Cadmium

The text on this page is taken from an equivalent page of the IEHIAS-project.

Cadmium (Cd), a by-product of zinc production, is a cumulative poison that can cause kidney and bone damage following prolonged exposure in the environment and the industry

Cadmium as a biomarker

Sample collection and storage

Matrix:

Blood and urine (untimed urine sample) are the biological samples commonly used to monitor exposure to Cd.

Kinetics:

• Inhalation is a main source of exposure in smokers and occupationally exposed persons. For others, food contributes to the majority of the intake
• Cadmium is mainly stored in the liver and kidneys, and is excreted via urine
• The biological half-life of Cd is about 100 days in blood and more than 10 years in urine

Sampling conditions:

Blood and urine should be collected in containers free of any metal contamination. Samples can be stored at 4°C or frozen.

Sample measurement

Analytical aspects:

• atomic absorption spectrometry (AAS) or inductively coupled plasma mass spectrometry (ICP-MS)
• Sensitivity in 0.01 to 0.1 µg/l

Performance characteristics:

• Analytical reproducibility is around 1-2 %
• Inter- and intralaboratory variability around 5-10%

Validation:

Various national and international intercomparison programs are in place, methods are well defined and a wide variety of certified standards and reference materials are available

Confounding factors:

Diuresis is a potential confounder of urinary Cd concentration. Smoking is a confounder for both blood and urinary Cd

Data interpretation

Concentrations reported in literature:

• Cd in blood of adult non-smoker: < 2 µg/l
• Cd in blood of adult smokers: < 5 µg/l
• Cd in blood of children: < 0.5 µg/l
• Cd in urine of adults: < 2 µg/g creatinin
• Cd in urine of children: < 0.5 µg/g creatinin

Dose-response/effect relationships:

Cd in blood (µg/l) or in urine (µg/g cr)
< 2	Normal
2-5	Tubular proteinuria unlikely
5-10	Risk of tubular proteinuria in susceptible individuals
> 10	Dose-dependent increase in the risk of tubular proteinuria

Time trend, geographical variation, susceptibel groups:

Few comparative data exist about the geographical and temporal variations of Cd body burden in Europe. Although a decrease of the Cd body burden has been reported in the general population of some countries, human exposure shows little change compared to the drastic decrease of lead exposure.