseous or liquid form of chlorine (CL2) is a water additive used by municipal water systems to control microbes.

Chlorine

• Chromium, a metallic element, is found in rocks, soil, plants, and animals. It is also used in steel making, metal plating, leather tanning, paints, dyes, and wood preservatives.

• Chromium-3 has relatively low toxicity and would be a concern in drinking water only at very high levels of contamination, unlike chromium-6 and -0, which are more toxic and pose potential health risks to people.

Chromium

• Copper is a metal found in natural deposits such as ores containing other elements.

• Copper is widely used in household plumbing materials.

• Copper may cause health problems if present in public or private water supplies in amounts greater than the drinking water standard set by EPA.

Copper

• Cyanide is a carbon-nitrogen chemical unit.

• The most commonly used form, hydrogen cyanide, is mainly used to make compounds and other synthetic fibers and resins.

• Cyanide may cause health problems if present in public or private water supplies in amounts greater than the drinking water standard set by EPA.

Cyanide

• Iron is a trace element needed by plants and animals in small amounts.

• Iron is derived from minerals in the soil and underlying rocks.

• Presence of iron in water results in “hard” water and creates an unpleasant odor and taste.

• Iron is not considered to present a risk to human health.

Iron

• Nitrates and nitrites are nitrogen-oxygen chemical units which combine with various organic and inorganic compounds.

• The greatest use of nitrates is as a fertilizer. Once taken into the body, nitrates are converted to nitrites.

• Nitrates may cause health problems if present in amounts greater than the drinking water standard set by EPA.

Nitrates

• Phosphorus is one of the key elements necessary for growth of plants and animals.

• Phosphates in high amounts are often due to use of fertilizers and organic pesticides.

• Phosphates do not affect human health unless present in very high amounts.

Phosphates

• Silica, the chemical compound silicon dioxide, is most commonly found in nature as sand or quartz

• Silica in drinking water does not pose a health risk for humans.

Silica

• Sulfates are one form of sulfur species found in water.

• Pesticide residuals and manufacturing wastes are sources of pollutant sulfur species.

• Sulfates are reduced by a strain of bacteria to hydrogen sulfide, which give the water a rotten egg smell.

• Sulfates in large amounts may cause negative health effects.

Sulfide