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ADI VALUE
"Acceptable Daily Intake" is the highest tolerable daily intake of a substance, expressed in mg/kg bodyweight, which does not represent a health risk over the entire lifespan, calculated on the basis of all currently available data. The wording Tolerable Daily Intake (TDI) is also often used.

AOX
Adsorbable Organic Halogens is a measurement often used in waste water testing to indicate the overall level of the halogens, fluorine, chlorine, bromine and iodine. This "sum parameter" comes from a standard analytical procedure, which gives no information on the source or nature of halogens present nor on their toxicity. It has the advantage of being simple to measure; alternative methods of measuring levels of individual compounds are complex and require costly equipment.

BATs
Best Available Techniques. BAT Standards are used to judge the performance of industrial processes and to provide a target for improvement plans.

BEPs
Best Environmental Practices. BEP means the application of the most appropriate combination of environmental control measures or strategies in order to reduce the impact of specific substances or applications.

BIOACCUMULATION
Bioaccumulation denotes the accumulation of a substance in a living organism as a result of its intake both in the food and also from the environment. Determination of the B-factor (Bioaccumulation Factor) is extremely important in the risk analysis of a compound.

BIOCONCENTRATION
Accumulation of a substance in an organism by absorption from the environment irrespective of any intake with food. The concept is of particular importance for aquatic life with regard to the absorption of those fat-soluble substances which are only broken down slowly.

BIOMAGNIFICATION
This term denotes the accumulation of substances in a living organism with the food intake. Simple organisms such as algae can absorb minute quantities of a substance which are transferred through the food chain to higher living species such as fish, bird, etc. Biomagnification along a food chain will result in the highest concentrations of a substance being found at the top of the food chain.

BLEACH
Bleach is produced by reacting chlorine into a dilute sodium hydroxide solution. Bleach is used for whitening paper, soap, straw and cotton, and for disinfection, water purification and in sanitary cleaners.

CARBON TETRACHLORIDE
Carbon tetrachloride is produced by the high temperature chlorination of propylene or methanes. It is used as a feedstock in the production of CFCs and of chlorine to extract nitrogen trichloride, and as a solvent to recover chlorine from tail gas.

CHLORINATED AROMATICS
Collective term for chlorinated derivatives of benzene, toluene, phenol, naphthalene and bi-phenyl and other compounds containing at least one benzene ring. Chlorinated aromatics are widely used as intermediates in the manufacture of medicines, agricultural chemicals and paints.

CHLORINATED ORGANIC COMPOUND (see Organic Chlorine Compounds)

CHLORINATED SOLVENTS
Trichloroethylene, tetrachloroethylene (also known as perchloroethylene), and methylene chloride, are the main solvents in this group. Due to their non-flammability, these compounds have been widely used for cleaning metals in the electronics industry and for dry cleaning of clothes. The use of 1,1,1-trichloroethane was phased out at the end of 1995 under the Montreal Protocol.

CHLORINATION
1. Introduction of chlorine into a chemical compound.
2. Sterilisation of drinking and swimming pool water or oxidation of undesirable impurities, using chlorine or its compounds.
3. Exposure of wool to chlorine solutions to prevent unwanted felting.

CHLOROBENZENES
Important intermediates in the production of pharmaceuticals, perfumes, agricultural chemicals and paints. Chlorobenzenes are produced by the chlorination of benzene.

CHLOROFORM
Produced mainly by the chlorination of methane, chloroform is used as an intermediate in the production of refrigerants, agrochemicals and fluoropolymers. It is no longer used as an anaesthetic.

DIOXINS/FURANS
Dioxin is the term often used to refer to 17 variably toxic polychlorinated organic compounds consisting of 7 chlorinated dibenzo-p-dioxins and 10 chlorinated dibenzofurans. Of these compounds, the most toxic and thoroughly studied one is 2,3,7,8-tetrachlorodibenzo-p-dioxin, or TCDD.

ECOTOXICOLOGY
Ecotoxicology is the study of the harmful effects of chemical compounds on species, population and the natural environment.

