Any metallic chemical element with a relatively high density and minimal toxicity or hazardous potential is defined as a heavy metal. Examples of heavy metals include lead, thallium (Tl), chromium (Cr), cadmium (Cd), arsenic (As), and mercury (Hg) (Pb). Humans have used heavy metals for thousands of years.
By Lubna Kanwal
Heavy metals (Metallotoxins)
Despite the fact that heavy metals have a number of long-known harmful impacts on health, exposure to them persists and in some places is even rising, especially in less developed nations, even though emissions have decreased in the majority of wealthy nations over the past century. The development of one’s physical, cognitive, and mental health can be negatively impacted by exposure to environmental toxins. Exposure to lead, cadmium, mercury, and arsenic are the principal heavy metal health risks to people. International organizations like the WHO constantly assess the effects that these metals have on human health after conducting considerable research on them.
Sources of heavy metals:
Currently, rechargeable nickel-cadmium batteries are the principal application for cadmium compounds. Cadmium emissions have rapidly increased over the past century, in part because cadmium-containing goods are frequently thrown with domestic waste rather than being recycled. A significant source of cadmium exposure is cigarette smoking. The main source of cadmium exposure in non-smokers is food. The detrimental health effects of cadmium exposure, which mostly manifest as kidney impairment but may also include bone problems and fractures, may occur at lower exposure levels than previously thought, according to recent findings.
The general public is mainly exposed to mercury through food, with fish serving as a significant source of methyl mercury exposure. While some populations with heavy fish intake may reach blood levels linked to a low risk of adult brain impairment, the general population does not suffer a significant health risk from methyl mercury. Pregnant women should avoid eating a lot of certain fish, such as shark, swordfish, and tuna, because they pose a risk to the developing child. Dental amalgams have been the subject of discussion regarding their safety. However, studies to date have not been able to demonstrate any links between amalgam fillings and poor health.
Approximately equal amounts of lead are consumed by and inhaled by the general population. Lead emissions to the atmosphere have been a significant source of pollution throughout the past century, mostly because of lead emissions from gasoline. Due to their rapid gastrointestinal absorption and permeable blood-brain barrier, children are especially vulnerable to lead exposure. Recent results suggest that lead exposure may have neurotoxic consequences at lower levels than previously thought, and blood levels in children should be decreased below those levels currently deemed tolerable.Lead should not be used in food containers, and lead-based paints should no longer be utilised. The general population should be especially cautious around glazed food containers since they can release lead into meals.
Food and drinking water are the main sources of arsenic exposure, with food being the most significant source for the majority of populations. Long-term drinking-water exposure to arsenic is mostly linked to an increased chance of developing skin cancer, but it has also been linked to other malignancies and other skin diseases such hyperkeratosis and pigmentation alterations. Lung cancer is causally linked to occupational arsenic exposure, particularly by inhalation. In Europe, many people already expose themselves to levels over these limits, and for big groups, the difference is really little. In order to lessen the possibility of negative health impacts, steps should be done to reduce cadmium exposure in the general population.
Figure 1. Map of Pakistan showing areas with high contamination of heavy metals
Heavy metals effecting the brain:
Dementias like Alzheimer’s, which have no viable treatments or cures, pose a serious threat to public health. Environmental variables play a role in some cases of Alzheimer’s disease and other dementias. Lead, cadmium, and manganese are persistent and common heavy metals in our environments. These metals are capable of infiltrating cells and the brain after being exposed to a person. Lead, cadmium, and manganese are well-known neurotoxicants that contribute to the canonical pathologies of Alzheimer’s disease in cell and animal model systems. Lead, cadmium, and manganese have repeatedly been linked to reduced cognitive function and cognitive ageing in adult human epidemiologic investigations.
Effect of heavy metals on Pregnancy:
Heavy metal exposure can affect brain-derived neurotrophic factor (BDNF), a crucial biomarker of pregnancy, and induce cognitive impairment and depressive disorders. Although there have been numerous research on heavy metal pollution, there have been few on the impact of heavy metals on BDNF during the early stages of pregnancy. Early pregnancy maternal blood samples found to contain heavy metals had reduced levels of BDNF, which is critical for the biological effects of maternal depressive disorder and neonatal neurodevelopment.
So in order to live a better life it’s very important to have a check on water you drink!