it is a risk based target concentration for contaminated sites and contaminates soils. The Hungarian low requires the calculation of this target concentration in the remedial plan. The D-value is land-use specific.
the unified atomic mass unit or Dalton (Da), named after the famous chemist John Dalton. it is a unit of mass used to express atomic and molecular masses. Per definitionem the atomic mass unit is one twelfth (1/12) of the mass of an isolated atom of carbon-12 (12C) at rest and in its ground state, consequently a single atom of carbon-12 has a mass of 12 Da. The relationship between the atomic mass unit (Da) and the gram (g) is: 1g = 6,022 141 79 x 1023 Da.
The Dangerous Substances Directive (as amended) is one of the main European Union laws concerning chemical safety. It was made under Article 100 (Art. 94 in a consolidated version ) of the Treaty of Rome. By agreement it is also applicable in the EEA, and compliance with the Directive will ensure compliance with the relevant Swiss laws.
The Directive applies to pure chemicals and to mixtures of chemicals (preparations) that are placed on the market in the European Union, therefore it does not apply directly to substances created purely for research purposes. Additional rules concerning preparations are contained in the Dangerous Preparations Directive (1999/45/EC) , these are very similar to the rules contained in the Dangerous Substances Directive 67/548/EEC.
Art. 2 of the Directive lists the classes of substances or preparations that are considered to be dangerous. Some, but not all, of these classes are associated with a chemical hazard symbols and/or a code.
- Explosives (E)
- Oxidizers agents (O)
- Flammable flammable substances or preparations, classified as extremely flammable (F+), highly flammable (F)
- Toxic substances or preparations, classified as very toxic (T+) or toxic (T)
- Harmful substances or preparations (Xn)
- Corrosive substances or preparations (C)
- Irritants (Xi)
- Carcinogens (Carc.), classified into three categories
- Mutagenic (Mut.), classified into three categories
- Substances or preparations that are reprotoxic (toxic for reproduction) (Repr.), classified into three categories
- Substances or preparations that are dangerous for the environment (N)
Substances or preparations falling into one or more of these classes are listed in Annex I of the Directive, which is regularly updated. A public database of substances listed in Annex I of the Directive is maintained by the Institute for Health and Consumer Protection.
The Directive does not apply to the following groups of substances and preparations (Art. 1):
- Cosmetics, which are covered by the Cosmetics Directive
- Foodstuffs for humans or animals
- Radioactive materials
The Directive does not apply to the transport of dangerous substances or preparations.
The standard phrases are defined in Annexes III and IV of the Directive. Annex III defines phrases relating to the Nature of special risks attributed to dangerous substances and preparations, often referred to as R-phrases (R-phrases). Annex IV defines phrases relating to Safety advice concerning dangerous substances and preparations, often referred to as S-phrases (S-phrases).
The appropriate standard phrases must appear on the packaging and label of the product and on its MSDS. Annex I specifies the standard phrases to be used for substances that are listed there: these are obligatory.
Labelling: (Arts. 23-25). In general, the label on the packaging of a dangerous substance or preparation must clearly indicate the following items: the name of the substance; (for substances listed in Annex I, the name indicated must be one of those listed in the Annex (many substances appear in the Annex under different synonyms): otherwise, the name should be "internationally recognized")
Art. 27 of the Directive imposes an obligation on suppliers to provide an MSDS, on paper or electronically, at or before the first delivery of a dangerous substance or preparation. The supplier is also obliged to inform users of any relevant new information which becomes known. Directive 2001/58/EC provides detailed guidance for the preparation of material safety data sheets.
- the name, full address and telephone number of the person or company which has placed the substance on the market (manufacturer, importer or distributor);
- the danger symbols, if any;
- the standard phrases, if any; (certain exemptions are permitted)
- the EINECS number or equivalent;
- for substances listed in Annex I, the words EEC label.
Data Quality Objectives (DQO) are qualitative and quantitative statements derived from the DQO process describing the decision rules and the uncertainties of the decision(s) within the context of the problem(s).
DQO process is a quality management tool that enables planners to focus their planning efforts by specifying the use of the data (the decision), the decision criteria (action level) and the decision maker’s acceptable decision error rates. The products of the DQO process are the DQOs.
