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Total health assessment of chemicals in indoor climate from various consumer products

6 Exposure assessment to less volatile substances

Most of the substances studied in DEPA’s consumer reports are volatile substances (VOC) released from consumer products to indoor air. Inhalation of vapors is the most important exposure route for volatile substances. Even the less volatile substances with a low vapor pressure generate small concentration of vapors but these will easily condense on air particles that fall down as dust of various composition. Activities inside a room, inclusive vacuum cleaning, mean a potential for reentrance of airborne dust with a diameter of 5-25 µm.

Evaporation increases with temperature and it will normally be highest in summertime. The dust may in addition receive substances from normal wearing of products or migration from products by contact with dirts. Depending on house cleaning quality, dust may accumulate substances during longer time, thus dust may be seen as a passive sampling device.

Individuals may also be exposed to migrated substances from consumer products, e.g. toys and clothes, by skin contact. Ingestion of dust will probably still be the most important exposure route indoors for less volatile substances such as phthalate plasticizers, brominated flame retardants, and perfluoroalkylated compounds.

House dust may be absorbed in the body from inhalation of airborne dust and intake of dust deposited on foodstuff and surfaces. Direct absorption of dirt through the skin is also possible. The issue of pollution of house dust has been reviewed thoroughly by Butte and Heinzow.[11]

6.1 Exposure of children to dust

Small children do have a special high intake of dust with less volatile chemicals, because they are crawling around on the floor, putting dirty fingers in the mouth and sucking toys and other items. However, everything depends on behavior, hygiene and actual conditions. A crawling toddler is special exposed to dust, and in special cases such a child may have a daily intake of up to 10 gram dust or soil. USEPA estimates, however, that a 2½ years old child normally only has a daily intake of 100 mg house dust in wintertime and 50 mg in the summer, where the child is more outdoor. In Germany daily dust intake estimations of 20-100 mg for 1-6 years old children, 5-25 mg for 7-14 years old children and 2-10 mg for adults are used. It is estimated that children daily alone have an intake of 100 µg wall paper dust.

6.2 Exposure to phthalates from consumer goods

Phthalates are used as plasticizers in many consumer goods, especially goods manufactured in PVC-plastic. The most used plasticizer is di(2-ethylhexyl) phthalate (DEHP). The plasticizer is not bound especially firmly to the polymer, and is able to leach and migrate relatively easily. The short chain dialkyl phthalates are released most easily.

There is information about phthalates in DEPA consumer reports no. 1, 7, 14, 23, 29, 38 and 43, however, only exposure- and risk assessment in report no. 23 and 43.

6.2.1 Phthalates in PVC products (Report no. 1)

Consumer goods made of PVC, such as bathing curtain, bags, gloves, vinyl floor, carpet tiles and vinyl wall paper were studied. At least one type of phthalates was found in all samples in concentrations from 2 to 63%. The most abundant was DEHP in 10 out of 12 goods followed by DINP/DIDP in half of the goods, DBP in a third and BBP in two products.

6.2.2 Phthalates in Beads (Report no. 7)

Some phthalates were found in every bead and bead plates.

6.2.3 Phthalates in moulding wax (Report no. 14)

In all products meant for heating a high content (16-22%) of phthalate plasticizers was determined.

6.2.4 DEHP in textile fabrics (Report no. 23)

The content of DEHP was determined to 2-8 mg/kg in 20 spot samples of textiles of cotton, wool, flax, PET and viscose.

Regards textiles a 100% dermal uptake corresponds to an uptake of 55 µg/kg bw/day for adults and 195 µg/kg bw/day for children. However, a dermal uptake of 5% for DEHP is estimated for both children and adults. The maximum dermal uptake of DEHP is thereafter calculated to 0.00275 mg/kg bw for an adult and 0.0096 mg/kg bw for a child.

In the report the oral uptake of DEHP is estimated to about 50% for adults and 100% for children. The evaluation of intake was based on a child, who is sucking/chewing a textile piece corresponding to 400 cm² or 20 gram. The weight of the child is set to 10 kg and absorption to 100%. Then the intake every time will be 15.4 µg/kg bw.

