Summary - Cd
Cadmium occurs naturally in the environment in its inorganic form as a result of volcanic emissions and weathering of rocks [1-link]. In addition, anthropogenic sources have increased the background levels of cadmium in soil, water and living organisms. Increases in cadmium levels in soil result in an increase in the uptake of cadmium by plants, depending on plant species, pH and other characteristics of the soil, and thus indirectly by animals feeding on the plants. Cadmium in water can contaminate shellfish and crustaceans. Fungi that are natural accumulators of cadmium can receive high levels from soil.
The general population is exposed to cadmium from multiple sources, including smoking, with food accounting for approximately 90 % of cadmium exposure in the non-smoking general population. Less than 10 % of total exposure of the non-smoking general population occurs due to inhalation of low levels of cadmium in ambient air (Vahter et al., 1991) and through drinking water (Olson et al., 2002)[2-Link,3-Link]. Cadmium absorption after dietary exposure in humans is relatively low (3?5 %), but cadmium is efficiently retained in the kidney and liver, with a very long biological half-life ranging from 10 to 30 years. Cadmium is primarily toxic to the kidney and may cause eventually renal failure. Cadmium can also cause bone demineralisation, either through direct bone damage or indirectly as a result of renal dysfunction.
The International Agency for Research on Cancer has classified cadmium as a human carcinogen (Group 1) on the basis of occupational studies (IARC, 1993)[4-Link]. Newer data on human exposure to cadmium in the general population have been statistically associated with increased risk of cancer in the lung, endometrium, bladder, and breast. In 2010, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) established a provisional tolerable monthly intake (PTMI) of 25 ?g/kg b.w. which corresponds to 5.8 ?g/kg b.w. as weekly intake [5-Link]. The EFSA Panel on Contaminants in the Food Chain nominated a tolerable weekly intake of 2.5 µg/kg body weight to ensure sufficient protection of all consumers [1-[file:///Y:/Unit_MANT/Algemeen/Research%20Programme/EU/FP7/2_Running%20Projects/FP7-KBBE-2011-2.4.02-TDS_EXPOSURE/03_Project/WP5/Task%205.4.2%20-X-%20Choice%20of%20adequate%20analytical%20methods/1.%09EFSA%20Panel%20on%20Contaminants%20in%20the%20Food%20Chain%20(CONTAM),%20Cadmium%20dietary%20exposure%20in%20the%20European%20population%20EFSA%20Journal%202012;10(1):2551%20%5b37%20pp.%5d. Link]].
High levels of cadmium were found in algal formulations, cocoa-based products, crustaceans, edible offal, fungi, oilseeds, seaweeds and water molluscs. In an attempt to calculate lifetime cadmium dietary exposure, a middle bound overall weekly average was estimated at 2.04 µg/kg body weight and a potential 95th percentile at 3.66 µg/kg body weight. Individual dietary survey results varied between a weekly minimum lower bound average of 1.15 to a maximum upper bound average of 7.84 µg/kg body weight and a minimum lower bound 95th percentile of 2.01 and a maximum upper bound 95th percentile of 12.1 µg/kg body weight reflecting different dietary habits and survey methodologies.
Food consumed in larger quantities had the greatest impact on dietary exposure to cadmium. This was true for the broad food categories of grains and grain products (26.9 %), vegetables and vegetable products (16.0 %) and starchy roots and tubers (13.2%). Looking at the food categories in more detail, potatoes (13.2 %), bread and rolls (11.7 %), fine bakery wares (5.1 %), chocolate products (4.3 %), leafy vegetables (3.9 %) and water molluscs (3.2 %) contributed the most to cadmium dietary exposure across age groups. Children and adults could exceed the 95th percentile exposure health-based guidance values.