Perfluorooctane sulfonate increases β-oxidation of palmitic acid in chicken liver

Purpose

Perfluorooctane sulfonate (PFOS) belongs to a group of chemicals called perfluoroalkyl acids that have been extensively used in various applications such as stain and oil resistant treatments for fabrics, fire-fighting foams, and insecticides. These chemicals present an environmental and health risk being present in many samples both in wildlife and humans. In this study, we investigate the effect of PFOS on fatty acid ??-oxidation in developing chicken embryos.

Methods

Fertilized chicken eggs were exposed in ovo to PFOS at day?4 of incubation. On day?10, the eggs were dissected and livers were incubated in vitro with ³H-palmitic acid for 2?h. The media were collected, and after clean up, the amount of tritiated water was measured with liquid scintillation counting to determine the rate of palmitic acid ??-oxidation.

Results

PFOS was found to induce fatty acid ??-oxidation at doses starting from a lowest observed effect level (LOEL) of 0.1???g/g egg weight. Maximum induction of 77?% compared to control was seen at 0.3???g/g.

Conclusions

The administered doses in which effects are seen are around and even lower than the levels that can be found in wild populations of birds. General population human levels are a factor of two to three times lower than the LOEL value of this study. The environmental contamination of PFOS therefore presents a possibility of effects in wild populations of birds.     

Comparison of tracer techniques for monitoring sewer losses

Two different experimental techniques employing conservative tracers to determine exfiltration losses in a sewer system are reported. Both techniques compare the in-sewer responses measured along designated indicator and reference sections to assess the level of exfiltration although with different degrees of reliability. The experimental and interpretation errors associated with a pulse dosing technique, in which Rhodamine WT is used as the single tracer, are described. The estimation of exfiltration requires the comparison of indicator and reference peaks which need to be well resolved and reproducible in order to provide realistic results. A more consistent technique involves the continuous dosing of two different tracers with the objective of producing simultaneous downstream peak tracer concentrations. Any errors due to flow variations are eliminated and the longer measurement period allows both peak and background concentrations to be more accurately determined. Rhodamine WT, Li and Br were used in different combinations over the approximately 20 min duration of each continuous dosing experiment and were found to demonstrate conservative behaviours with measured recoveries of 97.6-100.6%, 97.3-101.4% and 108.4-109.2%, respectively. The analytical problems associated with the determination of the different tracers in sewage are described and are shown to be responsible for the reduced accuracy of the results associated with the use of Br. The preferred combination of tracers is Rhodamine WT as the indicator and Li as the reference and these are shown to be capable of estimating sewer losses to an accuracy of +/-1.0% using the continuous dosing approach.     

Investigation of triclosan fate and toxicity in continuous-flow activated sludge systems

The purpose of this research was to study the fate and toxicity of triclosan (TCS) in activated sludge systems and to investigate the role of biodegradation and sorption on its removal. Two continuous-flow activated sludge systems were used; one system was used as a control, while the other received TCS concentrations equal to 0.5 and 2mgl(-1). At the end of the experiment, 1mgl(-1) TCS was added in the control system to investigate TCS behaviour and effects on non-acclimatized biomass. For all concentrations tested, more than 90% of the added TCS was removed during the activated sludge process. Determination of TCS in the dissolved and particulate phase and calculation of its mass flux revealed that TCS was mainly biodegraded. Activated sludge ability to biodegrade TCS depended on biomass acclimatization and resulted in a mean biodegradation of 97%. Experiments with batch and continuous-flow systems revealed that TCS is rapidly sorbed on the suspended solids and afterwards, direct biodegradation of sorbed TCS is performed. Regarding TCS effects on activated sludge process, addition of 0.5mgl(-1) TCS on non-acclimatized biomass initially deteriorated ammonia removal and nitrification capacity. After acclimatization of biomass, nitrification was fully recovered and further increase of TCS to 2mgl(-1) did not affect the performance of activated sludge system. The effect of TCS on organic substrate removal was minor for concentrations up to 2mgl(-1), indicating that heterotrophic microorganisms are less sensitive to TCS than nitrifiers.     

