Diary of Unknown Symptoms

Mystery of the Internal Vibration

Entry for May 30, 2006


Benzyl Butyl Phthalate can be found in our toothbrushes. Something that we are supposed to use three times a day contains a chemical that can cause Allergic Rhinitis…

Chemical substances in toothbrushes

As a part of the Danish Environmental Protection Agency’s survey of chemical substances in a number of consumer products, knowledge of which substances are contained in and migrates from the toothbrushes is requested. The project Survey and migration of chemical substances in toothbrushes is carried out in four phases. The examination includes survey of the market, qualitative and quantitative analyses and health evaluation of possible harmful effects from substances, which migrate from the toothbrushes.

Phase 1 concerns examination of the toothbrush market in Denmark. This information has been procured from four sources:

  • Search via the Internet
  • Purchase of toothbrushes in groceries and specialist shops
  • Through contact to suppliers and producers, whose identity appeared from the packaging
  • Through contact to a range of relevant shops and organisations

Approx. 8 million toothbrushes are sold in Denmark yearly, of these approx. 80% are one of the following three brands:

  • Aquafresh
  • Jordan
  • Colgate

They are primarily sold in groceries throughout the country.

According to the producers’ information most of the common toothbrushes are made of thermoplastic, e.g. polypropylene, SAN (Styrene-Acrylic Nitrile-copolymer) or other styrene copolymers. The bristles are made of polyamide. Furthermore, they inform that the dye used when manufacturing the toothbrushes is approved for foodstuff use, and they all have a policy not to use materials or packaging containing phthalates.

Phase two deals with qualitative analyses of constituents in toothbrushes. The following analyses have been carried out:

Screening by means of FT-IR for identification of antioxidants, types of polymer, phthalates and – to a certain extent – inorganic pigments of all 26 types of purchased toothbrushes GC-MS and ICP-MS for analysis and identification of antioxidants and organic pigments in order to evaluate the migration of substances from the toothbrush to artificial saliva on 10 types of toothbrushes chosen on the basis of information gained in Phase 1 and in the screening by means of FT-IR

Determination of calcined residue followed by an ICP-screening for identification of the possible inorganic pigments on the same 10 chosen types of toothbrushes, on which GC-MS analyses have been carried out

The results of the FT-IR-screening showed that the majority of the toothbrush handles are made from polypropylene, homopolymer or copolymer. At some of the handles smaller amounts of additives are identified in the polypropylene material. The brushes of all the examined toothbrushes are made of polyamide, which are evaluated to be identical – according to the FT-IR analysis.

At a subsequent GC-MS screening of 10 chosen toothbrushes almost 80 different compounds are identified. Of special interest for further quantification were 1-methyl-2-pyrrolidinone (toothbrush M-005), carvone (B-004 and B-005), 2-methyl-benzene sulphonamide (B-004 and B-006), 4-methyl-benzene sulphonamide (B-004 and B-006) and benzyl butyl phthalate (M-005). The selection is based on the classification of the substances and description of effects that potentially may cause concern to the consumer, if the concentration of the migrated substances from the toothbrushes is found to be too high.

Compared with the results from the FT-IR screenings, at which a high amount of chalk has been identified, a high amount of calcium has been found at the ICP-MS-screenings. In most cases also a high amount of magnesium has been identified. The deposit of calcium and/or magnesium in the toothbrushes probably derives from the use of chalk or dolomite as fillers. Titanium has been found in most cases and derives from titanium dioxide used as a white pigment. A high amount of aluminium derived from aluminium oxide could serve the same purpose or may have an opal effect.

In some cases a high amount of copper, nickel and zinc and traces of manganese has been found. These elements presumably derive from metal thread or otherwise for fastening the brushes on the toothbrush or from the mechanical parts in electrical toothbrush heads.

Phase 3 deals with screening for possible harmful effects from substances, which migrate from the toothbrushes. A screening has been made of the substances, which have been identified by the GC-MS-analyses. The screening is based on a literature survey in order to secure that the substances focused on at the quantitative analyses are the most relevant.

It was suggested to select 5 toothbrushes for a quantitative analysis. The suggested selection was based on the identified substances and the found descriptions of effects, which might be important for the consumer’s use of the toothbrushes.

Phase 4 deals with the quantitative analysis of substances migrated from the toothbrush during use under normal conditions (these substances are selected based on the results found in the first 3 phases of this project), and the evaluation of health effects of migrated substances and health risks from daily use of toothbrushes.

The health assessment was based on a specific quantitative analysis of the amount of the following migrated (released) substances from the 5 selected toothbrushes:

  • 2-Butoxy-ethanol
  • 2-Butoxyethyl acetate
  • 1-Butoxy-2-propanol
  • Benzyl butyl phthalate
  • Carvone
  • N,N-dimethylacetamide
  • 2-Methyl-benzene sulphonamide
  • 4-Methyl-benzene sulphonamide
  • 1-Methyl-2-pyrrolidinone
  • Naphthalene
  • 1,1,2,2-Tetrachlorethane
  • 3,5,5-Trimethyl-1-hexanol
  • Nickel 

Based on the measured concentrations of the 13 substances found migrated from the 5 toothbrushes and by the use of the suggested exposure scenario, it was concluded that none of the substances were found in concentrations exceeding the used values for tolerable daily intake. These reference values were based on established or suggested ADI, TDI or RfD values.

The evaluation does not comprise sensitive consumers (allergic or the like), who might experience problems using some of the toothbrushes. Overall it was concluded that the evaluated migrated substances do not constitute a health risk for the consumer of toothbrushes.

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May 30, 2006 - Posted by | Health | , ,

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