Mercury in Drinking Water

What is mercury?

Mercury, the “living silver”, is a toxic metal in a liquid aggregation state under average temperatures. This is because its melting point is -38.83°Celsius. It forms drops with a high surface tension and occurs in nature in pure form and as a mineral (cinnabar). Despite its toxicity, mercury was already used as a remedy in ancient times. It was administered for its antiseptic effect and used for disinfection. In the Middle Ages, it played a significant role in alchemy for refining metals. Along with sulphur and salt, it was one of the three essential substances used by alchemists.

It is no longer commonly used in measuring instruments (clinical thermometers) and photography (mercury vapour as an image developer). The “hatter’s syndrome” describes the mercury poisoning of the profession in the 18th century, when primarily mercury salts were processed in beaver skin hats, which were fashionable at the time.

Mercury forms alloys with other metals. These are called amalgams and are used in dentistry as dental fillings. Their advantages are plastic behaviour and inhibition of bacterial growth – the possible leaching out of mercury components is a severe disadvantage. In the spring of 2017, the European Parliament decided to restrict its medical use or to ban amalgam fillings for young people under 15 and pregnant and breastfeeding women from 2018.

Today, medicines with wound-healing and disinfecting properties, are on the market without mercury-containing compounds.

How does mercury get into drinking water?

In surface waters, mercury is usually present only in minimal trace concentrations (less than 1µg/l). The figures for rivers vary: 0.03 – 0.2 micrograms per litre. The pollutant enters the environment mainly through industrial emissions and effluents in orders of magnitude into the atmosphere. The most crucial polluter is the energy industry, with more than 70 %, followed by the metallurgical industry (gold, copper, zinc and lead extraction), the building materials industry (cement production) and small-scale gold extraction, which should not be underestimated. It is estimated that more than 2,000 tonnes of mercury are released into the atmosphere in gaseous form every year. These substances ultimately end up in the soil via precipitation and, thus, in the water cycle. The mercury content in sewage sludge and compost, distributed as fertiliser on the fields, is also problematic.

How does mercury affect the human body?

Harmful mercury is mainly absorbed through the respiratory tract. Inhaled vapours cause acute and longer-term chronic damage. Initial respiratory irritation, inflammation and tooth loss can end with tremors and personality loss. Oral ingestion of organic mercury compounds usually occurs via contaminated food. In 1956, industrial wastewater containing methylmercury entered the sea in Japan. After eating the contaminated fish, neurological symptoms, ataxia, and sensory and growth disorders appeared. Minimata disease was named after the site of the environmental disaster. Amalgam dental fillings are also controversial. The small doses dissolved by wear are considered controversial. They correspond to the amounts ingested from food.

Drinking water polluted by mercury: What to do?

The drinking water ordinance in the UK sets the limit value for the parameter mercury at 0.001 mg/l. Environmental authorities, such as the Environment Agency in England or their counterparts in Scotland, Wales and Northern Ireland, run monitoring programmes to measure mercury levels in biota samples. These programmes are used to monitor environmental quality and regulatory compliance. The processes for wastewater treatment and treatment of raw water are settling, heavy metal precipitation, filtration and flotation.

Get water tested for mercury levels

Find out more about your water: with a water test, you can find out precisely whether there are other substances of health concern in your own tap water or whether limit values are exceeded. The waterworks guarantee first-class tap water in accordance with the Drinking Water Ordinance right up to the house connection. Various heavy metals (lead, zinc, copper, nickel, chromium, iron, cadmium), arsenic or bacteria can subsequently impair drinking water quality from the domestic installation to the tap. Well owners should pay attention to their well water’s nitrate and phosphate levels. 

A water analysis by a recognised laboratory will clearly show whether your drinking water is of perfect food quality.


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