Fluxes of NO3-, NH4+, NO,NO2, and N2O in an Old Danish Beech Forest

The fluxes of the major nitrogen compounds havebeen investigated in many ecosystem studies over the world.However, only in few studies has attention been drawn to theimportance of the fluxes of minor gaseous nitrogen compoundsto complete the nitrogen cycle. In Denmark a detailed study onthe nitrogen cycle in an old beech forest has been implementedin 1997 at Gyrstinge near Sorø, Zealand. The study includesthe fluxes of the gases NO, N₂O and water mediatedtransport of NO₃ ^- and NH₄ ⁺. Measurementsof the fluxes of the gaseous compounds are performed withmicro-meteorological methods (eddy-correlation and gradient)and with chambers. Water mediated fluxes encompass rain,throughfall, stem-flow and leaching from the root zone. Thehydrological model is verified by TDR measurements. The findings show that the total water mediated N input tothe forest floor with throughfall and stemflow was 25.6 kg Nha^-1 yr ^-1, and open field wet deposition withprecipitation was 19.0 kg N ha^-1 yr ^-1. The internalcycling of N in the ecosystem measured as turnover oflitterfall and plant uptake was 100 kg N ha^-1 yr ^-1and 14 kg N ha^-1 yr ^-1, respectively. The fluxes ofthe gaseous N compounds NO and N₂O were of minorimportance for the total N turnover in the forest, NO_xemission being <1 kg N ha^-1 yr ^-1 and N₂Oemission from the soil being 0.5 kg N ha^-1 yr ^-1 withno significant difference between wet and dry soils.Concentrations of NO₃ ^- and NH₄ ⁺ in thesoil solution beneath the rooting zone are very small andconsequently the N leaching is almost negligible. It isconcluded that the nitrogen mass balance of this old beechforest ecosystem mainly is controlled by the input by dry andwet deposition and a large internal N cycle with a fast litterturnover. The nitrogen input tothe forest ecosystem which currently exceeds the critical loadby 5 kg N ha^-1 yr ^-1is mainly accumulated in the soil and no significant nitrateleaching is occurring.     

Wassertechnische Strategien zur Reduzierung der Trinkwasserbelastung durch Arzneimittelwirkstoffe

