The endogenous cannabinoid anandamide increases human airway epithelial cell permeability through an arachidonic acid metabolite

Injury to the bronchial epithelium in respiratory diseases such as asthma and COPD results in the lossof barrier function and an elevated sensitivity to environmental insults. An increased release of theendogenous cannabinoid, anandamide in response to inhalation of allergen in asthmatic patients hasbeen reported. The aim of this study was, therefore, to determine the effects of endocannabinoids onbronchial epithelial cell permeability and to investigate the mechanisms involved.Calu-3 human bronchial epithelial cells were cultured at air–liquid interface to allow developmentof tight junctions. Changes in Transepithelial Electrical Resistance (TEER), a reflection of epithelial per-meability, were measured at various time points post-treatment, and expression of the tight junctionproteins, occludin and ZO-1, were determined using Western immunoblotting.Anandamide produced a significant reduction in TEER, which was unaffected by cannabinoid receptorantagonists, but attenuated by URB597, an inhibitor of fatty acid amide hydrolase, and by a combinationof cyclooxygenase (COX) and lipoxygenase (LOX) blockade. The anandamide metabolite, arachidonicacid, showed similar TEER decrease that was also prevented in the presence of COX and LOX inhibitor.Expression of occludin and ZO-1 were also reduced by anandamide.These findings indicate a pro-inflammatory-like effect of anandamide on bronchial epithelial per-meability, mediated by cyclooxygenase and lipoxygenase metabolites, and suggest that inhibition ofanandamide degradation might provide a novel approach to treat airway inflammation

Scintillator ageing of the T2K near detectors from 2010 to 2021

The T2K experiment widely uses plastic scintillator as a target for neutrino interactions and an active medium for the measurement of charged particles produced in neutrino interactions at its near detector complex. Over 10 years of operation the measured light yield recorded by the scintillator based subsystems has been observed to degrade by 0.9–2.2% per year. Extrapolation of the degradation rate through to 2040 indicates the recorded light yield should remain above the lower threshold used by the current reconstruction algorithms for all subsystems. This will allow the near detectors to continue contributing to important physics measurements during the T2K-II and Hyper-Kamiokande eras. Additionally, work to disentangle the degradation of the plastic scintillator and wavelength shifting fibres shows that the reduction in light yield can be attributed to the ageing of the plastic scintillator. The long component of the attenuation length of the wavelength shifting fibres was observed to degrade by 1.3–5.4% per year, while the short component of the attenuation length did not show any conclusive degradation

Rehabilitating mine tailings water using constructed wetlands

Outukumpu Zinc-Tara Mines Ireland, located approximately 50 km north of Dublin, is Europe's largest producer of lead and zinc ores. Water used during extraction and purification of these ores is enriched with sulfate and heavy metals. Presently, this water together with suspended tailings, is pumped from the mine and stored in a large tailings settling pond. Two experimental artificial wetlands were built beside this settling pond to treat seepage. The primary strategy employed for treatment of the water is the reduction of sulfate to sulfide. The wetlands are maintained anaerobic to provide optimum conditions conducive to reduction reactions. This process is mediated by sulfate reducing bacteria, which are indigenous in the bedding substrate (spent mushroom compost) used. The alkaline nature of the mine tailings water (due to the strong buffering capacity of the prevailing limestone geology) facilitates the subsequent precipitation of metal sulfide complexes which form following reduction of sulfate. The constructed wetlands have been in operation for two years but have exhibited consistent removal of sulfate from water. Recent results suggest that algae, having spontaneously invaded the wetland ecosystems, also play a substantial role in the removal of heavy metals from the tailings water. To-date, this decontamination approach is showing to be efficacious and cost-effective

Constructed Wetlands for Treating Processed Mine Water - an Irish Case Study

Mine wastewater is characteristically elevated in metals and sulfate and conventionally treated with costly chemical applications. The development of passive treatment systems, employing both biotic and abiotic processes, has been recognized as an economically feasible, ecologically acceptable technology in the last decade. However, to-date most of these passive systems have been applied to abandoned mine waters for the primary purpose of increasing pH and removing metals. Two experimental-scale treatment wetlands were constructed and monitored at an active lead/zinc mine (Tara Mines) in Ireland, to treat alkaline mine seepage with elevated sulfate (and also metal) levels. Each system comprised three 12 m² (2 m depth) in-series surface-flow cells viz., inflow, vegetated and outflow and contained spent mushroom substrate (SMS). Typical aqueous concentrations of 830 mg L⁻¹ sulfate, 0.15 mg L⁻¹ lead and 2.0 mg L⁻¹ zinc entered the treatment wetlands at a flow rate of c. 650 mL min⁻¹. Anaerobic substrates, in which sulfate-reducing bacteria were indigenous, were conducive to biological reduction of sulfate to sulfide. Sulfide subsequently precipitated with metal cations. Monitoring of these wetlands over a 2-year period showed successful (maximum) removal of sulfate (29 g m⁻² day ⁻¹ (69%)), lead (6.6 mg m⁻² day ⁻¹ (64%)), and zinc (70 mg m⁻² day ⁻¹ (98%)). These contaminants were somewhat associated with the vegetation roots but more significantly so with the substrates. The interacting processes within the wetland ecosystems responsible for decontamination of the wastewater are currently being elucidated and quantified using a systems dynamic model. The communities of colonizing macroinvertebrates, macrophytes, algae and microorganisms also contributed to development of diverse ecosystems and a successful alternative treatment process

