Cadmium is a soft, silvery white metal found naturally in the Earth’s crust as a minor component in most zinc ores. Cadmium causes serious health effects including diarrhoea, bone fracture and reproductive failure. It also has more serious side effects including damage to the central nervous system, psychological disorders, potential DNA damage and cancer development. Even very small amounts of cadmium are dangerous because of bioaccumulation; the body cannot get rid of the metal and so small doses over time will build up.
Cadmium is used in many consumer products including cigarettes, batteries, jewellery and metal coatings. It is found in foods including some shellfish, kidney meats, grain cereals and vegetables. Emissions from fossil fuels also contain cadmium.
Smokers are exposed to a significantly higher level of cadmium. Tobacco smoke transports cadmium into the lungs, from here it is transported in the blood around the rest of the body. The cadmium already present in the body can increase the effect of cadmium present from cadmium-rich foods or drinking water.
Cadmium contamination of water can happen through a number of different routes. The most problematic is from industrial mining, refinery and battery production plants. Cadmium is a by-product for many of these processes and so is often present in the wastewater.
Cadmium is also naturally present in some rocks, and so weathering of these rocks can contaminate water with cadmium. Regular monitoring of cadmium is crucial in these regions and applications to protect human health.
Cadmium can leach from rocks into groundwater which can contaminate drinking water. Galvanised water pipes contain a protective zinc coating to prevent corrosion and rust. The protective coating also contains cadmium which can leach into the water supply.
Cadmium is also present in drinking water due to its use in multiple industrial processes which lead to cadmium waste contaminating water supplies and cadmium dust in the air settling into water sources.
A lot of cadmium is produced as a waste product when processing zinc from its ore and during the production of batteries, and therefore there can be large amounts of cadmium in industrial waste.
Phosphate fertilizers naturally contain cadmium. This accumulates in the soil and can contaminate water supplies. Irrigation water with high levels of cadmium can also contaminate produce and lead to high levels of human cadmium consumption.
Cadmium can be introduced to food produce through contaminated wash waters. Ingestion of cadmium is dangerous even at low levels, therefore water which is being used to wash food produce should be routinely monitored to ensure that produce is not compromised.
Dialysis patients are exposed to large volumes of water and so the risk of cadmium poisoning is increased significantly. Therefore, water for use in the renal application has a lower consent limit of 0.001 mg/L for cadmium.
Kemio Heavy Metals enables rapid on-site testing for both cadmium and lead. Verifying the safety of water samples at source, Kemio helps combat cadmium contamination. A truly simple sensor-based test, Kemio is suitable for all users with simple on-screen instructions. Ideal for samples which are turbid or coloured, Kemio uses an electrochemical method to accurately determine cadmium levels.