WATER CONTAMINATION AND

HUMAN HEALTH

Pam StewartBiomedical InnovationsCentral Magnet School

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

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

EXAMPLE CONTAMINANTS

Disinfectants and Disinfection ByproductsExamples 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 TESTINGDrinking 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

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

CONDITIONS REQUIRING TESTING

WATER TEST

Coliforms

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:

COMMON COLIFORMS

C. freundii SerratiaE. coliC. jejuni

MERCURY

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.

LEAD

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.

RADON

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.

AMMONIUM

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.

PH

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

CHLORINE

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

CHROMIUM

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.

COPPER

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.

CYANIDE

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.

IRON

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.

NITRATES

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.

PHOSPHATES

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.

SILICA

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.

SULFIDE

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.