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Groundwater and Nutrient Discharge into Jiaozhou Bay, North China 全文
2007
Liu, G. Q | Wang, S. Y | Zhu, X. J | Liu, S. M | Zhang, J
The health of near shore marine ecosystems has long been a concern because of its importance to coastal areas. Jiaozhou Bay (JZB) is one such marine ecosystem experiencing rapid water quality degradation in the last several decades. From the area surrounding the bay, the nutrients discharged into the bay through surface water and groundwater has been greatly changed. The thickness of the aquifers and the permeability is relatively high, the concentrations of nutrients in the groundwater are generally high, and so the groundwater discharged into JZB is very significant. However, no attempt has ever been made to evaluate the amount of nutrients discharged into the bay area via groundwater. In this study, the cross-section method and water balance method were used to estimate the amount of groundwater and nutrients discharged into JZB via the subsurface. Groundwater was monitored and sampled at aquifers surrounding the bay area, and some previously available data was also analyzed. The results indicated that groundwater from the Baisha Aquifer east of JZB now is the major source of nutrients (nitrate, dissolved SiO₂) being discharged into the bay. The concentrations of nutrients in the groundwater have been increasing with intensive agricultural land use. However, Dagu Aquifer, the largest aquifer north of JZB, only provides limited nutrients to the bay area because of the construction of a low permeability subsurface dam. Historically, during the 1970s to the 1990s, the Baisha Aquifer experienced seawater intrusion due to excessive groundwater withdrawal. The same was true for the Dagu Aquifer from the 1980s to the 1990s. Because of this, no significant nutrients were discharged into the bay.
显示更多 [+] 显示较少 [-]Long Term Trends in Sulphur and Nitrogen Deposition in Europe and the Cause of Non-linearities 全文
2007
Fowler, David | Smith, Rognvald | Muller, Jennifer | Cape, John Neil | Sutton, Mark | Erisman, J. W (Jan Willem) | Fagerli, Hilde
Emissions of sulphur and oxidized nitrogen compounds in Europe have been reduced following a series of control measures during the last two decades. These changes have taken place during a period in which the primary gases and the wet deposition throughout Europe were extensively monitored. Since the end of the 1970s, for example land based sulphur emissions declined by between 90 and 70% depending on the region. Over the same period the total deposition of sulphur and its partitioning into wet and dry deposition have declined, but the spatial pattern in the reduction in deposition differs from that of emission and has changed with time. Such non-linearities in the emission-deposition relationship are important to understand as they complicate the process of assessing the effects of emission reduction strategies. Observed non-linearities in terrestrial sulphur emission-deposition patterns have been identified in north west Europe due to increases in marine emissions, and are currently slowing the recovery of freshwater ecosystems. Changes in the relative amounts of SO₂ and NH₃ in air over the last two decades have also changed the affinity of terrestrial surfaces for SO₂ and have therefore changed the deposition velocity of SO₂ over substantial areas. The consequence of this effect has been the very rapid reduction in ambient SO₂ concentration in some of the major source areas of Europe, where NH₃ did not change much. Interactions between the different pollutants, generating non-linearities are now being incorporated in long-range transport models to simulate the effects of historical emission trends and to provide projections into the future. This paper identifies non-linearities in emission deposition relationships for sulphur and nitrogen compounds in Europe using data from the EMEP long-rang transport model and measured concentration fields of the major ions in precipitation and of SO₂ and NO₂ in surface air.
显示更多 [+] 显示较少 [-]UN/ECE ICP Materials Dose-response Functions for the Multi-pollutant Situation 全文
2007
Kucera, Vladimir | Tidblad, Johan | Kreislova, Katerina | Knotkova, Dagmar | Faller, Markus | Reiss, Daniel | Snethlage, Rolf | Yates, Tim | Henriksen, Jan | Schreiner, Manfred | Melcher, Michael | Ferm, Martin | Lefèvre, Roger-Alexandre | Kobus, Joanna
A “multi-pollutant exposure programme” reflecting the new pollution situation where SO₂ is no longer the dominating pollutant has been performed by the International Co-operative Programme on Effects on Materials, including Historic and Cultural Monuments (ICP Materials) within the activities of the Convention on Long-range Transboundary Air Pollution. The main results obtained in the period 1997-2003 are summarised. Dose-response functions are presented for carbon steel, zinc, copper, bronze and limestone. Parameters involved in the functions include besides SO₂ and pH, which were included in the previously developed functions from ICP Materials, also the effect of particulate matter and HNO₃.
