Refine search
Results 321-330 of 456
Effectiveness of an Open Limestone Channel in Treating Acid Sulfate Soil Drainage Full text
2008
Green, Ros M. W. | Waite, T David | Melville, Mike D. | Macdonald, Ben C. T.
An open limestone channel (OLC) was constructed within an existing drain to treat the acidic and metal-rich drainage waters generated from an acid sulfate soil (ASS) catchment. The OLC was constructed downstream of a catchment pump and it consisted of a series of ponds and limestone sections. The accumulation of sediment over the limestone, preventing contact of limestone with acidic water, was the greatest problem impacting the OLC in its first year of operation. The continuous or sporadic operation of the catchment pump (at 120 l/s) was not sufficient to flush sediment from the limestone. The accumulation of large amounts of sediment onto the limestone reduced the amount of alkalinity and calcium released into solution. However, if the sediment is removed by agitating the limestone then an equivalent or greater amount of alkalinity may be added to solution and more metals removed from solution compared to fresh limestone. The coating on the limestone had a high concentration of manganese oxides in addition to slightly lower concentrations of aluminium and iron. Removal of these metals from the water was due to the increase in pH produced by limestone dissolution in addition to sorption reactions of the existing coating which had natural microbial activity.
Show more [+] Less [-]Acting Environmentally Proactive in an Emerging Market-Oriented Economy Full text
2008
Constantin, L.-A. | Teodorescu, C | Nicolau, M
As a new member of the European Union (EU), Romania has to align its economy with that of other EU partners, including the addition of a proactive component to environmental protection. This requires the development of a transitive approach capable of overcoming the difficulties of implementing the sustainability paradigm within an emerging market-oriented economy, which despite its progress, is still not fully prepared to understand and accept sustainability. This paper describes such a transition, showing how INCD ECOIND (the main Romanian Research and Development entity in the field of industrial ecology) reshaped its policies to include in current projects developed with Romanian partners the following elements: the Integrated Pollution Prevention and Control (IPPC) Directive, components relating to the REACH Process; the Environmental Management Accounting (EMA) mainframe and assistance in cultivating Corporate Social Responsibility (CSR) as an intrinsic part of modern enterprise. Lessons learned from previous and current projects are presented, underlining the complexity of obstacles met and problem-solving procedures derived and verified in practice.
Show more [+] Less [-]Trace metals (Cu, Mn, Ni, Zn, Fe) Contamination in Marine Sediment and Zooplankton Samples from Izmir Bay. (Aegean Sea, Turkey) Full text
2008
Kontas, Aynur
Metal (Cu, Mn, Ni, Zn, Fe) concentrations in marine sediment and zooplankton were investigated in Izmir Bay of the Eastern Aegean Sea, Turkey. The study aimed to assess the levels of metal in different environmental compartments of the Izmir Bay. Metal concentrations in the sediment (dry weight) ranged between 4.26-70.8 μg g-¹ for Cu, 233-923 μg g-¹ for Mn, 14.9-127 μg g-¹ for Ni, 25.6-295 μg g-¹ for Zn, 12,404-76,899 μg g-¹ for Fe and 38,226-91,532 μg g-¹ for Al in the Izmir Bay. Maximum metal concentrations in zooplankton were observed during summer season in the inner bay. Significant relationships existed between the concentrations of certain metals (Al, Fe, Mn and Ni) in sediment, suggesting similar sources and/or similar geochemical processes controlling such metals. Higher concentrations of Cu, Zn and percent organic matter contents were found in the middle-inner bays sediments. Based on the correlation matrix obtained for metal data, organic matter was found to be the dominant factor controlling Cu and Zn distributions in the sediment. In general, mean Cu and Zn levels in the bay were above background concentrations in Mediterranean sediments. Zooplankton metal concentrations were similar to sediment distributions.
