Outflow Concentrations Research Articles

Surfactant-enhanced flushing enhances colloid transport and alters macroporosity in diesel-contaminated soil

Soil contamination by diesel has been often reported as a result of accidental spillage, leakage and inappropriate use. Surfactant-enhanced soil flushing is a common remediation technique for soils contaminated by hydrophobic organic chemicals. In this study, soil flushing with linear alkylbenzene sulfonates (LAS, an anionic surfactant) was conducted for intact columns (15cm in diameter and 12cm in length) of diesel-contaminated farmland purple soil aged for one year in the field. Dynamics of colloid concentration in column outflow during flushing, diesel removal rate and resulting soil macroporosity change by flushing were analyzed. Removal rate of n-alkanes (representing the diesel) varied with the depth of the topsoil in the range of 14%–96% while the n-alkanes present at low concentrations in the subsoil were completely removed by LAS-enhanced flushing. Much higher colloid concentrations and larger colloid sizes were observed during LAS flushing in column outflow compared to water flushing. The X-ray micro-computed tomography analysis of flushed and unflushed soil cores showed that the proportion of fine macropores (30–250μm in diameter) was reduced significantly by LAS flushing treatment. This phenomenon can be attributed to enhanced clogging of fine macropores by colloids which exhibited higher concentration due to better dispersion by LAS. It can be inferred from this study that the application of LAS-enhanced flushing technique in the purple soil region should be cautious regarding the possibility of rapid colloid-associated contaminant transport via preferential pathways in the subsurface and the clogging of water-conducting soil pores.

Removal of selected risk elements from wastewater in a horizontal subsurface flow constructed wetland

AbstractRemoval of Pb, Cd, Cr, Mo, V, Be and Ba from municipal wastewater using a horizontal subsurface flow constructed wetland was studied. The removal efficiencies attained for these elements were 50, 86, 71, 59, −53, 37 and 40%, respectively. The average inflow and outflow Pb concentrations were 1.5 and 0.7 µg/L. Similarly, the inflow and outflow concentrations of 0.14 and 0.02 µg/L were obtained for Cd. Cr inflow and outflow concentrations were 3.7 and 1.1 µg/L, respectively. Concentrations of 0.78 and 0.32 µg/L were measured for Mo. V was washed out from the system. Its average inflow and outflow concentrations were 4.8 and 7.4 µg/L, respectively. Be inflow and outflow concentrations were rather low (1.03 and 0.65 µg/L), however, the concentrations of Ba were significantly higher (189 and 113 µg/L). The main perspective of the constructed wetland is the removal of toxic elements forming insoluble compounds (e.g. CdS) depositing in the wetland bed.

Prospective crossover study for a standardized comparison of the dextrane sulfate whole blood and plasma apheresis system in patients with cardiovascular disease and severe dyslipidemia

Background and aimsThe objective of this study was a standardized comparison of the safety and effectiveness of the Kaneka (Kaneka Corporation, Osaka, Japan) whole blood (Liposorber DL-100) and plasma (Liposorber LA-15) lipoprotein apheresis (LA) system to optimize the individual therapy of patients with cardiovascular disease and severe dyslipidemia. MethodsSix chronic LA patients with a pre-treatment LDL-C < 6 mmol/l in steady state received a total of three treatments with the LA-15 device, followed by three treatments with the DL-100 device or vice versa. To achieve a standardized comparison the treated blood volume for any patient was kept identical for both procedures. Sampling points for total cholesterol, LDL-C, HDL-C, Lp(a), triglyceride, blood count, and bradykinin measurements were adjusted for both techniques. ResultsTotal cholesterol, LDL-C, HDL-C, Lp(a), and triglycerides were reduced by 59.2 ± 6.5%, 79.3 ± 6.9%, 7.1 ± 3.9%, 87.3 ± 3.1%, 22.5 ± 24.2% using the DL-100 system and by 51.4 ± 5.2%, 65.2 ± 3.7%, 2.2 ± 4.9%, 72.7 ± 2.2%, 46.5 ± 9.4% using the LA-15 system, showing that the DL-100 adsorber was significantly more effective for lowering total cholesterol (p = 0.044), LDL-C (p = 0.001), Lp(a) (p = 0.029), while triglycerides were reduced to a higher extent by the plasma system (p = 0.046) in this patient group. The regenerable LA-15 adsorber columns showed a higher removal capacity considering the difference between inflow and outflow concentrations. Bradykinin levels significantly increased up to 145 fold in the outflow lines using the plasma system (p = 0.028), but not systemically. There was no significant bradykinin generation using the whole blood adsorber. ConclusionIn conclusion, the whole blood system was faster and more effective in this LA patient group with pre apheresis LDL-C<6 mmol/l. Whether the regenerable plasma system is more effective in patients with higher LDL-C content should be evaluated in future standardized comparisons.

