Temporal Trends in Variability of Respirable Dust and Respirable Quartz Concentrations in the European Industrial Minerals Sector.

While between- and within-worker variability have been studied quite extensively, hardly any research is available that examines long-term trends in the variability of occupational exposure. In this first study on trends in occupational exposure variability temporal changes in the variability of respirable dust and respirable quartz concentrations within the European industrial minerals sector were demonstrated. Since 2000 the European Industrial Minerals Association's Dust Monitoring Program (IMA-DMP) has systematically collected respirable dust and respirable quartz measurements. The resulting IMA-DMP occupational exposure database contains at present approximately 40 000 personal full-shift measurements, collected at 177 sites owned by 39 companies, located in 23 European countries. Repeated measurements of workers performing their duties within a specific site-job-campaign combination allowed estimation of within- and between-worker variability in exposure concentrations. Overall day-to-day variability predominated the between-worker variability for both respirable dust concentrations and quartz concentrations. The within-worker variability in concentrations by job was two to three times higher for respirable quartz than for respirable dust. The median between-worker variability in respirable dust concentrations was low and further reduced over time. For quartz concentrations the same phenomenon albeit somewhat less strong was observed. In contrast, for the within-worker variability in concentrations downward and upward temporal trends were apparent for both respirable dust and respirable quartz. The study shows that the (relative) size of temporal variability is large and unpredictable and therefore regular measurement campaigns are needed to ascertain compliance to occupational exposure limit values.

Temporal trends in respirable dust and respirable quartz concentrations within the European industrial minerals sector over a 15-year period (2002-2016).

OBJECTIVES: Since 2000 the European Industrial Minerals Association's Dust Monitoring Programme (IMA-DMP) has systematically collected respirable dust and respirable quartz measurements from 35 companies producing industrial minerals. The IMA-DMP initiative allowed for estimating overall temporal trends in exposure concentrations for the years 2002-2016 and for presenting these trends by type of mineral produced, by jobs performed and by time of enrolment into the DMP. METHODS: Approximately 32 000 personal exposure measurements were collected during 29 sampling campaigns during a 15-year period (2002-2016). Temporal trends in respirable dust and respirable quartz concentrations were studied by using linear mixed effects models. RESULTS: Concentrations varied widely (up to three to four orders of magnitude). However, overall decreases in exposure levels were shown for the European minerals industry over the 15-year period. Statistically significant overall downward temporal trends of -9.0% and -3.9% per year were observed for respirable dust and respirable quartz, respectively. When analyses were stratified by time period, no downward trends (and even slight increasing concentrations) were observed between 2008 and 2012, most likely attributable to the recent global economic crisis. After this time period, downward trends became visible again. CONCLUSIONS: Consistent and statistically significant downward trends were found for both exposure to respirable dust and respirable quartz. These downward trends became less or even reversed during the years of the global economic crisis. To our knowledge, this is the first time that analyses of long-term temporal trends point at an effect of a global economic crisis on personal exposure concentrations of workers from sites across Europe.

15 years of monitoring occupational exposure to respirable dust and quartz within the European industrial minerals sector.

INTRODUCTION: In 2000, a prospective Dust Monitoring Program (DMP) was started in which measurements of worker's exposure to respirable dust and quartz are collected in member companies from the European Industrial Minerals Association (IMA-Europe). After 15 years, the resulting IMA-DMP database allows a detailed overview of exposure levels of respirable dust and quartz over time within this industrial sector. Our aim is to describe the IMA-DMP and the current state of the corresponding database which due to continuation of the IMA-DMP is still growing. The future use of the database will also be highlighted including its utility for the industrial minerals producing sector. METHODS: Exposure data are being obtained following a common protocol including a standardized sampling strategy, standardized sampling and analytical methods and a data management system. Following strict quality control procedures, exposure data are consequently added to a central database. The data comprises personal exposure measurements including auxiliary information on work and other conditions during sampling. RESULTS: Currently, the IMA-DMP database consists of almost 28,000 personal measurements which have been performed from 2000 until 2015 representing 29 half-yearly sampling campaigns. The exposure data have been collected from 160 different worksites owned by 35 industrial mineral companies and comes from 23 European countries and approximately 5000 workers. CONCLUSION: The IMA-DMP database provides the European minerals sector with reliable data regarding worker personal exposures to respirable dust and quartz. The database can be used as a powerful tool to address outstanding scientific issues on long-term exposure trends and exposure variability, and importantly, as a surveillance tool to evaluate exposure control measures. The database will be valuable for future epidemiological studies on respiratory health effects and will allow for estimation of quantitative exposure response relationships.

Validation of a questionnaire on hand hygiene in the construction industry.

INTRODUCTION: Construction workers are at risk of developing occupational contact dermatitis. Gloves, when used properly, may protect against chemicals and coarse materials. We investigated the prevalence and determinants of contact dermatitis in a population of Dutch construction workers and aimed at validating questionnaire items on hand hygiene. METHODS: A cross-sectional study was conducted at 13 construction sites, yielding data of 177 subjects (95% response rate). A questionnaire covering questions on hand hygiene and contact dermatitis symptoms was used. Agreement between workplace observations and a number of questionnaire items was assessed by calculating Cohen's kappa. Log-binomial regression analysis was used to assess the association between contact dermatitis and various hand hygiene-related determinants. RESULTS: The 1-year prevalence of self-reported contact dermatitis in our study sample was 46.9%. Multiple regression analysis showed a positive association with difficulties with hand cleaning (prevalence ratio [PR]: 1.26, 95% confidence interval [CI]: 1.05-1.52), hand contamination at the end of the working day (PR: 2.30, 95% CI: 1.14-4.65), and intensive hand cream use (PR: 2.07, 95% CI: 1.42-3.01). Observations of hand contamination, glove use, and glove types were found to agree well with the self-reported data from the questionnaire (Cohen's kappa's 0.75, 0.97, and 0.88). CONCLUSIONS: Self-reported contact dermatitis prevalence in construction workers was high and related to hand hygiene. A strong agreement was found between workplace observations and self-reported questionnaire data.

Two distinct classes of novel pyrazolinecarboxamides as potent cannabinoid CB1 receptor agonists.

The synthesis and SAR of 3-alkyl-4-aryl-4,5-dihydropyrazole-1-carboxamides 1-23 and 1-alkyl-5-aryl-4,5-dihydropyrazole-3-carboxamides 24-27 as two novel cannabinoid CB(1) receptor agonist classes were described. The target compounds elicited high affinities to the CB(1) as well as the CB(2) receptor and were found to act as CB(1) receptor agonists. The key compound 19 elicited potent CB(1) agonistic and CB(2) inverse agonistic properties in vitro and showed in vivo activity in a rodent model for multiple sclerosis after oral administration.

Synthesis and SAR of novel imidazoles as potent and selective cannabinoid CB2 receptor antagonists with high binding efficiencies.

The synthesis and structure-activity relationship studies of imidazoles are described. The target compounds 6-20 represent a novel chemotype of potent and CB(2)/CB(1) selective cannabinoid CB(2) receptor antagonists/inverse agonists with very high binding efficiencies in combination with favourable logP and calculated polar surface area values. Compound 12 exhibited the highest CB(2) receptor affinity (K(i)=1.03 nM) in this series, as well as the highest CB(2)/CB(1) subtype selectivity (>9708-fold).