Lexikon

different systems of classification and labelling C&L of chemicals are currently used throughout the world. The same substance may be classified as “toxic” in the United States, “harmful” in the European Union and “not dangerous” in China. To eliminate these disparities and to reinforce protection for people and the environment in all countries, it was decided to develop a Globally Harmonised classification and labelling System GHS under the aegis of the United Nations. The GHS was formally adopted in 2002 by the United Nations Economic and Social Committee UN ECOSOC and revised in 2005 and 2007.
It aims to improve the communication on hazards for workers, consumers, emergency responders and in transport, via harmonised labels and where relevant, harmonised safety data sheets.
European Commission adopted in late 2008 the so called "CLP" regulation EC No 1272/2008 on classification, labelling and packaging of hazardous substances and mixtures, which will replace in the medium term the current system.
This regulation takes into account the classification criteria and labelling rules of the GHS but it is also built on the 40 years of experience obtained through implementation of existing Community chemicals legislation.

Source: REACH, http://www.prc.cnrs-gif.fr/reach/en/classification.html

Animal experimentation is used for the development of new chemicals or medicines, for physiological studies, for studying environmental effects or for testing new food additives.The protection and welfare of animals is an area covered by a wide range of EU legislation. These include wildlife, zoo animals, farm animals, animals in transport and also animals used in scientific experiments. EU legislation on the protection of animals used for experimental and other scientific purposes is covered by Directive 86/609/EEC.

The 1997 Treaty of Amsterdam obliges the EU and its Member States to take animal welfare considerations into account in a number of policy areas and also in the practice by developing and using alternatíve testing methods instead of animal experiments.

The most pragmatic approach to reduce experiments on animals is the replacement of animal testing. Whenever replacement is not possible, all efforts should be made to apply those methods which use fewer animals and which cause least harm to the animals.

The replacement may happen by in vitro methods, which use living cells or tissue cultures instead of animals or by the application of mathematical methods, like QSAR.

the lactose operon contains three structural genes that code for enzymes involved in lactose metabolism.

• lac z gene codes for β-galactosidase, an enzyme that breaks down lactose into glucose and galactose
• lac y gene codes for a permease, which is involved in uptake of lactose
• lac a gene codes for a galactose transacetylase.

These genes are transcribed from a common promoter into a polycistronic mRNA, which is translated to yield the three enzymes.

body of standing inland surface water.

Local Area Network

in Hungary there are 6 large landscapes, 35 medium-soze and 230 small landscapes and 6000 ecotops.

The six large landscapes are:
1. Great Plain
2. Northern Medium Mountains
3. Western Hungary
4. Transdanubia
5. Little Plain
6. Transdanubian Medium Mountains

see also pyroclastic rock

Liquid Crystal Display)

toxicological endpoint: LD₅₀ value is the amount of a solid or liquid material that it takes to kill 50% of test animals (for example, mice or rats) in one dose.

LC₅₀ (50% lethal concentration) is a related term used for gases, dusts, vapors, mists etc.

low-density lipoprotein

a company which submits registration information to the Agency on behalf of other members of a joint registration. The information submitted by the lead registrant concerns classification and labelling, study summaries, test proposals and, if necessary, indication which of the information was reviewed by an assessor. If the members of the joint registration so decide, the lead registrant may also submit information on safe use and the CSR on behalf of the others. After the lead registrant submits the information, the other members of the joint registration submit the remaining information individually. (Source: REACH Glossary)

abbreviated as LOD, defined as the lowest concentration or quantity of analyte required to give a signal, which can be distinguished from the background noise. The signal to noise ratio of 3:1 is generally considered acceptable for estimating LOD.

limit of quantification (LOQ) is the lowest concentration, which can be determined with acceptable precision and accuracy. For determination of LOQ the precision and accuracy should be also quantified. It can be calculated from the standard deviation of the blank measurement and the slope of the calibration curve. Usually the LOQ is given as 10 times the background noise.

point noise sources placed one after the other one as, for instance, in a row of cars moving on a road or noise in a pipe.