Hydraulic and transport parameter assessment using column infiltration experiments

Abstract. The quality of statistical calibration of hydraulic and transport soil properties is studied for infiltration experiments in which, over a given period, tracer-contaminated water is injected into an hypothetical column filled with a homogeneous soil. The saturated hydraulic conductivity, the saturated and residual water contents, the Mualem–van Genuchten shape parameters and the longitudinal dispersivity are estimated in a Bayesian framework using the Markov chain Monte Carlo (MCMC) sampler. The impact of the kind of measurement sets (water content, pressure inside the column, cumulative outflow and outlet solute concentration) and that of the solute injection duration is investigated by analyzing the calibrated model parameters and their confidence intervals for different scenarios. The results show that the injection period has a significant effect on the quality of the estimation, in particular, on the posterior uncertainty range of the parameters. All hydraulic and transport parameters of the investigated soil can be well estimated from the experiment using only the outlet concentration and cumulative outflow, which are measured non-intrusively. An improvement of the identifiability of the hydraulic parameters is observed when the pressure data from measurements taken inside the column are also considered in the inversion.

The patterns of knowledge spillovers across technology sectors evidenced in patent citation networks

The innovation literature often argues that major inventions arise through the cumulative synthesis of existing components and principles. An important economic phenomenon associated with this argument is the knowledge spillover. Although increasing attention has been paid to knowledge spillovers as a means to grasp innovation, little is known about its structural characteristics. This study examines the structural patterns of knowledge flow evidenced in patent citations by focusing on two aspects: the reciprocity of citations between technology sectors and the concentration of citing and cited sectors. The results indicate that the knowledge flow tends to be highly reciprocal within pairs of technology sectors instead of having a clear direction and that there are relatively low inflow and outflow concentrations in most sectors, although there are some exceptions. These results suggest that most technological sectors become both a knowledge provider and a knowledge consumer at the same time and they coevolve with reciprocal knowledge exchanges with each other.

Remediation of synthetic greywater in mesocosm—Scale floating treatment wetlands

Two different chemical recipes comprising various pollutants were selected to create high (HC) and low (LC) levels of contaminated synthetic greywaters (SGW). Remediation in macrocosm–scale floating treatment wetlands (FTW) vegetated with Phragmites australis (Cav.) Trin. ex Steud. (common reed) was investigated under natural weather conditions. The presence or absence of vegetation, short or long contact time of treatment, and low or high contamination loads are the main operational variables in the experimental set-up design of the FTW. The focus on removal processes (other than sedimentation) such as the role of macrophytes in phytoremediation was achieved by agitation of the treated outflow before sampling. To assess the impact of interactions between the experimental operational variables on removal performances of FTW, different approaches of statistical analysis were applied. The results revealed that total suspended solids (TSS) and turbidity values dropped significantly (p<0.05) in the presence of vegetation compared with those values from unvegetated wetlands. The presence of vegetation can significantly (p<0.05) improve the biodegradation possibility of greywater by increasing the five-day biochemical oxygen demand (BOD) and decreasing the chemical oxygen demand (COD) concentrations. In vegetated FTW, higher removal rates of COD can be achieved when treating HC-SGS compared to LC-SGW. However, no significant differences (p>0.05) in the removal of BOD was noted. Significant increases (p<0.05) in BOD concentrations have been recorded with increasing contact time of treatment, while high removals of COD have been recorded. The presence of vegetation in wetlands affected significantly (p<0.05) the decrease of dissolved oxygen (DO) concentrations in outflow of both types of greywater. If limited sources of organic matter are available, vegetation has significantly (p<0.05) enhanced the nutrient balance with increasing nitrate-nitrogen (NO3-N) and decreasing ortho-phosphate-phosphorus (PO4-P) concentrations in the outflow. Furthermore, significant increases (p<0.05) in ammonia-nitrogen (NH4-N) and DO were observed with increasing contact time, while TSS, turbidity, and NO3-N concentrations significantly decreased (p<0.05). In addition, yellow leaves and considerably lower growth rates were observed for the hydroponic plant rhizomes of P. australis, which might be an effect of light-induced fluorescein degradation due to the relatively open water surfaces of the wetlands.