Regards inhalation it is estimated that the compound evaporates to the maximal concentration (saturated) and is distributed uniformly in the whole room. In addition it was assumed, that there was 10 kg clothes in the room, that the room had a volume of 20 m³, and that inhalation for an adult had duration of 24 hours. Exposure by inhalation was as expected very small and insignificant: 6.44x10-6 µg DEHP/kg bw/day.

6.2.5 Phthalates in hobby glues (Report no. 29)

In some wood glues, in one vinyl glue and in one school glue the analysis found a content of phthalate plasticizers. Only the content of diisobutyl phthalate (DIBP) in the school glue was declared.

6.2.6 Phthalates in sealings (Report no. 38)

Two acryl based sealings had a content of phthalate plasticizers, repectively 3 % dibutyl phthalate (DBP) and 16 % diisononyl phthalate (DINP). In a MS-polymer sealing contents of 32 % diisodecyl phthalate (DIDP) and 4 % di(2-ethylhexyl) phthalate (DEHP) were determined.

6.2.7 Dibutyl phthalate (DBP) in stain remover (Report no. 43)

The air concentration of DBP was calculated to 22.5 µg/m³, using the EUSES model, and the uptake via the airways was calculated to 3.19 x 10-6 mg/kg bw/day, which was far below the no-effect level (NOAEL) of 583 mg/m³ or 125 mg/kg bw/day. This indicated a minimal risk by application of DBP in stain remover.

6.3 Brominated flame retardants

Brominated diphenyl ethers may be used as flame retardant in many consumer products. Brominated flame retardants are only investigated in the latest report 66 about electronics. Only one single product (a pressing iron) did release brominated flame retardants in the form of nonaBDE and decaBDE. The source strength was less than 0.05 µg/unit/h for both substances.

6.4 Perfluoroalkylated substances

Perfluoroalkylated substances (PFAS) are studied in DEPA consumer reports no. 17, 50, 52 and 66 about electronics. These substances are also evaluated in other reports from DEPA.[12],[13]

6.4.1 PFAS in impregnation agents and floor wax/polish (Report no. 17)

In 2001, 21 different consumer products were purchased and analysed for 6 perfluorinated compounds. In 2 out of 11 investigated spray products a content of these compounds were detected.

In a spray product mend for impregnation of leather, hide and textiles a content of 3.5 mg/mL perfluorooctane sulfonamide (PFOSA) was determined. This result was in accordance with the declaration of the product stating that the impregnation agent was a fluorocarbon.

In a spray product to tents, sleeping bags etc. the content of perfluorooctane sulfonate (PFOS) was 212 mg/mL.

In one out of five liquid floor polishers to vinyl, cork, linoleum etc. a concentration of 10 mg/mL of N-ethyl perfluorooctane sulfonamide (EtFOSA) was determined.

The analysed substances are under phasing out but are probably substituted by other perfluorinated substances.

6.4.2 PFAS in impregnation agents (Report no. 50)

The substances perfluoroheptanoic acid (PFHpA) and perfluorooctanoic acid (PFOA) were identified in a migration test of the impregnation agent IM-05. IM-05 is a product used as a liquid in a.o. dry-cleaning shops. These two substances do have similar properties, similar effects and are released from the same impregnation agent. It was concluded that the uptake of the two substances may be added.

The exposure scenarios for use of impregnated products show that the two PFAS are taken up in amounts from 0.2 to 0.6 µg/kg bw/day. That means that a child can have a total uptake of about 0.9 µg/kg bw/day. The acceptable daily intake (ADI) is 3 µg/kg bw/day corresponding to the no-effect level (NOAEL) for reproductive effects and with a safety factor of 1,000.

There is a risk that the total exposure to these substances can reach levels, where adverse health effect may develop. If children are exposed to such substances from other sources, the report concludes that there is a risk of adverse effects such as damaged organs. However, it must be presumed that use of impregnated clothes occurs with another clothing under, and then the risk is further minimized.

6.4.3 Shoe care agents (Report no. 52)

These products were analysed for 8 different PFAS compounds. In one out of the four analysed products very low concentrations of perfluoroheptanoic acid (PFHpA) and perfluorooctanoic acid (PFOA) were determined, respectively 1.1 and 0.36 mg/kg.

