The history of drinking water treatment dates back to ancient times approximately 4000 BC. Ancient Greeks and Egyptians recommended cleaning water by filtering it through charcoal, exposing water to sunlight, boiling, and straining. Egyptians even used chemical alum in 1500 BC to cause particles to settle out of water. Many of the earliest water treatments were to improve the aesthetic value of water. The scientific explorations of the 1800’s left the understanding that disease could spread through water with the ‘germ theory’. In the late nineteenth and twentieth centuries concerns of water borne disease warranted concern for the public water supply. By the early 1900, many cities used slow sand filtration to reduce turbidity, which was discovered to harbor pathogens. In 1908, chlorine was used for the first time to disinfect water in the United States, which played the largest role in reducing disease. The United States government began federal regulation of drinking water in 1914 by setting standards for bacteriological levels. The standards applied to interstate carriers and only applied to contaminates that caused disease. The Public Heath Service revised and expanded those standards up to 1962. The revision of 1962 included 28 regulated substances and was the most comprehensive regulations until the Safe Drinking Water Act of 1974. In the late 1960’s chemicals became a health concern as well and increased awareness of chemical contamination led to the passage of the Safe Drinking Water Act in 1974 with revisions in 1986 and 1996 and is administered by the Environmental Protection Agency. Today water treatment is mostly carried out with chlorination and filtration as well as advancements such as ultraviolet light, ozonation, and reverse osmosis. The significance of clean drinking water was recognized by the Centers for Disease Control and Prevention and the National Academy of Engineering as the most significant public health advancement of the 20th Century. (11)
Federal legislation for water pollution and water quality has occurred relatively recently. The Federal Water Pollution Control Act was passed in 1972 and after further amendments, it became known as the Clean Water Act in 1977. The Clean Water Act established the foundations for regulating pollutants into the waters of the United States. The Clean Water Act has regulatory and non-regulatory tools to reduce pollutant discharge into waterways, finance municipal wastewater treatment facilities, and manage polluted runoff. The goal is to restore the nation’s waters so that they can support wildlife and recreation in and on the water. Initially the Act focused on point source polluters such as municipal sewage facilities and industrial facilities. In the late 1980’s efforts were made to deal with non-point source pollution such as runoff. The Clean Water Act now focuses on holistic watershed based strategies to reduce water pollution. (12)
Drinking water legislation was passed in 1974-The Safe Drinking Act. The goal was to ensure safe public drinking water supply. The law was amended in 1986 and again in 1996 and requires many actions to protect drinking water and its sources. The Safe Drinking Water Act (SDWA) covers individuals getting water from a system with at least 15 service connections or serve at least 25 people, but does not cover individuals getting their water from wells that serve less than 25 people. The SDWA authorizes the Environmental Protection Agency to set national health-based standards for drinking water to protect against water contaminants. The EPA sets standards through a three-step process: 1-The EPA identifies contaminants that may affect the public health adversely and occurs in drinking water as a threat to public health. 2-The EPA sets a maximum contaminant level (MCL) for the regulated contaminant. The MCL should be well below a level that causes harm. 3-The MCL is established for all facilities under the SDWA. Drinking water standards are legally enforceable and allow the EPA or governing body to take legal action for those in noncompliance. The SDWA also makes water providers provide a consumer confidence report on the quality of their water. (13)
A luxury of living in a technologically advanced society is that we take for granted much of the machinery that allows us to live healthy, happy lives. Having clean drinking water is one of those luxuries. Most Americans have no notion of the journey their water takes to get their faucet clean and drinkable. By the time water gets to our homes possible contaminants screened for have been eliminated or reduced to harmless levels, but not all. Though many harmful substances are eliminated from our water, some contaminants still persist, some even come from the purification process. Possible water contaminants are microbes, radionuclides, inorganic contaminants, synthetic organic contaminants including pesticides and herbicides, volatile organic contaminants, disinfectants, and disinfection byproducts. (14)
Microbes such as bacteria, viruses, and protozoa are common and are not generally harmful. Possible microbial contamination occurs through human and/or animal wastes through entering water supply. Common bacterial contaminants are Coliform bacteria, fecal coliform, E.coli, cryptosporidium, and Giardia lanblia. Coliform bacteria is a microbe that is usually harmless, but its presence in water is an indication that the water treatment process has failed and that other microbes that are harmful are present in the water supply. Fecal Coliform and E.coli are bacteria that contaminant the water supply through human and/or animal waste. A few symptoms of infection are nausea, cramps, diarrhea, and associated headaches. Cryptosporidium is a parasite that also enters the water supply through animal waste as well as sewage. Cryptosporidium causes diarrhea, vomiting, and cramps that is mild in people with normal immune systems, but can be severe to fatal in those with compromised immune systems. Giardia lamblia is also a parasite that enters the water supply through sewage and animal waste. A symptom of infection is gastrointestinal distress. Turbid water, though the turbidity itself is not harmful, can lead to microbial contamination. Turbidity increases the risk of contamination because it can interfere with the decontamination process and provide microbes with a medium in which to live. (15)
Radionuclides can enter the water supply through natural occurrences or could be the result of oil and gas production and mining activities. Possible radionuclides that contaminate water are alpha emitters, beta/photon emitters, combined radium 226/228, and radon. People who drink radionuclides in excess of the Environmental Protection Agency’s standards are at an increased risk of developing cancers. (16)
Many chemicals, both organic and inorganic, and synthetic and naturally occurring can contaminate water supplies. Inorganic contaminates can be naturally occurring or may be the result of urban storm water runoff, industrial or domestic wastewater discharge, oil and gas production, mining, or farming. Pesticides and herbicides enter the water supply through agriculture, urban storm water runoff, and residential uses. Organic chemical contaminants, both synthetic and volatile organic compounds, may enter the water supply through the by products of industrial processes and petroleum products, gas stations, urban storm water runoff, and septic systems. Common inorganic contaminants are arsenic, fluoride, and lead. Arsenic exposure in drinking water over many years can cause skin damage, circulatory system problems, and may have an increased risk of getting cancer. Many communities to promote dental health add fluoride. Drinking supplies that contain an excess of the EPA’s standard of 4mg/L over several years could develop bone disease, including pain and tenderness of bones. Children should not drink water that contains more than 2mg/L to prevent dental fluorisis. Dental fluorosis only occurs in developing teeth below the gum and may result in staining or pitting of permanent teeth. Lead enters water supplies through the leaching of old plumbing. Pregnant women and children are at the most risk from lead poisoning. Lead plumbing has been banned since 1998. MTBE is a fuel additive that is used to reduce carbon monoxide and ozone levels in automotive emissions. Its high use in the United States has caused increased levels in the water supply. Studies are underway to examine the health impact of MTBE in the water supply. (17)
Many do not realize that the chemicals added to disinfect their water also contaminate their water. Chlorine is a common disinfectant as well as chloramine and chlorine dioxide. People drinking water with excess chlorine could experience effects to their eyes, nose, and stomach. Excess chloramine can cause irritation to the eyes and nose as well as stomach discomfort and anemia. Excess chlorine dioxide can cause nervous system effects in infants, young children, and unborn fetus. It may cause anemia in adults as well. Disinfectant byproducts, such as trihalomethanes, haloacetic acid, bromate, and chlorite are formed when disinfectants react with naturally occurring organic matter in water. Trihalomethane may cause an increases risk of cancer and disorders of the liver, kidneys, and the central nervous system. Haloacetic acid and bromate also increase the risk of cancer. Excess chlorite affects the nervous system of unborn fetuses, infants, and young children. It may also cause anemia in adults. (18)
