Lexikon
p-tert-butylphenol is used as an intermediate for phenol resins and polycarbonate resins. It is also used as a raw material for construction elements and floors in buildings.
CAS NO: 98-54-4
Melting Point: 99.3 °C
Boiling Point: 237 °C (at 1,013 hPa)
Density: 0.92 g/m3 at 110 °C
Vapour Pressure: 1.3 x 102 Pa at 60 °C
Partition Coefficient (Log Pow): 3.29 at 25 °C
Water Solubility: 610 mg/l at 25 °C
pKa: 10.16 at 25 °Chttp://enfo.hu/mokka/secure/.tmp/glossary/glossary_edit.php
It is not photodegradable, not ready to hydrolyse, readily biodegradable, bioaccumulated by aquatic ecosystem: 34–120.
The production volume of p-t-butylphenol in Japan is 5,000 tonnes/year in 1993. According to ECDIN database, the production volume of USA is 11,000 tonnes/year in 1993. According to IUCLID database, maximum production volume is 10,000 tonnes/year. Less than 5000 tonnes/year are produced in France. Less than 1000 tonnes/year are sold to be used either as a chemical intermediate for the production of vulcanization agents or as for the production of phenolic resins.
The potential environmental distribution of p-t-butylphenol obtained from a generic fugacity model (Mackey level III) shows that it will be mainly distributed to water. The main route of human exposure is inhalation with a limited numbers of workers potentially exposed during sampling and bag or tank filling operations.
No concentration was measured and no presence of the substance was detected in the environment. Release into environment may happen only from production or transport, because the substance is not used out of the production site. Distribution in the environment when released into air, water and soil can be calculated by transport modelling:
released into air: air: 39.7%; water: 23.3%; soil: 35.9%; sediment: 1.1%;
released into water: air: 0.2%; water: 95.3%; soil: 0.2%; sediment: 4.4%;
release into soil: air: 0.0%; 99.6 %; soi: 0.4%; sediment: 0.0%.
Acute toxicity of p-t-butylphenol is low via any administration routes. This chemical is considered as an irritant to the skin, eyes and respiratory tract. The possibility of skin sensitization in humans still remains because of some positive results in human patch tests, despite negative results in animal experiments (OECD TG 406). The depigmentation was observed on the skin of various animals and humans exposed to this chemical. This change was likely induced by exposure to this chemical not only via direct contact but also via inhalation or ingestion route. In the OECD combined repeat dose and reproductive/developmental screening toxicity test (OECD TG 422) of rats by gavage at doses of 20, 60 and 200 mg/kg/day for 46 days, this chemical showed neither systemic toxicity nor reproductive toxicity even at the highest dose of 200 mg/kg/day. Although a noisy respiratory sound was induced in a few females at 200 mg/kg/day, it was considered due to irritation of the respiratory tract caused by this chemical. In a dose-finding study (14 days), this changed to respiratory difficulty, especially at 1,000 mg/kg/day. In other studies by the longer and higher exposure in diet (approx. 1 g/kg b.w./day, for 20 or 51 weeks), forestomach hyperplasia was induced. This chemical showed clear negative results in gene mutation tests. However, one
chromosomal aberration study indicated structural chromosome aberration and polyploidy with metabolic activation in CHL/IU cells (OECD TG 473) although other studies in rat lymphocytes (OECD TG 473) and in rat liver epithelial-type cells resulted in negative. Therefore, the possibility of in vivo genotoxicity still remains. There was no sufficient carcinogenicity study and no evidence of carcinogenesis in manufacturing workers, however, a two-stage carcinogenicity study indicated this chemical has promoting activity of forestomach carcinogenesis (papilloma and squamous carcinoma) in rats treated with N-methyl-N’-nitro-N-nitrosoguanidine (MNNG). Furthermore, since the structural related chemical, BHA, (2(3)-tert-butyl-methoxylphenol) is a clear carcinogen, a carcinogenic potential of this chemical could not be ruled out. It is a reprotoxic substance.
p-t-Butylphenol is a stable solid and is classified as a readily biodegradable chemical (OECD TG 301). Bioaccumulation factors range from 34-120. The lowest acute and chronic toxicity data were 48h EC50 (3.4 mg/l) of Daphnia magna and 21d NOEC (0.73 mg/l) of Daphnia magna, respectively. An assessment factor of 100 was chosen and applied to the chronic toxicity data (NOEC), because only two NOEC values (algae and Daphnia). PNEC of p-t-butylphenol is 7.3 x 10-3 mg/l (OECD classification categories for substances hazardous to the aquatic environment; Class: Acute II), p-tbutylphenol may have potential chronic toxicity to aquatic organisms, because NOEC of Daphnia is relatively low and the chemical has moderately bioaccumulative potential.
