Browsing Articles and other publications by RIVM employees by Submit Date
Now showing items 1-20 of 3024
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BMI trajectories after primary school-based lifestyle intervention: Unravelling an uncertain future. A mixed methods study.This mixed methods study aimed to examine plausible body mass index (BMI) trajectories after exposure to a primary school-based lifestyle intervention to aid in estimating the long-term intervention benefits. BMI trajectories for children at control schools (mean 7.6 years of age) were modelled until 20 years of age through extrapolating trial evidence (N = 1647). A reference scenario assumed that the observed 2-year effects of the 'Healthy Primary Schools of the Future' (HPSF) and 'Physical Activity Schools' (PAS) were fully maintained over time. This was modelled by applying the observed 2-year BMI effects until 20 years of age. Expert opinions on likely trends in effect maintenance after the 2-year intervention period were elicited qualitatively and quantitatively, and were used for developing alternative scenarios. Expert elicitation revealed three scenarios: (a) a constant exposure-effect and an uncontrolled environment with effect decay scenario, (b) a household multiplier and an uncontrolled environment with effect decay scenario, and (c) a household multiplier and maintainer scenario. The relative effect of HPSF at 20 years of age was -0.21 kg/m2 under the reference scenario, and varied from -0.04 kg/m2(a) to -0.06 kg/m2(b), and -0.50 kg/m2(c). For PAS, the relative effect was -0.17 kg/m2 under the reference scenario, and varied from -0.04 kg/m2(a, b), to -0.21 kg/m2(c). The mixed methods approach proved to be useful in modelling plausible BMI trajectories and specifying uncertainty on effect maintenance. Further observations until adulthood could reduce the uncertainty around future benefits. This trial was retrospectively registered at Clinicaltrials.gov (NCT02800616).
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Riverine microplastic and microbial community compositions: A field study in the netherlands.Plastic pollution in aquatic environments, particularly microplastics (<5 mm), is an emerging health threat. The buoyancy, hydrophobic hard surfaces, novel polymer carbon sources and long-distance transport make microplastics a unique substrate for biofilms, potentially harbouring pathogens and enabling antimicrobial resistance (AMR) gene exchange. Microplastic concentrations, their polymer types and the associated microbial communities were determined in paired, contemporaneous samples from the Dutch portion of the river Rhine. Microplastics were collected through a cascade of 500/100/10 μm sieves; filtrates and surface water were also analysed. Microplastics were characterized with infrared spectroscopy. Microbial communities and selected virulence and AMR genes were determined with 16S rRNA-sequencing and qPCR. Average microplastic concentration was 213,147 particles/m3; polyamide and polyvinylchloride were the most abundant polymers. Microbial composition on 100-500 μm samples differed significantly from surface water and 10-100 μm or smaller samples, with lower microbial diversity compared to surface water. An increasingly 'water-like' microbial community was observed as particles became smaller. Associations amongst specific microbial taxa, polymer types and particle sizes, as well as seasonal and methodological effects, were also observed. Known biofilm-forming and plastic-degrading taxa (e.g. Pseudomonas) and taxa harbouring potential pathogens (Pseudomonas, Acinetobacter, Arcobacter) were enriched in certain sample types, and other risk-conferring signatures like the sul1 and erm(B) AMR genes were almost ubiquitous. Results were generally compatible with the existence of taxon-selecting mechanisms and reduced microbial diversity in the biofilms of plastic substrates, varying over seasons, polymer types and particle sizes. This study provided updated field data and insights on microplastic pollution in a major riverine environment.
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The prevalence of occupational exposure to ergonomic risk factors: A systematic review and meta-analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury.Five studies (three cross-sectional studies and two cohort studies) met the inclusion criteria, comprising 150,895 participants (81,613 females) in 36 countries in two WHO regions (Africa, Europe). The exposure was generally assessed with questionnaire data about self-reported exposure. Estimates of the prevalence of occupational exposure to ergonomic risk factors are presented for all five included studies, disaggregated by country, sex, 5-year age group, industrial sector or occupational group where feasible. The pooled prevalence of any occupational exposure to ergonomic risk factors was 0.76 (95% confidence interval 0.69 to 0.84, 3 studies, 148,433 participants, 35 countries in the WHO Europe region, I2 100%, low quality of evidence). Subgroup analyses found no statistically significant differences in exposure by sex but differences by age group, occupation and country. No evidence was found for publication bias. We assessed this body evidence to be of low quality, based on serious concerns for risk of bias due to exposure assessment only being based on self-report and for indirectness due to evidence from two WHO regions only.
