Results of a cosmetovigilance survey in The Netherlands.

BACKGROUND: Cosmetic products contribute considerably to the incidence of contact dermatitis. In response to a resolution of the Council of Europe, the National Institute for Public Health and the Environment (RIVM) in The Netherlands set up a pilot project to report undesirable effects attributed to cosmetic products. OBJECTIVES: To provide an overview of undesirable effects attributed to cosmetic products and to identify the ingredients involved. The information could contribute to the assessment of whether current EU legislation on cosmetics provides adequate protection. PATIENTS/METHODS: General practitioners, dermatologists and consumers in The Netherlands completed questionnaires on reported undesirable effects of cosmetics. Dermatologists also carried out patch tests and, where necessary, tests with specific batch ingredients of the associated cosmetic product. A website and a public awareness campaign were launched to encourage consumers to report undesirable effects. RESULTS: Between July 2009 and May 2011, the RIVM received more than 1600 reports. Severe undesirable effects were claimed in 1-4% of the cases. The most frequently reported cosmetic products were make-up and moisturisers, and the most frequently identified allergens were isothiazolinones and fragrance ingredients. Three patients tested positive for co-polymers/cross-polymers. CONCLUSIONS: Further investigations are recommended on the prevalence of isothiazolinone-induced allergic contact dermatitis and the allergenic potential of co-polymers/cross-polymers.

Review of health safety aspects of nanotechnologies in food production.

Due to new, previously unknown, properties attributed to engineered nanoparticles many new products are introduced in the agro-food area. Nanotechnologies cover many aspects, such as disease treatment, food security, new materials for pathogen detection, packaging materials and delivery systems. As with most new and evolving technologies, potential benefits are emphasized, while little is known on safety of the application of nanotechnologies in the agro-food sector. This review gives an overview of scientific issues that need to be addressed with priority in order to improve the risk assessment for nanoparticles in food. The following research topics are considered to contribute pivotally to risk assessment of nanotechnologies and nanoparticles in food products. Set a definition for NPs to facilitate regulatory discussions, prioritization of research and exchange of study results. Develop analytical tools for the characterization of nanoparticles in complex biological matrices like food. Establish relevant dose metrics for nanoparticles used for both interpretation of scientific studies as well as regulatory frameworks. Search for deviant behavior (kinetics) and novel effects (toxicity) of nanoparticles and assess the validity of currently used test systems following oral exposure. Estimate the consumer exposure to nanoparticles.

Aggregate exposure approaches for parabens in personal care products: a case assessment for children between 0 and 3 years old.

In the risk assessment of chemical substances, aggregation of exposure to a substance from different sources via different pathways is not common practice. Focusing the exposure assessment on a substance from a single source can lead to a significant underestimation of the risk. To gain more insight on how to perform an aggregate exposure assessment, we applied a deterministic (tier 1) and a person-oriented probabilistic approach (tier 2) for exposure to the four most common parabens through personal care products in children between 0 and 3 years old. Following a deterministic approach, a worst-case exposure estimate is calculated for methyl-, ethyl-, propyl- and butylparaben. As an illustration for risk assessment, Margins of Exposure (MoE) are calculated. These are 991 and 4966 for methyl- and ethylparaben, and 8 and 10 for propyl- and butylparaben, respectively. In tier 2, more detailed information on product use has been obtained from a small survey on product use of consumers. A probabilistic exposure assessment is performed to estimate the variability and uncertainty of exposure in a population. Results show that the internal exposure for each paraben is below the level determined in tier 1. However, for propyl- and butylparaben, the percentile of the population with an exposure probability above the assumed "safe" MoE of 100, is 13% and 7%, respectively. In conclusion, a tier 1 approach can be performed using simple equations and default point estimates, and serves as a starting point for exposure and risk assessment. If refinement is warranted, the more data demanding person-oriented probabilistic approach should be used. This probabilistic approach results in a more realistic exposure estimate, including the uncertainty, and allows determining the main drivers of exposure. Furthermore, it allows to estimate the percentage of the population for which the exposure is likely to be above a specific value.

Dermatokinetics of didecyldimethylammonium chloride and the influence of some commercial biocidal formulations on its dermal absorption in vitro.

