Lexikon

thermally enhanced recovery is an in situ treatment process that uses heat to increase the volatilization rate of organics and facilitate extraction. Volatilized contaminants are typically removed from the vadose zone using soil vapor extraction. Specific types of thermally enhanced recovery techniques include radio frequency heating, conductive heating, steam heating, in situ steam stripping, hot air injection, dynamic underground stripping, in situ thermal desorption, and electrical resistive heating. Thermally enhanced recovery is usually applied to contaminated soil but may also be applied to groundwater.

thermolysis or thermal decomposition is defined as a chemical reaction in which a chemical substance brackes up into at least two chemical substances when heated. The reaction is usuallyendothermic, as heat is required to break the chemical bounds during decomposition.

a tidal turbine is similar to a wind turbine in that it consists of a rotor that turns due to its interaction with water during the ebb and flow of a tide. Tidal turbines are generally mounted on the sea floor. Since tides run about six hours in one direction before switching directions for six hours, tidal turbines can provide a predictable energy source.

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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. It is also called: Acceptable Daily Intake (ADI).

according to REACH A substance fulfils the toxicity criterion when:
– the long-term no-observed effect concentration (Noec) for marine or freshwater organisms is less than 0,01 mg/l, or
– the substance is classified as carcinogenic (category 1 or 2), mutagenic (category 1 or 2), or toxic for reproduction (category 1, 2, or 3), or
– there is other evidence of chronic toxicity, as identified by the classifications: T, R48, or Xn, R48 according to Directive 67/548/EEC.

toxic substances are those natural or man-made chemical substances, which are toxic for living organisms, including members of the ecosystem and humans.

Toxic substances can be inroganis or organic substances. Inorganic ones are mainly toxic metals, like arsenic, cadmium, lead, copper, chromium, nikkel, zinc, and their compounds.

Organic toxic substances are of natural origin or man-made ones (xenobiotica). The natural toxic substances maybe bacterial toxins, toxins or drugs of fungal, plant, insect or other animal origin. Other part of the toxic substances are designed and produced for the purpose of killing or inhibiting organisms or groups of organisms. These are desinficients, antimicrobial agents, antibiotics, pesticides, biological weapons, etc. These man-made toxic substances may effect not only the target group of organisms with their primary effect, but by discharging them into the environment any other organism, including man is endangered by mutagenic or reprotoxic effects, by immun- and endocrine disrupting effect, or sensitizing effects. The users of the environment, including man, cannot efficiently prevent themselves from these adverse effects, because we often do not know about the presence of these substances in the environment, we cannot predict their interaction with other substances or environmental compounds, and we do not know their long term effects.

See also toxic effect, toxicity, toxic metals, toxicity tests

see toxic effect, toxicity

the testing of physico-chemical characteristics of chemical substances is regulated by the COUNCIL REGULATION (EC) No 440/2008 of 30 May 2008 laying down test methods pursuant to Regulation (EC) No 1907/2006 of the European Parliament and of the Council on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH).

(1) Pursuant to Regulation (EC) No 1907/2006, test methods are to be adopted at Community level for the purposes of tests on substances where such tests are required to generate information on intrinsic properties of substances.

(2) Council Directive 67/548/EEC of 27 June 1967 on the approximation of the laws, regulations and administrative provisions relating to the classification, packaging and labelling of dangerous substances laid down, in Annex V, methods for the determination of the physico-chemical properties, toxicity and ecotoxicity of substances and preparations. Annex V to Directive 67/548/EEC has been deleted by Directive 2006/121/EC of the European Parliament and of the Council with effect from 1 June 2008.

(3) The test methods contained in Annex V to Directive 67/ 548/EEC should be incorporated into this Regulation.

(4) This Regulation does not exclude the use of other test methods, provided that their use is in accordance with Article 13(3) of Regulation 1907/2006.

(5) The principles of replacement, reduction and refinement of the use of animals in procedures should be fully taken into account in the design of the test methods, in particular when appropriate validated methods become available to replace, reduce or refine animal testing.

