How Dangerous Is Nickel & Can Nickel Cause Cancer?

Nickel is a silvery-white hard metal that can be combined with other metals to form alloys. Some of the metals that can be mixed with nickel are copper, iron, zinc, and chromium, which can be used to make jewelry, metal coins, industrial valves, heat exchangers and stainless steel. Nickel can also be mixed with non-metals, such as chlorine, oxygen, and sulfur. These compounds can be water-soluble and impart characteristic green color, although nickel compounds are usually odorless and tasteless. It is also used as a catalyst, in nickel plating, coloring ceramics, and making batteries and is released in the atmosphere by coal-burning power plants, oil-burning power plants, and trash incinerators.⁽¹⁾

How Dangerous Is Nickel?

The hazardous effect of nickel depends on the dose, duration, means of exposure, presence of other chemicals and personal traits and habits of an individual. It can be exposed via breathing, smoking, drinking, eating or by skin contact. Generally, the concentration of nickel is very low in the environment and major exposure to nickel is via food. The concentration of nickel in air ranges from 7-12 nanograms per cubic meter, in water, it ranges from 2-4.3 parts per billion, in soil it ranges from 4-80 parts per million, in waste sites it is around 9000 parts per million. Food is the major source of exposure and normally a person eats 170 micrograms per day. Foods that have high amounts of nickel are nuts, oatmeal, chocolate, and soybeans. Intake of nickel from drinking water is around 2 micrograms and via breathing is 0.1-1 microgram, excluding tobacco smoke. Exposure is greater for workers in nickel industries who can inhale dust and fumes from welding or by skin contact with nickel-containing metals, dust or solutions.⁽¹⁾

Can Nickel Cause Cancer?

The most common health hazard caused by nickel is an allergic reaction and approximately 10-20% population is allergic to nickel. Prolonged contact of nickel with the skin may lead to allergic skin reaction that may present as a skin rash at the site of contact, such as eczema and sometimes dermatitis (away from the site of contact). Some people exposed to nickel via inhalation may become sensitized and develop asthma. Nickel allergy is more common in women than in men and this could be related to greater exposure of women to jewelry and other metal items. People who are not sensitized to nickel will have to consume a large amount of nickel to develop harmful effects (such as 250 ppm). Serious health hazards of nickel exposure include chronic bronchitis, reduced lung function, and cancer of lung and nasal sinus.⁽¹⁾

Nickel and certain nickel compounds have been listed in the First Annual Report on Carcinogens in 1980 as reasonably anticipated human carcinogens. Later in the Tenth Report on Carcinogens in 2002, nickel compounds were listed as known human carcinogens; however, metallic nickel still remains in the list of reasonably anticipated human carcinogens.⁽²⁾

Several epidemiological studies, mechanistic studies and cancer studies in humans and rodents have supported the carcinogenicity of nickel compounds. Cancer studies in humans have shown that workers exposed to various nickel compounds have an increased risk of developing lung and nasal cancer and perpetual death. The most probable compounds of nickel that are known to cause cancer in humans include nickel sulfides, nickel sulfate, and oxides found in the nickel refining industry. The workers working in nickel refinery exposed to soluble nickel compounds had increased risk of lung and nasal cancer and smoking played a synergistic role.⁽²⁾

Both nickel compounds and metallic nickel are found to cause lung tumors, both benign and malignant and they are also known to cause tumors at other sites, other than lungs. However, cancer studies on humans regarding metallic nickel is limited due to inadequate information of exposure of metallic nickel, low levels of exposure, small number of cases and short follow-ups.⁽²⁾

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How Dangerous Is Nickel & Can Nickel Cause Cancer?