Sanitation

SANITATION

Sanitation is a basic, as well as a long-standing, public health issue. When early peoples settled in communities and started to cultivate crops and raise animals, sanitation became a primary concern for society. The Book of Leviticus, in the Torah, includes specific guidelines regarding the disposal of wastes, the placement and disinfection of wells, and related issues. Today, as urban areas grow, more pressure has been put on local water supplies, for the quality of the water that is available to a community greatly impacts all aspects of health. Worldwide, 40 percent of the population does not have ready access to clean, safe drinking water, and approximately 60 percent does not have satisfactory facilities for the safe disposal of human waste. Infectious agents in drinking water and food cause the diarrheal deaths of several million children annually.

In the United States, every person uses almost 100 gallons of drinking water per day, though only a small portion of this amount is actually used for drinking. Other uses include toilet flushing, bathing, cooking, cleaning, and lawn watering.

SOURCES OF WATER

Water sources are manifold. Many communities get their water from reservoirs. In 500 B.C.E., the Greeks supplemented local city wells with water supplied from the mountains as far as ten miles away. In later times, the Romans built aqueducts that were many miles long—there are more than two hundred that are still standing in the year 2001. Cities and other communities often provide for their water supply by allocating an open area that is pristine and protected as a watershed. The water is usually of high quality and free from chemical and microbial contamination. These sources are referred to as surface water sources and include lakes, streams, and rivers. Some surface water requires extensive treatment before it can be distributed for human consumption.

In other parts of the country, water is supplied to communities from groundwater sources through deep wells, often many thousands of feet down. Water from these sources is also usually free of chemical and microbial contamination. Groundwater is the main source of drinking water for almost half of the population in the United States. While it is usually free of solids and bacteria, as well as other chemical pollutants, it has often become contaminated by disposal of liquid waste and agricultural runoff. Groundwater is relatively inexpensive, but it is limited in volume and irreplaceable if depleted. By providing protection to the source, either through buffers from the reservoirs or by protecting the well head for the deep wells, water is available without much treatment.

Because of the increasing population and the increased use of water by each individual in the United States, there are less uncontaminated water supplies available. Many sources of water must be treated prior to consumption. Disinfection is an important step in the water treatment process to destroy pathogenic bacteria and other harmful agents. Most water is treated with chlorine, as it is a very effective and economical method of treatment. An important advantage to using chlorine is that it has residual properties and continues to provide germ-killing potential as the water travels from the distribution point to the end users. There are concerns, however, about the formation of disinfection by-products from the reaction of the chlorine with humic substances in the water. These by-products are referred to as trihalomethanes, or THMs. The most common THM is chloroform, which is a carcinogen.

Sanitation includes the appropriate disposal of human and industrial wastes and the protection of the water sources. Waterborne agents are the cause of many diseases in the United States and elsewhere in the world. These diseases may be caused by bacteria, viruses, and protozoans. Bacterial diseases include typhoid, shigellosis, and cholera. Viral agents cause diseases such as include polio and hepatitis. Parasites include the protozoa Entamoeba histolytica and Giardia lambdia, which cause amebiasis and giardiasis, respectively. For the last decade the primary agents in waterborne disease outbreaks in the United States have been the protozoal parasite Giardia, and the bacteria Shigella. Another common agent is Cryptosporidium.

Another example of sanitation as it relates to waterborne diseases globally is schistosomiasis. Schistosomiasis is a chronic debilitating disease with significant morbidity and mortality that affects more than 200 million people worldwide. Sanitation and water supply are important issues in an integrated schistosomiasis control program.

Content licensed from:

Author Info: MARK G. ROBSON, The Gale Group Inc., Macmillan Reference USA, New York, Gale Encyclopedia of Public Health, 2002

This feature is for informational purposes only and should not be used to replace the care and information received from your healthcare provider. Please consult a healthcare professional with any health concerns you may have.