Household hazardous waste disposal to landfill: using LandSim to model leachate migration

Municipal solid waste (MSW) landfill leachate contains a number of aquatic pollutants. A specific MSW stream often referred to as household hazardous waste (HHW) can be considered to contribute a large proportion of these pollutants. This paper describes the use of the LandSim (Landfill Performance Simulation) modelling program to assess the environmental consequences of leachate release from a generic MSW landfill in receipt of co-disposed HHW. Heavy metals and organic pollutants were found to migrate into the zones beneath a model landfill site over a 20,000-year period. Arsenic and chromium were found to exceed European Union and US-EPA drinking water standards at the unsaturated zone/aquifer interface, with levels of mercury and cadmium exceeding minimum reporting values (MRVs). The findings demonstrate the pollution potential arising from HHW disposal with MSW.     

Extreme Nitrogen Oxide and Ozone Concentrations in Athens Atmosphere in Relation to Meteorological Conditions

In the present study, we investigate the variation of NO _x (NO + NO₂) and O₃ concentrations and the relation between the extreme events (episodes) of NO _x and O₃ concentrations and the relevant meteorological conditions in the urban atmosphere of the Athens basin. Hourly data of NO, NO₂ and O₃ concentrations from 10 representative monitoring sites located in the Athens basin were used, covering the 10-year time period from 1994 to 2003. The results of our analysis show that the concentrations of air pollutants differ significantly from one monitoring site to another, due to the location and proximity of each station to the emission sources. For each site, there are also significant differences in NO _x and O₃ concentrations from day to day, as well as from month to month and/or from season to season. The annual and seasonal variations show higher NO values in winter and lower in summer. On the contrary, NO₂ and O₃ values are higher in summer (photochemical production of O₃) and lower in winter. These differences are attributed, to a large extent, to the prevailing synoptic and meteorological conditions, the most important between them being the wind direction and speed as well as the atmospheric pressure. Our analysis of the identified 179 extreme NO _x air pollution events shows that most of them took place under anticyclonic conditions, associated with calm or weak winds (speed <2.5 ms⁻¹) of mostly southern to southwestern directions, as well as with low air temperatures and intense stable surface atmospheric conditions. There exists a significant decreasing tendency in NO _x air pollution episodic events over the 10-year study period, resulting in very few to none events in the period from 2000 to 2003. As far as it concerns the extreme O₃ concentrations, 34 air pollution events were identified, occurring under high air temperatures, variable weak winds and intense solar irradiation. The trends of O₃ concentrations are stronger in suburban sites than in urban ones.     

Economic assessment of inherently safe membrane reactor technology options integrated into IGCC power plants

Pd/alloy-based (Pd/Cu, Pd/Au) membrane reactors embedded into Integrated Gasification Combined Cycle (IGCC) plants (IGCC-MR) enable the storage and/or use of the energy value of H₂ to produce electricity while the CO₂ enriched retentate exit stream becomes particularly suitable for high pressure CO₂ capture-sequestration. There is undoubtedly a lack of operating experience associated with IGCC-MR plants, and therefore, sound process intensification principles/practices should be followed not only to enhance process system performance but also to ensure process safety and economic feasibility of an IGCC-MR plant. Motivated by the above considerations, a comprehensive process economic assessment framework for an inherently safe membrane Pd/alloy-based reactor integrated into an IGCC plant is proposed. In particular, a detailed Net Present Value (NPV) model has been developed to evaluate the economic viability of an IGCC-MR plant where the membrane reactor module design conforms to basic inherent safety principles. Sources of irreducible uncertainty (market, regulatory and technological) are explicitly recognized such as the power plant capacity factor, Pd price, membrane life time and CO₂-taxes due to future regulatory action/policies. The effect of the above uncertainty drivers on the project's/plant's value is studied through Monte Carlo methods resulting in detailed NPV-distribution and process economic outcome profiles. The simulation results derived suggest that in the presence of (operational, economic and regulatory) uncertainties, inherently safe membrane reactor technology options integrated into IGCC plants could become economically viable. In particular, comparatively more attractive NPV distribution profiles are obtained when concrete safety risk-reducing measures are taken into account through pre-investment in process safety (equipment).     

