There is no "safe" level of lead in drinking water. And keep in mind that the government's 50 ppb standard only applies to water as it enters your house, not how it comes out of your tap.

Water contaminants

There are five principal groups of water contaminants: 1) particulate, which includes particles of rust, dirt and sediment; 2) dissolved inorganics, including heavy metals (mercury, lead, chromium, silver, etc.), and asbestos; 3) organics, which include calcium and magnesium carbonates, the components that make water "hard," and nitrates, chemical solvents, pesticide residues, and industrial pollutants; 4) radiological contaminants, both natural and industrial, such as radon and radium; and 5) biological pathogens, including bacteria, viruses and protozoa.

Lead
is a particulate. Particles of it can enter the water from home plumbing. Plumbing installed before 1930 most likely includes lead pipes. Even in homes built more recently; the solder used to connect copper pipes may contain lead.

Unfortunately, lead is merely one of the possible contaminants in your water. Testing by an independent laboratory may disclose that there are unacceptable levels of other toxins. Fortunately, there are various methods of home water treatment available for specific problems.

Particulate

Problems associated with the particulate category involve mainly appearance, smell and taste. Particulates can be removed with simple filters. Filters are inexpensive and are made from fabric such as cotton, wool or fiberglass. Filters are effective only against larger particles. They are ineffective against dissolved toxic chemicals.

Dissolved inorganics

Dissolved inorganics are a very serious problem, especially lead, as previously discussed. However, another major inorganic pollutant is nitrate. Nitrate contamination occurs mainly in groundwater, especially in agricultural areas. Chemical fertilizers and manure from animals are particularly concentrated sources. The danger is particularly great for children. Nitrates are converted to nitrites in the digestive tract, and nitrites interfere with the ability of blood to carry oxygen, which can result in brain damage and death.

Organics

Dissolved organics include some serious problems. Many public water supplies contain low levels of organic compounds created as byproducts of water chlorination. Although these compounds are highly toxic, they are justified as acceptable because of the effect that chlorination has on microorganisms. Pesticides, industrial effluent, and hazardous waste sites are other sources of organic pollutants. These chemicals are associated with liver, kidney, and nervous system damage, and possibly cancer.

Dissolved organics include some harmless, although annoying, chemicals such as calcium and magnesium carbonates. These may leave deposits on sinks and tubs, and they may interfere with the effectiveness of soap. From a nutritional viewpoint, these minerals are present in extremely small amounts, and, even if fully absorbed, would contribute little nutritional benefit.

Radiological contaminants

Radiological contaminants, such as uranium, radium and radon, occur naturally in various parts of the country. The most serious effects of radiation exposure include birth defects and cancer.

Biological pathogens

Biological pathogens, such as viruses, bacteria and protozoa, are uncommon in public water supplies due to chlorination. But some organisms are becoming resistant to chlorine, and this may become more of a problem in the future.

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