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Comparison of associations between mortality and air pollution exposure estimated with a hybrid, a land-use regression and a dispersion model.We followed a Dutch national cohort of approximately 10.5 million adults aged 29+ years from 2008 until 2012. We used Cox proportional hazard models with age as underlying time scale and adjusted for several potential individual and area-level socio-economic status confounders to evaluate associations of annual average residential NO2, PM2.5 and BC exposure estimates based on two stochastic models (Dutch LUR, European-wide hybrid) and deterministic Dutch dispersion models.
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Modeling multi-level survival data in multi-center epidemiological cohort studies: Applications from the ELAPSE project.We evaluated methods for the analysis of multi-level survival data using a pooled dataset of 14 cohorts participating in the ELAPSE project investigating associations between residential exposure to low levels of air pollution (PM2.5 and NO2) and health (natural-cause mortality and cerebrovascular, coronary and lung cancer incidence).
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Effect of UV/chlorine treatment on photophysical and photochemical properties of dissolved organic matter.Dissolved organic matter (DOM) is a ubiquitous component in effluents, DOM discharged with an effluent can affect the composition and properties of natural DOM in the receiving waters. As the photophysical and photochemical properties of effluent DOM can be changed by wastewater treatment processes, the effect of UV/chlorine treatment on the photophysical and photochemical properties of DOM was investigated using Suwannee River fulvic acid (SRFA) and Suwannee River natural organic matter (SRNOM) as representatives. Results showed that the absorbance of the two DOM was significantly decreased. The evolution trends of three representative photophysical parameters upon increase of chlorine dosages were observed. Also, a decrease in DOM aromaticity, molecular weight and electron-donating capacity was observed upon increasing chlorine dosage. Quantum yields of excited triplet state of DOM (3DOM*), singlet oxygen (1O2) and hydroxyl radicals (·OH) first decreases and then increased in the UV/chlorine systems upon increasing chlorine dosages due to the different reaction pathways of the two DOM. Moreover, 3DOM* can not only be regarded as a "controller" of other reactive intermediates, but also effectively promote the photodegradation of bezafibrate, which is classified as a persistent organic contaminant. This study gives deep insights into effects of UV/chlorine on the photophysical and photochemical properties of DOM, and is helpful for understanding the dynamic roles of DOM in the photodegradation of micropollutants.
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Adsorption of titanium dioxide nanoparticles onto zebrafish eggs affects colonizing microbiota.Teleost fish embryos are protected by two acellular membranes against particulate pollutants that are present in the water column. These membranes provide an effective barrier preventing particle uptake. In this study, we tested the hypothesis that the adsorption of antimicrobial titanium dioxide nanoparticles onto zebrafish eggs nevertheless harms the developing embryo by disturbing early microbial colonization. Zebrafish eggs were exposed during their first day of development to 2, 5 and 10 mg TiO2 L-1 (NM-105). Additionally, eggs were exposed to gold nanorods to assess the effectiveness of the eggs' membranes in preventing particle uptake, localizing these particles by way of two-photon microscopy. This confirmed that particles accumulate onto zebrafish eggs, without any detectable amounts of particles crossing the protective membranes. By way of particle-induced X-ray emission analysis, we inferred that the titanium dioxide particles could cover 25-45 % of the zebrafish egg surface, where the concentrations of sorbed titanium correlated positively with concentrations of potassium and correlated negatively with concentrations of silicon. A combination of imaging and culture-based microbial identification techniques revealed that the adsorbed particles exerted antimicrobial effects, but resulted in an overall increase of microbial abundance, without any change in heterotrophic microbial activity, as inferred based on carbon substrate utilization. This effect persisted upon hatching, since larvae from particle-exposed eggs still comprised higher microbial abundance than larvae that hatched from control eggs. Notably, pathogenic aeromonads tolerated the antimicrobial properties of the nanoparticles. Overall, our results show that the adsorption of suspended antimicrobial nanoparticles on aquatic eggs can have cascading effects across different life stages of oviparous animals. Our study furthermore suggests that aggregation dynamics may occur that could facilitate the dispersal of pathogenic bacteria through aquatic ecosystems.
