Documents International Journal of Hygiene and Environmental Health 5 results

"In an emerging field of nanotechnologies, assessment of exposure to carbon nanotubes (CNT) and carbon nanofibers (CNF) is an integral component of occupational and environmental epidemiology, risk assessment and management, as well as regulatory actions. The current state of knowledge on exposure to carbon-based fibrous nanomaterials among workers, consumers and general population was studied in frame of the International Agency for Research on Cancer (IARC) Monographs-Volume 111 “Some Nanomaterials and Some Fibres”. Completeness and reliability of available exposure data for use in epidemiology and risk assessment were assessed. Occupational exposure to CNT/CNF may be of concern at all stages of the material life-cycle from research through manufacture to use and disposal. Consumer and environmental exposures are only estimated by modeled data. The available information of the final steps of the life-cycle of these materials remains incomplete so far regarding amounts of handled materials and levels of exposure. The quality and amount of information available on the uses and applications of CNT/CNF should be improved to enable quantitative assessment of human exposure to these materials. For that, coordinated effort in producing surveys and exposure inventories based on harmonized strategy of material test, exposure measurement and reporting results is strongly encouraged."

"Due to their antifungal, antibacterial, antiviral, and antimicrobial properties, silver nanoparticles (AgNPs) are used in consumer products intended for use by children or in the home. Children may be especially affected by the normal use of consumer products because of their physiological functions, developmental stage, and activities and behaviors. Despite much research to date, children's potential exposures to AgNPs are not well characterized. Our objectives were to characterize selected consumer products containing AgNPs and to use the data to estimate a child's potential non-dietary ingestion exposure. We identified and cataloged 165 consumer products claiming to contain AgNPs that may be used by or near children or found in the home. Nineteen products (textile, liquid, plastic) were selected for further analysis. We developed a tiered analytical approach to determine silver content, form (particulate or ionic), size, morphology, agglomeration state, and composition. Silver was detected in all products except one sippy cup body. Among products in a given category, silver mass contributions were highly variable and not always uniformly distributed within products, highlighting the need to sample multiple areas of a product. Electron microscopy confirmed the presence of AgNPs. Using this data, a child's potential non-dietary ingestion exposure to AgNPs when drinking milk formula from a sippy cup is 1.53 ?g Ag/kg. Additional research is needed to understand the number and types of consumer products containing silver and the concentrations of silver in these products in order to more accurately predict children's potential aggregate and cumulative exposures to AgNPs."

"Over the past decade, the primary focus of nanotoxicology and nanoenvironmental health and safety efforts has been largely on inhalation exposure to engineered nanomaterials, at the production stage, and much less on considering risks along the life cycle of nano-enabled products. Dermal exposure to nanomaterials and its health impact has been studied to a much lesser extent, and mostly in the context of intentional exposure to nano-enabled products such as in nanomedicine, cosmetics and personal care products. How concerning is dermal exposure to such nanoparticles in the context of occupational exposures? When and how should we measure it?

In the first of a series of two papers (Larese Filon et al., 2016), we focused our attention on identifying conditions or situations, i.e. a combination of nanoparticle physico-chemical properties, skin barrier integrity, and occupations with high prevalence of skin disease, which deserve further investigation. This second paper focuses on the broad question of dermal exposure assessment to nanoparticles and attempts to give an overview of the mechanisms of occupational dermal exposure to nanoparticles and nano-enabled products and explores feasibility and adequacy of various methods of quantifying dermal exposure to NOAA. We provide here a conceptual framework for screening, prioritization, and assessment of dermal exposure to NOAA in occupational settings, and integrate it into a proposed framework for risk assessment."