Personal protection: safety glasses, good ventilation.
Source: http://www.inchem.org/documents/sids/sids/98544.pdf
PAH is an acronym for Poly-Aromatic hydrocarbons (PAH), a chemical compound that contains more than one fused benzene ring. They are commonly found in petroleum fuels, coal products, and tar; e.g. Naphthalene, anthracene, phenanthrene. (Source: EUGRIS Glossary)
the Pan-European Ecological Network (PEEN) is one of the implementation tools of the Pan-European Biological and Landscape Diversity Strategy (PEBLDS). PEEN aims to link the different European and national protected areas and ecological networks with goal of ensuring the favourable conservation status of Europe’s key ecosystems, habitats, species and landscapes.
Ecological network is a system of the most valuable sites, important for protection of threatened species, habitat types, ecological systems or landscapes. Ecological network sites must be relatively close to each other and connected with corridors, which allow them to communicate and exchange species.
Ecological networks contain four main elements:
1. Core areas: These are areas where the primary function is biodiversity conservation. They are usually legally protected under national or European legislation (e.g. Natura 2000 sites). These areas should provide a substantial representation of key natural or semi-natural ecosystems and contain viable populations of important or threatened species. Land use within these areas is managed to give priority to biodiversity conservation.
2. Corridors: These are areas of suitable habitat that provide functional linkages link between core areas. For example, they may stimulate or allow species migration between areas. Corridors can be continuous strips of land or ‘stepping stones’ that are patches of suitable habitat. Using corridors to improve ecological coherence is one of the most important tools in combating the fragmentation that is threatening so many of Europe’s habitats. Generally speaking corridors can be associated with higher levels of land use, as long as their function is maintained.
3. Buffer zones: Protected areas should not be considered as islands that are safe from negative external effects. The resource use that occurs outside them can have serious impacts on species and habitats within, for example air/water pollution from industrial activities around a protected area can have serious effects on species inside it. Buffer zones allow a smoother transition between core areas and surrounding land use. The size and utilisation of buffer zones depends heavily on the particular needs of the specific ecosystem and its local population.
4. Sustainable use areas: These are remaining areas that can come under more intensive land use. But they should still take full account of the successful provision of ecosystem goods and services.
Connecting organisations
- ECNC-http://www.ecnc.org
- IUCN Programme Office for Central Europe-http://www.iucn-ce.org
- Database of Central and Eastern European Ecological Networks
- Plantlife International - http://www.plantlife.org.uk/international/plantlife-ipas.html
- Council of Europe
- IUCN WCPA - http://www.iucn.org/themes/wcpa/
- IUCN CEM - http://www.iucn.org/themes/cem/
Source: http://www.countdown2010.net/archive/paneuropean.html
Personal Computer
polychlorinated dibenzofurans, see polychlorinated dibenzodioxins and polychlorinated dibenzofurans
Personal Computer Memory Card International Association
Personal Digital Assistant
perstane is a new peracid disinfectant (Perestane®). This is an equilibrium mixture of mixed acids and peracids, hydrogen peroxide, and water, together with stabilisers. It is a rapid acting oxidising biocide with a slightly fruity odour. It is particularly suitable for applications involving open handling. It is an effective biocide and can be formulated to provide the desired performance benefits in many uses. The formulations can be thickened, coloured and perfumed. It is decomposing after use to readily biodegradable species.
Properties: it is a 4% peracid product. The major components are listed below:
Peracid content: 4%
Hydrogen peroxide: >10%
Methanol: 3–10%
pH ~1
Perestane® has recently been tested independently and found to be effective against both MRSA (Methicillin Resistant Staphylococcus aureus) and Clostridium difficile.
