Cadmium is a natural element of the earth's crust. It is usually found as an inorganic element in combination with other elements, such as oxygen (cadmium oxide), chlorine (cadmium chloride) or sulfur (cadmium sulphate and sulfide). All soils and rocks, as well as coal and fertilizers, contain cadmium. Most cadmium is exported during the production of other metals such as zinc, lead, copper and others. Cadmium is not easily oxidized and has many uses, including batteries, paints, in metallic coatings and in plastics.
Exposure to cadmium occurs mainly in the workplace where various cadmium products are manufactured. The general population is exposed by inhaling cigarette smoke or eating cadmium-contaminated foods. Cadmium damages the kidneys, lungs and bones. Most of the toxic metals (mercury, lead, cadmium, arsenic) that humans encounter are natural constituents of the earth's crust, but their increase in air, water and soil is mainly due to industrial demand and energy production (pollution).
How does cadmium enter the environment?
- Cadmium enters soil, water and air from mining, industry and coal burning and household waste.
- Cadmium is not degraded in the environment but can change forms.
- Cadmium particles in the air can travel long distances before falling to the ground or water.
- Some forms of cadmium dissolve in water.
- Cadmium is strongly bonded to soil particles.
- Fish, plants and animals consume cadmium from the environment.
How is one exposed to cadmium?
- Eating foods containing cadmium. Low levels of cadmium are found in all foods (the highest levels are in shellfish and in the liver and kidneys of animals).
- By smoking cigarettes or by inhaling cigarette smoke.
- Breathing contaminated air in the workplace.
- Drinking contaminated water.
- Living near industrial installations that release cadmium into the air.
How Can Cadmium Affect Health?
Inhalation of high concentrations of cadmium can severely damage the lungs. Consuming food or drinking water with very high levels of cadmium strongly irritates the stomach, leading to vomiting and diarrhea.
Long-term exposure to lower levels of cadmium in the air, food or water leads to the accumulation of cadmium in the kidneys and possibly kidney disease. Other long-term effects are damage to the lungs and the creation of fragile bones.
Cadmium and its compounds are known to be carcinogenic to humans.
How can the risk of exposure to cadmium be reduced?
At home, cadmium-containing substances and nickel-cadmium batteries should be kept out of the reach of small children.
Cadmium is a component of cigarette smoke. Avoid smoking indoors, such as indoors or in the car, to limit exposure.
If you are exposed to cadmium at your workplace, use all safety precautions to prevent cadmium-containing dust from being transported home on your clothing, skin, hair or tools.
A balanced diet can reduce the amount of cadmium obtained from foods and beverages.
How can one determine if one has been exposed to cadmium?
Cadmium can be measured in blood, urine, hair or nails. Concentration of cadmium in the urine has been shown to accurately reflect the amount of cadmium in the body. Cadmium concentration in the blood reflects recent exposure to cadmium. Concentration of cadmium in urine indicates both recent and past exposure.
We can measure cadmium levels in blood and most biological materials.
Determination of metals is done by ICP-MS (Inductively Coupled Plasma Mass Spectrometry, Inductively Coupled Argon Plasma Mass Spectrometry), a method that enables the simultaneous detection of many metals. Its sensitivity and accuracy are significantly better than conventional atomic absorption, with the ability to measure metals at concentrations up to 1 in 1015 (1 in 1 quadrillion, ppq)!
More information on Cadmium toxicity
Cadmium concentration has been found to be 2-3 times higher in eye lenses with cataracts than in eye lenses without cataract of the same age. This is probably because cadmium displaces zinc from the active sites of the enzymes by binding it to sulfhydryl groups, thereby deactivating protective enzymes that remove free radicals and possible other protective / repairing mechanisms.