Results The available research results concerning the application of innovative methods of wastewater and drinking water purification to eliminate pharmaceuticals are summarized in the present paper. An increase of the activated sludge (aerobic sludge) age to 8–10 days in treatment plants can improve the metabolization of less persistent pharmaceutical agents whereas expansion of the sojourn time beyond 10 days will not result in a remarked increase of degradation for most pharmaceutical substances. First results have shown that wastewater treatment plants with integrated membrane bioreactors (MBR) using micro- and ultrafiltration membranes do not provide significantly better results compared to the conventional wastewater treatment plants with respect to the removal of organic micropollutants (including pharmaceutical residues). The use of powdered carbon in biologically treated wastewater is able to reduce pharmaceutical residues up to 80?% in the run-off water. Pilot studies scrutinize the treatment of highly contaminated effluents via catalytic photooxidation. Regarding the suitability of the method to reduce the contamination of drinking and wastewater with pharmaceuticals yet only few data from laboratory scale testing are available. Activated carbon filtration is preferably used for drinking water treatment. Primarily against the background of disinfection, ozonation is widely used for drinking water treatment, but for wastewater treatment the method is still at the experimental stage and will hardly become of practical importance because of high costs. Sustainable wastewater separation is grounded on decentralized concepts by considering material cycles (recycling) at the place of origin. In the long term, separation measures can significantly contribute to declining drug concentrations in drinking water. Regarding the quarrying of drinking water by bank filtration water, river water or artificially enriched ground water, end-of-pipe techniques are vital. Most commonly, activated carbon or activated carbon combined with ozonization is applied and assures a high drinking water quality. Discussion The advantages and disadvantages of the different water treatment methods mainly concern the varying degrees of effectiveness with respect to the elimination of very persistent pharmaceutical agents, the generation of problematical metabolites and additional waste materials, hygienic problems, energy needs and the necessity to employ appropriate technical staff for operation. Although the biodegradation of very persistent drugs cannot be enhanced by an extension of the activated sludge age, this modification should be considered in sewage plants to reduce the contamination with less persistent medical agents. Compared with conventional wastewater treatment, membrane bioreactors provide the advantage of a better control of biological activities on the plant and a comparably small plant size but high investment and operation costs. Additionally, pharmaceuticals such as carbamazepin are only insufficiently removed from wastewater by membrane bioreactors. The regular use of powdered activated carbon in sewage treatment plants would also increase the costs of wastewater treatment and would additionally exclude the further use of sewage sludge in agriculture. Currently, in Germany the further use of sewage sludge is handled differently by the Federal States and discussed controversially. The implementation of ozonation as an additional treatment method in wastewater treatment plants is not realistic because of cost concerns. Additionally, the method produces analytically as yet not assessed metabolites with unknown (eco-)toxicological impacts. For this reason ozonation should currently not be applied unless the reaction products are removed subsequently by filtration through activated carbon. For industrial sewage photooxidation is in a state of testing but an application for municipal wastewater is, up to now, out of question. When river bank filtration is used for the supply of drinking water the use of activated carbon for purification should be essential. The lifetime of the filters is often defined by the filter capacities to eliminate radiocontrast media (e.?g., iopamidole, amidotrizoic acid). Many water supply companies already apply the ozonization prior to activated carbon filtration which supports the elimination of pharmaceuticals from the sewage. The unique developmental potential of the wastewater separation can be seen in the possibility to link up these methods with sustainable exploitation techniques and concepts (re-use of sanitized water, production of fertilizer, compost and biogas). Wastewater separation will not make ‘middle/end-of-pipe’ techniques dispensable but will make their handling more effective because concentrations of pharmaceutical agents are higher in separated effluents compared to those usually found in municipal wastewater, which in mixing sewage systems is even diluted by surface runoff. Conclusions Following today’s state of knowledge activated carbon filtration (eventually coupled with ozonization) is best suited to remove drug residues and other xenobiotics from raw water. Water works that do not apply the activated carbon filtration technique for cleanup of bank filtration water should consider an upgrade. The ozonization is primarily required for disinfection of the water. As no acute health hazard proceeds from drinking water contamination by pharmaceuticals at the present time, the upgrade of wastewater treatment plants by one of the aforementioned innovative methods is currently not required in view of drinking water quality. This offers the opportunity to develop sustainable approaches that already aim to reduce drug contaminations of wastewater and hence of ground-, surface- and drinking water. Recommendations and perspectives On a short- to mid-term perspective enriched sewage of hospitals, nursing homes and other medical facilities should be collected and treated separately. From a technical point of view the conditioning of separated hospital effluents (yellow- and greywater) via activated carbon or membrane filtration is possible but should be combined with disinfection. On a mid- and long-term scale sustainable sanitary concepts based on wastewater separation (black-, grey- and/or rainwater) associated with the recycling of mineral nutrients (nitrogen, phosphorous and potassium) should be realized for development, industry and trade areas, buildings with public lavatories, airports, motorway service areas, and large office and hotel buildings. Strategies focusing primarily on up-grading of municipal wastewater treatment plants are currently existing but the related technologies are largely in a test phase. This is why a particular technique should not be favored at the moment. The combination of various techniques (i.?e., ozonization combined with activated carbon filtration) is known to be very efficient for the removal of pharmaceutical residues from water, but the combination cannot be expected to become of importance in treatment of domestic wastewater because of high costs. Moreover, improvement of wastewater treatment technologies to remove pharmaceutical residues will not make the employment of end-of-pipe techniques in water works redundant and therefore will not lead to saving of expenses.     

Sediment texture and nutrients of Arasalar estuary, Karaikkal, south-east coast of India

Sediment samples were collected for texture, composition and nutrient such as organic carbon, total nitrogen and total phosphorus for a period of two years from three stations in Arasalar estuary. The sediment temperature, pH and nutrients were higher during summer season and lower during monsoon season. At station 1, sediment texture was loamy sand during summer and premonsoon season. At station 2, clay type soil was recorded. Whereas, at station 3, clay was observed in summer and premonsoon and then it shifted to sandy loam type soil during monsoon. Sediment nutrients were lower than that of values of various ecosystem of India.     