It is classified as:
Muta. 2 H341 (DSD: Muta. Cat. 3; R68)
Skin Corr. 1B H314
Acute Tox. 4 * H332
Acute Tox. 4 * H312
Acute Tox. 4 * H302
Annex XV. Report has been prepared and STOT-SE 2 H371 recommended instead of Muta. 2 H341Muta. 2 H341
Sources:
http://echa.europa.eu/doc/consultations/cl/CLH_AXVREP_UK_PERESTANE.pdf
http://www.healthcare-inorganics.com/Products/perestane/perestane/0,,58880-2-0,00.htm
Solvay has a new peracid disinfectant called Perestane® . This is an equilibrium mixture of mixed acids and peracids, hydrogen peroxide, and water, together with stabilisers. Perestane® is a rapid acting oxidising biocide with a slightly fruity odour. It is particularly suitable for applications involving open handling. Perestane® is an effective biocide and can be formulated to provide the desired performance benefits in many uses. The formulations can be thickened, coloured and perfumed. Perestane® has minimal impact on the environment, decomposing after use to readily biodegradable species.
Properties
Perestane® is a 4% peracid product. The major components are listed below:
Component | Typical |
Peracid Content | 4% |
Hydrogen Peroxide (H2O2) | >10% |
pH | ~1 |
Perestane® has recently been tested independently and found to be effective against both MRSA (Methicillin Resistant Staphylococcus Aureus) and Clostridium Difficile
perestane is a new peracid disinfectant (Perestane®). This is an equilibrium mixture of mixed acids and peracids, hydrogen peroxide, and water, together with stabilisers. It is a rapid acting oxidising biocide with a slightly fruity odour. It is particularly suitable for applications involving open handling. It is an effective biocide and can be formulated to provide the desired performance benefits in many uses. The formulations can be thickened, coloured and perfumed. It is decomposing after use to readily biodegradable species.
Properties
it is a 4% peracid product.
The major components are listed below:
Peracid Content 4%
Hydrogen Peroxide (H2O2) >10%
methanol content: 3-10%
pH ~1
Perestane® has recently been tested independently and found to be effective against both MRSA (Methicillin Resistant Staphylococcus Aureus) and Clostridium Difficile
periphyton is a complex mixture of algae, cyanobacteria, heterotrophic microbes, and detritus that is attached to submerged surfaces in most aquatic ecosystems. It serves as an important food source for invertebrates, tadpoles, and some fish. It can also absorb contaminants; removing them from the watercolumn and limiting their movement through the environment. The periphyton is also an important indicator of water quality; responses of this community to pollutants can be measured at a variety of scales representing physiological to community-level changes.
permeable reactive barriers (PRBs) are applied for passive in situ groundwater remediation. PRBs enable physical, chemical or biological in situ treatment of contaminated groundwater by means of reactive materials, which are filled into the permeable barrier, which the groundwater flows through. The reactive materials are placed in underground trenches or reactors downstream of the contamination plume, forcing it to flow through them. The two main types of PRBs are continuous reactive barriers enabling a flow through its full cross-section, and "funnel-and-gate" systems in which only special "gates" are permeable for the contaminated groundwater. Generally, this cost-effective clean-up technology impairs the environment much less than other methods, being a so called passive technology, without using energy (no pumping, no injection, no heating, minimal care on technolgy maintenance.
persistence is the capacity of a substance to remain chemically stable. This is an important factor in estimating the environmental effects of substances discharged into the environment. Certain toxic substances (e.g. cyanides) have a low persistence, whereas other less immediately toxic substances (e.g. many organochlorines) have a high persistence and may therefore produce more serious effects.
persistent and very persistent substances are which persist in the environment for a long time. The cause for that is, that the substance is not degradable by light or other radiation, heat, oxygen, water or moisture nor on biological effects. Many of the xenobiotics are designed to be persistent in the environment (similar to drugs in the body), otherwise the amount to be applied and as a consequence the cost of the substance would be very high, while the efficiency , due to too short contact-time and not stable concentration would be limited.
Hazard and persistency together increase the risk of the substance, given as ecosystem or humans are exposed for longer time to the substance, so it has higher chance to effectuate its harm.
