Low Pollutant Concentrations Research Articles

Chemically Treated Chicken Bone Waste as an Efficient Adsorbent for Removal of Acetaminophen

Present of pharmaceutical as the emerging pollutants arise the concerns of environment community regarding the potential impact of acetaminophen (ACT) on ecological and human health. Adsorption process has been proven as an effective treatment being activated carbon as the adsorbent to remove many types of pollutant including low concentration of pollutants. However, on large scale industrial processes, utilisation of activated carbon is limited because of their high production cost. Synthesis of waste materials as a precursor of adsorbent is an attractive approach in sustainable management and economic availability. In this study, the removal of ACT from aqueous solution by chemically treated chicken bone (AC) waste was investigated. The adsorption process was conducted in a batch adsorption and affected by several experimental parameters including contact time, pH, adsorbent dose, initial concentration and temperature. With AC dosage of 0.1 g about 93 % of 1,000 mg/L ACT was removed from the aqueous solution that had pH of 2 and temperature of 25 °C. Kinetic of ACT adsorption was well described by pseudo-second order kinetic model. Meanwhile, effect of initial concentration of acetaminophen adsorption data was fitted well with Freundlich isotherm model with an R2 of 0.9909. Finally, the data obtained from effect of temperature was used to determine the adsorption thermodynamic including the enthalpy, ΔH, Gibbs energy, ΔG and entropy, ΔS. It was found that the ΔG was negative at all temperature while both, ΔH and ΔS was also negative between temperatures of 25 °C to 70 °C indicating the process of ACT adsorption was exothermic reaction and the adsorption reaction is spontaneous at low temperature.

Kinetics of the pollutant photocatalytic conversion in a Photo-CREC-Air Reactor

This research reports the kinetic studies for acetone and acetaldehyde photoconversion in the gas phase utilizing a scaled-up Photo-CREC-Air unit with TiO2. The inclusion of intermediate species in the reaction network is required for the kinetic modeling of a wide range of oxygenate pollutant concentrations. The proposed “in parallel-series” reaction network encompasses a Langmuir-Hinshelwood (L-H) kinetics including species adsorption and intrinsic reaction parameters. The estimated kinetic parameters provide a successful prediction of various measurable chemical species. It is shown that the proposed kinetic model can be simplified, under low initial model pollutant concentrations. This is critical to avoid model overparameterization. The proposed kinetic model while being restricted to two model pollutants (acetone and acetaldehyde) and one specific photoreactor (e.g. 55.1L Photo-CREC-Air), provides a framework to establish the photodegradation kinetics of other organic species in air, for larger photoreactor scales.

Photodegradation and sorption govern tetracycline removal during wastewater treatment in algal ponds

The degradation of the antibiotic tetracycline, supplied at 100µgL−1 in domestic wastewater, was studied in an outdoor, pilot scale, high rate algal pond (HRAP). Effective operation was demonstrated with the biomass concentration and the chemical oxygen demand removal efficiency averaging 1.2±0.1gTSSL−1 and 80±4%, respectively, across all operational periods. Tetracycline removal exceeded 93% and 99% when the HRAP was operated at hydraulic retention times of 4 and 7days, respectively. Batch tests and pulse testing during HRAP operation repeatedly evidenced the significance of photodegradation as a removal mechanism. Sorption dominated tetracycline removal during the night, but accounted for less than 6% of the total pollutant removal based on sorbed tetracycline extracted from biomass. Overall, these results provide the first demonstration of efficient antibiotic removal, occurring mainly via indirect photodegradation, during relevant HRAP operation (low pollutant concentration, domestic wastewater and natural sunlight).