"The paper reviews and critically assesses the evidence on the relevance of various skin uptake pathways for engineered nanoparticles, nano-objects, their agglomerates and aggregates (NOAA). It focuses especially in occupational settings, in the context of nanotoxicology, risk assessment, occupational medicine, medical/epidemiological surveillance efforts, and the development of relevant exposure assessment strategies.
Skin uptake of nanoparticles is presented in the context of local and systemic health effects, especially contact dermatitis, skin barrier integrity, physico-chemical properties of NOAA, and predisposing risk factors, such as stratum corneum disruption due to occupational co-exposure to chemicals, and the presence of occupational skin diseases. Attention should be given to: (1) Metal NOAA, since the potential release of ions may induce local skin effects (e.g. irritation and contact dermatitis) and absorption of toxic or sensitizing metals; (2) NOAA with metal catalytic residue, since potential release of ions may also induce local skin effects and absorption of toxic metals; (3) rigid NOAA smaller than 45 nm that can penetrate and permeate the skin; (4) non rigid or flexible NOAA, where due to their flexibility liposomes and micelles can penetrate and permeate the intact skin; (5) impaired skin condition of exposed workers.
Furthermore, we outline possible situations where health surveillance could be appropriate where there is NOAA occupational skin exposures, e.g. when working with nanoparticles made of sensitizer metals, NOAA containing sensitizer impurities, and/or in occupations with a high prevalence of disrupted skin barrier integrity. The paper furthermore recommends a stepwise approach to evaluate risk related to NOAA to be applied in occupational exposure and risk assessment, and discusses implications related to health surveillance, labelling, and risk communication."

"A summary of a critical review by a working group of the German Federal Environment Agency and the German Federal Institute for Risk Assessment on the carcinogenic potential of nanomaterials is presented. After a critical review of the available data, we conclude that the potential carcinogenic risk of nanomaterials can currently be assessed only on a case-by-case basis. There is certain evidence that different forms of CNTs (carbon nanotubes) and nanoscale TiO(2) particles may induce tumours in sensitive animal models. It is assumed that the mode of action of the inhalation toxicity of asbestos-like fibres and of inhalable fractions of biopersistent fine dusts of low toxicity (nano-TiO(2)) is linked to chronic inflammatory processes. Existing epidemiological studies on carcinogenicity for these manufactured nanomaterials are not sufficiently conclusive. Generally speaking, the database is not adequate for an assessment of the carcinogenic potential of nanomaterials. Whereas a number of studies provide evidence of a nano-specific potential to induce tumours, other studies did not. This is possibly due to insufficient characterisation of the test material, difference in the experimental design, the use of different animal models and species and/or differences in dosimetry (both with regard to the appropriate dose metric and the estimated effective dose quantities). An assessment of the carcinogenic potential and its relevance for humans are currently fraught with uncertainty. Furthermore, the nano-specificity of the carcinogenic effects observed cannot be conclusively evaluated. Specific carcinogenic effects of nanomaterials may be both quantitative and qualitative. In quantitative terms, the carcinogenic effects of nanoparticles are thought to be simply more pronounced compared to the corresponding bulk material (due, for example, to the considerably larger surface area and higher number of particles relative to the mass concentration). On the other hand, certain nano-properties such as small size, shape and reactivity, retention time and distribution in the body after overcoming biological barriers, as well as subcellular and molecular interactions may play a role in determining the toxicity in qualitative terms, i.e. the carcinogenic potential of the nanomaterial and the non-nanoscale comparison substance may be fundamentally different. All of these factors leave no doubt about the fact that there is a great need for research in this area and that new standardised test methods need to be developed or existing ones adapted at the very least to achieve valid answers regarding the carcinogenic potential of nanomaterials. Global production of nanomaterials is set to increase in the years to come, and new materials with new properties will be developed, so that greater human exposure to them must be anticipated. No reliable conclusions can currently be drawn about exposure to nanoparticles and their release from products. Firstly, there are substantial deficits in information about the processing of nanomaterials in products and preparations. Secondly, there are only a small number of studies on nanoparticle release, and reliable techniques for measuring and monitoring nanomaterials in different environmental media are still being developed which is both complex and costly. Despite the uncertainties, the findings to date on the carcinogenic potential of nanomaterials must be taken seriously, and precautionary measures to minimise exposure should go hand in hand with the development of a comprehensive and conclusive toxicological methodology and testing procedure for nanostructured materials that includes all possible exposure routes. With regard to possible legal classification of nanomaterials and the transferability of classifications of their non-nanomaterial counterparts, we believe it is necessary to have separate procedures for nano and non-nano forms. Furthermore, criteria for evaluating nano-specific carcinogenic properties should be constantly updated and adapted to the state of knowledge. There is a need here for amendments to be made to EU legislation, as currently nanoforms do not represent a separate category of substance in their own right."