According to REACH regulation substance fulfils the persistence criterion when:
– the half-life in marine water is higher than 60 days, or
– the half-life in fresh- or estuarine water is higher than 40 days, or
– the half-life in marine sediment is higher than 180 days, or
– the half-life in fresh- or estuarine water sediment is higher than 120 days, or
– the half-life in soil is higher than 120 days.
Annex XIII of REACH defines criteria for the identification of substances that are Persistent, Bio-accumulative and Toxic (PBTs) and Annex I lays down general provisions for PBT assessment. PBTs are substances of very high concern (SVHC) and may be included in Annex XIV and by that be made subject to authorisation (Source: REACH)
PET, the material of plastic bottles, is chemically polyethylene terephthalate, it contains no phthalates. Phthalates (i.e., phthalate ester plasticizers) are not used in PET, and PET is not a phthalate. Plasticizer phthalates are sometimes used to soften other types of plastic, but they are not used in PET. Some consumers may have incorrectly assumed that PET is a phthalate because PET's chemical name is polyethylene terephthalate. Despite the suffix, PET is not a phthalate. Phthalates are low molecular weight monoesters made from ortho-phthalic acid. By comparison, PET is a high molecular weight polyester made from tere-phthalic acid. Chemically they are very different.
Scientific studies documenting the widespread occurrence of low levels of endocrine disrupting compounds (‘EDC’s) in the environment and the food supply have triggered public concern and media attention. Among those are substances of natural origin or of industrial source which are known to be able to bind to estrogen receptors and thus may –theoretically – act in an organism in the same or a similar way as estrogens do. The scientific discussion about it is already going on for years. Up to now there is no clear evidence as to actual influence on humans.
Water samples from PET-bottles tested in an in vitro test system (YES assay) showed the presence of substances with a hormonal effect which were not identified more specifically. The scientists state that the effect was in particular detected in samples packaged in bottles made of the plastic PET. This has raised questions from the public about the possible effects on health of drinking mineral water from PET bottles.
The study from Goethe University Frankfurt highlights migration from packaging (namely PET) as a significant contributor to the measured estrogenic activity of the tested natural mineral waters. However the results presented are not sufficient to demonstrate such a contribution from the packaging since no compounds were identified, nor measured in the samples, and in addition, similar estrogenic activities were sometimes observed in the same water bottled in either glass or PET packaging. In the absence of detection and quantification of EDC’s or estrogenic substances, the observed estrogenic activity cannot simply be attributed to PET packaging.
The level of estrogenic activity detected in the study, if confirmed, would be in the range of nanograms (billionth of a gram per litre). Such activity resulting from the consumption of the tested waters would represent less than a thousandth of the total estrogens produced endogenously in the body and about one millionth of the allowed EU limit of 60 mg for total migration from packaging.
Sources:
http://www.petcore.org/content/does-pet-contain-phthalates
http://www.napcor.com/pdf/BfR_Assessment.pdf
http://www.napcor.com/pdf/EFBWstatement.pdf
polyethylene terephthalate (PET) is one of the most commonly used food grade packaging plastics due to it's chemical inertness and appealing physical properties. as with most plastics PET is derived from oil and is formed by a polymerisation reaction between an acid and an alcohol. its initial uses were as a synthetic fibre with excellent wash and wear properties as well as a substrate for video, photographic and x-ray film. as its use grew PET was modified for application in injection moulded and extruded products, and in the early 1970's the first three dimensional structures were produced by blow moulding techniques, initiating the rapid adoption of PET as a material for beverage bottles. Its properties as a lightweight, tough material with excellent optical properties and adequate gas barrier performance for the retention of PET bottles are manufactured by the process of injection stretch blow moulding (read more at http://www.bpf.co.uk) which was developed specifically to maximise the beneficial properties of PET. PET bottles are manufactured by the process of injection stretch blow moulding (read more at http://www.bpf.co.uk) which was developed specifically to maximise the beneficial properties
of PET.
Source: http://www.designboom.com/contemporary/petbottles.html
PFOA = Perfluorooctanoic Acid, a xenobiotic compound (does not occur naturally in the environment).
PFOA (also known as "C8") is used to make fluoro-polymers for use in non-stick cookware (teflon) and all-weather clothing.
