Lexicon

Phthalates

The phthalates are a group of chemical products (salts or esters) phthalic acid. They are therefore composed of a benzene ring with two groups positioned Ortho carboxylate and which may vary in the size of the alkyl chain. Phthalates are commonly used as plasticizers for plastics (in particular PVC, to form for instance of plastisols) to make flexible. They return, in the form of teraphtalate, in the composition of the PET.

Summary

1 Structure and properties
2 Industrial applications, consumer products
3 Exposure modes
4 Toxicity, risks to human health and the environment
5 Analysis of phthalates
6 Standards and regulation
7 Replacement of phthalates
8 Notes and references

Structure and properties

They are viscous liquids, transparencies, colourless, with little or no odor and very little volatile. Their flash point varies in the opposite direction with their volatility. Hydrophobic in normal, they will therefore have a particular affinity for FAT or heavy alcohol[1]. In the environment, phthalates are biodegradable but can persist longer in some circles as the aquatic environment where they mix with sediment, What will make more difficult their degradation in aerobic mode.

Industrial applications, consumer products

Phthalates have been used for 50 years and they are produced, Nowadays, by reason of 3 million tonnes per year. They are present in many consumer products. These are commonly used plasticisers in plastics and other materials. As a general rule, the plasticizers make them flexible, flexible, they improve shock and cold holding, the elongation at break and facilitate the implementation (for example by lowering the temperature of transformation).

Cosmetics are the second scope of phthalates where they are including incorporated as fixing agents in order to increase the power of penetration of a product on the skin or prevent the varnish cracking.

Use, as a plasticizer, represents 90 % applications of phthalates. As such, they are found in various flexible plastics, in particular the PVC[3]. They can be so present in :

. products, sealants for automotive ;
. coverings for floors and walls ;
. insulation for cables and flexible son ;
. consumer plastic products ;
. cosmetics and personal care products ;
. medical equipment ;
. toys and products for children ;
. food packaging ;
. sex toys[4],[5],[6].

However, their use in toys and food packaging is greatly reduced in Europe because of their dangerousness. Current regulations restrict their jobs, in many countries. For example, the Italy which was one of the last European countries to ban phthalates as plasticisers in food stretch film, their absence remains an argument : « No. ftalato ». The risk of their use remains high in these articles from elsewhere, Asia in particular, because phthalates have unmatched performance for a reasonable price.

It appears a contradiction : one side number of European countries grow (through regulations) the decrease in the use of these chemical agents, but on the other hand, import does not seem to have an adequate monitoring system to ensure a respectful job, not only regulations, but above all of the people.

This omnipresence in our consumer products aroused some concern on the part of public health organizations that study therefore since more of 20 years their toxicity and the possible effects of phthalates on humans and the environment[7],[8].

Exposure modes

The release of phthalates in the environment is possible due to a migration within the array (due to incompatibility with the) followed by exudation, and low volatility (which varies in direction inverse with the molar mass). In toxicology, four types of exposure are often studied : inhalation, ingestion, intravenous or skin contact.

Inhalation of phthalate is not predominate as these compounds are very little volatile, It must nevertheless consider the risk due to aerosols in cosmetics (perfumes, deodorants) and adhesives.

Exposure via ingestion of phthalates is already significantly more critical. In countries where phthalates are still allowed in plastic materials in contact with food, phthalates migrate fat-rich foods such as cheese or meat. The average value ingested in this way is 0,25 mg/day. Despite this, researchers from the national Institute of public health of Quebec (INSPQ) reported that 12 % people would exceed the dose tolerated for DEHP under the European Community (either 0,037 mg/kg body weight / day). Children have a higher risk because of their tendency to wear mouth plastic toys because phthalates can migrate in saliva.

The release of phthalates by the intravenous route would be an another not insignificant exposure pathway. In conjunction with these rather common exposures, It can also occur problems during a long hospitalization for which the body is exposed to phthalates through medical devices such as blood bags, or intravenous probes. The amount to which the patient is exposed is small but the exposure is direct since the compounds pass directly into the blood. This becomes even more critical when it comes to a baby or a pregnant woman because the effects on fertility and growth are recognized.

Finally the presence of phthalates in cosmetics is a source of additional exposure because the migration of phthalates in the fat of the body is done by skin contact directly.

The phthalates could also be transmitted via breast milk.

When all these exposures are combined, There may be risks but the amounts present in the environment are not large enough to be dangerous to. In addition, It does in general not biomagnify up in the food chain, which means that the contamination to which an animal could be exposed will not pass to one who will eat it if the time is long enough to allow the phthalates to degrade.

Toxicity, risks to human health and the environment

The toxicity of phthalate, as that of bisphenol A, depends primarily on its ability to migrate from the plastic in the human body. In other words, all plastic is not toxic because it contains phthalates. The risk, bringing more reliably on human reproduction, varies with body mass, the age (especially for reproductive), duration of exposure, the nature of the plastic, the damage suffered by the material and, Of course, the nature of the phthalate. Finally any risk rises next to a profit, for example in the case of the blood bags.

