Heavy Metals
What are heavy metals?
Heavy metals are a group of metals and metalloids that have relatively high density and some of them are toxic even at low concentrations (parts per billion (ppb) levels). Some of them are copper (Cu), iron (Fe), nickel (Ni), and zinc (Zn), cadmium (Cd), mercury (Hg) and lead (Pb). Heavy metals such as iron, cobalt and zinc are essential nutrients and others such as ruthenium, silver and indium are relatively harmless; however, they can be toxic in large quantities or in certain forms. Cadmium, mercury and lead, on the other hand, are very toxic. Although it has several applications for various important products in our daily lives, extensive and prolonged exposure can be hazardous to health and the environment.
What are their applications?
Heavy metals have diverse applications.
For example:
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Electronic devices: cables, mobile phones, computer monitors
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Batteries
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Solar panels
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Thermometers
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Cosmetics: moisturizers, makeup
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Food contact material: paper food packaging, infants feeding bottles
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Toys
What are the impacts on health and the environment?
Potential sources of heavy metal poisoning include tailings, industrial waste, agricultural runoff, occupational exposure, paints and treated timber. Also, human activities, such as industrial, mining and agricultural processes, have led to a wide distribution of heavy metals in ecosystems, posing a risk to ecological and human health. Due to their potential for bioaccumulation along the food chain, high toxicity, prevalence and persistence in the environment, heavy metals have become a major public health concern. For example, prolonged exposure to lead can cause learning, language and behavioral problems in infants and children. Mercury is linked to the nervous, reproductive, immune systems and respiratory toxicity problems. Chromium, on the other hand, is associated with asthma, chronic bronchitis, rhinitis, congestion and hyperemia.
