Heavy metals in drinking water and their effects on health
How dangerous are heavy metals in drinking water?
WHAT ARE HEAVY METALS?
The term "heavy metals" does not have a clear scientific definition. Today, when we talk about heavy metals in ecological or medical contexts, we mean a group of metals that are striking because of their toxic properties. In our food and drinking water, they have, for the most part, harmful effects on the body.
WHEN ARE HEAVY METALS DANGEROUS?
Copper and nickel are essential heavy metals. They are similar to iron or zinc, they are deemed necessary to a certain concentration as trace elements for the human body. They only develop their harmful effect when they are overdosed. The daily demand for copper and nickel can be met with a balanced diet.
All other heavy metals do not have a nutritional role. They are completely harmful to health. Mercury, lead, cadmium and uranium, are all harmful to the human body even in the smallest amounts.
Arsenic is highly toxic. It appears in the list of toxic heavy metals due to its dangerousness. Worryingly, arsenic content in drinking water has increased in recent decades. In 36 countries on five continents, the toxic metal can be found in groundwater. However, waterwork companies largely ensure that no questionable concentration of arsenic is in tap water.
WHY ARE TRACES OF HEAVY METALS IN DRINKING WATER AT ALL?
Heavy metals enter the natural water cycle via emissions during combustion processes with rainwater, it also happens in overfertilization in agriculture via leachate and the rainwater becomes contaminated when it falls.
How do heavy metals get into our drinking water?
WE'VE GOTTEN USED TO THINKING IN LIMITS
In each country a governing body will determine which contaminants are permitted and to what limit. Waterworks control water to the point where it is fed into the public grid. There, drinking water converts into tap water and evades the supervision of the waterworks in the stretch of pipe to your tap where contamination can happen.
A well-known example of this is high lead concentrations in tap water, which are due to outdated supply lines or house pipes made from lead. These pipes have been banned as components, yet cases of households with leaded water are still known.
CHEMICALLY SPEAKING: HOW METALLIC RESIDUES GET INTO LIQUIDS
How does lead from a pipe actually get into drinking water? Lead is known to be non-water soluble as a metal. The chemical process called substance migration is the cause of metals entering water. The surfaces of two substances on a molecular or atomic level interact.
Not every metal behaves the same when migrating. The less a metal releases traces of its substance to liquids, the more food-grade it is and therefore useable. For example Copper and stainless steel are a higher food grade as they do not release traces when in contact with water.
WHAT DO LIMIT VALUES FOR TOXIC HEAVY METALS IN DRINKING WATER MEAN?
The limit values protect us from acute symptoms of poisoning. However, long-term health consequences have not been taken into account with the permanent consumption of the smallest quantities of heavy metals. They can accumulate in the body over years and have a harmful effect on metabolism. They can disrupt natural cell functions or cause hormone failures.
There are many illnesses associated with heavy metal stress, Cancer, Multiple Sclerosis, Parkinson’s and Alzheimer’s and even depression. In principle, heavy metals, like all toxins, effect the kidneys, liver and pancreas – organs that primarily process foreign bodies and harmful substances.
HOW DOES DRINKING WATER BECOME FREE OF HEAVY METALS?
Today, water works and utilities use technologically advanced filter systems in drinking water treatment. The prescribed limit values can be largely met with the cleaning processes used. However, zero tolerance solutions are not to be expected from this field with the usual methods in the medium and long term.
REVERSE OSMOSIS: A RELIABLE PROCESS NOT ONLY FOR INDUSTRY
In industrial applications, wherever pure water is of great importance reverse osmosis is used for drinking water extraction and purification. Reverse osmosis plants discharge particles and substances from the water via semipermeable membranes and artificially generated osmotic pressure. The final result is pure H2O.
So why do water suppliers not use this procedure to remove all pollutants from the water? The answer is obvious: reverse osmosis works so well that it also removes substances that are valuable to the body. In the case of drinking water, essential minerals.
However, waterworks – as well as mineral water bottlers – are prohibited by law from re-enriching their products retrospectively with what they previously withdrew from them. If natural mineral water is enriched with ingredients that are not already present in the natural spring water, it may only be marketed as table water.