Effect of residence time on micropollutant removal in WWTP secondary effluents by continuous solar photo-Fenton process in raceway pond reactors

The removal of micropollutants (MPs) in wastewater treatment plants (WWTPs) secondary effluents by solar photo-Fenton is commonly carried out with low concentrations of iron and hydrogen peroxide due to the low pollutant concentration (ngL−1). This led to two main consequences being observed: short treatment times (tens of minutes) and excess of photons when using 5cm-diameter tubular reactors. To make better use of most of the photons reaching the reactor surface, the use of raceway pond reactors (RPRs) with longer light path length was implemented successfully. However, little attention was paid to the treatment time itself and the photo-Fenton process was applied in batch mode despite filling and emptying stages being much longer than reaction time. This paper deals with the performance of the solar photo-Fenton process in RPRs operated in continuous mode to remove MPs in WWTP secondary effluents. In this regard, first the continuous degradation of a model emerging contaminant, the pesticide Acetamiprid (ACTM), was studied in a synthetic secondary effluent at pH 2.8. Next, real secondary effluents were treated at two liquid depths, 5 and 15cm and three hydraulic residence times (HRTs), 80, 40 and 20min. Reactant concentrations were 5.5mgL−1 Fe2+ and 30mgL−1 H2O2 giving rise to a treated wastewater volume of 450Lm−2day−1 for a 5cm-deep RPR operated in continuous mode at 40min HRT for 6h a day in winter, with 84% MP removal and 66% hydrogen peroxide conversion. As far as the authors know, this is the first report on the solar photo-Fenton process operated in continuous mode displaying its advantages with regard to the batch operation.

Projection of North Atlantic Oscillation and its effect on tracer transport

Abstract. The North Atlantic Oscillation (NAO) plays an important role in the climate variability of the Northern Hemisphere, with significant consequences on long-range pollutant transport. We investigate the evolution of pollutant transport in the 21st century influenced by the NAO under a global climate change scenario. We use a free-running simulation performed by the ECHAM/MESSy Atmospheric Chemistry (EMAC) model coupled with the ocean general circulation model MPIOM, covering the period from 1950 until 2100. Similarly to other works, the model shows a future northeastward shift of the NAO centres of action and a weak positive trend of the NAO index (over 150 years). Moreover, we find that NAO trends (computed over periods shorter than 30 years) will continue to oscillate between positive and negative values in the future. To investigate the NAO effects on transport we consider carbon monoxide tracers with exponential decay and constant interannual emissions. We find that at the end of the century, the south-western Mediterranean and northern Africa will, during positive NAO phases, see higher pollutant concentrations with respect to the past, while a wider part of northern Europe will, during positive NAO phases, see lower pollutant concentrations. Such results are confirmed by the changes observed in the future for tracer concentration and vertically integrated tracer transport, differentiating the cases of “high NAO” and “low NAO” events.

The potential of microalgal biomass production for biotechnological purposes using wastewater resources

The utilization of microalgae for wastewater treatment represents an attractive opportunity for wastewater valorization through the use of the produced biomass. Five strains of microalgae were isolated from municipal wastewater and grown in autoclaved and non-autoclaved effluent at 30 °C and 150 μmol photons m−2 s−1 to study biomass production, nutrient removal, and the biochemical composition of the biomass. All strains reached high biomass productivity (35.6 to 54.2 mg dry weight L−1 day−1) within 4 days of batch culturing. In this period, ammonium-N and phosphate were reduced by more than 60 and 90 %, respectively. The high growth rate (0.57 to 1.06 day−1) ensured a rapid removal of nutrients and thereby a short retention time. By the fourth day of cultivation, the algal biomass contained 32 % protein, but only 11 % lipids and 18 % carbohydrates. It was found that the biomass was a suitable raw material for biogas production by anaerobic digestion. Biodigestion of obtained biomass was simulated by employing the Aspen HYSYS modeling software, resulting in methane yields comparable to those found in the literature. The elemental analysis of the algal biomass showed very low concentrations of pollutants, demonstrating the potential of use of the digestate from biodigestion as a bio-fertilizer.

Exposure to low ambient concentrations of criteria air pollutants in Ontario, Canada, and the incidence of acute myocardial infraction and congestive heart failure, 1996-2012

Exposure to low ambient concentrations of criteria air pollutants in Ontario, Canada, and the incidence of acute myocardial infraction and congestive heart failure, 1996-2012

Development of Land Use Regression Models for Predicting Exposure to Particulate Matters and Nitrogen Oxides in an Area with Low Air Pollutant Concentrations

Introduction: Perth, Western Australia represents an area where pollutant concentrations are considered low compared with international locations. Land Use Regression (LUR) models were developed to...

