Detection of Multiple Heavy Metals 2/5 – Why Care about Heavy Metals?

This chapter is the first in the series ‘Detection of Multiple Heavy Metals by Stripping Voltammetry’. This chapter highlights the relevance of heavy metal detection.

Importance of Heavy Metals

For a number of decades, pollution has been a widely known issue. There is an increased public interest in unhealthy or outright toxic substances in resources we use for creating everyday goods or even consume ourselves, for example water, meat, milk, vegetables.

For these reasons research focused on these topics brings a lot of funding opportunities. Spoiled water is the cause of many illnesses and other health issues. Monitoring drinking water is an important task to keep people healthy. While for surface-water bacteria are the main threat, in almost all urban areas water is consumed after flowing through pipelines. This or the direct pollution of groundwater can lead to heavy metals in drinking water. Many heavy metals are biologically active and cause illnesses. A well-known example is lead poisoning.

Originally the term ‘heavy metals’ referred to metals with a higher density than iron, but nowadays the term is used in general as a term for all metals that are toxic for nature.

Causes and cases of heavy metal exposition

The majority of heavy metals released into the food chain and water is due to human intervention. Most heavy metals are present in the earth’s crust, but mining is bringing them to the surface. Acid rain caused by air pollution or by other exposed minerals dissolves the metals from the ore and carries them into rivers and plants. Sometimes wastes containing heavy metal are disposed of directly into rivers or oceans.

All this had quite some impact on humans. The metal is not removed from the food chain but stays in it. And since the industrialization, heavy metal pollution has heavily increased. Many examples of the negative consequences of exposure to heavy metals are known. Mining waste containing cadmium was disposed of in a Japanese river in 1910. As a result, people eating the rice grown with river water got soft bones and suffered from kidney failures.

The Mad Hatter from the book Alice in Wonderland goes back to the expression “mad as a hatter”. The expression most likely derived from the negative effect of mercury used during manufacturing felt hats. Women drinking mercury-stained water, due to mining wastes, gave birth to mentally disabled children.

Lead is known to be poisonous since the times of ancient Greece and Rome. However, in 2013 the World Health Organization still estimated 143,000 deaths due to lead poisoning. Arsenic is also a rather common but highly toxic element. In ancient times only slaves would mine arsenic, because it was a sure death penalty. In 2014 thousands of people in Asia died due to arsenic poisoned groundwater.

Monitoring the heavy metal content of food and water is important to prevent many deaths and identify the sources of poisoning.