Heavy metals, such as cadmium, mercury, gold and lead are known to be nephrotoxic at high concentrations. Cadmium is of particular concern because of its extended duration in the kidneys. Therefore, in addition to urine levels testing to document cadmium toxicity, biomarkers of renal function should also be evaluated. Early markers of kidney damage due to cadmium include laboratory evaluation of proteinuria, glucosuria, amino aciduria, hypercalciuria and polyuria. A sensitive marker for advanced renal tubular damage due to cadmium is the low molecular weight β2-microglobulin protein in urine. Cadmium has also been shown to significantly increase the incidence of kidney stones.
The chelating agent Ca-EDTA has been used intravenously for many years as a therapeutic agent of choice for patients with high levels of lead in the blood. This factor is also effective in increasing the urinary excretion of iron, copper, nickel, cadmium and manganese. However, Ca-EDTA also has a high affinity for zinc and if not used properly, it can cause zinc deficiency.
Several toxic minerals, including mercury, lead, thallium and cadmium, are normally or partially excreted in the bile. Therefore, under certain conditions, analysis of stools for metals, without the use of chelating agents (challenge), may provide at least qualitative information on the rate of bile excretion of metals by the body. However, contaminated foods are an important source of exposure to heavy metals and metals not digested by the gastrointestinal tract can contribute a significant proportion to the total amount of metals measured in the faecal sample.
One category of toxic chemicals that can cause serious damage to health and that can mimic other disorders, especially in children, are heavy metals. Lead, mercury, arsenic, aluminum and cadmium are well documented examples. Long-term exposure to these minerals often results in accumulation in specific organs, thereby impairing the normal functioning of the organ. Also, many toxins are now known to exert their toxic activity at levels far below what was originally supposed. For example, cadmium has been shown to be able to mimic the effect of estrogen on tissues at extremely low levels (0.00001 ppb - parts per billion).
Toxic metals act as "chemical antagonists" with trace minerals that are chemically and physically similar (eg cadmium competes with zinc, lead competes with calcium, mercury competes with selenium). This phenomenon can lead to high rates of loss of the competing trace nutrient, or alternatively, the inhibition (or over-activation) of trace element-dependent physiological systems, such as enzymes.
One of the most important detoxification systems in all types of organisms, from bacteria to humans, depends on the production of a family of four different proteins known as metallothionein (MT). Metallothioneins are extremely unusual proteins that consist of about 30% cysteine and are responsible for the storage, transport, and removal of intracellular metal ions. The primary role of metallothionein in the absence of toxic metals is the transport and short-term storage of zinc and copper. Metallothionein are known to effectively bind many toxic metals (particularly cadmium and mercury) and act as transporters of the toxic metal to the liver or kidneys, where it is completed by its coupling to glutathione and subsequent secretion of the metal. As metallothioneins form high affinity complexes with several minerals, they can prevent toxic heavy metals from reacting with other biomolecules or acting as catalysts, thereby weakening their toxicity.
Dietary adequacy has a significant effect on the absorption, retention, toxicity and excretion of toxic metals. Lead and cadmium absorption is increased in situations of iron or calcium deficiency. In addition, iron deficiency is one of the many factors that lead to increased intestinal permeability.
Exposure of the body to heavy metals (lead, mercury, cadmium, arsenic, nickel and aluminum), as well as to solvents (formaldehyde, toluene, benzene), pesticides and herbicides, may result in the accumulation of these molecules. As a result, several psychological and neurological symptoms can occur:
- Psychiatric diseases
- Numbness of limbs
- Abnormal reflexes
- Other signs of nervous system dysfunction
Heavy metals, such as lead, mercury, cadmium, and aluminum, can cause seizures by disrupting neural function. Heavy metal toxicity should be considered as a possible cause in all seizures.
Exposure to food additives, to solvents (formaldehyde, toluene, benzene), to pesticides, to heavy metals (lead, mercury, cadmium, arsenic, nickel, aluminum), can have major effects on detoxification, a condition known as "impaired liver detoxification".
Sperm is also particularly susceptible to the harmful effects of heavy metals such as lead, cadmium, arsenic and mercury.
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. Correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.