Impact of Heavy Metals on Health

Heavy metals are considered hazardous materials, and as such people cannot just rent a dumpster and discard them to the nearest landfill. Anyone dealing with these products must follow the local regulation ruling how to handle them and dispose of them. Contact your local municipality for disposing of hazardous materials as the regulations for waste disposal vary from one place to the next.

In addition it is important to specify that the chemical form of heavy metals strongly influences their toxicity (ions, more complex molecules, …). The dose is also an essential parameter in the characterization of acute toxicity.

Acute toxicity

Arsenic (As)

The main acute effects, observed following ingestion of inorganic arsenic, are typically gastrointestinal, associating nausea, vomiting, gastrointestinal haemorrhage, abdominal pain and diarrhea. Effects on the nervous system and skin may also appear in the days or weeks following exposure.

Cadmium (Cd)

In humans, the digestive system is the first affected after cadmium poisoning. The symptoms observed are gastroenteritis, vomiting, diarrhea and myalgia (skeletal muscle pain). The emetic effect (which causes vomiting) of cadmium explains the low mortality by this route.

Inhalation, severe acute intoxication leads to chemical pneumonia, which causes a death in 15-20% of cases. The effects observed during this period are severe pulmonary irritation, accompanied by dyspnea (difficulty breathing), cyanosis (bluish or purple skin and mucous membranes) and coughing.

Chromium (Cr)

Ingesting chromium salts causes massive inflammation of the digestive tract followed by necrosis extending from the mouth to the jejunum (abdominal pain, vomiting, diarrhea, hematemesis). Ingestion of high doses of chromium (VI) induces vertigo, thirst, abdominal pain, haemorrhagic diarrhea, and in the most severe cases coma and death.

Nickel (Ni)

The nickel compound with the highest toxicity is tetracarbonylnickel. Acute toxicity of this compound occurs in two phases: immediate and delayed. Immediate symptomatology is headache, dizziness, nausea, vomiting, insomnia, and irritability. It is followed by an asymptomatic phase before the start of the delayed phase.

It is primarily pulmonary with constrictive chest pain, dry cough, dyspnea, cyanosis, tachycardia, occasional gastrointestinal symptoms, sweating, visual disturbances, and debility. Contact dermatitis, which results from dermal exposure to nickel, is the most common effect of nickel in the general population. Other symptoms are also possible.

Lead (Pb)

Most of the data reported in the literature report absorption of lead or its derivatives orally. Digestive disorders are the earliest symptoms: strong colic associated with pain, abdominal cramps and vomiting. There may also be kidney damage (tubular damage), damage to the central nervous system (encephalopathy convulsive, coma) and liver damage (reduced metabolism of some drugs). These various attacks can in some cases be fatal depending on the severity of the lesions.

Zinc (Zn)

Cases of mortalities have been reported in humans after inhaling vapors of zinc compounds (zinc chloride). Some of them died of respiratory distress, autopsy showed interstitial and intra-alveolar pulmonary fibrosis, and occlusion of the pulmonary arteries. In the workplace, some very specific operations (cutting, galvanized steel welding, for example) can lead to the formation of fumes containing ultrafine particles of zinc oxide.

Exposure to these fumes may result in “melter fever” characterized by the following symptoms: dry, sore throat, cough, dyspnea, fever, muscle aches, headache, and metallic taste in the mouth. Cardiac and gastrointestinal effects may also be associated with exposure to these fumes.