Development of Land Use Regression models for particulate matter and associated components in a low air pollutant concentration airshed

Perth, Western Australia represents an area where pollutant concentrations are considered low compared with international locations. Land Use Regression (LUR) models for PM10, PM2.5 and PM2.5 Absorbance (PM2.5Abs) along with their elemental components: Fe, K, Mn, V, S, Zn and Si were developed for the Perth Metropolitan area in order to estimate air pollutant concentrations across Perth. The most important predictor for PM10 was green spaces. Heavy vehicle traffic load was found to be the strongest predictor for PM2.5Abs. Traffic variables were observed to be the important contributors for PM10 and PM2.5 elements in Perth, except for PM2.5 V which had distance to coast as the predominant predictor. Open green spaces explained more of the variability in the PM10 elements than for PM2.5 elements, and population density was more important for PM2.5 elements than for PM10 elements. The PM2.5 and PM2.5Abs LUR models explained 67% and 82% of the variance, respectively, but the PM10 model only explained 35% of the variance. The PM2.5 models for Mn, V, and Zn explained between 70% and 90% of the variability in concentrations. PM10 V, Si, K, S and Fe models explained between 53% and 71% of the variability in respective concentrations. Testing the models using leave one-out cross validation, hold out validation and cross-hold out validation supported the validity of LUR models for PM10, PM2.5 and PM2.5Abs and their corresponding elements in Metropolitan Perth despite the relatively low concentrations.

Changes in catalase activity in leaves of woody and bushy plants in the conditions of air pollution by compounds of fluorine, sulfur and nitrogen

Recently environmental pollution by industrial waste products has become a significant environmental factor that essentially limits the vital functions of plants and reduces their species diversity. The antioxidant system is of special importance for tolerance reactions of plants to stressful environmental conditions, in particular, contamination by industrial pollutants. One of the constituents of this system is oxidoreductase, including catalase. Consequently, we have conducted experiments to determine how the nature of the complex compounds of fluorine, nitrogen and sulfur influences catalase activity in leaves of selected species of trees and shrubs. The investigation was made according to the complete factorial experiment that allowed us to study the effect of these pollutants both individually and in combination. We used the iodometric method to determine the level of catalase activity. Statistical analysis of the obtained results was performed by means of dispersion analysis with the comparison according to the Duncan method. The results of the research showed the possible impact of pollutants on the activity of catalase, which depends on the resilience of the plants, structure and duration of potency of the pollutants. With less resilient plant species (Sorbus aucuparia L., Fraxinus lanceolata Borkh.) air pollution with a combination of fluorine, sulfur and nitrogen in most cases caused a reduction of catalase activity. Thus, in S. aucuparia a 5-hour exposure to low concentrations of pollutants (HF – 0.2 ml/m3, NH3 – 1.2 ml/m3, SO2 and H2SO4 – 0.9–1.0 ml/m3) caused an inhibition of catalase activity by 40.5%, and a ten-hour exposure caused a 61.4% inhibition compared with the control plants. With increased concentrations of pollutants catalase function was inhibited by 35.8–73.6%, depending on the duration of their fumigation. For F. lanceolata, the pollutants’ effect on catalase activity caused a decrease in function of this enzyme by 20–77% compared with non-fumigated plants. In contrast to the less resilient plants, the species resilient against pollution (Ligustrum vulgare L., Quercus robur Sol., Lonicera tatarica L., Eleagnus angustifolia L., Philadelphus coronaria L.) were characterized by absence of possible changes in catalase activity caused by fumigation or by increase in catalase by 11–118%. A significant increase of catalase functions in these species mostly occurs because of the short-term effect (5 hours) of pollutants. In the absence of damage, the enzyme activity of species of variable resilience (Aesculus hippocastanum L., Acer negundo L., Populus simonii Carriere) remained at the level of the control plants. The gas mixture that damages leaves (necrosis) caused catalase functions to decrease by 11–80% compared with the control plants. Therefore, we can state that in the absence of visible damage to plants' enzyme activity either remained unchanged or increased compared with the control plants. Formation of necrosis caused a decrease in catalase functions. The patterns of changes in catalase activity we have identified allow us to conclude that this enzyme plays a significant role in liquidation of damage caused by air pollutants.

Marine pollution risk in a coastal city: use of an eco-genotoxic tool as a stress indicator in mussels from the Eastern Aegean Sea.