Metal contamination of surface water,sediment and <Emphasis Type="Italic">Tympanotonus fuscatus</Emphasis> var. <Emphasis Type="Italic">radula</Emphasis> of Iko River and environmental impact due to Utapete gas flare station,Nigeria

Inter-seasonal studies on the trace metal load of surface water, sediment and Tympanotonus fuscatus var. radula of Iko River were conducted between 2003 and 2004. The impact of anthropogenic activities especially industrial effluent, petroleum related wastes, gas flare and episodic oil spills on the ecosystem are remarkable. Trace metals analyzed included cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), nickel (Ni), vanadium (V) and zinc (Zn). Sediment particle size analysis revealed that they were characteristically psammitic and were predominantly of medium to fine grained sand (>73%), less of silt (<15%) and clay (<10%). These results correlated with low levels of trace elements such as Pb (0.03 ± 0.02 mg kg⁻¹), Cr (0.22 ± 0.12 mg kg⁻¹), Cd (0.05 ± 0.03 mg kg⁻¹), Cu (0.04 ± 0.02 mg kg⁻¹) and Mn (0.23 ± 0.22 mg kg⁻¹) in the sediment samples. This observation is consistent with the scarcity of clayey materials known to be good scavengers for metallic and organic contaminants. Sediments indicated enhanced concentration of Fe, Ni and V, while other metal levels were relatively low. The concentrations of all the metals except Pb in surface water were within the permissible levels, suggesting that the petroleum contaminants had minimal effect on the state of pollution by trace metals in Iko River. Notably, the pollutant concentrations in the sediments were markedly higher than the corresponding concentrations in surface water and T. fuscatus tissues, and decreased with distance from point sources of pollution.     

Generation of Monthly Precipitation Under Climate Change for the Upper Blue Nile River Basin,Ethiopia1

Abstract: This work develops a methodology to project the future precipitation in large river basins under limited data and climate change while preserving the historical temporal and spatial characteristics. The computationally simple and reliable conditional generation method (CGM) is presented and applied to generate reliable monthly precipitation data in the upper Blue Nile River Basin of Ethiopia where rain‐fed agriculture is prevalent. The results showed that the temporal analysis with the CGM performs better to reproduce the historical long‐term characteristics than other methods, and the spatial analysis with the CGM reproduced the historical spatial structure accurately. A 100‐year time series analysis using the outcomes of the six general circulation models showed that precipitation changes by the 2050s (2040 through 2069) can be ?7 to 28% with a mean increase of about 11%. The seasonal results showed increasing wet conditions in all seasons with changes of mean precipitation of 5, 47, and 6% for wet, dry, and mild seasons, respectively.     

Role of blue green algae biofertilizer in ameliorating the nitrogen demand and fly-ash stress to the growth and yield of rice (Oryza sativa L.) plants

Rice is a major food crop throughout the world; however, accumulation of toxic metals and metalloids in grains in contaminated environments is a matter of growing concern. Field experiments were conducted to analyze the growth performance, elemental composition (Fe, Si, Zn, Mn, Cu, Ni, Cd and As) and yield of the rice plants (Oryza sativa L. cv. Saryu-52) grown under different doses of fly-ash (FA; applied @ 10 and 100 tha(-1) denoted as FA(10) and FA(100), respectively) mixed with garden soil (GS) in combination with nitrogen fertilizer (NF; applied @ 90 and 120 kg ha(-1) denoted as NF(90) and NF(120), respectively) and blue green algae biofertilizer (BGA; applied @ 12.5 kg ha(-1) denoted as BGA(12.5)). Significant enhancement of growth was observed in the plants growing on amended soils as compared to GS and best response was obtained in amendment of FA(10)+NF(90)+BGA(12.5). Accumulation of Si, Fe, Zn and Mn was higher than Cu, Cd, Ni and As. Arsenic accumulation was detected only in FA(100) and its amendments. Inoculation of BGA(12.5) caused slight reduction in Cd, Ni and As content of plants as compared to NF(120) amendment. The high levels of stress inducible non-protein thiols (NP-SH) and cysteine in FA(100) were decreased by application of NF and BGA indicating stress amelioration. Study suggests integrated use of FA, BGA and NF for improved growth, yield and mineral composition of the rice plants besides reducing the high demand of nitrogen fertilizers.     

