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Predicted No-effect Concentration
The predicted no-effect concentration (PNEC) is the concentration of a chemical which marks the limit at which below no adverse effects of exposure in an ecosystem are measured. PNEC values are intended to be conservative and predict the concentration at which a chemical will likely have no toxic effect. They are not intended to predict the upper limit of concentration of a chemical that has a toxic effect.European Chemicals Bureau. 2003. Technical Guidance Document on Risk Assessment. European Communities. Available online at: https://echa.europa.eu/documents/10162/16960216/tgdpart2_2ed_en.pdf Predicted No Effect Concentration. 2015. Greenfacts. Available online at: http://www.greenfacts.org/glossary/pqrs/PNEC-predicted-no-effect-concentration.htmLei BL, Huang SB, Jin XW, Wang Z. 2010. Deriving the aquatic predicted no-effect concentrations (PNECs) of three chlorophenols for the Taihu Lake, China. Journal of environmental science and health. Part A, Toxic/hazardous substances & envir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adverse Effect
An adverse effect is an undesired harmful effect resulting from a medication or other intervention, such as surgery. An adverse effect may be termed a "side effect", when judged to be secondary to a main or therapeutic effect. The term complication is similar to adverse effect, but the latter is typically used in pharmacological contexts, or when the negative effect is expected or common. If the negative effect results from an unsuitable or incorrect dosage or procedure, this is called a medical error and not an adverse effect. Adverse effects are sometimes referred to as "iatrogenic" because they are generated by a physician/treatment. Some adverse effects occur only when starting, increasing or discontinuing a treatment. Adverse effects can also be caused by placebo treatments (in which case the adverse effects are referred to as nocebo effects). Using a drug or other medical intervention which is contraindicated may increase the risk of adverse effects. Adverse effects may c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chronic Toxicity
Chronic toxicity, the development of adverse effects as a result of long term exposure to a contaminant or other stressor, is an important aspect of aquatic toxicology. Adverse effects associated with chronic toxicity can be directly lethal but are more commonly sublethal, including changes in growth, reproduction, or behavior. Chronic toxicity is in contrast to acute toxicity, which occurs over a shorter period of time to higher concentrations. Various toxicity tests can be performed to assess the chronic toxicity of different contaminants, and usually last at least 10% of an organism's lifespan. Results of aquatic chronic toxicity tests can be used to determine water quality guidelines and regulations for protection of aquatic organisms. Chronic toxicity definition Chronic toxicity is the development of adverse effects as the result of long term exposure to a toxicant or other stressor. It can manifest as direct lethality but more commonly refers to sublethal endpoints such as decr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Safety
Chemicals as elements, compounds, mixtures, solutions and emulsions are very widely used and transported in the modern industrial society. Of necessity, they are also used in schools, universities and other training facilities to educate pupils in their safe use and handling and also are commonly used in domestic situations for cleaning, gardening and DIY. However, there are chemicals that should not mix or get in contact with others, as they can produce byproducts that may be toxic, carcinogenic, explosive etc, or can be dangerous themselves. To avoid disasters and mishaps, maintaining safety is considered paramount, especially by chemists. Chemical safety includes all those policies, procedures and practices designed to minimise the risk of exposure to potentially hazardous chemicals. This includes the risks of exposure to persons handling the chemicals, to the surrounding environment, and to the communities and ecosystems within that environment. The hazardous nature of many ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ECETOC
The European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) is a scientific, non-profit, non-commercial and non-governmental association. Established in 1978, ECETOC's main objective is to identify, evaluate, and through such knowledge help industry to minimise any potentially adverse effects on human health and the environment that may arise from the manufacture and use of chemicals, biomaterials and pharmaceuticals A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and rel .... Counting as its members the leading companies in the manufacture and use of chemicals, ECETOC facilitates the networking of suitably qualified scientists from its member companies and academia and co-operates in a scientific context with international agencies, governmental authorities and professional soc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Predicted Environmental Concentration
Calculated value of a chemical in the environment on the basis of exposure models such as the European Union System for the Evaluation of Substances (EUSES). Used in the context of Chemical Safety Assessments (CSA) and referenced in Chemical Safety Reports (CSR). PECs may be compared with Measured Environmental Concentration An Measured Environmental Concentration (MEC) relates to a chemical substance found in an environmental sample. The concentration of the compound may result from direct contamination, transformation and/or metabolization of a different chemical cont ...s (MEC) if available. Toxicology Chemical safety {{med-toxic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxicology
Toxicology is a scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms and the practice of diagnosing and treating exposures to toxins and toxicants. The relationship between dose and its effects on the exposed organism is of high significance in toxicology. Factors that influence chemical toxicity include the dosage, duration of exposure (whether it is acute or chronic), route of exposure, species, age, sex, and environment. Toxicologists are experts on poisons and poisoning. There is a movement for evidence-based toxicology as part of the larger movement towards evidence-based practices. Toxicology is currently contributing to the field of cancer research, since some toxins can be used as drugs for killing tumor cells. One prime example of this is ribosome-inactivating proteins, tested in the treatment of leukemia. The word ''toxicology'' () is a neocla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Registration, Evaluation, Authorisation And Restriction Of Chemicals
Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) is a European Union regulation dating from 18 December 2006. REACH addresses the production and use of chemical substances, and their potential impacts on both human health and the environment. Its 849 pages took seven years to pass, and it has been described as the most complex legislation in the Union's history and the most important in 20 years. It is the strictest law to date regulating chemical substances and will affect industries throughout the world. REACH entered into force on 1 June 2007, with a phased implementation over the next decade. The regulation also established the European Chemicals Agency, which manages the technical, scientific and administrative aspects of REACH. Overview When REACH is fully in force, it will require all companies manufacturing or importing chemical substances into the European Union in quantities of one tonne or more per year to register these substances with a n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European Chemicals Agency
The European Chemicals Agency (ECHA; ) is an agency of the European Union which manages the technical and administrative aspects of the implementation of the European Union regulation called Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH). ECHA is the driving force among regulatory authorities in implementing the EU's chemicals legislation. ECHA has to ascertain that companies comply with the legislation, advances the safe use of chemicals, provides information on chemicals and addresses chemicals of concern. It is located in Helsinki, Finland. ECHA is an independent and mature regulatory agency established by REACH. It is not a subsidiary entity of the European Commission. The agency, currently headed by Acting Executive Director Shay O’Malley, started working on 1 June 2007. Establishment The ECHA was created by European Union regulation dating from 18 December 2006 to manage the then-new legislation to regulate the manufacture and use of chemic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesocosm
thumb , Diagram of a small form closed system mesocosm. A mesocosm (''meso-'' or 'medium' and ''-cosm'' 'world') is any outdoor experimental system that examines the natural environment under controlled conditions. In this way mesocosm studies provide a link between field surveys and highly controlled laboratory experiments. Mesocosms tend to be medium-sized to large (e.g., aquatic mesocosm range: to +) and contain multiple trophic levels of interacting organisms. In contrast to laboratory experiments, mesocosm studies are normally conducted outdoors in order to incorporate natural variation (e.g., diel cycles). Mesocosm studies may be conducted in either an enclosure that is small enough that key variables can be brought under control or by field-collecting key components of the natural environment for further experimentation. Extensive mesocosm studies have been conducted to evaluate how organisms or communities might react to environmental change, through deliberate mani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NOEC
Measures of pollutant concentration are used to determine risk assessment in public health. Industry is continually synthesizing new chemicals, the regulation of which requires evaluation of the potential danger for human health and the environment. Risk assessment is nowadays considered essential for making these decisions on a scientifically sound basis. Measures or defined limits include: * ''no-observed-adverse-effect level'' (NOAEL), also called ''no-effect concentration'' (NEC), ''no-observed-effect concentration'' (NOEC) or similarly * ''lowest-observed-adverse-effect level'' (LOAEL) * ''acceptable operator exposure level'' (AOEL) * ECx (in percentage). No-effect concentration ''No-effect concentration'' (NEC) is a risk assessment parameter that represents the concentration of a pollutant that will not harm the species involved, with respect to the effect that is studied. It is often the starting point for environmental policy. There is not much debate on the existence o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trophic Level
The trophic level of an organism is the position it occupies in a food web. A food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves. The trophic level of an organism is the number of steps it is from the start of the chain. A food web starts at trophic level 1 with primary producers such as plants, can move to herbivores at level 2, carnivores at level 3 or higher, and typically finish with apex predators at level 4 or 5. The path along the chain can form either a one-way flow or a food "web". Ecological communities with higher biodiversity form more complex trophic paths. The word ''trophic'' derives from the Greek τροφή (trophē) referring to food or nourishment. History The concept of trophic level was developed by Raymond Lindeman (1942), based on the terminology of August Thienemann (1926): "producers", "consumers" and "reducers" (modified to "decomposers" by Lindeman). Overview The three basic ways in which org ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecosystem
An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the system through photosynthesis and is incorporated into plant tissue. By feeding on plants and on one another, animals play an important role in the movement of matter and energy through the system. They also influence the quantity of plant and microbial biomass present. By breaking down dead organic matter, decomposers release carbon back to the atmosphere and facilitate nutrient cycling by converting nutrients stored in dead biomass back to a form that can be readily used by plants and microbes. Ecosystems are controlled by external and internal factors. External factors such as climate, parent material which forms the soil and topography, control the overall structure of an ecosystem but are not themselves influenced by the ecosystem. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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