Lexikon
recombinant DNA technology means the procedure used to join together DNA segments in a cell-free system (an environment outside a cell or organism). Under appropriate conditions, a recombinant DNA molecule can enter a cell and replicate there, either autonomously or after it has become integrated into a cellular chromosome.
Recombinant DNA technology is also called genetic engineering or in vitro DNA recombination.
minimizing waste generation from site remediation by recovering and reprocessing usable products that might otherwise become waste (Source: EUGRIS).
the average composition of red mud is the following:
| Fe2O3 | 30−60% |
| Al2O3 | 10−20% |
| SiO2 | 3−50% |
| Na2O | 2−10% |
| CaO | 2−8% |
| TiO2 | 0−25% |
reference dose is the maximum acceptable oral or dermal dose of a toxic substance. The EPA defines an oral reference dose (abbreviated RfD) as an estimate, with uncertainty spanning perhaps an order of magnitude, of a daily oral exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. http://www.epa.gov/economics/children/basic_info/glossary.htm
Reference doses are chemical specific, i.e. the EPA determines a unique reference dose for every substance it evaluates. Often separate acute and chronic RfDs are determined for the same substance. Reference doses are specific to dietary exposure. When assessing inhalation exposure, EPA uses "Reference concentrations," (RfCs), instead of RfDs. Note that RfDs apply only to non-cancer effects. When evaluating carcinogenic effects, special risk assessment methodology is applied.
RfDs are usually derived from animal studies. Animals (typically rats) are dosed with varying amounts of the substance in question, and the largest dose at which no effects are observed is identified. This dose level is called the "No Observable effect Level," or NOEL. To account for the fact that humans may be more or less sensitive than the test animal, a 10-fold uncertainty factor is usually applied to the NOEL. This uncertainty factor is called the "interspecies uncertainty factor" or Ufinter. An additional 10-fold uncertainty factor, the "intraspecies uncertainty factor" or Ufintra, is usually applied to account for the fact that some humans may be substantually more sensitive to the effects of substances than others. Additional uncertainty factors may also be applied. In general:
Frequently, a NOAEL is used in place of a NOEL. If adverse effects are observed at all dose levels tested, then the smallest dose tested, the "Lowest Observed adverse effect Level" or LOAEL, is used to calculate the RfD. An additional uncertainty factor usually applied in these cases, since the NOAEL, by definition, would be lower than the LOAEL had it been observed.
registration is the submission to the Agency of a technical dossier and, if required, a chemical safety report for a substance being manufactured in or imported into the European Union (and in the European Economic Area (EEA) once implemented in these countries). (Source: REACH Glossary)
registration is the submission to the Agency of a technical dossier and, if required, a chemical safety report for a substance being manufactured in or imported into the European Union (and in the European Economic Area (EEA) once implemented in these countries).
Manufacturers or Importers of substances on their own or in preparations or Producers or importers of articles will have in certain circumstances to provide a registration dossier to the European Chemicals Agency according to Articles 10, 11, 12, 17 and 18. It consists of a technical dossier and, when required, a Chemical Safety Report. (Source: REACH Glossary)
REGULATION (EC) No 1272/2008 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 16 December 2008
on classification, labelling and packaging of substances and mixtures, amending and repealing Directives 67/548/EEC and 1999/45/EC, and amending Regulation (EC) No 1907/2006
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2008:353:0001:1355:en:PDF
gene (a functional part of DNA) is transcripted into RNA (ribonucleic acid) and RNA translated into proteins in every living cells.
Some proteins are constitutively expressed (present all of the time), but cells can regulate the expression of proteins that are not needed all of the time or in large amounts. This provides cells with control mechanisms for turning metabolic reactions on and off. Cells use a variety of mechanisms to regulate gene expression, and thus which proteins are produced.
Proteins can be controlled or regulated at the level of their synthesis (regulation of gene transcription), gene translation, various post-translation mechanisms and feedback inhibition, or the recently discovered actions of RNAi and microRNA.
regulatory toxicology gathers and evaluates existing toxicological information, develops uniform, standardized, comparable methods for testing and evaluating not only the effects but also the fate and behavior of chemical substances both in the environment and in the organisms. Regulatory toxicology means the interpretation and use of toxicity-results for the establishment of effect based quality criteria for food, drinking water, other water uses (e.g. irrigation), animal feed, all environmental compartments, such as air, surface waters, sediments, subsurface waters, soils, depending their use and users (land use) as well as for waste utilization (e.g. sewage sludge utilization on soil). Regulatory toxicology tries to control hazardous substances and materials in a safe matter, ensuring an acceptable risk level, or with other words, a safe exposure.