Mitigation of Wastewater-Borne Chlorpyrifos in Constructed Wetlands: the Role of Vegetation on Partitioning

Constructed wetlands (CWs) are regarded as a risk mitigation strategy for alleviating the risks associated with agricultural runoff that contains pesticides. We investigated the partitioning pattern of wastewater-borne chlorpyrifos, a widely used organophosphorus pesticide, in non-vegetated and vegetated CWs. Removal rates of chlorpyrifos calculated from inflow and outflow concentrations ranged from 87.65% to 96.57%. The average removal rate was significantly higher and more stable in vegetated CWs than in non-vegetated CWs. As determined using a mass-balance method, outflows, macrophytes, substrate micro-degradation, and other accounted for 5.23%, 22.7%, 15.96%, and 56.11%, respectively, of the chlorpyrifos in the vegetated system. Of all Iris pseudoacorus organs examined, the rhizome was dominant in biomass and gathered the largest amount of chlorpyrifos. Except for the uptake of chlorpyrifos by plants, the primary difference between vegetated and non-vegetated CWs was that there was a relatively low potential for chlorpyrifos micro-degradation and volatilization and photolysis in vegetated CWs than in non-vegetated CWs. Identification of this partitioning pattern elucidates the mechanisms underlying chlorpyrifos removal from wastewater in CWs.

Sezonowość odpływu z wybranych zlewni karpackich = Seasonality of outflow in selected Carpathian catchments

This article details an analysis of seasonality of outflow carried out for 12 Carpathian catchments. The latter were selected in such a way as to fully represent various conditions of outflow formation in the Carpathian Mountains, i.e. the region of Poland in which hydrological processes are most dynamic. Daily series of discharges for the years 1951-2010 provided the basis for the research, albeit with the series lengths used in analyses of particular rivers varying in length from 40 to 60 years. In the case of each water-gauge section selected, calculations were made for the seasonality index (IS), time of concentration coeffi cient (WPK), outflow concentration index (GMO) and half-outflow term index (TPO). Multiannual variability and mutual correlation coefficients for the above parameters were also calculated, with these characteristics together describing various aspects to the seasonality of river outflow. The results of the research conducted show that values for the mean seasonality indexes characterising the outflow in Carpathian catchments are slightly lower than those calculated for amounts of precipitation. In addition, their spatial differentiation is relatively weak, while their variability over time is distinctly high. The mean time of concentration coefficient (WPK) for the Carpathian catchments does differ markedly from place to place, occurring between 4th Apri l and 3rd June. However, in the cases of the rivers draining the western part of the Beskid Mountains and Tatras, the outflow concentration occurs relatively late (after 5th May), while it is relatively early (before 5th May) in the cases of the rivers in the eastern part of the Beskids. The long-term variability of WPK in the Carpathian Mountains is less than half as great as that characterising the seasonality index (25.2% to 55.7% on average), though no significant trends could be noted for long-term series of those characteristics. Timing related to Oliver’s concentration coefficient (GMO) reveals aspects of seasonality similar to those presented by Markham’s seasonality index (IS). Due to this fact it would be more appropriate to name it an “outflow seasonality index” rather than an “outflow concentration index”. Mean multiannual half-outflow terms (TPOśr) in the Carpathian catchments are strongly diversified and appear between 15th April and 21st May. Low TPOśr was noted in rivers of a nival-pluvial and nival well-shaped regime. Low TPOśr was found with the pluvial-nival regime. The spatial differentiation to the multiannual variability of TPOśr in the Carpathian Mountains is limited. It is most limited in the case of rivers in the Tatra Mountains. Statistical analyses of multiannual series for all the seasonality parameters examined show that, in the Carpathian area, the seasonal structure to the outflow is relatively stable over the long term (given a lack of significant trends), with year-to-year fluctuations and changes being random in nature. The relative mean mass diagram curve for Carpathian catchments has two points of inflection confirming the nival-pluvial or pluvial-nival regimes. The regional curve offers a very effective presentation of the seasonal distribution of outflow in the Carpathian Mountains.

