Pure nickel is a hard, silvery white metal and is a very abundant element. Nickel combined with other elements occurs naturally in the earth's crust, primarily combined with oxygen (oxides) or sulfur (sulfides) and is found in all soils. It is also emitted from volcanos. Nickel is also found in meteorites and in lumps of minerals on the floor of the ocean, known as sea floor nodules. The earth's core is believed to contain large amounts of nickel. Small nickel particles in the air settle to the ground or are taken out of the air in rain. Because nickel attaches to particles that contain iron or manganese, it is often present in soil and sediments.
Nickel has properties that make it very desirable for combining with other metals such as iron, copper, chromium, and zinc to form alloys. These alloys have important uses such as in the making of metal coins and jewelry and in industry for making items such as valves and heat exchangers. Most nickel is used to make stainless steel. Nickel compounds are used for nickel plating, to color ceramics, to make some batteries, and as substances known as catalysts to increase the rate of chemical reactions.
Nickel is released into the atmosphere during nickel mining and by industries that convert scrap or new nickel into alloys or nickel compounds or by industries that use nickel and its compounds. These industries may also discharge nickel in waste water. Nickel is also released into the atmosphere by oil-burning power plants, coal-burning power plants, and trash incinerators. The nickel that comes out of the stacks of the power plants is attached to small particles of dust that settle to the ground or are taken out of the air in rain. It will usually take many days for nickel to be removed from the air particularly if it is bound to very small particles. Acidic conditions render nickel more mobile in soil and may lead to seepage into groundwater.
Many nickel compounds dissolve fairly easily in water and have a characteristic green color.
Nickel and its compounds have no characteristic odor or taste.
Poisonous gases are produced in fire, including nickel carbonyl.
Nickel is one of the most common metals occurring in surface waters.
Nickel and its compounds are highly persistent in water, with half-lives greater than 200 days.
| BENCHMARKS | |
| Canadian Water Quality Guidelines | |
| Drinking water guideline | under review |
| Protection of freshwater aquatic life | 0.025 - 0.15 mg/l dependent on hardness |
| Irrigation water | 0.2 mg/l |
| Livestock watering | 1.0 mg/l |
Ontario Water Quality Objectives | |
| PWQO | 0.025 mg/l |
U.S. EPA | |
| Drinking water (children) | 0.04 mg/L for 1-10 days of exposure. |
OSHA | |
| Legal airborne permissible exposure limit (PEL) | 1 mg/m3 for an 8-hour workday, 40-hour workweek |
NIOSH | |
| Recommended airborne exposure limit | 0.015 mg/m3 averaged over a 10-hour workshift. |
ACGIH | |
| Recommended airborne exposure limit | 1 mg/m3 averaged over an 8-hour workshift. |
LC50 Values | |
| Rainbow Trout | 35.5 mg/l |
| Daphnia magna | 0.26 - 4.8 mg/l (depending on hardness) |
| Fathead minnow | 8.2 - 25.8 mg/l |
HUMAN HEALTH
Exposure to nickel occurs through breathing air or smoking tobacco containing nickel, eating food containing nickel (the major source of exposure for most people), drinking water which contains nickel, handling coins and touching other metals containing nickel.
A small amount of nickel is probably essential for humans, although a lack of nickel has not been found to affect the health of humans.
The most common adverse health effect of nickel in humans is an allergic reaction. People can become sensitive to nickel when jewelry or other things containing this metal come into direct contact with the skin. Once a person is sensitized to nickel, further contact with it will produce a reaction. Symptoms include burning, itching, redness and bumps or other rashes. A rash may spread to other areas and last for weeks after exposure stops, but usually improves in about a week.
Less frequently, some people who are sensitive to nickel have asthma attacks following exposure to nickel.
Eye or skin contact may cause irritation.
Lung effects, including chronic bronchitis and reduced lung function, have been observed in workers who inhaled large amounts of nickel.
High exposure can cause cough, shortness of breath and fluid in the lungs, which is sometimes delayed for 1 to 2 days after exposure.
Single high or repeated lower exposures may damage the lungs, with scarring of lung tissues, and may cause damage to heart muscle, liver and/or kidney.
Fumes from heated nickel can cause a pneumonia-like illness, with cough and shortness of breath. Higher exposures can cause a build-up of fluid in the lungs (pulmonary edema), a medical emergency, with severe shortness of breath.
People who are not sensitive to nickel must ingest very large amounts to show adverse health effects. Workers who accidently drank water containing very high levels of nickel (100,000 times more than in normal drinking water) had stomachaches and effects to their blood and kidneys.
Exposure to Nickel can cause a sore or hole in the "bone" dividing the inner nose (septum).
Nickel and certain nickel compounds may reasonably be anticipated to be carcinogens. Cancers of the lung, nasal sinus, and throat have resulted when workers breathed dust containing high levels of nickel compounds while working in nickel refineries or nickel processing plants. There may be no safe level of exposure to carcinogens.
Carcinogens may also have the potential for causing reproductive damage in humans.
Nickel may damage the developing fetus.
MEDICAL TESTS
Measurements of the amount of nickel in blood, feces, and urine can be used to estimate exposure to nickel. These measurements are most useful if the type of nickel compound exposed to is known.
Lung function tests. These may be normal if the person is not having an attack at the time of the test.
Urine or plasma test for Nickel (unexposed persons have urine levels less than 10 mg/l, persons with urine nickel concentrations over 100 mg/l need medical attention).
Chest x-ray after acute over-exposure.
Evaluation by a qualified allergist, including careful exposure history and special testing, may help diagnose skin allergy.
Liver and kidney function tests.
ANIMAL HEALTH
Nickel is required to maintain health in animals although large doses have harmful effects.
Animal studies show that breathing high levels of nickel compounds may result in inflammation of the respiratory tract. Eating or drinking large amounts of nickel has been reported to cause lung disease in dogs and rats and to affect the stomach, blood, liver, kidneys, immune system, and reproduction and development in rats and mice.
When rats and mice breathed nickel compounds for a lifetime, nickel compounds that were hard to dissolve caused cancer, while a soluble nickel compound did not cause cancer.
Nickel has been shown to cause lung cancer in animals.
Nickel and its compounds have high acute and chronic toxicity to aquatic life. Insufficient data are available to evaluate or predict the effects of nickel and its compounds to plants, birds, or land animals.
Acute toxic effects may include the death of animals, birds, or fish, and death or low growth rate in plants.
Water hardness affects nickel toxicity to aquatic organisms; the softer the water, the higher the toxicity.
The concentration of nickel and its compounds found in fish tissues is expected to be somewhat higher than the average concentration of nickel and its compounds in the water from which the fish was taken.
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