Name and other identifiers of the substance
Chemical Name: Perfluorooctanic acid (PFOA)
EC Name: Pentadecafluorooctanoic acid (PFOA)
CAS Number: 335-67-1
IUPAC Name: Pentadecafluorooctanoic acid
Composition of the substance
Chemical Name: Perfluorooctanic acid (PFOA)
EC Number: 206-397-9 (PFOA)
CAS Number: 335-67-1 (PFOA)
IUPAC Name: Pentadecafluorooctanoic acid
Molecular Formula: C8HF15O2 (PFOA)
Molecular Weight: PFOA: 414.09
Typical concentration (% w/w): 98% , impurities: not known.
Physical state at 20°C and 101.3 KPa PFOA is a solid.
Melting/freezing point PFOA: 52–54 oC, PFOA: 54.3 oC
Boiling point PFOA: 189 oC, PFOA: 189–192 oC/736 mm Hg
Density/specific gravity. 1.792 g/ml
Vapour pressure (Pa) PFOA: 4.2 (25 oC) extrapolation from measured data PFOA: 2.3 (20 oC) extrapolation from measured data PFOA: 128 (59.3 oC) measured
Surface tension NO DATA
Water solubility (g/L) NO DATA
Partition coefficient noctanol/water NO DATA
Flash point NO DATA
Flammability NO DATA
Dissociation Constants: pKa = in 50% aqueous ethanol pKa = 2.5
pH: 1 g/l (20 oC) and 1 g/l (20 oC)
Recently, scientists have found great concern about how exposure to PFOA could affect people's health. Both US-EPA and European ECHA is dealing with the risks of this compound. The growing number of results led to the classification of PFOA as hazardous substance together with APFO (the ammonium-derivatiove of PFOA).
PFOA persists indefinitely in the environment. It is a toxicant and carcinogen in animals. In people, it is detected in the blood of general populations in the low and sub-parts per billion range. Chemical plant employees and surrounding subpopulations have been identified with higher blood levels. Exposure is most consistently associated with increased cholesterol and uric acid levels, but there is insufficient evidence to conclude that PFOA exposure results in adverse health effects in people.
As a result of a class-action lawsuit and community settlement with DuPont, three epidemiologists are conducting studies on the population surrounding a chemical plant that was exposed to PFOA at levels greater than in the general population. If PFOA exposure is found to be likely to lead to an increased risk of disease, future liabilities for DuPont will be triggered. Full results from the studies are expected in 2012.
How general populations are exposed to PFOA is not completely understood. PFOA has been detected in industrial waste, stain resistant carpets, carpet cleaning liquids, house dust, microwave popcorn bags, water, food, and PTFE. Although some cookware is marketed as PFOA-free, PTFE non-stick cookware is considered an insignificant exposure pathway.
Toxicity
PFOA is a carcinogen, liver toxicant, a developmental toxicant, an immune system toxicant, and also exerts hormonal effects including alteration of thyroid hormone levels. Animal studies show developmental toxicity from reduced birth size, physical developmental delays, endocrine disruption, and neonatal mortality. PFOA causes liver cancer in rodents and also induces testicular and pancreatic cancer through induction of Leydig cell tumors and pancreatic acinar cell tumors. PFOA alters lipid metabolism. It is an agonist of PPARα and is a peroxisome proliferator in rodents contributing to a well understood form of oxidative stress. Humans are considered less susceptible to peroxisome proliferation than rodents. However, PFOA has been found to be a liver carcinogen in rainbow trout via a potential estrogenic mechanism, which may be more relevant to humans.[91] A study found PFOA to be an obesogen in female mice at mid-age—with altered levels of insulin and leptin—at the lowest dose of 0.01 milligrams per kilogram of body weight during development.
While a USEPA review notes PFOA has not "been shown to be mutagenic in a variety of assays" in 1991 researchers from Japan demonstrated oxidative liver DNA damage in an experiment with rats. PFOA has been described as a member of a group of "classic non-genotoxic carcinogens". However, a provisional German assessment notes that a 2005 study found PFOA to be genotoxic via a peroxisome proliferation pathway. A 2006 study demonstrated the induction and suppression of a broad range of genes; therefore, it states that the indirect genotoxic (and thus carcinogenic) potential of PFOA cannot be dismissed. Criteria have been proposed that would allow PFOA, and other perfluorinated compounds, to be classified as "weakly non-specific genotoxic."
