Cadmium poisoning: sources, symptoms, health effects and what to do

Cadmium is a naturally occurring element. UKHSA explains that it is found in the Earth's crust, in soil and rocks, in air and in water, and is spread more widely by volcanoes, forest fires and human activities such as burning fossil fuels, use of phosphate fertilisers and industrial processes. It may enter water and soil from industrial waste or waste from disposal plants.

Cadmium has previously been used in many consumer and industrial materials, though UKHSA says many uses are declining and are now heavily restricted. The largest use currently is in nickel-cadmium batteries. Other uses include conductors in electronic devices, pigments, plastic stabilisers, electroplating and alloys.

UKHSA says food and cigarette smoke are the biggest sources of cadmium exposure for people in the general population. Cadmium enters the food chain from the environment, with some foods accumulating more than others. In the UK the greatest sources in the diet are cereals, vegetables and potatoes; offal such as liver and kidney and seafood contain more cadmium, but people typically eat less of them. People can also be exposed by breathing air near where fossil fuels are burnt or near waste plants, and soil can be a source, especially for children.

Welders or workers producing batteries or plastics may be exposed at work. UKHSA stresses that safe exposure levels are enforced and are below those thought to cause harmful effects, and that the presence of cadmium in the environment does not always lead to exposure: you must come into contact with it by breathing or ingesting it. Health effects depend on the dose, route, duration and form of the chemical and on other exposures.

UKHSA describes the effects of a single high exposure. Breathing air with high levels of cadmium can cause a metallic taste in the mouth, shortness of breath, chest pain, cough and flu-like symptoms (metal fume fever), which may occur some hours after exposure. Its toxicological overview says symptoms may be delayed for 4 to 8 hours, and that severe cases can lead to fluid on the lungs, chemical pneumonitis, respiratory failure and death within days.

If swallowed, cadmium can cause irritation of the digestive tract with nausea, vomiting, abdominal pain and diarrhoea. The overview says there may be an asymptomatic period of up to 60 minutes before symptoms start, and that higher doses may affect the nervous system, liver and cardiovascular system and may lead to kidney failure and death. UKHSA stresses that levels of cadmium in the environment are typically not high enough to cause these effects.

UKHSA says exposure to cadmium for a long period may result in damage to the kidneys and bones and may cause cancer. The toxicological overview explains that cadmium accumulates in the kidney and liver; chronic oral exposure leads to kidney failure characterised by protein in the urine, and accumulation in the kidney affects vitamin D metabolism, leading to osteomalacia and osteoporosis. Chronic inhalation causes loss of kidney tubular function and impairs lung function, causing bronchitis, obstructive lung disease and in some cases fibrosis.

UKHSA notes that the International Agency for Research on Cancer classified cadmium and its compounds as carcinogenic in humans, that breathing cadmium can cause lung cancer, and that ingesting it is not believed to increase cancer risk.

UKHSA says there is little evidence on the effects of cadmium exposure during pregnancy, so no definitive conclusions can be drawn. It says children are likely to be affected in the same way as adults. Soil exposure can matter more for children because of hand-to-mouth behaviour.

UKHSA says that if you have any health concerns regarding exposure to cadmium, seek guidance from your GP or contact NHS 111. If someone has been exposed to fumes at work and is breathless, has chest pain or is struggling to breathe, call 999 or go to A&E, because symptoms can be delayed and lung effects can worsen over hours. Workers who think they are exposed should also raise it with their employer or occupational health service, because workplace exposure limits are enforced.

UKHSA also advises that nickel-cadmium batteries should be recycled at a designated recycling centre, and that your local authority can give further advice.

Because cigarette smoke is one of the biggest general sources according to UKHSA, stopping smoking is the most practical personal step. UKHSA indicates that cereals, vegetables and potatoes make the largest dietary contribution in the UK because they are eaten in quantity, so there is no simple food to avoid. At work, using the protective equipment and controls provided is the main protection.

Concerns about exposure are handled through a GP, NHS 111, occupational health services and, for chemical incidents, UKHSA. Kidney function and urine protein tests, chest assessment and bone assessment, where indicated, are arranged through the NHS. Employers may also use occupational health providers, and any results should be interpreted by a clinician who knows your work and health history.