Water Quality Effects of Switchgrass Intercropping on Pine Forest in Coastal North Carolina

Abstract. Interplanting a cellulosic bioenergy crop (switchgrass, L.) between loblolly pine ( L.) rows could potentially provide a sustainable source of bio-feedstock without competing for land currently in food production. The objectives of this study were to: (1) quantify the concentrations and loads of drainage water nitrogen (N) and phosphorus (phosphate) associated with establishment and growth of switchgrass treatments and compare them with those for a mid-rotation pine forest (control), and (2) quantify the treatment effects on drainage water N and phosphate (IC) and switchgrass only (SG). Thinned mid-rotation loblolly pine with natural understory (MP) was used as the control. Pretreatment calibration equations for nutrients were obtained using a paired watershed approach and bootstrap geometric regression with 2007-2008 data, when pine on all sites had reached canopy closure. Treatment effects were calculated as the difference between expected values from the pretreatment relationship and measured data for the treatment period. Precipitation, outflow, and N and phosphate concentrations in the outflow were measured during calibration (Jan. 2007 to Dec. 2008), site preparation for switchgrass establishment (Nov. 2009 to Mar. 2012), and switchgrass growth (Apr. 2012 to Apr. 2014). Mean NO3-N concentrations and loads were significantly (a = 0.05) greater for SG than for IC during the switchgrass growth period. Average treatment concentrations with standard errors and total load effects during switchgrass growth for NO3-N followed the trends SG (-0.002 ±0.01 mg L-1) &amp;gt; IC (-0.12 ±0.04 mg L-1) and SG (0.75kg ha-1) &amp;gt; IC (0.23kg ha-1), respectively. For phosphate average concentrations and loads, the treatment effects during switchgrass growth followed the trends SG (-0.004 ± mg L-1) &amp;gt;IC ( -0.02 ± mg L-1) and IC (-0.43 kg ha-1) &amp;gt; SG (-0.70 kg ha-1), respectively. Average concentration effects for NO3-N and phosphate and total load effects for phosphate significantly (a = 0.05) decreased for IC compared to the MP control. These results suggest that the intercropping treatment (IC) with loblolly pine and switchgrass improved water quality by reducing NO3-N and phosphate concentrations and phosphate loads. Keywords: Bioenergy crop, Bootstrap geometric regression, Loblolly pine, Nutrients, Paired watershed.

Do salt and low temperature impair metal treatment in stormwater bioretention cells with or without a submerged zone?

Although seasonal temperature changes and (road) salt in winter and/or coastal stormwater runoff might interfere with the metal treatment performance of stormwater bioretention cells, no previous study has evaluated the effect of these factors and their interactions under controlled conditions. In this 18week long study 24 well established pilot-scale bioretention columns were employed to evaluate the individual and combined effect(s) of low/high temperature, salt and presence of a submerged zone with an embedded carbon source on metal removal using a three factor, two-level full factorial experimental design. In most instances, the three factors significantly influenced the metal outflow concentrations and thus the treatment performance; the effect of temperature depended on the metal in question, salt had an overall negative effect and the submerged zone with carbon source had an overall positive effect. Despite these statistically significant effects, the discharge water quality was generally markedly improved. However, leaching of dissolved Cu and Pb did occur, mainly from bioretention cells dosed with salt-containing stormwater. The highest concentrations of metals were captured in the top layer of the filter material and were not significantly affected by the three factors studied. Overall, the results confirmed that bioretention provides a functioning stormwater treatment option in areas experiencing winter conditions (road salt, low temperatures) or coastal regions (salt-laden stormwater). However, validation of these results in the field is recommended, especially focusing on dissolved metal removal, which may be critically affected under certain conditions.

Phosphorus removal from lagoon-pretreated swine wastewater by pilot-scale surface flow constructed wetlands planted with Myriophyllum aquaticum