Epidemiology
The levels of PFOA exposure in humans vary widely. While an average American might have 3 or 4 parts per billion of PFOA present in his blood serum, individuals occupationally exposed to PFOA have had blood serum levels over 100,000 parts per billion (100 parts per million or 0.01%) recorded. In a study of individuals living around DuPont's Washington Works WV plant, those who had no occupational exposure had a median blood serum level of 329 parts per billion while the median of those with occupational exposure was 775 parts per billion. While no amount of PFOA in humans is legally recognized as harmful, DuPont was "not satisfied" with data showing their Chinese workers accumulated an average of about 2,250 parts per billion of PFOA in their blood from a starting average of around 50 parts per billion less than a year prior.
Single cross-sectional studies on consumers have been published noting multiple associations. Blood serum levels of PFOA were associated with an increased time to pregnancy — or "infertility "— in a 2009 study. PFOA exposure was associated with decreased semen quality, increased serum alanine aminotransferase levels, and increased occurrence of thyroid disease. In a study of 2003–2004 US samples, a higher (9.8 milligram per deciliter) total cholesterol level was observed when the highest quartile was compared to the lowest. Along with other related compounds, PFOA exposure was associated with an increased risk of attention deficit hyperactivity disorder (ADHD) in a study of US children aged 12–15.[103] In a paper presented at the 2009 annual meeting of the International Society of Environmental Epidemiology, PFOA appeared to act as an endocrine disruptor by a potential mechanism on breast maturation in young girls. A C8 Science Panel status report noted an association between exposure in girls and a later onset of puberty.
PFOA has been associated with signs of reduced fetal growth including lower birth weight.However, other studies have not replicated the lower birth weight finding including a study on the DuPont exposed community.PFOA exposure in the Danish general population was not associated with an increased risk of prostate, bladder, pancreatic, or liver cancer.Maternal PFOA levels were not associated with an offspring's increased risk of hospitalization due to infectious diseases, behavioral and motor coordination problems, or delays in reaching developmental milestones.
Regulation
On January 15, 2009, the USEPA set a provisional health advisory level of 0.4 parts per billion in drinking water. On March 1, 2007, the Minnesota Department of Health lowered its Health Based Value for PFOA in drinking water from 1.0 parts per billion to 0.5 parts per billion, where "the sources are landfilled industrial wastes from a 3M manufacturing plant."
PFOA contaminated waste was incorporated into soil improver and spread on agricultural land in Germany, leading to PFOA drinking water contamination of up to 0.519 parts per billion. The German Federal Environmental Agency issued guidelines for the sum of PFOA and PFOS concentrations in drinking water: 0.1 parts per billion for precaution and 0.3 parts per billion for a threshold. Residents were found to have a 6–8 factor increase of PFOA serum levels over unexposed Germans, with average PFOA concentrations in the 22–27 parts per billion range. An expert panel concluded that "concentrations were considered too low to cause overt adverse health effects in the exposed population."
In 2011 European Union started with the classification of PFOA and APFO on the initiative of the Climate and Pollution Agency (Norway), who prepared the CLH report for PFOA.
The recommendation of Norway is the following classification of PFOA as carcinogenic, reprotoxic, toxic for specific target organs, acutely toxic and eye irritant:
Carc. 2, H351
Repr. 1B, H360D
STOT RE 1, H372
STOT RE 2, H373
Acute Tox. 3, H331
Acute Tox. 3, H301
Eye Irrit. 2, H319
Pictogram: GHS07, GHS08
Signal word: Danger
Hazard statement codes: H351, H360D, H372, H373, H331, H301, H319
Precautionary statements: Not required as PS are not included in Annex VI
Sources:
http://echa.europa.eu/doc/consultations/cl/clh_axrep_pfoa.pdf
http://www.pfoa.com/
http://en.wikipedia.org/wiki/Perfluorooctanoic_acid
a virus for which the natural host is a bacterial cell.
pharmacokinetics or toxicokinetics is "defined as the study of the rates of absorption, distribution, metabolism, and excretion of toxic substances or substances under toxicological study" (OECD). Pharmacokinetics/toxicokinetics testing involves describing "the bioavailability of a substance and its kinetic and metabolic fate within the body". Pharmacokinetics is also the term used to describe the assessment of absorption, distribution and metabolism in the context of drug preclinical testing.
