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C
Caddie
The Government’s preferred term for what used to be known as a ‘slop bucket’. This item is to be used for the storage of wet kitchen waste (e.g. leftover chicken innards, fish heads, etc.). This is to be emptied weekly for recycling, presumably by ANAEROBIC DIGESTION.
Cadmium (Cd)
A soft silvery HEAVY METAL, atomic weight 112.4. It is used in semiconductors, control rods for nuclear reactors, electroplating bases, PVC manufacture, and batteries. World production is around 18000 tonnes per year produced in conjunction with zinc smelting.
Cadmium serves no biological function, is toxic to almost all systems, and is absorbed into the human organism without regard to the amount stored. Very small doses can cause severe vomiting, diarrhoea and colitis; pneumonia can develop as a consequence. Poisoning has developed from sources such as home-made punch stored in a cadmium-plated bowl. Changes in the heartbeat rate of persons in atmospheres containing as little as 0.002 micrograms per cubic metre (µg/m3) have been reported (maximum allowable concentration is 100 µg/m3). Hypertension is a common complaint of those who have ingested the metal at doses well below those regarded as toxic. Long exposure in lead and zinc smelting areas in Japan led to the so-called Ouch-ouch (Itai-itai) disease where the sufferers had severe joint pains and eventual immobility as a result of skeletal collapse. Cadmium leads to bone porosity and inhibition of bone-repair mechanisms.
Figure 16 shows how close co-operation by industry can significantly lower Cd levels in sewage
SLUDGE. This enables it to be spread on land (not always the case in the UK due to high Cd levels). (
POLYVINYL CHLORIDE).
Figure 16
Source: J. A. Hansen, ‘A new biowaste agenda’, ISWA Times, issue number 2, 1995. (Reproduced by permission of ISWA)
However, caution on land use is necessary as abnormally high levels of the toxic metal can accumulate in the kidneys and livers of sheep grazing on pasture fertilized for years with sewage sludge.
Mike Wilkinson of the consultancy Chalcombe Agricultural Resources in Lincoln, working with Julian Hill of Writtle College in Chelmsford, Essex, measured levels of heavy metals accumulated by sheep when they grazed on one field that was treated with sewage sludge and another that was untreated. After 150 days, average levels of cadmium in sheep livers were 1.24 milligrams per kilogram (mg/kg) of dried tissue for the animals that had grazed on heavily treated pasture, eight times higher than the level found in sheep grazing on untreated land. In sheep kidneys, the levels in animals that had grazed on the treated land averaged 2.57 mg/kg of dried tissue, six times as high as in the sheep that had grazed on clean pasture.
Source: M. Wilkinson and J. Hill, ‘Lamb’s liver with cadmium garnish’, New Scientist, 22 March 1997, p. 4.
Caesium-137
Caesium-137 is a radioactive isotope which is formed mainly by nuclear fission. It has a half-life of 30.23 years, and decays by pure beta decay to a metastable nulcear isomer of barium-137m which has a half-life of 2.55 minutes and is responsible for all of the gamma ray emission.
The photon energy of Ba-137m is 662 keV. These photons can be used in food irradiation, or in radiotherapy of cancer. Cs-137 is not widely used for industrial radiography as other isotopes offer higher gamma activities per given volume. It can be found in some moisture and density gauges, flow meters, and other sensor equipment.
The biological behavior of Cs-137 is similar to potassium. After entering the organism, all caesium gets more or less uniformly distributed through the body, with higher concentration in muscle tissue and lower in bone. The biological half-life of caesium isotopes is long (30.17 years for Cs-137).
Small amounts of Cs-134 and Cs-137 were released into the environment during nuclear weapon testing and nuclear accidents, most notably the Chernobyl disaster As of 2005, Cs-137 is the principal source of radiation in the exclusion zone around the Chernobyl power plant. Together with caesium- 134, iodine-131, and strontium-90, it was among the most important isotopes regarding health impacts after the reactor explosion.
Improper handling of Cs-137 sources can lead to release of the isotope and radiation contamination and injuries. Perhaps the best known case is the Goiania accident, when a radiation therapy machine from an abandoned clinic in Goiania, Brazil, was scavenged and the glowing caesium salt sold to curious buyers. Metallic caesium sources can be also accidentally mixed with scrap metal, resulting in production of contaminated steel; a notable example is the case from 1998, when recycler Acerinox in Cadiz, Spain, accidentally melted a source. Many abandoned sources are scattered over the area of the former Soviet Union.
Source: en.wikipedia.org/wiki/Caesium-137.
Accessed 27 February 2007.
Calcium (Ca)
Metal element found principally as CALCIUM CARBONATE.
Calcium carbonate
Limestone (also chalk), CaCO3. Used in the production of CALCIUM OXIDE and CEMENT. CaCO3 also causes temporary hardness in water if there is carbon dioxide in solution (as there invariably is in public supplies).
Calcium deficiency
DDT and other CHLORINATED HYDROCARBONS such as polychlorinated biphenyls severely interfere with a bird’s ability to metabolize calcium. The result is the production of egg shells which are so thin that they are crushed by the weight of the nesting birds.
Calcium oxide
Also known as quicklime. Made by calcining (roasting) CALCIUM CARBONATE limestone CaCO3 at 900 °C; this drives off carbon dioxide and produces calcium oxide:
The addition of water produces SLAKED LIME:
The addition of water and sand and CO2 from the atmosphere produces mortar, i.e. reversion or hardening:
Calibration
All the operations for the purpose of determining the values of errors of a measuring instrument. Calibration of an instrument results in a correction factor or a series of correction factors that can subsequently be applied to readings given by the instrument.
Calorie (cal)
Physicists define the calorie as the heat required to raise the temperature of 1 gram of water by 1 °C. This is a minute quantity of heat in practical terms. The term used on diet sheets refers to the kilocalorie (Cal), which is 1000 times larger.
Calorific value CV, gross
The number of heat units measured as being liberated when a unit mass of fuel is burned in oxygen saturated with water vapour under standardized conditions. (The remainder being gaseous oxygen, CARBON DIOXIDE, sulphur dioxide, and nitrogen, water and ash.) Used as a reference for fuel evaluation purposes.
Calorific value CV, net
The gross calorific value less the heat of evaporation of the water originally contained in the fuel and that formed during its combustion. It is important to clarify the basis on which CV is quoted.
Camelford
Area of N. Cornwall, UK where a 20 tonne load of ALUMINIUM SULPHATE solution was accidentally tipped into public drinking water supplies on 6 July 1988.
Various ailments were attributed to this incident and out-of-court settlements have been accepted by most claimants.
In 2002, a committee investigated claims of joint problem, brain damage & memory loss as a result of the incident but no conclusive links were found. The committee urged the government to study the i...