Coastal areas, such as bays, estuaries, and harbors, are heavily polluted since these areas are the settlements to which toxic chemicals from industrial and domestic wastes are discharged. The genetic damage was evaluated using bioindicator mussel Mytilus galloprovincialis caused by toxic chemicals (metals and polycyclic aromatic hydrocarbons) in İzmir and Çandarlı Bays (the Eastern Aegean Sea) through comet assay. Three sampling sites from the two bays were selected and the study was conducted during the spring and autumn periods. The highest levels of DNA damage expressed as %Tail-DNA were observed in İzmir Bay (34.60% Tail-DNA) in the spring. Analysis of the correlation between PAHs and metals in mussels and %T-DNA in the hemolymph and gill cells showed a statistically significant positive correlation between %T-DNA and ∑PAH, chromium (p < 0.05). This study determined the pollution level of the İzmir and Çandarlı Bays by using the DNA damage to the mussel, which can identify the effects of environmental pollutants at the cellular levels. These results confirm that comet assay can be used to determine the temporal and spatial differences of DNA damage, and as a suitable tool for the measurement of genotoxicity in regions with low pollutant concentrations.

The effects of air mass transport, seasonality, and meteorology on pollutant levels at the Iskrba regional background station (1996–2014)

Our main goal was to estimate the effects of long-range air transport on pollutant concentrations measured at the Iskrba regional background station (Slovenia). We cluster back-trajectories into categories and simultaneously model the effects of meteorology, seasonality, trends, and air mass trajectory clusters using a Bayesian statistical approach. This simplifies the interpretation of results and allows us to better identify the effects of individual variables, which is important, because pollutant concentrations, meteorology, and trajectories are seasonal and correlated. Similar to related work from other European sites, we find that slow and faster moving trajectories from eastern Europe and the northern part of the Balkan peninsula are associated with higher pollutant levels, while fast-moving trajectories from the Atlantic are associated with lower pollutant concentration. Overall, pollutant concentrations have decreased in the studied period.

Spatiotemporal patterns of particulate matter (PM) and associations between PM and mortality in Shenzhen, China.

BackgroundMost studies on air pollution exposure and its associations with human health in China have focused on the heavily polluted industrial areas and/or mega-cities, and studies on cities with comparatively low air pollutant concentrations are still rare. Only a few studies have attempted to analyse particulate matter (PM) for the vibrant economic centre Shenzhen in the Pearl River Delta. So far no systematic investigation of PM spatiotemporal patterns in Shenzhen has been undertaken and the understanding of pollution exposure in urban agglomerations with comparatively low pollution is still limited.MethodsWe analyze daily and hourly particulate matter concentrations and all-cause mortality during 2013 in Shenzhen, China. Temporal patterns of PM (PM2.5 and PM10) with aerodynamic diameters of 2.5 (10) μm or less (or less (including particles with a diameter that equals to 2.5 (10) μm) are studied, along with the ratio of PM2.5 to PM10. Spatial distributions of PM10 and PM2.5 are addressed and associations of PM10 or PM2.5 and all-cause mortality are analyzed.ResultsAnnual average PM10 and PM2.5 concentrations were 61.3 and 39.6 μg/m3 in 2013. PM2.5 failed to meet the Class 2 annual limit of the National Ambient Air Quality Standard. PM2.5 was the primary air pollutant, with 8.8 % of days having heavy PM2.5 pollution. The daily PM2.5/PM10 ratios were high. Hourly PM2.5 concentrations in the tourist area were lower than downtown throughout the day. PM10 and PM2.5 concentrations were higher in western parts of Shenzhen than in eastern parts. Excess risks in the number of all-cause mortality with a 10 μg/m3 increase of PM were 0.61 % (95 % confidence interval [CI]: 0.50–0.72) for PM10, and 0.69 % (95 % CI: 0.55–0.83) for PM2.5, respectively. The greatest ERs of PM10 and PM2.5 were in 2-day cumulative measures for the all-cause mortality, 2-day lag for females and the young (0–65 years), and L02 for males and the elder (>65 years). PM2.5 had higher risks on all-cause mortality than PM10. Effects of high PM pollution on mortality were stronger in the elder and male.ConclusionsOur findings provide additional relevant information on air quality monitoring and associations of PM and human health, valuable data for further scientific research in Shenzhen and for the on-going discourse on improving environmental policies.