ENVIRONMENTAL POLLUTANTS
Substances introduced into the environment by man which may occur in quantities and concentrations sufficient to endanger living organisms or damage the environment.

EOX
Abbreviation for "Extractable Organohalogens". The fraction of AOX which is extractable by a non-polar organic solvent. This fraction contains the relatively lipophilic (fat-soluble) organic compounds. EOX gives a better indication of the amount of organic halogens susceptible to lipophilic absorption. It often represents about one tenth of the AOX measured.

HYDROGEN CHLORIDE
Hydrogen chloride is a colourless gas with a pungent odour; its aqueous solution is known as hydrochloric acid. Hydrogen chloride is produced by burning hydrogen and chlorine together and is also a by-product of the chlorination of organic compounds. HCl is used in the production of PVC and silicones.

MERCURY
Mercury is a naturally occurring element which is present in various ores. The major source in Europe is in Spain (Almadén). Mercury has been used for 100 years in electrolytic chlorine production.

MONITORING
Area-wide analytical monitoring of chemical contamination.

NATURAL CHLORINE COMPOUNDS
Chlorine is one of the elements most frequently found in nature; it is even more abundant than carbon. Chlorides, i.e., salts containing chlorine, are one of the few raw materials which will not be exhausted within the foreseeable future, even if chlorine consumption were to increase.

Naturally-occurring chlorine compounds are present in our blood, skin and teeth, and chlorine in the form of hydrochloric acid has an important part to play in the digestive process. There are also organic compounds present in nature which contain chlorine; marine algae, for example, produce about 5 million tons of methyl chloride annually (ie: circa 15 times more than yearly industrial production). In total, more than 2000 natural organic chlorine compounds have already been identified.

ORGANIC CHLORINE COMPOUNDS
Organic chlorine compounds constitute a group of more than 2000 substances which are based on organic compounds (i.e., carbon-containing) with one or more chlorine atoms. The exceptional reactivity of chlorine enables it to be introduced into virtually all basic substances in organic chemistry. It is also very easy to trace, even in minute quantities. A large number of different products with a wide range of chemical and physical properties can be produced by selecting suitable reaction conditions. Organic chlorine compounds are important synthetic building blocks in the chemical industry, and they are also formed in nature in large quantities.

ORGANOHALOGEN COMPOUNDS
Organohalogen compounds is the collective term used for compounds containing, in addition to carbon, elements of the halogen group, including fluorine, chlorine, bromine and iodine. Organochlorine compounds form a sub-group of the organohalogen group.

PBTs
Chemicals which are persistent, toxic and liable to bioaccumulate. These have primarily local effects.

PCBs (POLYCHLORINATED BIPHENYLS)
PCBs form a group of compounds which were developed in the 1930s and were mainly used in the electricity supply industry and mining. Due to their accumulation in the food chain, production of PCBs was halted world-wide at the beginning of the 1980s. PCBs are, however, still found in trace concentrations in the sea and in the fatty tissue of marine animals.

PCDDs and PCDFs
Customary abbreviations for polychlorinated dibenzo-p-dioxins and dibenzofurans referring to the dioxins and furans.

PERSISTENCE
Stability of chemical compounds in the environment. Persistence is an important negative criterion in the ecological assessment of chemicals.

PHTHALATES
A family of chemicals, produced from phthalic anhydride and alcohols, frequently used as plasticisers to give flexibility to PVC.

POPs
Persistent organic pollutants, a group of PBTs which are capable of long-range transport and deposition; they are believed to be transported primarily in the atmosphere. These have global effects. Most are already banned in Western Europe but some are still in use in developing countries. The POPs include the following 12: PCBs, dioxins and furans, aldrin, dieldrin, DDT, endrin, chlordane, hexachlorobenzene, Mirex, toxaphene and heptachlor. They fall into three groups: chlorinated pesticides; industrial chemicals; and emissions and by-products.

Adapted from Euro Chlor