显示更多 [+] 显示较少 [-]Calibration and Evaluation of a Mercury Model for a Western Stream and Constructed Wetland 全文
2007
Brown, Scott | Saito, Laurel | Knightes, Christopher | Gustin, Mae
Numerous studies have shown that Steamboat Creek in Nevada is highly contaminated with mercury, with aqueous mercury concentrations more than two orders of magnitude greater than nearby mountain streams. One objective of this study was to determine if the new Spreadsheet-based Ecological Risk Assessment for the Fate of Mercury (SERAFM) model could be calibrated to the concentrations of unfiltered and dissolved total mercury, and unfiltered and dissolved MeHg in the water column for a reach on SBC and a related constructed wetland mesocosm for different seasons and residence times. SERAFM is a new U.S. Environmental Protection Agency steady state, single segment, mass balance mercury model that has been applied to lakes, and this study also examined the model’s applicability for modeling an arid flowing water environment in different seasons. The average combined error between observed and model-estimated mercury concentrations was 12% and 17% for the reach and mesocosm, respectively. Some recommendations are proposed that may allow SERAFM to better model flowing systems.
显示更多 [+] 显示较少 [-]How standards drive taxes: the political economy of tailpipe pollution 全文
2007
Gulati, Sumeet | Roy, Devesh
To control tailpipe pollution, governments often use environmental product standards and consumption taxes in conjunction (for example, the use of fuel economy standards and gasoline taxes to restrict automobile pollution in the US). Further, the choice of standards and consumption taxes is often independently influenced by special interests. For example, domestic producers have the incentive to influence environmental product standards, and likewise, domestic consumers have the incentive to influence the choice of the consumption tax. In this paper we explore the political link between environmental standards and consumption taxes in the presence of independent special interests. We find that despite the independence of special interests, the political outcome is inextricably linked. This political link is different from the welfare maximizing second-best link usually expected between two related policies, and is crucial in correctly anticipating policy outcomes. Specifically, we find that the government's choice of an environmental standard influences political incentives in the choice of the consumption tax. As the environmental standard falls, a higher demand for the environmentally damaging product develops. This higher demand increases the incentives for consumers to lobby for lower consumption tax. Under certain conditions, this political link is large enough to result in a complementary relationship between the two policies in equilibrium. The complementary relationship implies that a lower standard results in a lower consumption tax and vice versa when the standard is higher.
显示更多 [+] 显示较少 [-]How standards drive taxes: the political economy of tailpipe pollution 全文
2007
Gulati, Sumeet | Roy, Devesh
To control tailpipe pollution, governments often use environmental product standards and consumption taxes in conjunction (for example, the use of fuel economy standards and gasoline taxes to restrict automobile pollution in the US). Further, the choice of standards and consumption taxes is often independently influenced by special interests. For example, domestic producers have the incentive to influence environmental product standards, and likewise, domestic consumers have the incentive to influence the choice of the consumption tax. In this paper we explore the political link between environmental standards and consumption taxes in the presence of independent special interests. We find that despite the independence of special interests, the political outcome is inextricably linked. This political link is different from the welfare maximizing second-best link usually expected between two related policies, and is crucial in correctly anticipating policy outcomes. Specifically, we find that the government's choice of an environmental standard influences political incentives in the choice of the consumption tax. As the environmental standard falls, a higher demand for the environmentally damaging product develops. This higher demand increases the incentives for consumers to lobby for lower consumption tax. Under certain conditions, this political link is large enough to result in a complementary relationship between the two policies in equilibrium. The complementary relationship implies that a lower standard results in a lower consumption tax and vice versa when the standard is higher.
显示更多 [+] 显示较少 [-]Aquifer Vulnerability Zoning, an Indicator of Atmospheric Pollutants Input? Vanadium in the Salamanca Aquifer, Mexico 全文
2007
Mejia, J. A. | Rodriguez, R. | Armienta, A. | Mata, E. | Fiorucci, A.
Aquifer vulnerability assessments can be incorporated in groundwater contamination studies. Atmospheric pollutants as vanadium, V, can reach aquifers after soil deposition if the system is vulnerable. Vanadium concentrations were detected in soil and groundwater in Salamanca Mexico. V origin is related mainly to particulate emissions from a thermoelectric plant that is using fuel oil number 6 with high V content. To determine the V origin in groundwater, a soil and groundwater monitoring was carried out. A SINTACS vulnerability zoning was done. Vanadium in soil, emissions and groundwater is well correlated. The V input is associated to aquifer vulnerable zones.