Regulatory toxicology is the study of the adverse effects of chemicals, not just on humans, but also on all living organisms including plants, animals, fungi and insects. The integration of metabolism, toxicity, pathology and mechanism is playing a much greater role today than ever before. A better understanding of these areas is essential for proper regulation of chemical substances and drugs and every other material, product or waste which contains hazardous chemical substances. It can also play an important role in the development of backup drugs and chemicals. We have to emphasize, that the origin of chemical risk is not only the hazard of a substance, but also the abnormal concentration or presence of a chemical substances at a not proper place and time.
environmental toxicology should serve regulation, scientists should know the concepts of regulation and the way how to fill the gaps with methodologies and information, moreover to advise on the need for their integration into the regulatory decision making.
The importance of regulatory toxicology is highly certified by the regulations on pesticides, biocides, food additives, cosmetics and the regulation of hazardous chemical substances and materials all over the world.
each gene is a linear stretch of DNA nucleotides that codes for the assembly of amino acids into a polypeptide chain (protein). DNA is transcribed into RNA (transcription), and RNA carries the message for making the protein to another part of the cell where it is translated into the amino acid chains that will make up the protein (translation).
for the in situ or ex situ remediation of hydrocarbons, pesticides, chlorinated substances contaminated soils the altering oxic-anoxic or aerobic-anaerobic treatment is an efficient bioremediation alternative. The steps of the technology application are:
1. Addition of organic soil amendment, zero valent iron, and water to produce anoxic conditions.
2. Periodic tilling of the soil to promote oxic conditions.
3. Repetition of the anoxic-oxic cycle until the desired cleanup goals are achieved.
The addition of DARAMEND® organic amendment, zero valent iron, and water stimulates the biological depletion of oxygen, generating strong reducing anoxic conditions within the soil matrix. The diffusion of replacement oxygen into the soil matrix is prevented by near saturation of the soil pores with water. The depletion of oxygen creates a low redox potential, which promotes dechlorination of organochlorine compounds. A cover may be used to control the moisture content, increase the temperature of the soil matrix and eliminate runon/run off.
The soil matrix consisting of contaminated soil and the amendments is left undisturbed for the duration of the anoxic phase of treatment cycle typically 1-2 weeks. In the oxic phase of each cycle, periodic tilling of the soil increases diffusion of oxygen to microsites and distribution of irrigation water in the soil. The dechlorination products formed during the anoxic degradation process are subsequently removed trough aerobic oxic biodegradation processes, initiated by the passive air drying and tilling of the soil to promote aerobic conditions.
all kind of risk reduction options which are able to mitigate risk of contaminated soil. During the decision-making procedure the remediation options should be collected, enlisted, evaluated and based on the priority point of views make the selection between them to find the best possible solution for a certain problem.
remote sensing - in a very general sense - is a technique for getting information about objects by analysing data collected by instruments that were not in direct contact with the objects. However, in environmental monitoring the term of remote sensing is generally used for observation of the Earth via instruments placed on board planes or satellites.
renewable energy is kind of energy which is generated from natural resources such as sun-energy, wind-energy, hydropower, tides, geothermal energy and biomass. These all are naturally replenished sources.
In 2006, about 18% of global final energy consumption came from renewables, with 13% coming from traditional biomass, such as wood-burning and 3% from hydroelectricity. New type renewable resources (biomass, wind, solar, geothermal, and biofuels) accounted for 2.4% and are growing very rapidly. The share of renewables in electricity generation is around 18%, with 15% of global electricity coming from hydroelectricity and 3.4% from new renewables (source: http://en.wikipedia.org/wiki/Renewable_energy).
repeatability is the degree to which repeated measurements under unchanged conditions show the same results.
the repeated dose toxicity comprises the general toxicological effects occurring as a result of repeated daily exposure to a substance for a part of the expected lifespan (sub-acute or sub-chronic exposure) or for the major part of the lifespan (chronic exposure).
These general toxicological effects include effects on body weight and/or body weight gain, absolute and/or relative organ and tissue weights, alterations in clinical chemistry, urinalysis and/or haematological parameters, functional disturbances in the nervous system as well as in organs and tissues in general, and pathological alterations in organs and tissues as examined macroscopically and microscopically. Besides this information on possible adverse general toxicological effects, repeated dose toxicity studies may also provide other information on e.g. reproductive toxicity or carcinogenicity or may identify specific manifestations of toxicity such as e.g., neurotoxicity, immunotoxicity, endocrine-mediated effects...