Fungicidal values of bio-oils and their lignin-rich fractions obtained from wood/bark fast pyrolysis

Pine wood, pine bark, oak wood and oak bark were pyrolyzed in an auger reactor. A total of 16 bio-oils or pyrolytic oils were generated at different temperatures and residence times. Two additional pine bio-oils were produced at the National Renewable Energy Laboratory in a fluidized-bed reactor at different temperatures. All these bio-oils were fractionated to obtain lignin-rich fractions which consist mainly of phenols and neutrals. The pyrolytic lignin-rich fractions were obtained by liquid-liquid extraction. Whole bio-oils and their lignin-rich fractions were studied as potential environmentally benign wood preservatives to replace metal-based CCA and copper systems that have raised environmental concerns. Each bio-oil and several lignin-rich fractions were tested for antifungal properties. Soil block tests were conducted using one brown-rot fungus (Gloeophyllum trabeum) and one white-rot fungus (Trametes versicolor). The lignin-rich fractions showed greater fungal inhibition than whole bio-oils for a impregnation solution 10% concentration level. Water repellence tests were also performed to study wood wafer swelling behavior before and after bio-oil and lignin-rich fraction treatments. In this case, bio-oil fractions did not exhibit higher water repellency than whole bio-oils. Comparison of raw bio-oils in soil block tests, with unleached wafers, at 10% and 25% bio-oil impregnation solution concentration levels showed excellent wood preservation properties at the 25% level. The good performance of raw bio-oils at higher loading levels suggests that fractionation to generate lignin-rich fractions is unnecessary. At this more effective 25% loading level in general, the raw bio-oils performed similarly. Prevention of leaching is critically important for both raw bio-oils and their fractions to provide decay resistance. Initial tests of a polymerization chemical to prevent leaching showed some success.     

The removal of lignin and phenol from paper mill effluents by electrocoagulation

This study aims to investigate the treatment of paper mill effluents using electrocoagulation. Removal of lignin, phenol, chemical oxygen demand (COD) and biological oxygen demand (BOD) from paper mill effluents was investigated at various current intensities by using different electrodes (Al and Fe) and at various electrolysis times (1.0, 2.5, 5.0 and 7.5min). It was observed that the experiments carried out at 12V, an electrolysis time of 2min and a current intensity of 77.13mA were sufficient for the removal of these pollutants with each electrode. The removal capacities of the process using an Al electrode were 80% of lignin, 98% of phenol, 70% of BOD, and 75% of COD after 7.5min. Using an Fe electrode the removal capacities were 92%, 93%, 80% and 55%, respectively. In addition, it was found that removal of lignin, phenol, BOD and COD increased with increasing current intensity. In the experiments carried out at different current intensities, higher removal can be explained through a decrease in intra-resistance of solution and consequently an increase at the transfer speed of organic species to electrodes. It was also found that Al electrode performs higher efficiency than Fe electrode except for COD removal. However, the time required for removal of BOD was more than that of COD. The results suggest that electrocoagulation could be considered as an effective alternative to paper mill effluents treatment.     

Comparative evaluation of a bioluminescent bacterial assay in terrestrial ecotoxicity testing

Despite the widespread and successful use of luminescence-based bioassays in water testing, their applications to soils and sediments is less proven. In part this is because such bioassays have mainly been carried out in an aqueous-based medium and, as such, favour contaminants that are readily water-soluble. In this study, aqueous solutions and soils contaminated with heavy metals (HM), polar organic contaminants and hydrophobic organic contaminants (HOCs) were tested using a range of luminescence-based bioassays (Vibrio fischeri, Escherichia coli HB101 pUCD607 and Pseudomonas fluorescens 10586r pUCD607). For the first two chemical groups, the assays were highly reproducible when optimised extraction procedures were employed but for HOCs the bioassay response was poor. Quantitative structure-activity relationships (QSARs) obtained from aqueous solutions had a linear response although correlation for the chemicals tested using bacterial bioassays was significantly less sensitive than that of sublethal tests for Tetrahymena pyriformis. Bacterial and Dendrobaena veneta bioassay responses to extracts from HM amended soils showed that a clear relationship between trophic levels could be obtained. There is no doubt that the wide range of bioluminescent-based bioassays offers complementary applications to traditional testing techniques but there is a significant need to justify and optimise the extraction protocol prior to application.