Constructed wetlands for treatment of mine tailings at Tara Mines, Ireland

Natural and constructed wetlands can filter pollutants from water. Recently this property has been exploited in utilising wetlands for passive water treatment. Using relatively concentrated waste, wetlands have been shown to be effective in retaining in excess of 90% metals (MAY et al. 1993) and over 70% sulphate (WINTER & KICKUTH 1989). This approach to water quality improvement is more favourable than traditional treatment methods requiring intensive chemical and labour inputs. Experimental wetlands have been constructed on site at Tara Mines, County Meath, Ireland to facilitate a research project investi- gating the capacity of filter systems in retaining sulphate and metals from mine tailings water. It is expected that such systems, based on natural processes, will be efficient yet require little maintenance and will, therefore, be economically attractive

Ecological development of constructed wetlands built for treating mine tailings water at Tara Mines, Ireland

Mine associated wastewater is characteristically elevated in metals and other contaminants and has been conventionally treated with costly chemical applications. The development of passive treatment systems such as wetlands, which employ both biotic and abiotic processes, has been recognized as an economically feasible, ecologically acceptable treatment technology in the last decade. Not only can constructed wetlands provide an efficient facility for treating wastewater, they can also offer ancillary benefits such as ecological niches and therefore be of educational and often recreational value to society as well. Two experimental-scale treatment wetlands were constructed at an active lead/zinc mine near Navan, Ireland in 1997 to treat water enriched with sulfate and metals. Each system comprised three 12 m2 (2 m depth) in-series surface-flow cells viz., inflow, vegetated and outflow. Sulfate-reducing bacteria were indigenous in the anaerobic spent mushroom substrate used, where biological reduction of sulfate to sulfide occurred. Sulfide subsequently precipitated with metals from the water. The treatment efficiency of the wetlands was promising with concentrations of sulfate (up to 29 g m-2 day -1 (69%)), lead (6.6 mg m-2 day -1 (64%)) and zinc (70 mg m-2 day -1 (98%)) successfully removed from the wastewater. The ecological functioning of these constructed wetlands was also demonstrated with food webs, nesting niches and refuge sites afforded by colonizing communities of macroinvertebrates, macrophytes, microorganisms and other visiting wildlife. By 15 months following construction of the treatment wetlands, 30 species of macroinvertebrates were identified in system 1 and 21 species in system 2, while 3 plant species, 3 algae species and 1 moss had also colonized the ecosystems. Sulfate reducing bacteria genera included Desulfotomaculum, Desulfovibrio, Desulfococcus and Desulfobulbus. Annual dieback of planted species Typha latifolia and Phragmites australis contributed substantial amounts of biomass to the ecosystems, which led to a renewal of the carbon supply that drove the biologically mediated treatment process. It is speculated that the ecological diversity of the wetlands contributed to their treatment success based on inherent ecosystem complexity

Performance of Mesocosm Sulfate-Reducing Bioreactors for Treating Acid Mine Drainage in New Zealand

Water chemistry was monitored monthly for ten months from an acid mine drainage (AMD) seep emanating at Stockton Coal Mine within the Mangatini watershed in New Zealand. Metal concentrations of the seep water were Fe (4.31-146 mg/L), Al (7.43-76.7 mg/L), Cu (0.0201-0.0669 mg/L), Ni (0.0629-0.261 mg/L), Zn (0.380-1.39 mg/L), Cd (0.000540-0.00134 mg/L) and Pb (0.0049-0.0056 mg/L), pH was 2.49-3.34 and total acidity (pH 8.3) was 78.5-626 mg/L as CaCO3. Water chemistry signature prompted laboratory mesocosm studies measuring the effectiveness of sulfate-reducing bioreactors (SRBRs) for generating alkalinity and sequestering metals. Alkaline materials utilized in the SRBRs included industrial waste products such as mussel shells, nodulated stack dust (NSD) derived from the cement industry, and limestone. Organic substrate materials included post peel, a by-product from fence post manufacture, Pinus radiata bark and compost. Seven SRBRs comprised of varying substrate mixes received aerated AMD for nearly four months. AMD was sourced from the pond that collected the seep water. The SRBR containing NSD successfully removed all metals, but effluent was caustic with pH>9. Bioreactors consisting of 20-30% mussel shells were most successful at immobilizing metals and generating circumneutral effluent. Systems containing mussel shells sequestered more than 0.8 moles of metals/m3 of substrate/day at stable operating conditions and yielded effluent concentrations (removal efficiencies) of 0.120-3.46 mg/L Fe (96.5-99.8%), 0.0170-0.277 mg/L Al (99.5-99.9%), 99.7->99.9%), 99.7%), 98.3->98.9%) and <0.0001-0.0001 Pb (99.5-<99.7%). The system consisting of limestone as the only alkalinity generating material was less effective (15.4-64.3 mg/L Fe). Results from duplicate systems but different reactor shapes indicated reactor dimensions influence flow characteristics and therefore treatment efficacy