Chromium species behaviour in the activated sludge process

The purpose of this research was to compare trivalent chromium (Cr(III)) and hexavalent chromium (Cr(VI)) removal by activated sludge and to investigate whether Cr(VI) reduction and/or Cr(III) oxidation occurs in a wastewater treatment system. Chromium removal by sludge harvested from sequencing batch reactors, determined by a series of batch experiments, generally followed a Freundlich isotherm model. Almost 90% of Cr(III) was adsorbed on the suspended solids while the rest was precipitated at pH 7.0. On the contrary, removal of Cr(VI) was minor and did not exceed 15% in all experiments under the same conditions. Increase of sludge age reduces Cr(III) removal, possibly because of Cr(III) sorption on slime polymers. Moreover, the decrease of suspended solids concentration and the acclimatization of biomass to Cr(VI) reduced the removal efficiency of Cr(III). Batch experiments showed that Cr(III) cannot be oxidized to Cr(VI) by activated sludge. On the contrary, Cr(VI) reduction is possible and is affected mainly by the initial concentration of organic substrate, which acts as electron donor for Cr(VI) reduction. Initial organic substrate concentration equal to or higher than 1000 mgl(-1) chemical oxygen demand permitted the nearly complete reduction of 5 mgl(-1) Cr(VI) in a 24-h batch experiment. Moreover, higher Cr(VI) reduction rates were obtained with higher Cr(VI) initial concentrations, expressed in mg Cr(VI) g(-1) VSS, while decrease of suspended solids concentration enhanced the specific Cr(VI) reduction rate.     

Arsenic mobility in contaminated lake sediments

An arsenic contaminated lake sediment near a landfill in Maine was used to characterize the geochemistry of arsenic and assess the influence of environmental conditions on its mobility. A kinetic model was developed to simulate the leaching ability of arsenic in lake sediments under different environmental conditions. The HM1D chemical transport model was used to model the column experiments and determine the rates of arsenic mobility from the sediment. Laboratory studies provided the information to construct a conceptual model to demonstrate the mobility of arsenic in the lake sediment. The leaching ability of arsenic in lake sediments greatly depends on the flow conditions of ground water and the geochemistry of the sediments. Large amounts of arsenic were tightly bound to the sediments. The amount of arsenic leaching out of the sediment to the water column was substantially decreased due to iron/arsenic co-precipitation at the water-sediment interface. Overall, it was found that arsenic greatly accumulated at the ground water/lake interface and it formed insoluble precipitates.     

Composition and production rate of medical waste from a small producer in Greece

The objective of this work was to determine the composition and production rate of medical waste from the health care facility of social insurance institute, a small waste producer in Xanthi, Greece. Specifically, produced medical waste from the clinical pathology (medical microbiology) laboratory, the X-ray laboratory and the surgery and injection therapy departments of the health facility was monitored for six working weeks. A total of 240 kg medical solid waste was manually separated and weighed and 330 L of liquid medical waste was measured and classified. The hazardous waste fraction (%w/w) of the medical solid waste was 91.6% for the clinical pathology laboratory, 12.9% for the X-ray laboratory, 24.2% for the surgery departments and 17.6% for the injection therapy department. The infectious waste fraction (%w/w) of the hazardous medical solid waste was 75.6% for the clinical pathology laboratory, 0% for the X-ray laboratory, 100% for the surgery departments and 75.6% for the injection therapy department. The total hazardous medical solid waste production rate was 64 ± 15 g/patient/d for the clinical pathology laboratory, 7.2 ± 1.6 g/patient/d for the X-ray laboratory, 8.3 ± 5.1 g/patient/d for the surgery departments and 24 ± 9 g/patient/d for the injection therapy department. Liquid waste was produced by the clinical pathology laboratory (infectious-and-toxic) and the X-ray laboratory (toxic). The production rate for the clinical pathology laboratory was 0.03 ± 0.003 L/patient/d and for the X-ray laboratory was 0.06 ± 0.006 L/patient/d. Due to the small amount produced, it was suggested that the most suitable management scheme would be to transport the hazardous medical waste, after source-separation, to the Prefectural Hospital of Xanthi to be treated with the hospital waste. Assuming this data is representative of other small medical facilities, medical waste production can be estimated for such facilities distributed around Greece.     

Cadmium levels in Europe: implications for human health

In this study we used the Forum of European Geological Surveys geochemical baseline data to examine the distribution of cadmium (Cd) in Europe, with a particular reference to the international soil and water guideline values. The highest cadmium levels were found to occur in topsoil and to follow closely the distribution of P₂O₅, suggesting that the contamination was from the use of rock phosphate fertilizer in intensive arable agriculture. In terms of human health impacts, food (up to several hundred μg/day) was found as the only major route of exposure to Cd for the non-smoking general population. It appeared that low levels of chronic exposure to Cd resulted in completely different human health impacts than those high levels that had caused the ‘itai–itai’ disease. Some correlations were suggested between cadmium levels and the age-adjusted prostate or breast cancer rates distributed in the European countries under study.