Although constructed wetlands (CWs) are used as one relatively low-cost technology for livestock wastewater treatment, the improvement of phosphorus removal in CWs is urgently needed. In this study, a three-stage pilot-scale CW system consisting of three surface flow CWs (SFCWs; CW1, CW2, and CW3) in series from inlet to outlet was constructed to treat swine wastewater (SW) from a lagoon. The CWs were planted with Myriophyllum aquaticum. Considering different inlet loading rates, three strengths of swine wastewater (low: 33% SW, medium: 66% SW, and high: 100% SW) were fed to the CW system to determine total phosphorus (TP) removal efficiency and clarify the important role of plant harvest. Results from the period 2014–2016 indicate that the three-stage CW system had mean TP cumulative removal efficiencies and removal rates of 78.2–89.8% and 0.412–0.779gm−2d−1 respectively, under different inlet loading rates. The TP removal efficiency and removal rate constant had temporal variations, which depended on temperature condition and the annual growth pattern of M. aquaticum. The harvested phosphorus mass was 15.1–40.9gm−2yr−1 in the CWs except for CW1 with high strength SW, and contributed 22.5–59.6% of TP mass removal rate by the SFCWs. The TP removal was mainly by adsorption and precipitation in the substrate in CW1 but by uptake and multiple harvests of M. aquaticum in CW2 and CW3. The results suggest the three-stage CW system planted with M. aquaticum is suited for removing high TP concentrations from swine wastewater with a high removal efficiency. However, TP removal in high strength SW amounted to 70.1±23.3%, and the outflow concentration of 17.0±14.9mgL−1 was still high. Optimal loading rates for high strength SW still need to be investigated for the CW system presented here.

Reliability of nitrogen removal processes in multistage treatment wetlands receiving high-strength wastewater

Treatment wetlands have been proved to be more effective than conventional treatment processes in case of high-strength wastewater containing high concentrations of ammonium nitrogen and recalcitrant organic matter. In this study nitrogen removal processes and reliability of nitrogen removal at two identical pilot-scale multistage treatment wetlands (MTWs) receiving real, non-synthetic wastewater were discussed. The wastewater discharged to pilot-scale subsurface flow MTWs contained high ammonium nitrogen concentrations and limited biodegradable organic matter (OM) concentrations. One of the pilot MTWs was fed with landfill leachate (LL) and another one with reject water from sewage sludge centrifugation (RW). In the first season of operation both MTWs reached very high (95–99%) efficiency of total nitrogen (TN) removal, which was explained by adsorption to the substrate. In the later period, TN was removed in a sequence of nitrification and denitrication processes with lower efficiency (40–86%). The denitrification process was the limiting one at the LL treating site because of too low carbon supply. Still, during the whole investigation period TN outflow concentrations were at the level that allows for co-treatment of the effluent in municipal wastewater treatment plants without risk for biological treatment processes. In 90% of samples TN concentration was below 200mg/l and in 60% of samples it was below 145mg/l.

Commentary on “Mitsch et al., 2015, Protecting the Florida Everglades wetlands with wetlands: Can stormwater phosphorus be reduced to oligotrophic conditions?”

Constructed wetlands have been utilized with varying levels of success in an effort to reduce nutrient concentrations entering waterways. In south Florida, stormwater treatment areas (STAs) have been utilized to remove excessive phosphorus (P) from surface waters for more than two decades with remarkable results. Even though the STAs have been operational for more than two decade, further improvement of P removal performance is necessary to achieve the desired outflow concentrations. This commentary critically reviews a recently published manuscript concerning the ability of alternative vegetative communities’ ability to improve STA treatment efficiency. The commentary provides clarification of Everglades STA effluent limit and the total P water quality criterion established for the Everglades Protection Area. The commentary also addresses fundamental issues with the authors’ experimental design and interpretability in light of the studies treatment fidelity, controls and scalability.

Should harvest residues be left on site in peatland forests to decrease the risk of potassium depletion?

Sufficiency of potassium (K) is one of the biggest concerns for forestry in boreal peatlands, since the rooting zone stores of K in thick peat soils are generally small and significant proportion of the K in ecosystem is bound in stand biomass. Increased demand for bioenergy may lead to intensified harvesting also in such forests. There is thus an urgent need to study the significance of the nutrients in harvest residues for the next-generation forest productivity. The specific questions in peatland forests are whether the harvest residues are an important source of K to the restock or whether the K in harvest residues is lost by leaching. We quantified K losses from drained peatland forests following management by clear-felling with stem-only harvesting (SOH), whole-tree harvesting (WTH) and whole-tree harvesting plus stump harvesting (WTHS). Calibration period – control area method and mixed modelling approach were used to analyze the ditch-outflow K-concentration and water-borne K-export data from 17 harvested and 5 control catchments in southern and central Finland. K concentrations and runoff were monitored for 1–2years before and 3–4years after treatment. Supplementary long-term data from one pair of harvested and non-managed catchments was used to assess the duration of the harvest impact on K export.Mean annual K concentrations in ditch outflow were higher after than before harvesting. The concentrations started to increase during the second or third post-harvest year, reaching the peaks of 1.1–2.2mgL−1 in WTHS, 0.8–1.7mgL−1 in WTH, and 1.0–1.9mgL−1 in SOH. The concentrations correlated positively with the amount of K in the surface peat. In nutrient-poor ombrotrophic sites, the K concentrations were higher for sites with shallower water-table level.Using the supplementary data, the impact of harvesting on K losses was estimated to last for about eight years. The overall estimated K loss was about 28kgha−1 from minerotrophic sites, and about 9kgha−1 from ombrotrophic sites. There was no significant difference in K losses between the harvest treatments SOH, WTH and WTHS, indicating that the K in harvest residues was largely retained onsite. The role of K losses induced by harvesting in the site K stores in drained peatland forests is discussed.