Metabolism has been "defined as all aspects of the fate of a substance in an organism ..." by OECD; however, metabolism generally refers to the biotransformation of a substance (via an enzymatic or nonenzymatic process) within the body to other molecular species (usually called the metabolites). For ingested substances, metabolism primarily takes place in the liver, although many organs and tissues have metabolic capability. Two types of enzymes are involved in metabolism: phase 1 (cytochrome P450 enzyme family) and phase 2 enzymes.
An understanding of the metabolism of a substance in the body is critical to understanding its toxicity. For example, biotransformation sometimes results in a molecular species being generated that is more toxic than the original substance. The lack of metabolism of a substance can result in its bioaccumulation in the body. Understanding a substance's metabolism can also facilitate identification of possible target organs and the route of clearance.
Pharmacokinetic/toxicokinetic data may be used to:
- assist in the interpretation of other toxicological data,
- select doses for other toxicological studies, and/or
- extrapolate data from animals to the human (OECD).
Source: http://alttox.org/ttrc/toxicity-tests/pharmacokinetics-metabolism/
pharmacology is the closest related branch of applied science to human toxicology, which is the study of drug action. The methodology is very similar to human toxicity assessment, the difference is, that drugs are applied for their beneficial effects on human or other organisms, and the main effect has a special target (e.g. to kill pathogens or harmful cells, etc.). More specifically, pharmacology is the study of the interactions that occur between a living organism and the chemicals substance, the drug, that affect biochemical function. If the substances have medicinal properties, they are considered pharmaceuticals and the assessment is pharmacological assessment. If the drug is a toxicant, toxicology is dealing with its effects. As all drugs, even if they have a dose range, which leads to medicinal application, they are toxicants, it also underlines that the methodologies are very closely related, mainly the aim differentiates pharmacology from toxicology.
phenols, sometimes called phenolics, are a class of chemical compounds consisting of an -OH group attached to anaromatic benzene ring. The simplest of the class is phenol (C6H5OH).
phenols have unique properties and are not classified as alcohols (since the hydroxyl group is not bonded to a saturated carbon atom). They have relatively high acidity.
Some phenols are germicidal and are used in formulating disinfectants. Others possess endocrine disrupting activity.
Some others are biological active molecules with positive health effects, such as flavonoids and tannins, capsaicine or salicilic acid.
the physical characteristics of an organism or the presence of a disease that may or may not be genetic.
Hypertext Preprocessor
phthalates, or phthalate esters, are esters of phthalic acid and are mainly used as plasticizers (substances added to plastics to increase their flexibility, transparency, durability, and longevity). They are used primarily to soften polyvinyl chloride. Phthalates are being phased out of many products in the United States, Canada, and European Union over health concerns.
DEHP has been the main “general purpose” phthalate used over the last 50 years. It has had applications in a wide range of soft-PVC and non-PVC polymer materials, these being further processed in the production of a range of indoor and outdoor products, both for industrial/professional and consumer uses. In addition to polymer applications DEHP has also been used in adhesives, sealants (which are often applied to windows and doors for improved insulation), rubber, lacquers, paints and printing
inks. Therefore, DEHP can be found in building and construction materials (e.g. in flooring, roofing, industrial doors, wires, cables, hoses and profiles), in coated fabrics (such as artificial leather for bags and automotive applications, book covers and bindings, maps and folders), in medical devices (e.g. blood bags, dialysis equipment) as well as in a multitude of other products such as traffic cones, buoys, curtains for lorries and train compartments, tarpaulins, signs, flexible containers, disposable gloves or dipped tool handles, sports mats, swimming pool covers, shower curtains, napkins, stationery films, water beds, furniture, luggage or shoe soles. It has also been reported to be used in primary packaging of medicinal products and active pharmaceutical substances (EU, 2008; ECHA, 2009; www.dehp-facts.com).