(6) The provisions of this Regulation are in accordance with the opinion of the Committee established under Article 133 of Regulation (EC) No 1907/2006

Article 1: The test methods to be applied for the purposes of Regulation 1907/2006/EC are set out in the Annex to this Regulation.

Article 2: The Commission shall review, where appropriate, the test methods contained in this Regulation with a view to replacing, reducing or refining testing on vertebrate animals.

Article 3: All references to Annex V to Directive 67/548/EEC shall be construed as references to this Regulation.

Article 4: This Regulation shall enter into force on the day following its publication in the Official Journal of the European Union.

It shall apply from 1 June 2008.

LIST OF METHODS FOR THE DETERMINATION OF TOXICITY

B.1 bis. Acute oral toxicity – fixed dose procedure
B.1 tris. Acute oral toxicity – acute toxic class method
B.2. Acute toxicity (inhalation)
B.3. Acute toxicity (dermal)
B.4. Acute toxicity: dermal irritation/corrosion
B.5. Acute toxicity: eye irritation/corrosion
B.6. Skin sensitisation
B.7. Repeated dose (28 days) toxicity (oral)
B.8. Repeated dose (28 days) toxicity (inhalation)
B.9. Repeated dose (28 days) toxicity (dermal)
B.10. Mutagenicity – in vitro mammalian chromosome aberration test
B.11. Mutagenicity – in vivo mammalian bone marrow chromosome aberration test
B.12. Mutagenicity – in vivo mammalian erythrocyte micronucleus test
B.13/14. Mutagenicity: reverse mutation test using bacteria
B.15. Mutagenicity testing and screening for carcinogenicity gene mutation – saccharomyces cerevisiae
B.16. Mitotic recombination – saccharomyces cerevisiae
B.17. Mutagenicity – in vitro mammalian cell gene mutation test
B.18. Dna damage and repair – unscheduled dna synthesis – mammalian cells in vitro
B.19. Sister chromatid exchange assay in vitro
B.20. Sex-linked recessive lethal test in drosophila melanogaster
B.21. In vitro mammalian cell transformation tests
B.22. Rodent dominant lethal test
B.23. Mammalian spermatogonial chromosome aberration test
B.24. Mouse spot test
B.25. Mouse heritable translocation
B.26. Sub-chronic oral toxicity test repeated dose 90-day oral toxicity study in rodents
B.27. Sub-chronic oral toxicity test repeated dose 90-day oral toxicity study in nonrodents
B.28. Sub-chronic dermal toxicity study 90-day repeated dermal dose study using
Rodent species
B.29. Sub-chronic inhalation toxicity study 90-day repeated inhalation dose studusing rodent species
B.30. Chronic toxicity test
B.31. Prenatal developmental toxicity study
B.32. Carcinogenicity test
B.33. Combined chronic toxicity/carcinogenicity test
B.34. One-generation reproduction toxicity test
B.35. Two-generation reproduction toxicity study
B.36. Toxicokinetics
B.37. Delayed neurotoxicity of organophosphorus substances following acute exposure
B.38. Delayed neurotoxicity of organophosphorus substances 28 day repeated dose study
B.39. Unscheduled dna synthesis (uds) test with mammalian liver cells in vivo
B.40. In vitro skin corrosion: transcutaneous electrical resistance test (ter)
B.40 bis. In vitro skin corrosion: human skin model test
B.41. In vitro 3T3 NRU phototoxicity test
B.42. Skin sensitisation: local lymph node assay
B.43. Neurotoxicity study in rodents
B.44. Skin absorption: in vivo method
B.45. Skin absorption: in vitro method

the expression of toxicity arising from exposure to a substance is a consequence of a chain of events that results in the affected tissues of an organism receiving the ultimate toxicant in amounts that cause an adverse effect. The concentration of the ultimate toxicant at the biological target site depends on the absorption, distribution, metabolism and excretion. According to REACH annexe VIII, the assessment of these processes, i.e. the toxicokinetics behaviour is required from the relevant available information. There is no obligation to generate new data.