Transport Characteristics of Nitrite in a Shallow Sedimentary Aquifer in Northwest China as Determined by a 12-Day Soil Column Experiment

The transport behaviour of nitrite in a shallow sedimentary aquifer in northwest China was investigated in the laboratory by conducting a soil column experiment under flow velocity and temperature conditions likely to be encountered in field situations. The transport characteristics of nitrite are not well known scientifically and the purpose of the study was to provide data that are considered essential for the development of programs for aquifer remediation and groundwater quality protection. The soil column experiment was performed at a constant flow rate for a period of 12 days using a 40 cm column. It involved a 1.5 mmol/L solution of sodium nitrite to which sodium bromide had been added as a chemically conservative tracer. The data were analysed using the CXTFIT 2.0 model code for the one-dimensional convective–dispersive transport of solutes. The breakthrough curve (BTC) for bromide revealed an average linear flow velocity of 0.3445 cm/h for the experiment and a longitudinal dispersivity of 4.16 cm for the sediment. The effective porosity was determined to be 29 %. The BTC for nitrite showed a significant delay compared to the bromide BTC, presumably due to some form of chemical reaction. Significantly, outflow concentrations of nitrite approached 1.5 mmol/L (the input value) towards the end of the experiment (after 10 days) indicating that the nitrite emerging at that time had not undergone significant chemical transformation during its passage through the column. Curve matching showed that nitrite behaviour could be represented by invoking chemical retardation using a retardation factor that begins at 2.5 and gradually decreases over time to a value of 1. However, the BTC for nitrite is better explained by the pH-dependent, chemical transformation of nitrite, presumably to nitrate or nitrogen gas, at the leading edge of the advancing chemical front that gives the appearance that nitrite is being retarded. Nitrite in more alkaline conditions behind the advancing front is significantly less affected by chemical transformation such that the apparent retardation effect diminishes. Further work is required to provide details on the nature of the reactions taking place and the constraints under which they operate.

Postmortem redistribution mechanism of donepezil in the rat

Population aging is rapidly advancing in numerous parts of the world and, accordingly, the prevalence of Alzheimer's disease (AD) is rising. The safety of donepezil (DPZ), which is used for AD treatment, has been established in clinical trials. However, some studies have indicated that DPZ may be associated with severe cardiac side effects, and excessive doses may induce toxicity-related symptoms or death. Therefore, the measurement of blood DPZ levels is important for the postmortem investigation of related causes of death. However, postmortem drug concentrations in the blood may not always reflect those obtained antemortem because of the postmortem redistribution (PMR) of drugs. Therefore, the aim of this study was to investigate the potential PMR of DPZ using a rat model. The DPZ concentration was measured using a validated HPLC/Q-TOF-MS system in cardiac and peripheral blood, and in the brain, lungs, myocardium, liver, and thigh muscle at different postmortem intervals (0, 1, 3, 6, 12, and 24h). Overall, the DPZ tissue to peripheral blood ratio decreased throughout the postmortem period. Furthermore, the DPZ concentration increased in the peripheral and cardiac blood but decreased in both of the lungs, postmortem. Furthermore, the blood pH was significantly lowered. We used a perfusion approach to examine the rat lung and heart to further investigate the relationship between the pH and DPZ release from the lungs. The outflow concentrations when the inflow pH changed from 7.4 to 5.5 were approximately 2-fold higher than the inflow pH fixed 7.4. These findings suggest that the antemortem accumulated DPZ in the lungs is released into the pulmonary blood owing to postmortem acidification of blood, and subsequently flows into the cardiac blood, leading to the observed increase in concentration. Although we could not determine the underlying mechanism, we confirmed that PMR occurs similarly in the cardiac and peripheral blood.