Show more [+] Less [-]Decomposition of Zn-rich Arabidopsis halleri Litter in Low and High Metal Soil in the Presence and Absence of EDTA Full text
2008
Chander, Krishan | Joergensen, Rainer Georg
Hyperaccumulating plants are increasingly investigated in combination with EDTA addition to soil for phytoremediation of heavy metal contaminated soils. A 60-day incubation experiment was carried out to investigate the effects of heavy metal release during the decomposition of Zn-rich (15.7 mg g-¹ dry weight) Arabidopsis halleri litter on C mineralization, microbial biomass C, biomass N, ATP, and adenylate energy charge (AEC). These effects were investigated in two soils with different Zn, Cu, and Pb levels, with and without EDTA addition to soil. The sole addition of Zn-rich A. halleri litter to the two soils did not increase the contents of NH₄NO₃ extractable Zn, only with the combined additions of EDTA and litter was there a considerable increase, being equivalent to three times the added amount in the low metal soil and to 50% in the high metal soil. Litter amendment increased the CO₂ evolved; being equivalent to 44% of the added C in the two soils, but EDTA addition had no significant effect on CO₂ evolution. Litter amendment resulted also in an 18% increase in microbial biomass C, 27% increase in ATP and 6% increase in AEC in the two soils, but EDTA had again no effect on these indices at both metal levels. In contrast, the sole addition of litter had no effect on microbial biomass N, but EDTA addition increased microbial biomass N on average by 49%. The application of EDTA for chelate-assisted phytoextraction should in the future consider the risk of groundwater pollution, which is intensified by resistance of EDTA to microbial decomposition.
Show more [+] Less [-]Utilization Potential of Peats - a Study on Peat Biodegradability Determined by Respirometric Method Full text
2008
Roppola, Katri | Kuokkanen, Toivo | Kujala, Kauko | Kuokkanen, Matti
The biodegradation of different peat types was studied with a manometric respirometric test. Compaction peat and sphagnum peat samples were analysed, and the effect of peat pH on biodegradation behaviour was evaluated. Only minor (BOD/ThOD < 0.4%) biodegradation was observed with compaction peat samples, and the stable state, in which biodegradation stopped, was achieved during a two month period. As expected, sphagnum peat samples with a lower decomposition rate degraded more than compaction peat samples. Alkalinity (pH between ca. 4-9) of the peat was noticed to reduce the degree of biodegradation and accelerate the achievement of the stable state.
Show more [+] Less [-]Using Synchronous Fluorescence Technique as a Water Quality Monitoring Tool for an Urban River Full text
2008
Hur, Jin | Hwang, Soon-Jin | Shin, Jae-Ki
The development of a monitoring tool for predicting water quality and tracing pollution sources are important for the management of sustainable aquatic ecosystems in urban areas. In this study, synchronous fluorescence technique was applied to 18 sampling sites of a typical urban watershed in Korea, some of which are directly affected by the effluent from a wastewater treatment plant (WWTP), to investigate the capability of the technique for biochemical oxygen demand (BOD) prediction and source discrimination. Sampling was conducted three times at the same sites during the low flow period between October and November, 2005. Protein-like fluorescence intensities of the samples showed a positive linear relationship with the BOD values (Spearman’s rho = 0.90, p < 0.0001). The BOD prediction capability was superior to other monitoring tools such as UV absorption and conductivity measurements particularly for the upstream sites from the WWTP, which ranged from 0.0 to 5.0 mg/l as BOD. The protein-like fluorescence and a ratio of protein-like/fulvic-like fluorescence were suggested as good fluorescence signatures to discriminate different sources of dissolved organic matter (DOM). The samples collected from four different DOM source regions including upstream sites from the WWTP, downstream sites, discharge from a reservoir, and headwater were distinguished from one another by varying ranges of the two selected fluorescence signatures. Our results suggest that the synchronous fluorescence technique has the potential to be developed into a real-time water quality management tool for the comprehensive monitoring of urban rivers.
Show more [+] Less [-]Composition, Distribution, and Characterization of Organochlorine Pesticides in Sandstorm Depositions in Beijing, China Full text
2008
Fu, S. | Li, K. | Yang, Z. Z. | Xu, X. B.