Source: REACH

toxicology involves all aspects of the adverse effects of chemical substances on living systems. Those effects which are damaging to either the survival or normal function of any living organism or their communities.

is a measure of the electrical impedance of the skin, as a resistance value in kilo Ohms. A simple and robust method of assessing barrier function by recording the passage of ions through the skin using a Wheatstone bridge apparatus. It is used in skin corrosivity tests, the value of the eletrical impedance gives the damage of the skin disk used int he test treated by the test substance.

a transgenic animal is one that carries a foreign gene that has been deliberately inserted into its genome. The foreign gene is constructed using recombinant DNA methodology. In addition to the gene itself, the DNA usually includes other sequences to enable it

• to be incorporated into the DNA of the host and
• to be expressed correctly by the cells of the host.

Transgenic sheep and goats have been produced that express foreign proteins in their milk.

Transgenic chickens are now able to synthesize human proteins in the "white" of their eggs.

These animals should eventually prove to be valuable sources of proteins for human therapy.

In July 2000, researchers from the team that produced Dolly reported success in producing transgenic lambs in which the transgene had been inserted at a specific site in the genome and functioned well. [More]

Transgenic mice have provided the tools for exploring many biological questions.

An example: Normal mice cannot be infected with polio virus. They lack the cell-surface molecule that, in humans, serves as the receptor for the virus. So normal mice cannot serve as an inexpensive, easily-manipulated model for studying the disease. However, transgenic mice expressing the human gene for the polio virus receptor can be infected by polio virus and even develop paralysis and other pathological changes characteristic of the disease in humans.

Two methods of producing transgenic mice are widely used:

• transforming embryonic stem cells (ES cells) growing in tissue culture with the desired DNA;
• injecting the desired gene into the pronucleus of a fertilized mouse egg.

Source: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/T/TransgenicAnimals.html

Xenotransplantation

Transplant organs may soon come from transgenic animals. Patients die every year for lack of a replacement heart, liver, or kidney. For example, about 5,000 organs are needed each year in the United Kingdom alone. Transgenic pigs may provide the transplant organs needed to alleviate the shortfall. Currently, xenotransplantation is hampered by a pig protein that can cause donor rejection but research is underway to remove the pig protein and replace it with a human protein.

Nutritional supplements and pharmaceuticals

Milk-producing transgenic animals are especially useful for medicines.
Products such as insulin, growth hormone, and blood anti-clotting factors may soon be or have already been obtained from the milk of transgenic cows, sheep, or goats. Research is also underway to manufacture milk through transgenesis for treatment of debilitating diseases such as phenylketonuria (PKU), hereditary emphysema, and cystic fibrosis.

In 1997, the first transgenic cow, Rosie, produced human protein-enriched milk at 2.4 grams per litre. This transgenic milk is a more nutritionally balanced product than natural bovine milk and could be given to babies or the elderly with special nutritional or digestive needs. Rosie’s milk contains the human gene alpha-lactalbumin. A transgenic cow exists that produces a substance to help human red cells grow.

Human gene therapy

Human gene therapy involves adding a normal copy of a gene (transgene) to the genome of a person carrying defective copies of the gene. The potential for treatments for the 5,000 named genetic diseases is huge and transgenic animals could play a role. For example, the Virtanen Institute in Finland produced a calf with a gene that makes the substance that promotes the growth of red cells in humans.

transgenic animals may be produced as disease models, meaning genetically manipulated animals, which exhibit disease symptoms so that effective treatment can be studied. For example, Harvard scientists made a major scientific breakthrough when they received a U.S. patent (the company DuPont holds exclusive rights to its use) for a genetically engineered mouse, called OncoMouse® or the Harvard mouse, carrying a gene that promotes the development of various human cancers.

transgenic organism is an experimentally produced organism in which DNA has been artificially introduced and incorporated into the organism's germ line.