Downstream emissions of CH4 and CO2 from hydroelectric reservoirs (Tucuruí, Samuel, and Curuá-Una) in the Amazon basin

Carbon dioxide (CO2) and methane (CH4) generated in reservoirs are released downstream of dams, and few studies have considered these downstream emissions. Fluxes downstream of 3 Amazon hydroelectric reservoirs (Tucuruí, Samuel, and Curuá-Una) are reported here. Degassing through turbines was calculated as the difference between intake and outflow concentrations. Additional releases along the Tocantins, Jamari, and Curuá rivers were measured at downstream sites over a distance of 30 km. About 50% of the CH4 and 30% of the CO2 emitted downstream of the dam were liberated at the turbine outflow. The total downstream emissions are sufficiently large to require consideration in assessments of greenhouse gas emissions from hydroelectric reservoirs.

Natural Rock Phosphate: A Sustainable Solution for Phosphorous Removal from Wastewater

In application of the European Water Framework directive aiming to achieve a “good ecological status” for all waters, phosphorous removal from domestic wastewater can be of importance before discharging into natural receiving bodies, especially for small communities localized upstream of catchment areas or in zones sensitive to eutrophication.As rural communities in France often choose to treat their wastewater with extensive treatment systems such as constructed wetlands, because these natural processes are easy to operate, equivalent P-removal technologies have been asked for. Research has therefore focused on adsorption or precipitation mechanisms on specific reactive materials. In this context, recent studies undertaken by Irstea (French public research institute, formerly Cemagref) in collaboration with SINT and Epur Nature have shown the interest of natural rock phosphate (apatite) as an efficient and sustainable solution for phosphorous removal from wastewater. Epur Nature (Syntea group) has recently developed and patented a specific filter configuration filled with apatite pellets for high phosphorous removal efficiencies (P outflow concentrations < 2mg P/L). The mechanisms and key factors for an optimal treatment (apatite quality, particle size, kinetics) are explained and synthetized in the paper. The results from lab scale columns and first results rom full scale wastewater treatment plants in operation since several years are also presented.Finally the possible reuse of the apatite enriched with P from wastewater after 10 to 20 years of operation will be discussed.

CO2 Emission to the Atmosphere from Carbonate Waters: The Study Case of the Lublin Upland and Roztocze Regions

Abstract The concentration of carbon dioxide dissolved in water (CO2(aq)) was measured in consecutive phases of the hydrological cycle. Its potentially possible degassing from groundwaters to the atmosphere was also assessed. The research was conducted in the area of occurrence of carbonate rocks of the Lublin Upland and Roztocze (SE Poland). The results of the measurements of CO2(aq) concentration varied as follows (min-max/mean): precipitation waters &lt; 1-3/2.6 mg · dm−3, soil waters 3-50/14.2 mg · dm−3, groundwaters 10-70/30.3 mg · dm−3, river waters &lt; 1-21/7.6 mg · dm−3. The measure of degassing of carbon dioxide from groundwaters to the atmosphere was a decrease in CO2(aq) concentration in fluvial outflow. Based on the value of groundwater outflow from the Lublin Upland and Roztocze, the annual carbon dioxide emission from waters to the atmosphere was calculated at a level of 50 thousand Mg · year−1. This value constitutes approximately 1% of anthropogenic emission of carbon dioxide originating from environmentally harmful industrial plants in the Lublin province.

Nitrogen and Phosphorus Removal in a Rain Garden Flooded with Wastewater and Simulated Stormwater

Rain gardens, also known as bioretention cells, are low-impact developments designed to mitigate several problems associated with urban stormwater. This four-month field study involved a rain garden at a wastewater treatment plant in north-central Texas in the United States of America. Partially treated wastewater from an anaerobic digester spilled into the rain garden at the beginning of the study. Subsequently, inflow and outflow concentrations of nitrogen and phosphorus were measured for nine simulated floods, preceded by dry-spell intervals of 5, 8, or 12 days. Despite large inputs from the wastewater spill, the rain garden gradually processed and flushed the nitrogen. Longer dry spells tended to produce relatively higher outflow nitrate concentrations. A large pool of phosphorus in the soil restricted the rain garden's ability to reduce outflow orthophosphate concentrations, which were stable and lower than inflow concentrations throughout the study; however, adsorptive processes attenuated a relatively high inflow concentration by the end of the study.