  • The side effects of phthalates in relatively high concentrations in laboratory animals : the decline in fertility, testicular atrophy, reduced fetal weight, Fetal mortality, and malformations. Some phthalates also have an endocrine disruptive and can cause abnormal sexual development in young male rats exposed in utero. In addition, recorded effects on the liver, the kidneys and the male reproductive system. The effects vary from one to another phthalate[9]. The tolerable daily intake (NOAEL) for rats is between 50 and 600 mg/kg/day, the lowest dose at which no toxic effect is observed in animals is 50 mg/kg/day[10].

The toxicity of most phthalates, as DEHP, is pretty well known. However, there are some suspicions about the carcinogenic effects of these phthalates. Although effects have been proven in rodents (liver tumours), the biological mechanisms are not strictly identical, It is not possible to say that phthalates are carcinogenic to humans.

  • The toxic effects of phthalates are dependent on the type and concentration. When all these exposures are combined, individual exposure is considerably higher than previously thought. In children, they are considered most at risk because they absorb a greater amount of food than adults relative to their body weight and because they carry plastic objects in the mouth. For example, internal eight phthalates exposure studies (DMP, DEP, DBP, DnBP, BBzP, DEHP, DINP and DIDP) in ?g/kg of body weight per day, gave the following daily intakes[11] :
exposure dose of phthalates per day
Person Age (years) Weight (kg) Daily dose (?g/kg body weight / day)
children 0-1 5,5 55-380
children 1-3 13 20-183
children 4-10 27 5-54
women 18-80 60 8-124
men 18-80 70 8-92

 

  • Phthalates are semi-volatile organic pollutants widely distributed in the environment in urban areas. Phthalates are bioaccumulative and are limited by biodegradation. In the environment, biodegradation is achieved through aerobic or anaerobic microorganisms. low molecular weight phthalates, lighter, are more readily biodegraded. It should also reflect the content of lipid bodies which increases the concentration of these hydrophobic compounds. Levels of DEHP in the atmosphere : 0,3 – 77 NG/m³ ; surface waters : 0,3 – 98 ?g/L ; sediment : 0,2 – 8,4 mg/kg DW[12],[13].

Symbols of toxicity of phthalates

Symbols of toxicity of phthalates.

The labelling of these compounds requires the mention 'Toxic' and some also marked 'dangerous for the environment '., particularly for aquatic organisms, because being hydrophobic phthalates, they have an affinity for fat fish.

Similarly, prolonged exposure causes plant bioaccumulation of phthalate esters which biodegradation is not fast enough (see footnote on the Bok Choy). It is also estimated at a few days in our body, It is however not excluded that monoesters resulting from the degradation of phthalates are also partly responsible for their toxicity.
It should therefore be to identify which are the most exposed to the risk of contamination, which is to identify the most important exposure modes.

Analysis of phthalates

One of the difficulties of the assay and determination of phthalates is that these groups of compounds are frequently present as plasticizers in analytical equipment, in solvents and air in laboratories (as such, subtract a 'white' to the results obtained for the sample).

The method of the most sensitive and most selective analysis for the determination of phthalates in various environments is the gas chromatography or liquid chromatography coupled with a mass spectrometer (GC/MS, LC/MS). The sample preparation depends on the type of phthalate and the matrix. Where phthalates are of micropollutants or are presented to trace (NG/L to mg/L), a preconcentration step is necessary. The extraction methods used are : liquid-liquid extraction, the solid phase extraction (SPE) and the solid phase extraction micro (SPME). The solid phase extraction is based on the distribution of compounds between a solid phase (adsorbent) and a liquid phase (sample). The selection of an adsorbent leading to a high retention is paramount, because it will be possible to reduce the large volume of the sample. The most frequently used solid phases for phthalates are : polydimethylsiloxane (PDMS), polydimethylsiloxane/divinylbenzene (PDMS/DVB), polydimethylsiloxane-divinylbenzenecarboxen-divinylbenzene (DVB/CAR/PDMS)[14]. The first step in the procedure is the conditioning of the adsorbent contained in the extraction cartridge. This step helps to moisten the support starts the functional groups present on its surface. In the second step, shall be the percolation of the sample on the media. Target molecules, who have a strong affinity with the adsorbent, are fixed to the bracket. The next step, washing, is performed to eliminate interfering compounds poorly chosen by bracket. The solvent must be a weak way to elute eluent force interfering while keeping fixed compounds of interest. Finally, is the elution of the compounds targeted by a solvent that breaks the interactions involved between the analytes of interest and solid support[15].

The pre-treatment of the sample for determination of phthalates in PVC consumer products involves cutting the sample, extraction with dichloromethane and methanol, then preconcentration by evaporation. Finally, the determination is done by gas chromatography in the presence of an internal standard. The limit of detection varies depending on the type of phthalate from 3,5 to 350 ?g/g and the limit of quantification of 0.001 to 10?g/g[16],[17].