Synthesis of three-dimensional carbon felt supported TiO2 monoliths for photocatalytic degradation of methyl orange

Three-dimensional carbon felt supported TiO2 (TiO2@CF) monoliths were synthesized via a solvothermal process. The structural properties of TiO2@CF were characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, N2 adsorption–desorption, Raman and contact angle tests. The as-prepared TiO2@CF monoliths exhibited a large surface area, hydrophilic surface as well as a well-defined three dimensional structure. Using methyl orange as a model pollutant, the photocatalytic activity of TiO2@CF monolith was studied. The effects of substrate concentrations, pHs of pollutant solutions and H2O2 concentrations in the degradation of methyl orange were examined. It was revealed that a low pollutant concentration, adequate H2O2 concentration and acidic environment facilitated the degradation of methyl orange. To explore the mechanism, controlled experiments were conducted by adding three scavengers including isopropanol, p-benzoquinone and ethylenediaminetetraacetic acid disodium salt. Mechanistic studies suggested that in the presence of H2O2, hydroxyl radicals played a dominant role in the degradation of methyl orange while the photo-induced holes were mainly responsible in the absence of H2O2. The TiO2@CF monolith catalysts could be easily regenerated via combustion and showed excellent recyclability.

Chemical simulation of greywater

ABSTRACTSustainable water resources management attracts considerable attention in today's world. Recycling and reuse of both wastewater and greywater are becoming more attractive. The strategy is to protect ecosystem services by balancing the withdrawal of water and the disposal of wastewater. In the present study, a timely and novel synthetic greywater composition has been proposed with respect to the composition of heavy metals, nutrients and organic matter. The change in water quality of the synthetic greywater due to increasing storage time was monitored to evaluate the stability of the proposed chemical formula. The new greywater is prepared artificially using analytical-grade chemicals to simulate either low (LC) or high (HC) pollutant concentrations. The characteristics of the synthetic greywater were tested (just before starting the experiment, after two days and a week of storage under real weather conditions) and compared to those reported for real greywater. Test results for both synthetic greywater types showed great similarities with the physiochemical properties of published findings concerning real greywater. Furthermore, the synthetic greywater is relatively stable in terms of its characteristics for different storage periods. However, there was a significant (p < .05) reduction in 5-day biochemical oxygen demand (BOD5) for both low (LC) and high (HC) concentrations of greywater after two days of storage with reductions of 62% and 55%, respectively. A significant (p < .05) change was also noted for the reduction (70%) of nitrate–nitrogen (NO3–N) concerning HC greywater after seven days of storage.

Adsorption and Desorption of Emerging Water Contaminants on Activated Carbon Fabrics

Nowadays, a wide variety of organic contaminants are present at trace concentrations in wastewater effluents. In order to face these pollution problems, the implementation of the REACH European regulation has defined lists of targeted pollutants to be eliminated selectively in water. It therefore implies the development of innovative and more efficient remediation techniques. In this sense, adsorption processes can be successfully used to achieve the removal of organic compounds in waste water treatment processes, especially at low pollutant concentration. Especially, activated carbons possessing a highly developed porosity demonstrate high adsorption capacities. More specifically, carbon cloths show high adsorption rates, an easily handling, a good mechanical integrity and regeneration potentialities. When loaded with pollutants, these materials can be indeed regenerated using an electrochemical polarization.

Characterisation of suspended particulate matter in the Rhone River: insights into analogue selection

