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Geophysical and Geochemical Approach for Seawater Intrusion Assessment in the Godavari Delta Basin, A.P., India
2011
Gurunadha Rao, V. V. S. | Rao, G Tamma | Surinaidu, L. | Rājēṣ, Ār. | Mahesh, J.
Coastal lands around Bay of Bengal in Central Godavari Delta are mainly agriculture fields and two times annually paddy crops putting in the study area. Canals of Godavari River are the main source of water for irrigation. Geophysical and geochemical investigations were carried out in the study area to decipher subsurface geologic formation and assessing seawater intrusion. Electrical resistivity tomographic surveys carried out in the watershed-indicated low resistivity formation in the upstream area due to the presence of thick marine clays up to thickness of 20–25Â m from the surface. Secondly, the lowering of resistivity may be due to the encroachment of seawater in to freshwater zones and infiltration during tidal fluctuation through mainly the Pikaleru drain, and to some extent rarely through Kannvaram and Vasalatippa drains in the downstream area. Groundwater quality analyses were made for major ions revealed brackish nature of groundwater water at shallow depth. The in situ salinity of groundwater is around 5,000Â mg/l and there is no groundwater withdrawal for irrigation or drinking purpose in this area except Cairn energy pumping wells which is using for inject brackish water into the oil wells for easy exploration of oil. Chemical analyses of groundwater samples have indicated the range of salt concentrations and correlation of geophysical and borehole litholog data in the study area predicting seawater-contaminated zones and influence of in situ salinity in the upstream of study area. The article suggested further studies and research work that can lead to sustainable exploitation/use and management of groundwater resources in coastal areas.
显示更多 [+] 显示较少 [-]Nitrogen Leaching of Two Forest Ecosystems in a Karst Watershed
2011
Jost, Georg | Dirnböck, Thomas | Grabner, Maria-Theresia | Mirtl, Michael
Karst watersheds are a major source of drinking water in the European Alps. These watersheds exhibit quick response times and low residence times, which might make karst aquifers more vulnerable to elevated nitrogen (N) deposition than non-karst watersheds. We summarize 13 years of monitoring NO3 −, NH4 +, and total N in two forest ecosystems, a Norway spruce (Picea abies (L.) Karst.) forest on Cambisols/Stagnosols (IP I) and a mixed beech (Fagus sylvatica L.) spruce forest on Leptosols (IP II). N fluxes are calculated by multiplying concentrations, measured in biweekly intervals, with hydrological fluxes predicted from a hydrological model. The total N deposition in the throughfall amounts to 26.8 and 21.1 kg/ha/year in IP I and IP II, respectively, which is high compared to depositions found in other European forest ecosystems. While the shallow Leptosols at IP II accumulated on average 9.2 kg/ha/year of N between 1999 and 2006, the N budgets of the Cambisols/Stagnosols at IP I were equaled over the study period but show high inter-annual variation. Between 1999 and 2006, on average, 9 kg/ha/year of DON and 20 kg/ha/year of DIN were output with seepage water of IP I but only 4.5 kg/ha/year of DON and 7.7 kg/ha/year of DIN at IP II. Despite high DIN leaching, neither IP I nor IP II showed further signs of N saturation in their organic layer C/N ratios, N mineralization, or leaf N content. The N budget over all years was dominated by a few extreme output events. Nitrate leaching rates at both forest ecosystems correlated the most with years of above average snow accumulation (but only for IP I this correlation is statistically significant). Both snow melt and total annual precipitation were most important drivers of DON leaching. IP I and IP II showed comparable temporal patterns of both concentrations and flux rates but exhibited differences in magnitudes: DON, NO3 −, and NH4 + inputs peak in spring, NH4 + showed an additional peak in autumn; the bulk of the annual NO3 − and DON output occurred in spring; DON, NO3 −, and NH4 + output rates during winter months were low. The high DIN leaching at IP I was related to snow cover effects on N mineralization and soil hydrology. From the year 2004 onwards, disproportional NO3 − leaching occurred at both plots. This was possibly caused by the exceptionally dry year 2003 and a small-scale bark beetle infestation (at IP I), in addition to snow cover effects. This study shows that both forest ecosystems at Zöbelboden are still N limited. N leaching pulses, particularly during spring, dictate not only annual but also the long-term N budgets. The overall magnitude of N leaching to the karst aquifer differs substantially between forest and soil types, which are found in close proximity in the karstified areas of the Northern Limestone Alps in Austria.