Sandstorms which distribute a great number of particles are a special atmospheric occurrence and are uncommon in northern China. This study was conducted to determine, for the first time, the concentration of organochlorine pesticides (OCPs) in sandstorm depositions. Samples were collected from urban areas of Beijing and a total of eight OCPs were measured. All samples contained OCP residues. The total hexachlorocyclohexane (HCHs) concentration ranged from 20.6 to 59.8ng g⁻¹ and the total dichlorodiphenyltrichloroethane (DDTs) concentration ranged from 12.0 to 14.3ng g⁻¹. Furthermore, increasing HCH contamination was observed from the northwest to the southeast and a uniform distribution of DDT contamination was discovered in Beijing. Analysis of the sources of contamination showed that HCHs in the sandstorm depositions were derived from a relatively old source of lindane, and DDTs mainly originated from an old source of dicofol in Beijing. The preliminary pollution assessment of the samples indicated that HCH levels might be categorized as low pollution and DDT levels might be categorized as no pollution. The present study suggests that sandstorm depositions may not produce the special risk of adverse health effect from OCPs for the residents of Beijing, China.
Show more [+] Less [-]Sequencing Zerovalent Iron Treatment with Carbon Amendments to Remediate Agrichemical-Contaminated Soil Full text
2008
Boparai, Hardiljeet K. | Shea, Patrick J. | Comfort, Steve D. | Machacek, Thomas A.
Agrichemical spills and discharges to soil can cause point-source contamination of surface and ground waters. When high contaminant concentrations inhibit natural attenuation in soils, chemical treatments can be used to promote degradation and allow application of treated soils to agricultural lands. This approach was used to remediate soil containing >650 mg atrazine, >170 mg metolachlor and >18,000 mg nitrate kg⁻¹. Results indicated a decrease in metolachlor concentration to <1 mg kg⁻¹ within 95 days of chemical treatment with zerovalent iron (Fe⁰, 5% w/w) and aluminum sulfate (Al₂(SO₄)₃, 2% w/w) but after one year >150 mg atrazine and >7000 mg nitrate kg⁻¹ remained. Laboratory experiments confirmed that subsequent additions of sucrose (table sugar) to the chemically pretreated soil promoted further reductions in atrazine and nitrate concentrations. Field-scale results showed that adding 5% (w/w) sucrose to windrowed and pretreated soil significantly reduced atrazine (<38 mg kg⁻¹) and nitrate (<2,100 mg kg⁻¹) concentrations and allowed for land application of the treated soil. These results provide evidence that zerovalent iron in combination with Al₂(SO₄)₃ and sucrose can be used for on-site, field-scale treatment of pesticide- and nitrate-contaminated soil.
Show more [+] Less [-]An Approach to Air Pollution Source-Receptor Solution by Angular Distances Full text
2008
Magallanes, Jorge F | Murruni, Leonardo | Gómez Sánchez, Juan Dario | Smichowski, Patricia | Gettar, Raquel
This study presents the analysis of two series of concentrations of airborne particulate matter (APM) collected in two exploratory campaigns aimed at elucidating the source-receptor problem (SRP) in the metropolitan area of Buenos Aires. Although several techniques have been previously applied to interpret these measurements, we have almost exclusively used here the method of angular distances among objects (ADO) to discuss its advantages as a tool in understanding environmental questions within the source-receptor framework. We present a simple method of calculating the ADO, explain its chemical interpretation and the information that is possible to get by classifying the angular distances. A comparison among ADO with principal component analysis and Kohonen artificial neural networks is also discussed.
Show more [+] Less [-]Seasonal Differences in Atmospheric Nitrous Acid near Mediterranean Urban Areas Full text
2008
Amoroso, Antonio | Beine, Harry J. | Esposito, Giulio | Perrino, Cinzia | Catrambone, Maria | Allegrini, Ivo
The major objective of this paper is to provide insights to sources and sinks of nitrous acid in urban areas, and their seasonal dependency on meteorology, photochemistry and long range transport. With this aim, nitrous acid (HONO) mixing ratios and other compounds were measured in Ashdod (south of Tel Aviv, Israel), a typical Mediterranean urban area. Statistical data analysis revealed the expected correlation between HONO and nitrogen oxides during the autumn campaign when HONO sources appeared to be traffic-, harbor-, and industry-related. Conversely, during summer HONO and NO₂ were no longer correlated: NO₂ at nighttime was probably deposited onto surfaces, soil and plants, whereas HONO at daytime was likely destroyed photolytically contributing to the OH concentration. Photolysis was expected to be the dominant HONO sink at daytime, especially during the summer period. Using modeled photolytical HONO lifetimes we estimate the magnitude of heterogeneous and/or organic electron transfer source reactions of HONO as 6-8 ppbv/h.
Show more [+] Less [-]