Double Data Rate Synchronous Dynamic Random Access Memory
German Society for Chemical Engineering and Biotechnology is a non-profit scientific and technical society based in Frankfurt am Main, Germany. It has more than 5,500 private and institutional members, among them scientists, engineers, companies, organisations and institutes.
One aim of DECHEMA is to promote and support research and technological progress in Chemical Technology and Biotechnology DECHEMA regards itself as interface between science, economy, state and public.
a unit used to express relative difference on power, usually between acoustic or electric signals, equal to ten times the common logarithm of the ratio of the two level.
wind-erosion deflation is the detachment and transport of fine solid particles soil, sediment or rock by wind action. Its stages are detachment, abrasion, deposition and accumulation of the transported material. The extent of wind erosion depends on the wind velocity, wind direction, texture and organic matter content of the surface layer, soil moisture and relief. The areas mostly exposed to wind erosion are the arid environments such as deserts.The action of the wind in removing material from a surface can result even in lowering that surface below sea level. Most of the dust carried by dust storms is in the form of silt-size particles forming loess deposits. The Glacial loess having a high content of glacially ground flour-like and clay entrained by the wind and then deposited downwind had an important role in the formation of soils in Hungary.
delayed death in toxicity testing means that an animal does not die or appear moribund within 48 hours but dies later during the 14-day observation period.
a disease or an injury that happens as a result of exposures that might have occurred in the past.
is the production of irreversible damage of the skin; namely, visible necrosis through the epidermis and into the dermis, following the application of a test substance for up to four hours. Corrosive reactions are typified by ulcers, bleeding, bloody scabs, and, by the end of observation at 14 days, by discoloration due to blanching of the skin, complete areas of alopecia, and scars. Histopathology should be considered to evaluate questionable lesions.
is the production of reversible damage of the skin following the application of a test substance for up to 4 hours.
desertification means land degradation in arid, semi-arid and dry sub-humid areas resulting from various factors, including climatic variations and human activities;
Combating desertification includes activities which are part of the integrated development of land in arid, semi-arid and dry sub-humid areas for sustainable development which are aimed at:
- prevention and/or reduction of land degradation;
- rehabilitation of partly degraded land;
- reclamation of desertified land.
UNCCD, the United Nations Convention to Combat Desertification in Countries Experiencing Serious Drought and/or Desertification, Particularly in Africa joins forces and actions all over the world.
See also: http://www.unccd.int/convention/text/convention.php
the lowest concentration of a chemical that can reliably be distinguished from a zero concentration.
in analytical chemistry, the detection limit is the lower limit of detection, or LOD (limit of detection), is the lowest quantity of a substance that can be distinguished from the absence of that substance (a blank value) within a stated confidence limit (generally 1%). The detection limit is estimated from the mean of the blank, the standard deviation of the blank and some confidence factor. Another consideration that affects the detection limit is the accuracy of the model used to predict concentration from the raw analytical signal.
There are a number of different "detection limits" that are commonly used. These include the instrument detection limit (IDL), the method detection limit (MDL), the practical quantification limit (PQL), and the limit of quantification (LOQ). Even when the same terminology is used, there can be differences in the LOD according to nuances of what definition is used and what type of noise contributes to the measurement and calibration.
Diabetes mellitus - often simply referred to as diabetes - is a condition in which a person has a high blood sugar (glucose) level as a result of the body either not producing enough insulin, or because body cells do not properly respond to the insulin that is produced. Insulin is a hormone produced in the pancreas which enables body cells to absorb glucose, to turn into energy. If the body cells do not absorb the glucose, the glucose accumulates in the blood (hyperglycemia), leading to various potential medical complications.
in geology and oceanography, diagenesis is any chemical, physical, or biological change undergone by a sediment after its initial deposition and during and after its lithification, exclusive of surface alteration (weathering) and metamorphism. These changes happen at relatively low temperatures and pressures and result in changes to the rock's original mineralogy and texture. The boundary between diagenesis and metamorphism, which occurs under conditions of higher temperature and pressure, is gradational.
the aim of dietetics is topromote good health through proper eating. The dietitian supervise the preparation and service of food, develop modified diets, participate in research, and educate individuals and groups on good nutritional habits. In a medical setting, a dietitian may provide specific artificial nutritional needs to patients unable to consume food normally.