an extraction technique (LLE) in which one liquid is shaken with or contacted by an extraction solvent to transfer molecules of interest into the solvent phase. Typical sample preparation (concentration) method e.g. organic contaminants in water are extracted into an organic solvent to be measured by gas or liquid chromatography.

in the Earth, the lithosphere includes the crust and the uppermost mantle, which constitute the hard and rigid outer layer of the Earth. The lithosphere is underlain by the asthenosphere, the weaker, hotter, and deeper part of the upper mantle. The boundary between the lithosphere and the underlying asthenosphere is defined by a difference in response to stress: the lithosphere remains rigid for very long periods of geologic time in which it deforms elastically and through brittle failure, while the asthenosphere deforms viscously and accommodates strain through plastic deformation. There are two types of lithosphere: 1) oceanic lithosphere, which is associated with oceanic crust and exists in the ocean basins, 2) continental lithosphere, which is associated with continental crust. The composition of the two types of crust differs markedly, with basaltic rocks ("mafic") dominating oceanic crust, while continental crust consists principally of lower density granitic rocks ("felsic"). The lithosphere is broken into tectonic plates. The following tectonic plates currently exist on the earth's surface with roughly definable boundaries. There are seven primary plates (African Plate, Antarctic Plate, Eurasian Plate, Indo-Australian Plate, North American Plate, Pacific Plate, South American Plate) and some secondary smaller plates (Arabian-, Caribbean-, Cocos-, Scotia-, Adria-, Aegean-, Arab-, Iranian-, Nazca-, Philippine Sea -plates).These plates are rigid segments that move in relation to one another at one of three types of plate boundaries: 1) convergent boundaries, at which two plates come together, (an example of such a boundary is the San Andreas fault in California) 2) divergent boundaries, at which two plates are pulled apart (the Atlantic Ocean was created by this process, the mid-Atlantic Ridge is an area where new sea floor is being created), and 3) transform boundaries, in which two plates slide past one another laterally. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation can occur along these plate boundaries. The tectonic plates ride on top of the asthenosphere, the solid but less-viscous part of the upper mantle that can flow and move along with the plates, and their motion is strongly coupled with patterns convection inside the Earth's mantle. An example of this is the Nazca plate being subducted under the South American plate to form the Andes Mountain Chain.

unit of volume. Its conversion to other units:

Lowest Observed Adverse Effect Level is the lowest tested dose of a substance that has been reported to cause harmful (adverse) health effects in people or animals.

In the everyday language loam refers either to the soil type, soil texture or construction material. The term loam in soil sciences has two main meanings:

1. soil type: loam is a soil material composed of sand, silt, and clay in relatively even concentration (about 40-40-20% concentration respectively). It is like a natural mortar within which the clay has the role of the binder, while sand, silt and small boulders are the aggregates. Loams are gritty, moist, and retain water easily. Loam is ideal for growing crops because it retains nutrients well due to its clay minerals content and retains water while still allowing the water to flow freely. Loam, combined with straw, is used as a construction material to build walls.

2. soil texture is a soil property used to describe the relative proportion of different grain sizes of mineral particles in a soil. In terms of soil texture loam is a medium-textured soil material. The soil texture triangle is a diagram often used to figure out soil textures and it is based on the fractions of soil separates present in a soil. These separates are typically named clay, silt, and sand. According to the fraction of the sand, silt and clay in the soil the soil texture classification would result clay loams, sandy loams, silt loams, sandy clay loams, loamy sand etc

limit of detection is defined as the lowest concentration or mass of analyte required to give a signal, which can be distinguished from the background noise, and can be reliably detected with a given method. The LOD is the lowest concentration obtained from a measurement of a sample (containing the component) that can be discriminated from the concentration obtained from the measurement of a blank sample (a sample not containing the component). (Source: ISO 11843-1. Capability of detection. Part 1: Terms and definitions. ISO, Geneve, 1997) The signal to noise ratio of 3:1 is generally considered acceptable for estimating LOD. The rigorous determination of LOD is important when an analytical method is used for trace analysis or in cases where the legislation requires the absence of certain components.