The Safe Drinking Water Act (Public Law 93-523) was passed in 1974 due to congressional concerns about organic chemical contaminants in drinking water and the inefficient manner by which states supervised and monitored drinking water supplies (Pontius 1990). The essential aim of Congress was to assure that all citizens served by public water systems would be provided high quality water (Cook & Schnare 1986). Except for the coliform standard under the Interstate Quarantine Act, drinking water standards were not enforceable until the SDWA was passed (Pontius 1990). Under legislation of the SDWA, the United States Environmental Protection Agency (USEPA) was required to set enforceable standards for health-related drinking water contaminants. The act also established programs intended to protect underground sources of drinking water from contamination (Cook & Schnare 1986). These standards were to effect all public water systems serving at least 25 persons (Pontius 1990).
The regulations of the SDWA were set in two steps: The first step was to set interim regulations immediately. These regulations were based primarily upon the United States Public Health Service (USPHS) guidelines set in 1962. The second step was for these interim regulations to be revised. Revisions were to take place only after a comprehensive study in which the National Academy of Science assessed the effects of human exposure through drinking water and the toxicology of contaminants in drinking water was complete (Pontius 1990). Interim standards developed in 1975 set specific maximum contaminant levels(MCLs) for several substances classified as contaminants. Amendments were made to the interim standards in 1976, 1979, and 1980. In addition to the health-related enforceable guidelines set by the SDWA, the act mandated the USEPA to set nonenforcable federal guidelines for contaminants that may adversely affect the aesthetic quality of drinking water (Pontius 1990). The non-enforceable federal guidelines developed the set of initial secondary drinking water standards and their specific secondary MCLs (SMCLs). The SMCLs were set in 1979 (Pontius 1990).
During the middle and late-1970s the
USEPA concentrated on regulating two classes of drinking water
contaminants: 1- synthetic organic chemicals (SOCs) and 2- organic
contaminants. The release of SOCs into drinking water sources results
from industrial contamination of surface water supplies. Organic contaminants
result from the disinfection process of water treatment, these organic
contaminants are known as trihalomethanes (THMs). Some synthetic
organic chemicals are considered toxicants. Some SOCs are also suspected
cancer causing agents (Pontius 1990). These SOCs were not recognized prior
to the early 1970s due to a lack of sophisticated analytical chemistry
measurement techniques. As analytical chemistry technology developed,
measurement techniques developed as well. With this development,
scientists were able to reveal the presence and importance of SOCs in
drinking water.
The first time the public became aware of chemical contamination in drinking water was In 1972. In a report named "Industrial Pollution of the Lower Mississippi River in Louisiana", scientists presented evidence of the presence of THMs and SOCs in drinking water (Pontius 1990). A study produced by the USEPA during 1976 and 1977 called the National Organics Monitoring Survey, concluded that the four THMs of concern; chloroform, bromodichloromethane, dibromochloromethane, and bromoform were all formed during the disinfection process of water treatment. THMs are produced in the course of water treatment as by-products of the chlorination process (Pontius 1990).
Volatile organic chemicals (VOCs) were also discovered as having presence in drinking water and drinking water supplies. VOCs are the result of commonly used chemical solvents spilled or dumped into the groundwater. To contain the threat of VOCs in the environment, the USEPA conducted the National Ground Water Supply Survey from 1981 to 1982 (Pontius 1990). The team for the survey sampled close to 1000 ground water supplied public water systems to find that approximately one quarter of the systems tested contained at least one VOC at concentrations above the detection limit (Pontius 1990). The presence of these man-made chemicals in drinking water made it clear to the public that resources once thought invulnerable were subject to man and his pollution.
The presence of pesticides in drinking water was another verification that drinking water supplies were not safe. Some pesticides commonly found in water supplies across the nation are aldicarb, chlordane, and ethylene dibromide (Pontius 1990). A survey of the prevalence of pesticides in major surface water supplies performed by the USEPA in 1980 showed that 20 percent of the supplies tested had atrazine concentrations at levels of concern (Pontius 1990). A national survey finished by the USEPA in 1990 noted that out of the 1300 public and private groundwater supplies tested for pesticides, 10 percent of community wells and 4 percent of rural domestic wells had detectable amounts of at least one pesticide or degradation product (Pontius 1990). These detected concentrations were generally below MCLs or health concern levels (Pontius 1990).
Another cause for concern in drinking water and drinking water sources were outbreaks of waterborne diseases. During the years 1972 to 1981, there were 335 reported outbreaks of waterborne disease involving approximately 78,000 cases (Pontius 1990). The most common microbiological agents of concern are Giardia lamblia and Cryptosporidium. Giardia infections are caught by ingestion of viable cysts from water or food by the fecal-oral route (Pontius 1990). Between 1972 and 1981, 50 outbreaks of waterborne giardiasis were reported (Pontius 1990). Viruses are also major contributors to microbiological contamination in drinking water. Between 1972 and 1981, 5000 cases were related to 11 waterborne outbreaks of viral infections (Pontius 1990).
The last of the contaminants to require monitoring under the SDWA during the 70s and 80s were inorganic chemicals and radionuclides. The major inorganics of concern were and still are arsenic, barium, lead, natural fluoride and nitrate (Pontius 1990). Another frequently occurent inorganic chemical in drinking water, asbestos, comes from natural mineral sources and from the degradation of asbestos-cement piping systems (Pontius 1990). Because asbestos is a suspected carcinogen, it is regulated under the SDWA.
Natural radionuclides of concern because of their carcinogenicity are radium, uranium and radon (Pontius 1990). The National Inorganics and Radionuclides Survey (NIRS), completed in 1987, indicated that of 1200 groundwater supplies tested for radionuclides, 72 percent of supplies tested positive for radon (Pontius 1990). Data from the survey along with information gathered from other studies and the individual risk rate for radon determined from uranium miner data, helped scientists to conclude that radon probably contributes the most significant cancer risk of any substance in drinking water (Pontius 1990).
In 1986 amendments were made to the Safe Drinking Water Act, making the act the Safe Drinking Water Act and its Amendments (SDWAA). " Emphasis shifted from a primary concern with treated drinking water to attainment of standards at the point of consumption" (Clark et.al 1995). The most important reason for the amendments of 1986 was to re-establish drinking water MCLs set under the interim regulations of 1974. These revised regulations were established on the basis of a comprehensive review of the occurrence of contaminants in drinking water and the potential health effects of human exposure (Pontius 1990). Responsible for the study was the National Academy of Sciences (NAS). The study helped to identify changes that needed to made to the original 1974 SDWA, hence the 1986 amendments.
Two new regulations brought about by the amendments were the Surface Water Treatment Rule (SWTR) and the Total Coliform Rule (TCR) (Clark et.al 1995). The USEPA ,under the SWDAA, is required to regulate chemical contaminants and microorganisms in drinking water. Both the SWTR and TCR set forth specific treatment and monitoring requirements that must be followed by all public treatment works (Clark et.al 1995).
A more extensive list of important changes under 1986 SDWAA; to be enforced by USEPA
Overview of the public's perception of the Water Treatment WorksRecent Legislation of the SDWAHow the SDWA directly affects Gerry Higgin's plantPartnership For Safe WaterFor a more comprehensive look at the Water Industry, check out theAmerican Water Works Association
Take a look at site for a complete list of Drinking Water Legislation
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