Application of a silicone rubber passive sampling technique for monitoring PAHs and PCBs at three Belgian coastal harbours

A 4-year monitoring was performed to study the freely dissolved water concentrations of PAHs and PCBs in three coastal harbours and at an offshore station in the North Sea. The results are part of a more extensive study to provide information on occurrence, distribution and effects of pollutants in the Belgian coastal zone. Several methods for the estimation of freely dissolved water concentrations are reported in the literature. In the present study silicone rubber passive samplers were used. The non-linear least-square (NLS) method proved to be suitable for estimating sampling rates when using the following performance reference compounds: fluorene-d10, phenanthrene-d10, fluoranthene-d10, benzo(e)pyrene-d12, coronene-d12, CB10, CB14, CB50, CB104, CB145 and CB204. The application of two NLS methods for estimating the sampling rate (Rs) resulted in significant differences for freely dissolved concentrations for individual compounds of up to 30% between the two methods. A model that takes into account the decrease of sampling rate for compounds with higher molecular weight should give a more accurate Rs and was the preferred estimation method. Rs varied from 0.9 to 34.8 L d-1 for the different target compounds, while estimated freely dissolved concentrations for sum 15 PAHs varied between 3.9 and 170 ng L-1 and for sum 14 PCBs between 0.030 and 3.1 ng L-1. The stations located within marinas showed the highest level of contamination, while the offshore station (5 mile from coastline) exhibited the lowest level. The implications of the use of passive samplers for monitoring programs are discussed

Estrogenic and toxic effects of methoxychlor on zebrafish (Danio rerio)

Although zebrafish (Danio rerio) have been suggested as a good candidate for screening potential endocrine disruptors, little information is available on the effects of weak estrogens on this species. We investigated the sensitivity of different life stages of zebrafish toward toxic and estrogenic properties of methoxychlor (MXC). Short-term tests with adults resulted in a sex-specific 96-h lethal concentration for 50% (LC50) of the test animals of 36 mug/L for males and 129 mug/L for females. To determine the estrogenic capacity of MXC, adult zebrafish were exposed to 0, 0.5, 5, and 50 mug MXC/L for 14 d. Induction of vitellogenin ([VTG] measured with protein electrophoresis and Western blot) in males was detected at 5 and 50 mug MXC/L. Females, however, did not exhibit higher blood VTG concentrations at the tested MXC concentrations. In a second series of experiments, juvenile zebrafish were exposed to 0, 0.05, 0.5, and 5 mug MXC/L for 33 d. Survival, length, weight, and condition of larvae were examined as indicators of toxic stress and the VTG content in whole body homogenates of juveniles was measured to determine xenoestrogenic effects. No effects of the tested concentrations of MXC were observed. Finally, the effect of MXC on zebrafish eggs, exposed to 0, 1, 10, and 32 mug MXC/L, was examined. Hatching and survival of hatched zebrafish were affected at 10 and 32 mug MXC/L. This study demonstrated that adult male zebrafish are sensitive toward the estrogenic effects of MXC. However, the use of VTG induction to detect effects of (xeno)estrogens in early life stages has to be further investigated, as low concentrations of VTG were detectable in exposed as well as unexposed juvenile fish

Rapid quantification of pharmaceuticals and pesticides in passive samplers using ultra high performance liquid chromatography coupled to high resolution mass spectrometry

The presence of both pharmaceuticals and pesticides in the aquatic environment has become a well-known environmental issue during the last decade. An increasing demand however still exists for sensitive and reliable monitoring tools for these rather polar contaminants in the marine environment. In recent years, the great potential of passive samplers or equilibrium based sampling techniques for evaluation of the fate of these contaminants has been shown in literature. Therefore, we developed a new analytical method for the quantification of a high number of pharmaceuticals and pesticides in passive sampling devices. The analytical procedure consisted of extraction using 1:1 methanol/acetonitrile followed by detection with ultra-high performance liquid chromatography coupled to high resolution and high mass accuracy Orbitrap mass spectrometry. Validation of the analytical method resulted in limits of quantification and recoveries ranging between 0.2 and 20 ng per sampler sheet and between 87.9 and 105.2%, respectively. Determination of the sampler-water partition coefficients of all compounds demonstrated that several pharmaceuticals and most pesticides exert a high affinity for the polydimethylsiloxane passive samplers. Finally, the developed analytical methods were used to measure the time-weighted average (TWA) concentrations of the targeted pollutants in passive samplers, deployed at eight stations in the Belgian coastal zone. Propranolol, carbamazepine and seven pesticides were found to be very abundant in the passive samplers. These obtained long-term and large-scale TWA concentrations will contribute in assessing the environmental and human health risk of these emerging pollutants

Realistic environmental mixtures of hydrophobic compounds do not alter growth of a marine diatom

In this paper we determine whether a realistic mixture of hydrophobic chemicals affects the growth dynamics of a marine diatom and how this effect compares to the effect of temperature, light regime and nutrient conditions. To do so, we examine the specific growth rate of Phaeodactylum tricornutum in a 72 h algal growth inhibition test using a full factorial design with three nutrient regimes, two test temperatures, three light intensities and three chemical exposures. Passive samplers were used to achieve exposure to realistic mixtures of organic chemicals close to ambient concentrations. Nutrient regime, temperature and time interval (24, 48 and 72 h) explained 85% of the observed variability in the experimental data. The variability explained by chemical exposure was about 1%. Overall, ambient concentrations of hydrophobic compounds present in Belgian coastal waters, and for which the passive samplers have affinity, are too low to affect the intrinsic growth rate of P. tricornutum

Monitoring micropollutants in marine waters: can quality standards be met?

