The toxicity of heavy metals depends on many factors. While the dose, chemical species and method of exposure all play a role on the heavy metal’s end, there is also an individual risk element depending on your genetics, age, gender and nutritional status. However, researchers have identified a few priority metals that are of concern to everyone on account of their high toxicity: lead, mercury, arsenic, chromium and cadmium.
Researchers from Jackson State University estimate that several million people around the world are subject to chronic arsenic exposure. In places like India, Mexico, and Taiwan, the groundwater is highly contaminated with arsenic, and it also exists in the air. Most people’s biggest source of exposure is diet. This is very concerning because arsenic has been linked in epidemiological studies to problems like vascular disease, neurological disorders, diabetes, and cancer. Exposure to this metal affects all the organs.
Cadmium occurs naturally in the Earth’s crust, but its use in industrial applications like batteries, alloys and pigments is very concerning. The most common methods of exposure to this metal are through ingesting food and inhaling air or cigarette smoke that contains it. Chronic exposure to low levels of the metal has been linked to osteoporosis and emphysema. It has long been linked to lung cancer as well as that of the stomach, prostate, liver and kidney.
Chromium exposure comes from its use in wood preservation, industrial welding, pigments, leather tanning and chrome plating. Although it’s an essential nutrient that helps with metabolism, exposure to higher amounts is very dangerous. For those who aren’t exposed to it at work or due to their proximity to manufacturing plants, ingestion of food and water containing it is the most common form of exposure. It usually targets the lungs, but it is also shown to cause multi-organ toxicity, asthma, and respiratory tract cancer; those who have greater contact with it are subject to even more serious conditions.
Most people are already familiar with how toxic lead can be thanks to public awareness campaigns and the reduction of the heavy metal to a large degree from many industrial uses. Nevertheless, a quarter of homes with more than one child younger than six in the U.S. still have significant amounts of lead in dust, paint, or soil. In fact, lead poisoning is still a common pediatric health problem. It is also found in many people’s drinking water thanks to decaying infrastructure and pipes.
Lead concentrations of just one part per billion can be problematic. Lead exposure has been linked to diminished intelligence, speech problems, attention disorders, social problems, and stunted growth in children, while adults may note spontaneous miscarriage or lower sperm count from low levels of exposure. At higher exposure levels, people might experience brain or kidney damage, blood problems, and gastrointestinal disease.
Mercury is so ubiquitous in our environment that it is impossible to avoid it entirely. However, one of the biggest sources of exposure to mercury in humans comes from dental amalgams, which is something that can be easily avoided. Consumption of mercury-contaminated fish is also a major source. Mercury is toxic to the nervous system, and it can also damage the digestive, nervous, respiratory and immune systems.
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