The objectives of assessing repeated dose toxicity are to evaluate:
- whether repeated exposure of humans to a substance has been associated with adverse toxicological effects; these human studies potentially may also identify populations that have higher susceptibility;
- whether repeated administration of a substance to experimental animals causes adverse toxicological effects; effects that are predictive of possible adverse human health effects;
- the target organs, the potential cumulative effects and the reversibility of the adverse toxicological effects;
- the dose-response relationship and the threshold for any of the adverse toxicological effects observed in the repeated dose toxicity studies;
Source: REACH
reproducibility is the variation arising using the same measurement process among different instruments and operators, and over longer time periods.
It can be distinguished from repeatability, which is the variation arising when all efforts are made to keep conditions constant by using the same instrument and operator, and repeating during a short time period.
reproductive toxicity includes adverse effects on sexual function and fertility in adult males and females, as well as developmental toxicity in the offspring. As a short name "reprotox" is also used. Those chemical substances which may cause reproductive toxicity are reprotoxic substances.
Reproductive Toxicity is differentiated into:
– adverse effects on sexual function and fertility;
– adverse effects on development;
– effects on or via lactation. (REACH)
Animal tests include evaluating the effects of prenatal exposure on pregnant animals and their offspring [OECD Test Guideline (TG) 414]. This test is usually performed with female rats and rabbits. The test substance is administered orally, the pregnant animals are killed just prior to delivery, and the fetuses are examined for toxic effects. A one-generation reproduction toxicity study (OECD TG 415) in rats or mice is used to evaluate toxic effects on male and female reproduction. Males and females are dosed orally before mating, and females during pregnancy. A two-generation reproduction toxicity study (OECD TG 416) continues dosing with the test substance to the first generation offspring. OECD TG 421 (Reproductive/Developmental Toxicity Screening Assay) uses male and female rats with the test substance administered orally for 4-9 weeks. Pathological effects are determined by daily observation, necropsy, and microscopic histopathology.
The Organisation for Economic Cooperation and Development (OECD) adopted two draft proposals for new reproductive/developmental toxicity TGs in October 2007. Draft Proposal 426,
An ICCVAM-NICEATM workshop reviewed the Frog Embryo Teratogenesis Assay: Xenopus (FETAX) as a potential alternative for assessing developmental toxicants. The method was deemed not ready for validation, so recommendations were made for its continued development.
The ECVAM Scientific Advisory Committee (ESAC) "endorsed three in vitro methods for embryotoxicity testing as scientifically validated" (ESAC Statements, May 1, 2002):
- Embryonic stem cell test for embryotoxicity
- Micromass embryotoxicity assay
- Whole rat embryo embryotoxicity assay
The ESAC recommended these in vitro methods as ready for regulatory acceptance but acknowledged they cannot replace the animal tests. However, when used as part of a testing strategy, they could contribute to reducing animal use. (Source: http://www.alttox.org/ttrc/toxicity-tests/repro-dev-tox/)
see as reproductive toxicity.
reprotoxic is a chemical substance, which may cause reproductive toxicity. Reproductive toxicity includes adverse effects on sexual function and fertility in adult males and females, as well as developmental toxicity in the offspring.
Reproductive Toxicity is differentiated into:
– adverse effects on sexual function and fertility;
– adverse effects on development;
– effects on or via lactation.
reproductive toxicity is of obvious high concern because the continuance of the human species is dependent on the integrity of the reproductive cycle. It is characterised by multiple diverse endpoints, such as impairment of male and female reproductive functions or capacity (fertility), induction of non-heritable harmful effects on the progeny (developmental toxicity) and effects on or mediated via lactation.
The objectives of assessing reproductive toxicity are to establish:
- whether exposure of humans to the substance of interest has been associated with reproductive toxicity;
- whether, on the basis of information other than human data, it can be predicted that the substance will cause reproductive toxicity in humans;
- whether the pregnant female is potentially more susceptible to general toxicity;
- the dose-response relationship for any adverse effects on reproduction.
Source: REACH
A parameter used in chromatographic separation techniques. The time it takes for an eluate to move through a chromatographic system and to REACH the detector. The retention time for the components might be different depending on the interaction with the stationary phase. retention times are reproducible and can therefore be compared to a standard for analyte identification. In gas chromatography the retention time of the compounds with similar structure, e.g. non-branched saturated hydrocarbons is proportional with the carbon number.