Environmental contextThe fate and behaviour of pollutants such as pesticides, metals and nanoparticles in natural waters will influence their effects on the environment and human health. Owing to the complexity of natural waters and suspended particulate matter (SPM) that can interact with pollutants, as well as low pollutant concentrations, determination of pollutant fate and transport is non-trivial. Herein, we report a characterisation of the Rhone River chemistry to provide insight into selecting SPM analogues for experimental and modelling approaches. AbstractSelection of realistic suspended particulate matter (SPM) analogues remains vital for realising representative experimental and modelling approaches in predicting the environmental fate of pollutants. Here, we present the characterisation of dissolved-ion and SPM compositions for nine sampling sites over the length of the Rhone River. Dissolved-ion concentrations remained stable, but SPM concentrations varied among sampling sites. Size fractionation and mineralogical characterisation of the SPM revealed that the same minerals (e.g. quartz, calcite, muscovite) constituted every size class from 0.5 to &gt;50µm, as is usually found with allochthonous and large-scale systems. To gain insight into SPM analogue selection, aggregation kinetics of silica, calcite, muscovite, feldspars and clays were monitored in the native filtrate and related to the respective zeta potentials (ζ). An SPM mixture of calcite (49%), muscovite (14%), feldspar (23%) and chlorite (14%) proved the best match for the Rhone SPM, demonstrating that mineral surface chemistry, structure and size are all important in selecting a realistic SPM analogue for a riverine system.

Chemical Sensor for Haemodialysis Application

The water used to supply a haemodialysis center requires particular mode of treatment in order to achieve the best technical, economic and therapeutic distribution. Dialysis patients come in contact weekly with a large amount of water through the dialysis apparatus. It is therefore essential that this solution has a high quality and purity in terms of proper electrolyte composition, low concentration or absence of organic and inorganic chemical pollutants, low concentration or absence of bacteria, yeasts, fungi and endotoxins. The chemical and microbiological quality of water intended for medical and biomedical treatments, such as haemodialysis, is generally defined on the basis of a plurality of international reference standards (ASTM International standards D1193 and D5196; International Pharmacopoeia and European Pharmacopoeia CAP / NCCLS 1988). In this work the authors have designed an electrochemical device used to characterize pure and ultrapure water for biomedical applications (Patent: TO2014A000765). The results obtained show a good ability of the device in the discrimination of different bacteria and of their concentration (CFU); Pseudomonas and E-coli have been here tested.

Evaluation of Genotoxic Potential of Waters from Two Italian Rivers in Gammarus elvirae (Amphipoda).

The aim of the present work is to evaluate the genotoxic impact of contaminants along the whole course of Ninfa-Sisto and Amaseno (Latium, Italy) rivers. The authors performed the alkaline Comet assay to assess DNA damage in the freshwater amphipod Gammarus elvirae, exposed ex situ for 24 hours and 7 days to water collected at different sites. The assay, applied on haemocytes, provides a sensitive tool to reveal effects even at low concentrations of pollutants. The results indicate significant increase of DNA damage along the course of the two rivers, compared to the unpolluted upstream sites, even if the analytes do not exceed the permissible limits. Moreover, the results show that there is not a linear correlation between the concentration of analytes and DNA damage. Based on this study's results, it would be desirable to use Comet assay, on proposed test species, as an early warning method to detect genotoxic potential of waters.

Aerobic capacity and hematological response to exercise: A study on school-going regularly exercising boys in two different air pollution zones

Background/ObjectiveThe purpose of this study was to evaluate the effects of exercise on aerobic power and hematological profile among trained school-going boys in an environment with similar climatic characteristics but different concentrations of air pollutants. MethodsThis trial comprised 40 school-going trained boys (age range 14–16 years) from West Bengal, India. Two places with similar climatic conditions (altitude, temperature, and humidity), but low and high concentrations of air pollutants were selected. Height and weight of all the participants were measured. Participants underwent a shuttle run test for assessment of aerobic capacity (VO2max) in both areas after a 1-week gap. Venous blood sample was drawn from the cubital vein immediately after completion of the shuttle run test and red blood cell (RBC) count, white blood cell (WBC) count, packed cell volume (PCV), hemoglobin (Hb) concentration, mean corpuscular volume (MCV), and mean corpuscular hemoglobin concentration (MCHC) were determined by standard methods. Measured parameters were compared between the two areas. ResultsCompared with the area having low pollution levels, we obtained significantly lower value in mean VO2max, RBC count, Hb, PCV, and MCHC, but significantly higher value in WBC count and MCV in the area with high pollution levels. Performing exercise in high-polluted air may lead to a significant reduction in the performance level of school-going trained boys. ConclusionThe study findings suggest that air pollution could have negative effects on the hematological profile of boys and longitudinal studies may be carried out for assessing its clinical importance.