6.4.4 Electronic products (Report no. 66)

From the household oven was detected a release of a fluorinated compound. Probably, it was evaporation of substance from the self cleaning coating at the inner side of the oven.

6.5 Assessment of a crawling children’s intake of phthalates, PBDE and PFAS in house dust

The available data on phthalates, brominated flame retardants and perfluoroalkylated compounds in DEPAs consumer product reports are as seen above very scarce, limited and difficult to use for an exposure and risk assessment. Instead, Danish and foreign studies of house dust content can be used for estimating children exposures for these less volatile substances from various indoor sources. More information and references in Annex A and B (only in Danish).

6.5.1 Phthalates

The content of phthalates in house dust is typically about 1,000 mg/kg (0.1%), of which DEHP amounts to 60-70%. In rooms with vinyl flooring or vinyl wall paper and with poor cleaning the content may be ten times higher.

An intake of 100 mg dust daily implies an average child intake of about 100 µg phthalates/day or 10 µg/kg bw/day, if the body weight of the child is 10 kg. There is assumed a 100% absorption.

In addition there may be direct migration from contact with and suckling of toys (sold before the phthalate ban), textiles etc. Regards skin contact to DEHP-treated textiles it was calculated in DEPA Consumer Report no. 23 that a child with, respectively, 5% and 100% absorption through the skin, absorbe 9.6 to 195 µg DEHP/kg bw/day. It was also calculated that a child weighing 10 kg, who sucks/chews a impregnated textile of 400 cm² or 20 gram will absorb 15.4 µg DEHP/kg bw each time.

As expected, exposure by inhalation was small and insignificant at 6.4 x 10-6 µg DEHP/kg bw/day.

In all, a typical daily child absorption of DEHP from all indoor sources will normally amount 10-20 µg/kg bw/d or 100-200 µg/d, but in worst case probably as much as 50-250 µg/kg bw or 0.5-2.5 mg/day for a much exposed crawling child on a PVC-floor. In addition to the indoor exposure, there is an intake of DEHP in foods, which in Germany is estimated to 18 µg/kg bw/d for a child or 180 µg/day, thus in the same order of magnitude as the usual indoor exposure.

The highest oral exposure to DEHP in long-term rat experiments without adverse effects (NOAEL) is 3.7 mg/kg bw/day or 37 mg/day. If rats and humans do have the same sensitivity, there seems to be a very small safety factor for the most exposed children. To this comes the possible exposure to the other phthalates.

6.5.2 Polybrominated diphenyl ethers (PBDE)

No Danish studies of brominated flame retardants in the indoor environment are available, thus the assessment has to be based on international experience. Measured concentrations of brominated flame retardants in human tissues are higher than expected from the intake by foods, thus there must be other exposures and sources. It is likely to be the indoor environment and car driving.[14],[15],[16]

6.5.2.1 PBDE in air

In existing surveys there has been a correlation between PBDE concentration in indoor air and the number of electrical apparatus and the number of upholstered furniture in the home. Soft polyurethane foam applied to office chairs, car seats and furniture may release several hundred microgram PBDE per day. Concentrations of PBDE in indoor air are typical 20-50 times higher than in outdoor air. However, in air measurements the less volatile congener BDE209 is not measured and excluded.

Median concentrations are often 100-200 pg PBDE/m³ with maximum concentrations of >15.000 pg PBDE/m³. If the inhalation rate of a child is set to 1 m³/h, the inhaled amount will be up to 36 ng PBDE a day but, typically, the amount will be below 1 ng and thus not significant.

6.5.2.2 PBDE in house dust

There are large variations in content of PBDE in dust from the various homes investigated. Maximum concentrations may be >20.000 ng PBDE/g dust. BDE 47, BDE99 and BDE209 are the most abundant congeners in house dust with common median concentrations of 17, 24 and 265 ng/g for these three congeners, which typically amount to 95% of the content.