The in vitro dermal absorption kinetics of didecyldimethylammonium chloride (DDAC) was studied after single and multiple exposure. In addition, the influence of biocidal formulations on the absorption of DDAC was investigated. Following dermal exposure to DDAC in aqueous solution, less than 0.5% of the applied dose reached the receptor fluid after 48h. The apparent permeability coefficient (K(p)) was 5+/-1cm/h x 10(-6) for concentrations <12.5mg/mL, and 12+/-3 cm/h x 10(-6) for concentrations >or=12.5 mg/mL, suggesting that DDAC decreases the skin barrier function. DDAC distributed readily into the stratum corneum, but the dermis appeared to be the main barrier for DDAC penetration. Multiple dosing of DDAC increased its flux across the skin, when applied in high concentrations (>11 mg/mL). However, the amount of DDAC reaching the receptor fluid remained low (<1% over a 48 h period). Selected biocidal formulations tended to reduce DDAC skin absorption. The degree of reduction appeared to be correlated to the amount of aldehydes present. Based on the comparison of the distribution of DDAC in full-thickness skin and epidermal membranes, we conclude that approximately one-third of the DDAC measured in the full-thickness membranes resides in the dermis. As a reasonable worst case assumption, this fraction could be considered systemically available when estimating the daily systemic body burden of DDAC.

Local effects in the respiratory tract: relevance of subjectively measured irritation for setting occupational exposure limits.

OBJECTIVES: Chemosensory effects of stimulation by a chemical can either be irritating (trigeminal stimulation) or odorous (olfactory stimulation) or both. For odorous irritants, a clear-cut distinction between odour and irritation is difficult to make. The differences in the lowest concentration found to be irritating to the respiratory tract in humans when compared to experimental animals has brought much debate in the process of setting occupational exposure limits (OELs) for such chemicals. In this paper it will be discussed as to how far subjectively measured sensory irritation threshold levels can be used to establish OELs. METHODS: Data on respiratory irritation of four odorous irritants were retrieved from public literature and discussed, viz. acetone, formaldehyde, furfural and sulphur dioxide. RESULTS: Objective measures of irritation yielded results that differed from subjective evaluations. Important factors modulating the reported levels of irritation and health symptoms include the perception of odour intensity, exposure history and the individual's bias to report irritation on the basis of his/her prejudice or knowledge of the compound. CONCLUSIONS: Subjective measures alone are less appropriate for establishing sensory irritation thresholds of odorous irritants and are, therefore, less suitable to establish OELs without supporting evidence. Objectively measured irritation in humans, the Alarie assay (an experimental animal test assessing the concentration that results in a 50% reduction of the breathing frequency) and repeated exposure studies in animals may be of help to study objective irritation. If subjective measurements are used to study sensory irritation, the study design should at least include: measurement of both incidence and severity determined at several concentrations, an appropriate (0 ppm) control condition, preferably a non-irritant odorant control exposure, validated questionnaires and correct concentration measurements.

Dose-response relationships and threshold levels in skin and respiratory allergy.

A literature study was performed to evaluate dose-response relationships and no-effect levels for sensitization and elicitation in skin- and respiratory allergy. With respect to the skin, dose-response relationships and no-effect levels were found for both intradermal and topical induction, as well as for intradermal and topical elicitation of allergenic responses in epidemiological, clinical, and animal studies. Skin damage or irritation may result in a significant reduction of the no-effect level for a specific compound. With respect to the respiratory tract, dose-response relationships and no-effect levels for induction were found in several human as well as animal studies. Although dose-response relationships for elicitation were found in some epidemiological studies, concentration-response relationships were present only in a limited number of animal studies. Reported results suggest that especially relatively high peak concentrations can induce sensitization, and that prevention of such concentrations will prevent workers from developing respiratory allergy. Moreover, induction of skin sensitization may result in subsequent heightened respiratory responsiveness following inhalation exposure. The threshold concentration for the elicitation of allergic airway reactions in sensitized subjects is generally lower than the threshold to induce sensitization. Therefore, it is important to consider the low threshold levels for elicitation for recommendation of health-based occupational exposure limits, and to avoid high peak concentrations. Notwithstanding the observation of dose-response relationships and no-effect levels, due to a number of uncertainties, no definite conclusions can be drawn about absolute threshold values for allergens with respect to sensitization of and elicitation reactions in the skin and respiratory tract. Most predictive tests are generally meant to detect the potential of a chemical to induce skin and/or respiratory allergy at relatively high doses. Consequently, these tests do not provide information of dose-response relationships at lower doses such as found in, for example, occupational situations. In addition, the observed dose-response relationships and threshold values have been obtained by a wide variety of test methods using different techniques, such as intradermal exposure versus topical or inhalation exposure at the workplace, or using different endpoints, which all appear important for the outcome of the test. Therefore, especially with regard to respiratory allergy, standardized and validated dose-response test methods are urgently required in order to be able to recommend safe exposure levels for allergens at the workplace.

Inhaled formaldehyde: evaluation of sensory irritation in relation to carcinogenicity.