显示更多 [+] 显示较少 [-]The Impact of Cl × Cd Interrelationship on Planning Wastewater Reuse in Cabbage
2011
Kalavrouziotis, Ioannis K. | Kostakioti, Eirini | Koukoulakis, Prodromos H. | Papadopoulos, Aristotelis H. | Leotsinidis, Michalis | Sakazli, Eleni
Two greenhouse pot experiments were conducted in Agrinion, Greece, using a randomized block design in four replications, respectively, as follows: The first one included five levels of treated municipal wastewater (TMWW), being used as an irrigation water source. The second one, five levels of applied Cl at a constant soil applied Cd level of 10.36 mg/kg soil, the plants being irrigated with fresh well water. The purpose of these experiments was to study the impact of the Cl × Cd interrelationship on planning TMWW reuse, for the irrigation of Brassica oleracea var. Capitata (cabbage) cv F1 Gloria, ehich was used as test plant, in both of these experiments. It was found that the TMWW Cl content, originating mainly from the procedure of wastewater chlorination, was synergistically interrelated with the toxic heavy metal Cd, increasing its soil availability and cabbage plant leaf uptake (edible plant part). As this increase is directly associated with the consumer's health, it was suggested that the TMWW be subjected to dechlorination process or the disinfection be made by ozonation or UV, which do not include Cl.
显示更多 [+] 显示较少 [-]Bioremediation of Mangroves Impacted by Petroleum
2011
Santos, Henrique F. | Carmo, Flávia L. | Paes, Jorge E. S. | Rosado, Alexandre S. | Peixoto, Raquel S.
The majority of oil from oceanic oil spills (e.g. the recent accident in the Gulf of Mexico) converges on coastal ecosystems such as mangroves. Microorganisms are directly involved in biogeochemical cycles as key drivers of the degradation of many carbon sources, including petroleum hydrocarbons. When properly understood and managed, microorganisms provide a wide range of ecosystem services, such as bioremediation, and are a promising alternative for the recovery of impacted environments. Previous studies have been conducted with emphasis on developing and selecting strategies for bioremediation of mangroves, mostly in vitro, with few field applications described in the literature. Many factors can affect the success of bioremediation of oil in mangroves, including the presence and activity of the oil-degrading microorganisms in the sediment, availability and concentration of oil and nutrients, salinity, temperature and oil toxicity. More studies are needed to provide efficient bioremediation strategies to be applicable in large areas of mangroves impacted with oil. A major challenge to mangrove bioremediation is defining pollution levels and measuring recuperation of a mangrove. Typically, chemical parameters of pollution levels, such as polycyclic aromatic hydrocarbons (PAHs), are used but are extremely variable in field measurements. Therefore, meaningful mangrove monitoring strategies must be developed. This review will present the state of the art of bioremediation in oil-contaminated mangroves, new data about the use of different mangrove microcosms with and without tide simulation, the main factors that influence the success of bioremediation in mangroves and new prospects for the use of molecular tools to monitor the bioremediation process. We believe that in some environments, such as mangroves, bioremediation may be the most appropriate approach for cleanup. Because of the peculiarities and heterogeneity of these environments, which hinder the use of other physical and chemical analyses, we suggest that measuring plant recuperation should be considered with reduction in polycyclic aromatic hydrocarbons (PAHs). This is a crucial discussion because these key marine environments are threatened with worldwide disappearance. We highlight the need for and suggest new ways to conserve, protect and restore these environments.
显示更多 [+] 显示较少 [-]Dynamics of Dissolved Forms of Carbon and Inorganic Nitrogen in Small Watersheds of the Coastal Atlantic Forest in Southeast Brazil
2011
Andrade, Tatiana M. B. | Camargo, Plínio B. | Silva, Daniela M. L. | Piccolo, Marisa C. | Vieira, Simone A. | Alves, Luciana F. | Joly, Carlos A. | Martinelli, Luiz A.
Based on the fact that streamwater quality reflects landscape conditions, the objectives of this study were: to investigate nitrogen (N), carbon (C), and major ion concentrations in six streams crossing minimally disturbed Atlantic Forest areas, with similar geomorphological characteristics; to determine N and C fluxes in one of these pristine streams (Indaiá); and assess the impact of human activity on the biogeochemistry of two other streams in the same region, crossing urbanized areas. The distribution pattern of carbon and inorganic nitrogen dissolved forms, as well as the major ion and biogenic gas concentrations in the streamwater, was similar in pristine streams, indicating that the C and N dynamics were determined by influence of some factors, such as climate, atmospheric deposition, geology, soil type, and land covering, which were analogous in the forested watersheds. The urban streams were significantly different from the pristine streams, showing low dissolved oxygen concentrations, high respiration rates, and high concentrations of carbon dioxide, dissolved inorganic nitrogen, dissolved inorganic carbon, and major ion. These differences were attributed to anthropogenic impact on water quality, especially domestic sewage discharge. Additionally, in the Indaiá stream, it was possible to observe the importance of rainfall over temporal dynamics of dissolved carbon forms, and also, the obtained specific flux of dissolved inorganic nitrogen was relatively elevated (approximately 11 kg ha⁻¹ year⁻¹). These results reveal the influence of human activity over the biogeochemistry of coastal streams and also indicate the importance N export of Atlantic Forest to the ocean.