If the dust intake is 100 mg/day, then a child may have an intake of 30 and in few cases up to 2000 ng PBDE/day. This should be compared with an average intake from foods of 40-150 ng/day,[17] and about 2000 ng/day for breastfed children, because human milk contains very high concentrations of PBDE. On that background the maximal amount a child may be exposed to will be <5 µg/day.

For PBDE as a group, a no-adverse-effect-level (NOAEL) of 1 mg/kg bw/day can be used. It is based on classical toxicological effects and do not take into account e.g. endocrine disrupting effects and bioaccumulation. Compared with this NOAEL there is a sufficient safety factor at present pollution levels. A comparison with the USEPA’s Reference Doses (RfD) of 2-10 µg/kg bw/day, which includes safety factors shows that only breastfed infants may reach near of the Reference Dose.

Exposure via house dust is in the same order of magnitude as in foods. This is surprising, because 90% of people’s exposure to persistent organic pollutants normally is through food intake.

6.5.3 PFAS

The concentration of perfluoroalkylated compounds (PFAS) in indoor air is commonly 25-100 times higher than outdoors. Average levels are typically >3,000 ng/m³ with maximum concentrations of >16,000 ng/m³. This means a potential inhalation of 60-300 µg/day.16

The PFAS content in house dust varies extremely much. Up to 13 different derivatives have been measured but, normally, there are most of perfluorohexane sulfonate (PFHxS) and perfluorooctane sulfonate (PFOS). Average concentrations of >2,000 to 20,000 ng/g and maximum concentrations of >80,000 to 500,000 ng/g have been determined. With a dust intake of 100 mg/day the daily average exposure will be 200-2,000 ng PFAS with a maximum of 8-50 µg PFAS.

In DEPA Consumer Report no. 50 about impregnation agents, exposure scenarios for PFAS were presented showing that an exposed child in total may have an intake of 0,9 µg/kg bw/day or 9 µg PFAS/day; thus, in the high end of the assessment above.

Because these PFAS derivatives are not lipophile, intake of animal fat and foods in general will not be as important a source, as it is for the lipophile persistent organic pollutants (POPs). The indoor climate seems to be the most important source of these substances.

Inhalation seems to be more important than dust intake but even combined there is a very large safety factor, because the acceptable daily intake (ADI) for perfluoroalkylated compounds is not exceeded. The ADI is 3 µg/kg bw/day, corresponding to no-effect-level (NOAEL) for reproductive effects with a safety factor of 1,000.

However, the present knowledge about the toxicological properties of the PFAS substances is limited.

Fodnoter

[11] Butte W, Heinzow B. Pollutants in house dust as indicators of indoor contamination. Rev Environ Contam Toxicol 2002;175:1-46.

[12] Havelund S. Kortlægning af perfluoroktanylsulfonat og lignende stoffer i forbrugerprodukter – fase 2, COWI Rådgivende Ingeniører A/S. Miljøprojekt nr. 691, 2002. Miljøstyrelsen.

[13] Poulsen PB, Jensen AA, Wallstrùm E. More environmentally friendly alternatives to PFOS-compounds and PFOA. Environmental Project No. 1013. Danish Environmental Protection Agency, 2005.

[14] Jones-Otazo HA, Clarke JP, Diamond ML et al. Is house dust the missing exposure pathway for PBDE? An analysis of the urban fate and human exposure to PBDEs. Environ Sci Technol 2005;39:5121-5130.

[15] Wilford BH, Shoeib M, Harner T, Zhu J, Jones KC.. Passive sampling survey of polybrominated diphenyl ether flame retardants in indoor and outdoor air in Ottawa, Canada: Implication for source and exposure. ES&T 2004;38:5312-5318.

[16] Shoeib M, Harner T, Wilford BH, Jones KC, Zhu J. Indoor and outdoor air concentrations and phase partitioning of perfluoralkyl sulfonamides and polybrominated diphenyl ethers. ES&T 2004;38:1313-1320.

[17] Data from Denmark is missing but Denmark might be in the lower part as the mean ingestion in Sweden is 41 ng/day with a maximum value of 666 ng/day (Lind Y et al. Organohalogen Compounds 2002;58:181-184).

 

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Version 1.0 September 2006, © Danish Environmental Protection Agency