Are Metals Micropollutants?

Although it might sound counterintuitive, heavy metals are almost found in our water supplies, including those we use for drinking. In small concentrations, they’re completely harmless. However, many of them are extremely persistent in both the natural environment and the human body, meaning they can bioaccumulate over time and pose a real danger to our health.

The term micropollutants refers to a wide variety of substances which are emitted into our environment in small concentrations as a result of domestic or industrial processes, but which can build up over time into larger quantities. As such, heavy metals are included within the definition of micropollutants.

Which are the most common heavy metal micropollutants?

There is a large range of different heavy metals which are found in our water sources, though the following five are most prevalent:

• Cadmium. Cadmium is a metal that is a common element in rechargeable batteries, cameras, cordless power tools, computers, mobile phones, nuclear reactors and other common items. Most cadmium micropollutants come from galvanised water pipes, industrial sites and metal refineries.
• Arsenic. This substance might be infamous for its use as a poison in detective novels, but it’s actually present all throughout the natural world. However, anthropogenic processes and products have drastically increased the concentration of arsenic in the environment. It’s generally leached through semiconductors, dyes, drugs, paints and mining.
• Lead. One of the most toxic heavy metals, lead-based paint has now been outlawed due to its environmental and health consequences. However, high levels of lead can still persist in our water due to corrosion of water pipes, industrial and manufacturing processes and the erosion of natural lead deposits.
• Iron. Some iron is actually crucial to the normal functioning of the human body – but too much of a good thing is highly poisonous. Iron is generally found as a natural element in soils, plants and rocks, but levels in drinking water can become elevated when iron plumbing corrodes or when excessive rainfall causes run-off into our lakes, streams and waterways.
• Mercury. Mercury poisoning is a familiar phenomenon to all of us. Although thankfully rare these days, it can still occur when levels are allowed to reach dangerous proportions. It normally finds its way into the environment through the improper disposal of batteries, switches and fluorescent light bulbs, among other electronic items.

What are the health effects of heavy metal exposure?

As mentioned above, certain metals are beneficial and indeed integral to the normal functioning of the human body. However, when humans are exposed to unsafe levels, they can cause health ramifications. In small quantities, the symptoms are generally not life-threatening, manifesting themselves in the shape of nausea, vomiting, dizziness and irritability, among others.

However, if an individual is exposed to heavy metal micropollutants over a concerted period of time, the repercussions can be far more concerning. Depending on the metal in question, they can cause serious damage to the motor, vision, hearing, speech, renal and immune systems, as well as causing cancer and leading to death in the most extreme cases. It’s for this reason that environmental analysis of heavy metals in water sources is of the utmost importance.