| Front page | | Contents | | Previous | | Next |

Survey of nanotcnological consumer products

4 Application and exposure

• 4.1 Exposure assessment
• 4.2 Method – Grouping of surveyed products
• 4.3 Quantification of exposure based on applied quantity of the product

4.1 Exposure assessment

The legislation does not specifically demand declaration of the content of chemical substances or nano-sized structures. The identification of nanoproducts in this project is most often based on claims. Therefore, it may include products using the designation ‘nano’ for products that is applied in a nano layer and as such do no contain nano-sized chemical substances.

In the present project, the nanomaterial of most of the identified products is not known^[4]. As far as the few known nanomaterials are concerned, uptake, transformation, excretion and the toxicological effects of the substances still remain to be fully examined. Thus, it is not possible to determine the critical effects^[5] of the substances which are the basis of a risk assessment.

Therefore, the surveyed products in the project are divided on the basis of expected exposure in the application phase. A proper risk assessment of the products awaits the availability of further toxicological information on the substances.

Exposure assessment is a crucial element of a risk assessment. To be complete, an ideal exposure assessment must cover the complete life cycle of the product from production via application to discharge. This report focuses on exposure in the application phase – exposure after application, e.g. by tear and wear of the surface or discharge has not been taken into consideration.

With respect to consumer exposure, intentional use and forseable other use of a product are normally taken into account - however not accidental exposure or misuse. Consumer exposure may be of shorter or longer duration depending on type of product and mode of application. It is important to establish an exposure scenario as close to reality as possible.

4.2 Method – Grouping of surveyed products

In this project, the grouping of the surveyed products is based on considerations on expected exposure in the application phase and the categorization in section 1.4.

The objective of this grouping is to prepare a list on products that:

• are expected to cause exposure,
• may cause exposure, and
• are not expected to cause exposure to the consumer

Most attention should be given to the products that are expected to cause exposure. In this project with a great number of products to be systematized, the exposure assessment has been carried out in a simplified manner.

Consumer products that can be defined as articles^[6] do not often have intended release of chemicals (however with few exceptions such as fragrance chemicals that are released from a fragrance napkin). Consequently, the first pragmatic categorization is based on the definition of the consumer products as either an article or a chemical product.

Consumer products, defined as articles and categorized as ‘suspended in solid’ (e.g. a tennis racket) are not expected to cause exposure to the consumer (No exposure). For consumer products defined as articles and categorized as ‘surface-bound nanoparticles’ (eg. socks produced from polypropylene impregnated with nano silverparticles) release is difficult to estimate. The nanoparticles are supposed to be effective in the article, but a certain tear and wear and consequent release must however be anticipated (Possible exposure)

The remaining products that are not articles and can be categorized as ‘nanoparticles suspended in liquids’ must be expected to cause an exposure in the application phase (Expected exposure). This would also apply to products that can be categorized as ‘free airborne nanoparticles’. However, in the survey project, no examples of this type of products have been found.

Figure 12: Concept for relative exposure to products depending on type of nanomaterial.

4.2.1 Consumer products not causing exposure

The consumer products defined as articles and categorized as ‘Nanoparticles suspendes in solids’ belong to a group with expected low exposure. This mainly applies to sports equipment, where nanoparticles eg. are encapsulated in the core of a golf ball and are thus not expected to cause consumer exposure. These products are marked with an N (No exposure) in Attachment C.

4.2.2 Consumer products possibly causing exposure

It is not possible to estimate a daily or a yearly consumption of articles categorized by the categorization tools in ‘Surface-bound nanoparticles’, such as for instance socks containing silver nanoparticles and refrigerators with silver coating. In these products, the silver particles are not meant to be released, as they are supposed to be effective in the sock or on the surface. However, a certain wear and tear and therefore release must be anticipated. In literature, there are no data on release of particles from this type of products. Thus, no indication of exposure can be given and the products are marked with a P (Possible exposure) in Attachment C.

4.2.3 Consumer products with expected exposure

For the remaining products that are not articles and can be categorized as ‘Nanoparticles suspended in liquids’, the humane exposure will at first be quantified based on the expected applied quantity of the product compared with the application frequency, section 4.3. These products have been marked with an E (Expected exposure) in Attachment C.

This quantification can be based on topical application data or alternatively, default values from Technical Guidance Document (TGD) on Risk Assessment for Existing Substances (European Commission, 2003). In this chapter the internal prioritization in the product groups in question is discussed, exclusively based on exposure of the complete product.

