Bio accessibility of tire-associated organic chemicals in fish gut (Oncorhynchus mykiss): insights from an in vitro digestion model

Tire and Road Wear Particles (TRWP) account for an important part of the anthropogenic particles released into the environment. There are scientific knowledge gaps as to the potential bio accessibility of chemicals associated with TRWP to aquatic organisms. This study aimed to investigate the solubilization of five tire-associated chemicals into fish gut using an in vitro digestion model (Oncorhynchus mykiss). Our results show that the targeted compounds were partly and rapidly solubilized into simulated fluids (SF) present in the gastrointestinal tract within a typical gut transit time for fish (3h in SFGASTRIC and 24h in SFINTESTINAL). The effects of food co-ingestion on the solubilization of tire-associated chemicals was compound-specific and either lowered or stimulated their solubilization into the gut fluids. Therefore, the uptake of the tire associated chemicals by the epithelial cells and related toxicity to fish need to be investigated

Toxicity of 2 pg ethynylestradiol in brown trout embryos (Salmo trutta)

Endocrine disrupting chemicals are a threat to natural fish populations in the aquatic environment. Their toxicity is usually discussed relative to concentrations in the water the fish are exposed to. In the case of the synthetic compound 17-alpha-ethynylestradiol (EE2), a common and persistent estrogen, concentrations around 1 ng/L have repeatedly been found to induce toxic effects in fish. Here, we used brown trout (Salmo trutta) from a natural population to study EE2 take up and how it affects early life-history. We collected adults during the spawning season, produced 730 families in vitro (to control for potential maternal and paternal effects on embryo stress tolerance), and singly raised 7,300 embryos (in a 2 mL static system) that were either exposed to one dose of EE2 at 1 ng/L (i.e., 2 pg/embryo) or sham-treated. We found that EE2 concentration did not significantly change over a period of 3 months in control containers without embryos. Embryos took up most of the 2 pg EE2 within about 4 weeks at 4.6°C. EE2 treated embryos experienced higher mortality, delayed hatching of the survivors, and had reduced size at hatching. Our findings suggest that the toxicity of EE2 is often underestimated when discussed at the level of concentrations in water only

Simultaneous multi-residue pesticide analysis in soil samples with ultra-high-performance liquid chromatography-tandem mass spectrometry using QuEChERS and pressurised liquid extraction methods

To assess soil contamination, it is important to be able to measure different classes of pesticides simultaneously. For this reason we developed a sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry method for the simultaneous analysis of 25 pesticides in soil samples. Multi-class pesticides (triazines, phenylureas, phenoxy acid pesticides etc.) were analysed using a single mass spectrometry method with a fast polarity switching option, allowing the analysis of 19 compounds in the positive ionisation mode and six compounds in the negative ionisation mode. Extraction of pesticides from soil samples was performed employing a pressurised liquid extraction (PLE) and a quick, easy, cheap, effective, rugged and safe (QuEChERS) procedure, recently developed for the extraction of multi-residue pesticides from food matrices. The extraction efficiency, performance and recoveries of these two procedures were evaluated and compared. In addition, we studied the effect of matrix on signal suppression or enhancement. Isotope-labelled internal standards (ILIS) were used to compensate the suppression or enhancement of signal intensities in the extracted samples. The method was validated using reference soil material (EUROSOIL 7) spiked with 50 mu g/kg of each pesticide. The average recovery by PLE varied between 65.1% and 122.2% with RSDs of 1.7-23.4%. QuEChERS provided better recoveries for most of the pesticides, the extraction recovery ranging from 79.4% to 113.3% with RSDs of 1.0-12.2%. Limits of quantification for all target compounds were within a range of 0.1-2.9 mu g/kg

Integrative sampling properties of Empore SDB-disks - using desorption of polar organic compounds from PDMS to assess effects of environmental factors on passive sampling

Empore SDB disks have been used as a receiving phase in passive samplers for polar organic compounds. However, there is uncertainty with respect to the duration of integrative sampling of SDB disks. Thus, using chemicals with an octanol water partitioning coefficient (logKow) between 0 and 4, we explored the duration of integrative sampling in short (one week) and long-term experiments (four weeks). Trials were conducted in a channel system (450 L) that receives a constant input of ambient river water at 20 L/h. Water in the channel system was dosed continuously with a cocktail of chemicals (mainly pesticides and pharmaceuticals) to reach aqueous concentrations of 1000 ng/L. At the start of a trial, the channels were filled with 20 SDB disks. During the trials, water was sampled frequently and disks were removed at intervals and extracted. Using LC/MS/MS, spiked compounds were analysed in SDB extracts and in water samples. Sampling time was plotted against concentrations in SDB disks to determine the duration of integrative sampling. Passive sampling of polar compounds with SDB disks is dependent of environmental factors such as the water flow rate. Unfortunately, this dependency cannot simply be corrected for by using the established performance reference compound (PRC) technique: adsorption and desorption are not isokinetic for SDB. For these reasons we explored the possibilities of a surrogate system to adjust passive sampling data for environmental effects: PDMS disks spiked with PRCs in tandem with SDB disks as the sampling phase. First, we established the diffusion parameters and the desorption kinetics of a cocktail of chemicals from PDMS. Second, we used the channels to assess the effect of flow on sampling by SDB disks in tandem with desorption from PDMS disks

Comparison of yeast estrogen screening on HPTLC and in microtiter plates

In contrast to testing whole mixtures in microtiter plates, separation on HPTLC plates with subsequent bioassay detection has the potential to reveal multiple toxic chemicals and help identify responsible entities. The planar-YES gas been used to screen various samples on HPTLC plates, but there has been little to no comparison to teh official method. Herein, the p-YES and the microtiter YES were compared in their sensitivity to screen for endocrine active compounds related to food packaging materials