Silver in Drinking Water

What is silver?

Silver is a shiny white precious metal. It occurs in solid form – primarily as grains – in the earth’s crust. Its element name, Ag, is derived from the Latin name Argentum. The metal can be quickly processed due to its easy malleability. Its excellent electrical and thermal conductivity and almost absolute light reflection make silver a sought-after material. Electronics, electrics and optics are the main areas of application. Silver has been one of civilisation’s most highly valued raw materials for about 7000 years. Assyrians, Egyptians, Greeks, Romans, Goths and Germanic tribes all traded in it. In the Middle Ages, there were European silver mines in Tyrol, Bohemia, Slovakia, Franconia, Saxony, Thuringia and the Harz Mountains. Silver gained significant importance as a monetary metal before it was displaced by gold in the 19th century.

In addition to elemental deposits, there are also many silver ores. Most of these are sulphide ores, such as acanthite, stromeyerite or allargentum. So far, 167 silver minerals are known. In addition, silver-bearing ores with a low silver content of 0.01 to 1 per cent are also mined. Today, the most essential silver deposits are located on the American continent. But silver resources are limited, so recycling (electronic scrap, photographic paper, batteries) is increasingly important.

How does silver get into drinking water?

In surface waters, the silver content is minimal, as it occurs in the soil as a solid or bound mineral, such as sulphides. From there, it is released into the environment. It is found in varying concentrations in water bodies, suspended matter and sediments, and sewage treatment plants. Therefore, the natural silver content in surface and groundwater could be more significant.

How does silver affect the human body?

As silver has a bactericidal effect, it is used in medicine in wound therapy as a disinfectant. The bacteria-killing silver ions are used as coatings, colloidal silver or nano-silver in medical products such as wound dressings, creams or prostheses.

In the food industry, silver is used as colourant E 174, for example, for glazing confectionery. The element is not essential for humans. Silver is absorbed through food, about 20-80 µg daily. In the human body, the average amount is about 2 mg. In case of significantly increased intake, silver can accumulate in the body in many ways and manifest in perceptual disturbances of taste and smell organs. In addition, however, some silver compounds, such as silver oxide or silver nitrate, can be toxic.

Drinking water contaminated by silver: What to do?

The silver content in surface and groundwater is low and hardly plays a role. If necessary, various water purification technologies are available to eliminate silver from drinking water: Using ion exchangers, activated carbon and sand filters as well as the method of precipitation, silver and silver compounds can be removed. The toxic effect also strongly depends on other parameters, such as water hardness, chlorides, sulphides, sulphates and the pH value.

The probability of measurable silver contamination in the water supplier’s drinking water is very low. However, a water test can accurately determine whether other substances in your tap water are of health concern or whether limit values are exceeded. Heavy metals (lead, zinc, copper, nickel, chromium, iron, cadmium) or bacteria within the domestic installation can subsequently affect the drinking water. Well owners should pay attention to their well water’s nitrate and phosphate values. A water test clearly shows whether your drinking water meets the Drinking Water Standards and Regulations requirements.

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