In October 2008, the low phthalates DEHP, DBP and BBP were included in the REACH “Candidate List” and in April 2009 ECHA proposed them for inclusion in the REACH Authorisation List (Annex XIV). The inclusion in the Authorisation List was confirmed officially in February 2011, with a phase-out date of February 2015 for these low phthalates unless they Authorised through submission of a dossier by manufacturers or users. Another low phthalate, DIBP, was proposed by Germany in September 2009 and was included on the REACH “Candidate List” in January 2010. As expected, these low phthalates were included on the list due to their EU hazardous classification. The full list of substances is available here.
In the case of low phthalates DEHP, DBP and BBP, they will have to undergo Authorisation. The main DEHP producer has already declared that they intend to seek Authorisation to ensure the continued availability of DEHP in the future.
The inclusion of DEHP, DBP, BBP and DIBP on the “candidate list” means that any EU manufacturer or importer of an article containing more than 0.1% weight by weight (w/w) of these phthalates must notify ECHA as of June 2011, unless the articles manufacturer or importer can clearly demonstate that their use has already been registered. In addition the article manufacturer or importer must now provide information to the recipient of that article. As a minimum, recipients – meaning anyone in the supply chain from distributors and retailers to professional end-users - need to be told that the article contains one or more of the substances. Further down the supply chain, retailers also have an obligation to provide the same information to consumers, but only if a consumer requests it. A retailer has 45 days to provide the information.
Six phtalates (DEHP, BBP, DINP, DIDP and DNOP) are under consideration to be restricted in Europe (under REACH) on the initiative of Denmark, who prepared a restriction dossier for phtalates and submitted it to ECHa (European Chemicals Agency).
Denmark submitted a dossier in May 2011, which proposes the restriction of bis(2-ethylhexyl) phthalate (DEHP), benzyl butyl phthalate (BBP), dibutyl phthalate (DBP) and diisobutyl phthalate (DIBP) in articles that are for indoor use, or in articles that come into contact with skin or mucous membranes, on the grounds that they are classified as category 1B reprotoxins under the CLP Regulation (CW 21 May 2011(http://chemicalwatch.com/7262/danes-cite-combined-exposure-in-reach-phthalates-proposals).
High phthalates are not classified as PBT or vPvB substances. They do not fulfill the criteria to be considered Substances of Very High Concern (SVHC) and therefore are not included on the EU REACH Candidate List nor do they need Authorisation to be placed on the EU market.
Sources:
http://www.plasticisers.org/regulation/reach
http://reseau-environnement-sante.fr/wp-content/uploads/2011/06/Veille_phtalates_au_26-06-11.pdf
http://en.wikipedia.org/wiki/Phthalate
physical weathering is caused by the effects of changing temperature on rocks, causing the rock to break apart. The process is sometimes assisted by water.
There are two main types of physical weathering:
- Freeze-thaw occurs when water continually seeps into cracks, freezes and expands, eventually breaking the rock apart.
- Exfoliation occurs when minerals in the rocks are continuously heated and cooled in hot climates.
- On the effect of cristal-formation of salts or oxide formation of iron or other metals. Increased volume of these chemical componunds break the rock.
- Plnat root growth is able to break the rock too.
Physical weathering happens especially in places places where there is little soil and few plants grow, such as in mountain regions and hot deserts. Either through repeated melting and freezing of water (mountains and tundra) or through expansion and contraction of the surface layer of rocks that are baked by the sun (hot deserts).
hysico-chemical testing methods for chemical substances: 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 PHYSICO-CHEMICAL PROPERTIES OF CHEMICAL SUBSTANCES
A.1. Melting/freezing temperature
A.2. Boiling temperature
A.3. Relative density
A.4. Vapour pressure
A.5. Surface tension
A.6. Water solubility
A.8. Partition coefficient
A.9. Flash-point
A.10. Flammability (solids)
A.11. Flammability (gases)
A.12. Flammability (contact with water)
A.13. Pyrophoric properties of solids and liquids
A.14. Explosive properties
A.15. Auto-ignition temperature (liquids and gases)
A.16. Relative self-ignition temperature for solids
A.17. Oxidising properties (solids)
A.18. Number – average molecular weight and molecular weight distribution of Polymers
A.19. Low molecular weight content of polymers
A.20. Solution/extraction behaviour of polymers in water
A.21. Oxidising properties (liquids)
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