显示更多 [+] 显示较少 [-]Nutrient Removal from Simulated Wastewater Using Canna indica and Schoenoplectus validus in Mono- and Mixed-Culture in Wetland Microcosms 全文
2007
Zhang, Zhenhua | Rengel, Zdenko | Meney, Kathy
Emergent wetland plant species may exhibit different nutrient removal efficiencies when grown in monoculture and mixed stands in constructed wetlands for tertiary purification of wastewater. A glasshouse study was conducted to investigate the influence of mono- and mixed-culture between Canna indica Linn and Schoenoplectus validus (Vahl) A. Löve & D. Löve on their growth in, and nutrient removal from, simulated wastewater in the surface water of vertical-flow wetland microcosms. Plants were grown for 50 days before imposing nutrient treatments that simulated secondary-treated municipal wastewater effluent with either low (17.5 mg N and 10 mg P per litre) or high (35.0 mg N and 20 mg P per litre) nutrient concentrations. Treatment solutions were renewed in weekly intervals. After 65 days of nutrient and plant treatments, the total and above-ground biomass was significantly (P < 0.01) greater in the high compared with the low nutrient treatment, but there were no significant differences in below-ground biomass. Significant (P < 0.01) differences in above-ground and below-ground biomass were observed, but no significant difference in total biomass was detected among plant treatments. The highest below-ground biomass was in monoculture of C. indica, whereas the highest above-ground biomass was in the monoculture of S. validus. The biomass of mixed-culture was intermediate to that in the two monoculture treatments. There was significant interspecific competition between C. indica and S. validus in mixed-culture, with C. indica being the superior competitor. The concentrations of N and P in plant tissues (except P in above-ground tissues) were significantly (P < 0.01) higher in the high than in the low nutrient treatment. The accumulation of N and P in above- and below-ground tissues largely reflected patterns of biomass allocation. No significant difference was observed between the nutrient treatments in nutrient removal efficiencies. Plant uptake was the major nutrient removal pathway in the wetland microcosms. Nutrient removal from simulated wastewater in mixed-culture was not greater than in mono-cultures, due to interspecific competition. The results suggested that plant nutrient uptake was the major removal mechanism at the establishment stands in the constructed wetlands.
显示更多 [+] 显示较少 [-]Characterization of Waste Tar Associated with Abandoned Wood Chemical Plant Sites in Northwest Pennsylvania, USA 全文
2007
Edenborn, Harry M. | Severson, Dessie
Over 70 wood chemical plants operated in northern Pennsylvania between ca. 1890 and 1950, all located within 72 km of the New York state border. Their original purpose was to salvage the small unwanted hardwood trees left behind by the lumber mills, and to make charcoal, calcium acetate and methanol for a number of industrial uses via destructive distillation. At many old wood chemical plant sites, unknown quantities of wood tar remain as a residual contaminant and pose a pollution threat to aquatic life in nearby streams. Research on the composition and properties of residual wood tars from five abandoned industrial sites in Pennsylvania are described. Weathered wood tars were more viscous and contained fewer volatile and semivolatile organic compounds than did soil-buried tars. Phenol, 2-methylphenol (o-cresol), 4-methylphenol (p-cresol), and 2, 4-dimethylphenol were found in all sampled tars. These water-soluble phenolic compounds were released quasi-instantaneously in aqueous solution, followed by a slower rate of release, consistent with the behavior of similar compounds in other dense non-aqueous liquids. Air-exposed wood tar deposits developed a hard crust, which contained fewer volatiles and semivolatiles and had a higher softening point than other samples. These tars eroded to form a powdered soil colonized by lichens and mosses. Residual wood tar material found at one site was shown to be thermally altered, likely during the historical destruction of the chemical plant by fire. Recovered wood tar wastes have a relatively high heating value and may have use as a potential, but limited, alternate energy source.
显示更多 [+] 显示较少 [-]Heavy Metal Pollution and Eutrophication in the Lower Salado River Basin (Argentina) 全文
2007
Gagneten, A.M. | Gervasio, S. | Paggi, J.C.
Levels of heavy metals (chromium, copper, lead and cadmium) in water and sediments of the lower Salado River (Argentina) are presented and compared to Canadian and Argentinian environmental standards. Measurement of metal levels was performed using atomic absorption spectroscopy. In order to interpret analytical results, one way ANOVA, hierarchical cluster analysis and correlations were used. Geoaccumulation Index was used as a measure of metal pollution in sediments. There were differences between the accumulation of metals in sediments and water and the control sampling site. Heavy metals, especially chromium, copper and lead, appear to be an important problem to these freshwater environments.
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