OBJECTIVES: The critical health effects of formaldehyde exposure include sensory irritation and the potential to induce tumours in the upper respiratory tract. In literature, a concentration as low as 0.24 ppm has been reported to be irritating to the respiratory tract in humans. Nasal tumour-inducing levels in experimental animals seem to be 1-2 orders of magnitude larger. In this paper, the subjectively measured sensory irritation threshold levels in humans are discussed in line with findings obtained in animal experiments. In addition, a Benchmark dose (BMD) analysis of sensory irritation was used to estimate response incidences at different formaldehyde concentrations. METHODS: Data on respiratory irritation and carcinogenicity of formaldehyde were retrieved from public literature and discussed. BMD analysis was carried out on human volunteer studies using the US-EPA BMD software. RESULTS: Subjective measures of irritation were the major data found in humans to examine sensory (eye and nasal) irritation; only one study reported objectively measured eye irritation. On a normalized scale, mild/slight eye irritation was observed at levels 1 ppm, and mild/slight respiratory tract irritation at levels 2 ppm. With the BMD software, it was estimated that at a level of 1 ppm, only 9.5% of healthy volunteers experience 'moderate' (i.e., annoying) eye irritation (95% upper confidence limit). An important factor modulating the reported levels of irritation and health symptoms most probably includes the perception of odour intensity. In several studies, the 0-ppm control condition was missing. From the results of the long-term inhalation toxicity studies in experimental animals, a level of 1 ppm formaldehyde has been considered a NOAEL for nasal injury. CONCLUSIONS: Sensory irritation is first observed at levels of 1 ppm and higher. From both human and animal studies, it was concluded that at airborne levels for which the prevalence of sensory irritation is minimal both in incidence and degree (i.e., <1 ppm), risks of respiratory tract cancer are considered to be negligibly low.

Within-animal variation as an indication of the minimal magnitude of the critical effect size for continuous toxicological parameters applicable in the benchmark dose approach.

In this study, the within-animal variation in routinely studied continuous toxicological parameters was estimated from temporal fluctuations in individual healthy nonexposed animals. Assuming that these fluctuations are nonadverse, this within-animal variation may be indicative of the minimal magnitude of the critical effect size (CES). The CES is defined as the breaking point between adverse and nonadverse changes in a continuous toxicological parameter, at the level of the individual organism. The total variation in the data from individual nonexposed animals was divided in variation parts due to known factors (differences in sex, animal, and day) and a residual variation, by means of analysis of variance. Using the residual variation and the estimated analytical measurement error of a toxicological parameter, the within-animal variation can be estimated. The data showed within-animal variations ranging between 0.6% and 34% for different clinical chemistry and hematological parameters in 90-day rat studies. This indicates that different (minimal) CES values may be applicable for different parameters.

Effects of single and repeated exposure to biocidal active substances on the barrier function of the skin in vitro.

The dermal route of exposure is important in worker exposure to biocidal products. Many biocidal active substances which are used on a daily basis may decrease the barrier function of the skin to a larger extent than current risk assessment practice addresses, due to possible skin effects of repeated exposure. The influence of repeated and single exposure to representative biocidal active substances on the skin barrier was investigated in vitro. The biocidal active substances selected were alkyldimethylbenzylammonium chloride (ADBAC), boric acid, deltamethrin, dimethyldidecylammonium chloride (DDAC), formaldehyde, permethrin, piperonyl butoxide, sodium bromide, and tebuconazole. Of these nine compounds, only the quaternary ammonium chlorides ADBAC and DDAC had a clear and consistent influence on skin permeability of the marker compounds tritiated water and [(14)C]propoxur. For these compounds, repeated exposure increased skin permeability more than single exposure. At high concentrations the difference between single and repeated exposure was quantitatively significant: repeated exposure to 300 mg/L ADBAC increased skin permeability two to threefold in comparison to single exposure. Therefore, single and repeated exposure to specific biocidal products may significantly increase skin permeability, especially when used undiluted.

Prediction of local irritant effects after repeated dermal and respiratory exposure to chemicals.

Health risks resulting from occupational exposure to chemicals are controlled by the establishment of acceptable dermal and respiratory exposure levels. Due to a lack of route-specific toxicity data, acceptable levels are frequently established by means of route-to-route extrapolation. A pitfall in route-to-route extrapolation is the occurrence of local effects. Often, the results of acute irritation studies are used to assess the likelihood of the occurrence of local effects also following repeated exposure and thereby the validity of route-to-route extrapolation. We questioned this working practice and considered whether local effects observed in a given study are of any predictive value with respect to the occurrence of local effects after repeated exposure. Our database analysis indicates that substances inducing skin and/or eye irritation frequently induce local effects after repeated respiratory exposure. In contrast, observations made in any type of study show little or no positive predictive value for the occurrence of local effects after repeated dermal exposure. Notably, the absence of any indication of local effects in any type of study does not exclude the occurrence of local effects on repeated dermal or respiratory exposure. We conclude that the presumed reliability of route-to-route extrapolation in the absence of route-specific toxicity data can be questioned.