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Micro- and nanoplastic particles (MNPs) have emerged as pollutants of high public concern. Assessing and managing the risks of these particles remains challenging for several reasons. A long-term goal is to establish a comprehensive risk-governance framework that includes risk framing, scientifically sound risk assessment that accounts for human and environmental safety, evaluation, and risk management/decision making. A realistic short-term goal is to develop a comprehensive human health risk assessment framework (RAF). Very recently, RAFs for evaluating the human-health risks of MNPs have become available; however, comparative analyses of these frameworks are lacking. Here, we discuss six established frameworks to assess their technological and regulatory readiness. We begin by proposing nine technical criteria that a risk-assessment framework should meet to inform policy and action. These include the degree of quantifiability of outputs; the provision for systematic evaluation of the quality of input data; the consistency between exposure and effect data with respect to underlying mechanisms; the extent to which the complexity and diversity of environmentally realistic microplastics are addressed; readiness for integration into existing regulatory approaches; and the extent of real-world implementation to date. We discuss the specific strengths of each framework and recommend combining them into a single overarching framework that integrates these strengths.
The impact of indoor air pollutant (IAP) exposure due to increased building airtightness to meet nearly zero energy standards remains largely underexamined. By extrapolating data from pre- and post-retrofit IAP measurements in a small sample of NZEB-retrofitted homes, we estimate potential health consequences from long term exposure at the measured concentrations. Health effects, driven mainly by PM2.5, may exceed current estimates for outdoor PM2.5 exposure in Ireland. This study provides a practical example of the use of IAQ exposure data to estimate the likely health consequences resulting from changes in exposure due to deep energy retrofit. Comprehensive, large-scale studies are needed to fully understand the implications of energy retrofit measures on indoor air quality and public health.
Due to the rapid evolution and densification of mobile communication networks, there is an increased interest in the long-term assessment of environmental exposure to radiofrequency electromagnetic fields (RF-EMF). While numerous studies have investigated RF-EMF exposure using short-term or spatial measurement campaigns, the number of comprehensive analyses capturing temporal variability across multiple frequency bands and countries remain limited. This pilot study aims to establish a multi-country sensor network to collect data on long-term RF-EMF exposure, including 5G, and to investigate whether temporal trends occur. Twenty frequency-selective sensors were deployed at fixed indoor and outdoor locations in ten European countries, continuously measuring E-field (electric field) strengths in four mobile communication frequency bands (806 MHz, 942 MHz, 1842 MHz, and 3625 MHz) over a period of 17 months with a temporal resolution of 1 s. The raw measurement data were calibrated and analyzed to describe RF-EMF exposure levels, temporal patterns, and variability across environments and spatial characteristics. A strong and recurring diurnal pattern was observed across the four frequency bands. The highest day-night contrasts occurred in the 806 MHz and 1842 MHz bands, where nighttime values decreased by 35.1% and 48.4%, respectively compared to daytime values. Milder contrasts were observed between weekdays and weekends with the most pronounced decrease of 16.6% for the 1842 MHz band. Temporal variability, quantified using the R-factor (i.e. the ratio of the median field strength to the maximum field strength measured during the period of interest), varied substantially across frequency bands and locations, with lower R-factors observed for higher-frequency bands (with a median R-factor of 0.45 for 3625 GHz), indicating a greater variability. Given the scope and duration of this study, it aims to serve as a pilot study for long-term exposure monitoring at fixed sites in multiple countries.
BACKGROUND:The Safe and Sustainable by Design (SSbD) concept facilitates the design of safer and more sustainable chemicals and materials and is a crucial approach towards reaching the goals set out in the European Green Deal. It is critical that suitable guidance is provided on how to use new approach methodologies (NAMs) to fill hazard data gaps for nanomaterials (NMs) to facilitate SSbD decisions. Here, we showcase a nano-specific in vitro SSbD case study. The five colloidal silica nanoforms (SiO2-NFs) under investigation in this study are surface modified with varying amounts of glycerolpropyl-organosilane groups. In this study, we use a simple yet comprehensive in vitro test battery along with thorough particle characterization to investigate the effect of surface silanization on in vitro toxicity to inform SSbD decisions. RESULTS:Cytotoxic, pro-inflammatory and oxidative stress responses in A549, dTHP-1, and BEAS-2B cells after exposure to SiO2-NFs submerged and at the air-liquid interface (ALI) decreased with increasing silane surface modification. None of the SiO2-NFs showed surface reactivity or haemolytic potential. Deposition assessment using inductively coupled plasma - optical emission spectrometry (ICP-OES) revealed that increasing silane surface modification decreased particle settling. The two SiO2-NFs with the highest amount of surface silanization did not reach the cells in a submerged exposure setting, and they were therefore only tested at the ALI. Identical dose-response curves were observed for both the submerged testing and testing at the ALI for the SiO2-NFs without and with low/intermediate surface functionalization, again showing a decrease in effects with increasing surface functionalization. CONCLUSION:We show that in vitro toxicity assays provide valuable information for SSbD decision making. In vitro cytotoxic, pro-inflammatory and oxidative stress responses can be reduced with increasing surface silane functionalization. The reduced deposition efficiency with increasing silane functionalization, however, highlights that thorough characterization of particle behaviour in cell culture medium should always be performed for SSbD hazard testing. The amount of silane required to reduce toxicity is important information for the future production of safer SiO2-NFs and nano-enabled products. Exposure, functionality, and sustainability remain to be investigated to draw full SSbD conclusions.
There is an increasing need for new approach methodologies (NAMs) for safety assessment of nanomaterials (NMs) in order to keep pace with innovation. In vitro assays are useful tools during pre-market hazard screening approaches of NMs to prioritize safe(r) candidate NMs and reduce the amount of regulatory testing required. For pre-regulatory hazard screening applications, it is crucial that in vitro assays have the capacity to distinguish between NMs based on their hazard potency and have the ability to provide accurate hazard rankings. In this paper, four types of silica particles (crystalline, pyrogenic, colloidal, and silane functionalized colloidal) were subjected to twenty-four in vitro assays to obtain hazard rankings using dose–response modelling. The assays were chosen for their relevance in the mechanism of action towards pulmonary inflammation upon inhalation of silica particles. The hazard rankings of silica particles were affected by cell type (alveolar or bronchial epithelial cells, macrophages), read-out method (cell viability, release of pro-inflammatory mediators, reactive oxygen species), and exposure method (submerged, air–liquid interface), complicating the assessment of the actual human hazard. Of particular note was an often muted in vitro response to the crystalline silica used in this study (DQ12), when in vivo data ranked this material as high hazard, due to the chronic and persistent in vivo inflammatory response to crystalline silica, highlighting an important functional discord between these models. However, the potency ranking of the silica particles to induce secretion of the pro-inflammatory mediator IL-1β by THP-1 cells differentiated to M0 macrophages as well as red blood cell haemolysis corresponded more closely to the hazard ranking based on data from rat inhalation studies. These assays should be further explored as indicators for human hazard potential of silica particles and other particles following a similar mechanism of action.