In Attachment B preliminary scenarios are shown including an estimated quantification of the exposure to the active substance (chemical nano-sized substance) in the product. The estimate comprises four different types of products of the group of expected exposure. The four products represent a facial crème, a sunlotion, a spray product for indoor surface treatment and a liquid product for outdoor surface treatment.

The quantification, which is an estimate of the consumer exposure, is based on a number of assumptions and preconditions and should be adjusted when more precise product information is available.

Figure 13: Expected possible or no exposure based on category and type of product

4.3 Quantification of exposure based on applied quantity of the product

The products with expected exposure are grouped in two main groups:

• Cosmetics
• Products for surface treatment

The quantification is solely based on applied quantity of the products regardless of the variation of the content of active substance in the products.

4.3.1 Cosmetics

The Technical Guidance Document (TGI) contains default values for cosmetics (products for facial care, body care, and products for sun protection) and indicates typical quantities and frequency of application. Default values are taken from part 1, appendix II ‘Consumer Exposure’ of the Technical Guidance Document on risk assessment for existing substances (European Commission, 2003). The cosmetics in question are products with intended exposure that are not diluted or rinsed off after use. It is possible to calculate an expected daily and yearly exposure of the products.

Table 4: Calculation of daily and yearly applied quantity based on typical application modes (European Commission, 2003)

a. If the frequency is indicated as an interval, the upper value has been used to calculate the daily and yearly dose of the product.

b.; Quantity/application based on data from lipstick

c. Frequency based on frequency for sun lotion

d. If a facial lotion containing nanoparticles is applied as both night and day lotion, the quantity is 1.6 g.

e. With reference to the recommendation of the Commission of 22 September on the effectiveness of sun protection preparations, they must be applied in quantities corresponding with the quantities used in the tests in order to reach the protection level indicated together with the sun protection factor.The quantity/application mentioned is approx. 36 g for an average-sized adult. This is more than 4 times higher than the value indicated in the TGD corresponding to exposure to the active substance, which is more than 4 times higher for humans applying the recommended quantity.

Assuming that the concentration of the active substance is the same in the different cosmetic products in table 4, the use of for examble a body lotion, will cause an exposure that is 20 times higher than the use of a facial creme.

4.3.2 Products for surface treatment

It is more difficult to quantify an expected daily and yearly exposure of the products of the other group not yet comprised by the TGD. The default values of ordinary product types for surface cleaning indicated by TGD can be seen in the below table.

Table 5: Values for ‘habits and practicises’ in the EU for products used for surface cleaning (European Commission, 2003)

^a) Diluted by. 5 l washing water

The surveyed products are marketed as products giving a dirt repelling and maintenance-free surface for a longer period than ordinary (nano-free) products for surface cleaning. From distributors of the surveyed products the durability and consequently the required application frequency depend on the wear and tear of the treated surface and possibly also on the concentration of the active substance in the product. The TGD default values are not considered applicable to quantify the use of this kind of products.

For liquid products, which for instance are applied with a cloth, skin exposure is a possibility. For spray products exposure both by inhalation and by dermal contact has to be considered. The degree of exposure by inhalation depends among other things on the duration of the application that varies according to the size of the treated surface and wheater it is a product for indoor or outdoor use. Therefore, it is not possible to state a generic value for the daily and yearly applied quantity of surface treatment products is not possible.

Attachment B shows scenarios of the human exposure. The scenarios are based on four fictive products representing a facial lotion, a sun lotion, a liquid product for outdoor surface treatment and a spray product for indoor surface treatment. The calculations are preferably based on default values and formulas indicated in Part 1, Appendix II – ‘Consumer exposure’ of Technical Guidance Document (TGD) on risk assessment for existing substances (European Commission, 2003). If no data were available in the TGD, the default values were estimated based on contact with relevant actors and partly as values estimated by DHI.

Footnotes

^[4] Sunscreen products often contain titanium dioxide or zinc oxide. Titanium dioxide was assessed by the European Commission’s Scientific Committee on Consumer Products (SCCP) to be safe for consumers when used in sunscreens in concentrations up to 25% regardless of the particle size (SCCP, 2000). Zinc oxide is not allowed for use as a UV filter in cosmetic products because sufficient documentation has not been presented to the SCCP (SCCP, 2005).

^[5] Critical effect: The unwanted effect that is present at the lowest dose.

^[6] An article is a product which during the production phase has been given a special form, surface or design which to a higher degree than its chemical composition determines its function.

| Front page | | Contents | | Previous | | Next | | Top |

Version 1.0 August 2007, © Danish Environmental Protection Agency