The environmental risks of 33 micropollutants occurring in Belgian coastal zone were assessed as single-substances and as mixtures. Water and sediment samples were taken in harbors, coastal waters and the Scheldt estuary during 2007–2009. Measured environmental concentrations were compared to quality standards such as Predicted No Effect Concentrations (PNECs), Environmental Quality Standards (EQSs), and Ecotoxicological Assessment Criteria (EAC). Out of a total of 2547 samples analyzed, 232 and 126 samples exceeded the EQS and EAC, respectively. Highest risks were observed for TBT, PBDEs, PCBs and the PAHs anthracene, indeno(1,2,3-cd)pyrene, benzo(g,h,i)perylene, benzo(k)fluoranthene, and benzo(b)fluoranthene in the water compartment and for TBT and PCBs in the sediment compartment. Samples taken at all stations during the April 2008 campaign indicate a potential risk of the contaminant mixtures to the aquatic environment (except W06 station). This study argues the need to revise quality standards when appropriate and hence the overall regulatory implication of these standards

Preparation and evaluation of sufficiently homogeneous and stable reference materials for priority hazardous substances in whole water

We have prepared and evaluated three whole water test materials containing eight polycyclic aromatic hydrocarbons (PAHs), six polybrominated diphenyl ethers (PBDEs) and tributyltin (TBT) with respect to homogeneity and short-term stability. The test materials were used as samples in two inter-laboratory comparisons. The materials were composed of natural mineral water and model suspended particulate matter (SPM) containing the target compounds at ng L-1 levels. The expanded uncertainty of the estimated mass concentrations in the final test materials was obtained by combining contributions from the homogeneity, the stability and the model-SPM characterization. The whole water materials were sufficiently homogeneous and stable at 4 °C for their intended use. Twelve out of fifteen investigated target parameters could be assessed to be present with a relative combined expanded uncertainty below 25 %. The outcome of the two inter-laboratory comparisons confirmed the good quality of the test materials and the level of uncertainties associated with the estimated mass concentrations. These findings are an important contribution towards the development of whole water matrix reference materials certified for PAH, PBDE and TBT in support of the Water Framework Directive of the European Union.JRC.D.2-Standards for Innovation and sustainable Developmen

Efficacy and safety of baricitinib in hospitalized adults with severe or critical COVID-19 (Bari-SolidAct): a randomised, double-blind, placebo-controlled phase 3 trial

International audienceAbstract Background Baricitinib has shown efficacy in hospitalized patients with COVID-19, but no placebo-controlled trials have focused specifically on severe/critical COVID, including vaccinated participants. Methods Bari-SolidAct is a phase-3, multicentre, randomised, double-blind, placebo-controlled trial, enrolling participants from June 3, 2021 to March 7, 2022, stopped prematurely for external evidence. Patients with severe/critical COVID-19 were randomised to Baricitinib 4 mg once daily or placebo, added to standard of care. The primary endpoint was all-cause mortality within 60 days. Participants were remotely followed to day 90 for safety and patient related outcome measures. Results Two hundred ninety-nine patients were screened, 284 randomised, and 275 received study drug or placebo and were included in the modified intent-to-treat analyses (139 receiving baricitinib and 136 placebo). Median age was 60 (IQR 49–69) years, 77% were male and 35% had received at least one dose of SARS-CoV2 vaccine. There were 21 deaths at day 60 in each group, 15.1% in the baricitinib group and 15.4% in the placebo group (adjusted absolute difference and 95% CI − 0.1% [− 8·3 to 8·0]). In sensitivity analysis censoring observations after drug discontinuation or rescue therapy (tocilizumab/increased steroid dose), proportions of death were 5.8% versus 8.8% (− 3.2% [− 9.0 to 2.7]), respectively. There were 148 serious adverse events in 46 participants (33.1%) receiving baricitinib and 155 in 51 participants (37.5%) receiving placebo. In subgroup analyses, there was a potential interaction between vaccination status and treatment allocation on 60-day mortality. In a subsequent post hoc analysis there was a significant interaction between vaccination status and treatment allocation on the occurrence of serious adverse events, with more respiratory complications and severe infections in vaccinated participants treated with baricitinib. Vaccinated participants were on average 11 years older, with more comorbidities. Conclusion This clinical trial was prematurely stopped for external evidence and therefore underpowered to conclude on a potential survival benefit of baricitinib in severe/critical COVID-19. We observed a possible safety signal in vaccinated participants, who were older with more comorbidities. Although based on a post-hoc analysis, these findings warrant further investigation in other trials and real-world studies. Trial registration Bari-SolidAct is registered at NCT04891133 (registered May 18, 2021) and EUClinicalTrials.eu ( 2022-500385-99-00 )