Standards and regulation

Several standards have been adopted worldwide to limit see ban the use of phthalates in products at risk.

The use of certain phthalates in childcare articles or toys intended for children under the age of 3 years including was banned in recent years and is frequently revised (see directive 2005/84/EC [PDF] in the European Union and the Decree of transposition no. 2006-1361 the 9 November 2006 in France).

Relating to cosmetic products, the regulation varies, the European Union banned the use of The highest DEHP toxic potential, While the Canada requires that all cosmetic products are labelled to inform consumers about the presence of phthalates or not.

For other plastics, no regulation is applied because the doses to which we are exposed are not considered dangerous. It remains however to make the effort to find substitutes non-toxic, especially for the manufacture of medical equipment.

The most common phthalates (DEHP, DBP, DINP, DIDP and BBP) are always investigated by various international organizations (Food and Drug Administration, European Chemicals Bureau and Institut National de Santé Publique in Quebec) in order to clarify some outstanding issues regarding toxicity and the standards to be applied towards the phthalates.

Replacement of phthalates

Under the substitution of phthalates, the most important is the substitution of the phthalates used in the production of toys and products for children and in the manufacture of medical equipment. Substitutes must have the same properties of resistance and flexibility than phthalates, especially for the medical sector. Anyway, previously, it will be essential to the demonstration of the safety and effectiveness of these alternatives.

Some plastics have properties of rigidity and resistance without any need to add a phthalate or bisphenol A, but they agree, because of these properties, to certain uses. These are HDPE (polyethylene high density), LDPE (polyethylene low density) and the PP (polypropylene). Normally, composed of one of these plastics packaging, and so perfectly non-toxic, must mention, In addition to the symbol, a recycling label with in its centre the mention of a figure, respectively 2, 4 and 5.

Manufacturers seek ways to replace DEHP by other higher molecular weight phthalates. Other plasticizers are envisaged to be used in PVC, including di-2-ethylhexylene adipate (food contact packaging), the alkyl-aryl phosphates (flame retardants in cables), trimellitates of trialkyle (cables running hot), Polymeric polyesters (for their durability high).

The first version (dated November 2008) of the list of European regulation Reach identifies fifteen chemical substances, including three phthalates well-known for their harmfulness : DEHP, DBP, BBP[18].

Notes and references

    1. ? The MSDS of the INRS website DEHP [Archive], DIDP [Archive], DINP [Archive], DBP [Archive].
    2. ? [PDF] Louis St. Laurent and Marc Rhainds, phthalates : state of knowledge on the toxicity and exposure in the general population [Archive], press toxicological eve, National Institute of public health of Quebec, 7 January 2004.
    3. ? a and b [PDF] Factsheet : phthalates [Archive], Federal Office of Public Health FOPH – Directorate Consumer Protection Unit, 2006.
    4. ? Greenpeace, How safe is your sex toy? [Archive], 8 September 2006.
    5. ?Video on Dailymotion [Archive].
    6. ? See also Wikipedia articles in English entitled "Phthalate" and "Sex Toy".
    7. ? [xls] EFSA opinion [Archive] (2008).
    8. ?Portal [Archive] the Scientific Panel on Food Additives, the aromas, Processing Aids and Materials in Contact with Food (AFC).
    9. ? INRS ED Sheet 5010, The state of knowledge on phthalates [Archive], 2e Edition, April 2004.
    10. ? Press release by Swissmedic, Phthalates in drugs [Archive], 2005.
    11. ? U. Heudorf and al., Phthalates: Toxicology and exposure [Archive], International Journal of Hygiene and Environmental Health, 210 (2007) 623-634.
    12. ? Fromme H., Kuchlert T., Otto T., Pilz K., Müller J. & Wenzel has., Occurrence of phtalates and bisphenol A and F in the environment [Archive], Water Research, 36, (2002) 1429-1438.
    13. ? Z. Xie et al., Atmospheric concentrations and air–sea exchanges of phthalates in the North Sea (German Bight) [Archive], Atmospheric Environment, 39 (2005) 3209–3219.
    14. ? X.-L. Cao, Determination of phthalates and adipate in bottled water by headspace solid-phase microextraction and gas chromatography/mass spectrometry [Archive], J. Chromatogr. A 1178 (2008) 231-238.
    15. ? [PDF] F. Chapuis, V. Mr. Pichon and-C. Hennion, Method of preconcentration by solid phase extraction : principle and application in environmental and petroleum industries [Archive], Oil & Gas Science and Technology – Rev. IFP, Flight. 60 (2005), No.. 6.
    16. ? Health Canada : Determination of phthalates in consumer products poly(vinyl chloride). [Archive]
    17. ? [PDF] INRS, Phthalates by gas chromatography [Archive], Plug 096/V01.01, 17/11/2006.
    18. ? List of products to replace established by the European Agency Echa, on a proposal from the Member States. [Archive]

Content submitted to the CC-BY-SA license. Source : Article Phthalate Wikipedia in French (authors)



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