Metals with a relatively high density compared to water, are referred to as heavy metals.
Not all heavy metals are toxic in low doses, for example, Iron, is the main component of hemoglobin, a transporter of oxygen in the blood. But, Even iron in high doses is toxic to the body.
The term "toxic metals" is frequently used to refer to thallium, cadmium, manganese
, lead, mercury, and radioactive metals. Also, metalloid substances which have some properties from metals and some from nonmetals. Such substances are arsenic and polonium.
Lead poisoning
Lead poisoning symptoms include::
Abdominal pain, constipation, feeling Tired, Irritable, Loss of appetite, Memory loss, Pain or tingling in the hands and feet.
Prolonged and high levels of lead poisoning can cause: Anemia, paralysis, kidney, and brain damage, and even death. Lead poisoning affects children more easily and may cause neuronal damage and intellectual disability.
Lead dust and fumes have no smell, so exposure to lead is easy in areas where metal welding or working.
Older homes with lead paint and water pipes are major sources of lead intoxication.
Other sources include firing ranges, battery manufacturing, and cosmetics.
Mercury poisoning:
Mercury poisoning sources are sea products, also amalgam for dentists, alamgam is filling material for cavities, and in some countries it is still allowed.
Mercury thermometers and mercury light bulbs also can cause intoxication if broken.
Because mercury is hard to collect.
If available, powdered sulfur may be applied to the spill, in order to create a solid compound that is more easily removed from surfaces than liquid mercury.
Mercury Poisoning symptoms include:
Peripheral neuropathy, which manifests as paresthesia or itching, burning, discomfort, or even a sensation resembling little insects crawling on or beneath the skin (formication).
Other symptoms include: profuse sweating, tachycardia, increased salivation, and hypertension.
It can also cause psychiatric symptoms, emotional lability, memory impairment and insomnia.
Most of mercury intoxication cases are reversible, it can have a much stronger effect on children.
Cadmium:
Smoking is a significant source of cadmium.
Other causes include sea products and plastics production, and nickel-cadmium battery manufacturing.
Acute exposure to cadmium fumes may cause flu-like symptoms.
Heavy and chronic exposure to cadmium can cause: Complications of cadmium poisoning including cough, anemia, and kidney failure (possibly leading to death).
Cadmium exposure increases risk of cancers. Similar to zinc, long-term exposure to cadmium fumes can cause lifelong anosmia, also known as smell blindness.
Arsenic poisoning:
Arsenic commonly ingested from contaminated water and food.
Arsenic is highly toxic in its inorganic form.
Contaminated water used for drinking, food preparation, and irrigation of food crops poses the greatest threat to public health from arsenic.
long-term exposure to arsenic from drinking-water and food can cause cancer and skin lesions. It increases risk of lung and kidney cancers.
It has also been associated with cardiovascular disease and diabetes
Treatment:
Most important treatment and prevention same time is to avoid exposure to heavy metals.
Generally, Heavy metal toxicity treatment is chelation: Clinically available chelators include EDTA, DMPS, DMSA, and British Anti-Lewisite (BAL).
DSMA or Succimer, sold under the brand name Chemet among others, is a medication used to treat lead, mercury, and arsenic poisoning. But during chelation accurate dosage is crucial to avoid additional toxicity or side effects.
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