显示更多 [+] 显示较少 [-]Effects of Soil Amendments on Growth and Metal Uptake by Ocimum gratissimum Grown in Cd/Zn-Contaminated Soil
2011
Chaiyarat, Rattanawat | Suebsima, Rujira | Putwattana, Narupot | Kruatrachue, Maleeya | Pokethitiyook, Prayad
Hydroponic and pot experiments were conducted to assess the uptake of heavy metals (Cd and Zn) by a common crop plant, African basil, Ocimum gratissimum. In addition, the effects of soil amendments, hydroxyapatite (HA) and cow manure on plant growth and metal accumulations were compared. In the hydroponic study, plants were exposed to various concentrations of Cd (2.5 and 5 mg L⁻¹) and Zn (10 and 20 mg L⁻¹) for 15 days. O. gratissimum was shown to be a Cd accumulator more than a Zn accumulator. Cadmium concentration in its shoots exceeded 100 mg kg⁻¹. In the pot experiments, soils from a heavily Cd-contaminated site (Cd 67.9 mg kg⁻¹ and Zn 2,886.8 mg kg⁻¹) were treated with cow manure and HA at the rates of 10% and 20% (w/w), and 0.75 and 1.5% (w/w), respectively. Plants were grown in the greenhouse for 3 months. The addition of cow manure resulted in the highest biomass production and the lowest accumulations of Cd in plant parts, while HA was more efficient than cow manure in reducing Zn uptake. Leaves of African basil showed a decreased Cd concentration from 1.5 to 0.3 mg kg⁻¹ (cow manure) and decreased Zn concentration from 69.3 to 34 mg kg⁻¹ (HA). This clearly demonstrates the efficiency of HA and cow manure in reducing metal content in leaves of plants grown on high metal-contaminated soil to acceptable or close to acceptable values (0.2 mg kg⁻¹ for Cd, 99.4 mg kg⁻¹ for Zn).
显示更多 [+] 显示较少 [-]An Efficient Implementation of the Method of Lines for Multicomponent Reactive Transport Equations
2011
Fahs, Marwan | Younes, Anis | Ackerer, Philippe
Modeling reactive transport with chemical equilibrium reactions requires solution of coupled partial differential and algebraic equations. In this work, two formulations are developed to combine the method of lines (MOL) with the global implicit approach. The first formulation has a non-conservative form and leads to a nonlinear system of ordinary differential equations with a reduced number of unknowns. The second formulation presents better conservation properties but leads to a nonlinear system of differential algebraic equations with a large number of unknowns. In both formulations, the resulting systems are integrated in time using the DLSODIS time solver which adapts both the order of the time integration and the time step size to provide the necessary accuracy. Numerical experiments show that higher-order time integration is effective for solving the non-conservative formulation and point out the high benefit of the MOL for solving reactive transport problems.
显示更多 [+] 显示较少 [-]Comparison Between Industrial–Urban and Rural Particle Stations in a Ceramic Cluster (NE, Spain)
2011
Vicente, Ana Belen | Sanfeliu, Teofilo | Jordan, Manuel Miguel
Since the beginning of the twentieth century, the province of Castellón, in eastern Spain, has been one of the most important areas of floor and wall tile production on both a national and worldwide scale. As a result of this sector’s productive rate of development (in the 1970–2005 interval), a series of pollution-producing chemical substances has been introduced into the atmosphere. The objective of this study is the comparison between industrial–urban and rural zones in this province, with the goal of establishing the causes of the contamination in order to apply corrective measures upon the different emission sources. Sustainable development is sought after to guarantee that, in the future, the environmental quality parameters fall within legal limits, ensuring the population’s well-being as well as conserving natural ecosystems and material assets. Total suspended particles and PM10 are the parameters studied. The reason for choosing this pollutant type is because particulate matter may present a much higher potential risk despite its low representativeness as compared to the gas pollutant’s group. A positive correlation between high particle concentrations and deterioration in public health has been shown in recent studies. The elements As, Cd, Ni, and Pb in PM10 were also analyzed to determine the toxicity of these particles. This study has demonstrated the different behaviors of the parameters studied at different types of stations (industrial–urban and rural), leading to the conclusion that anthropogenic factors are very important in the area studied and that they determine the area’s air quality to a great extent.
显示更多 [+] 显示较少 [-]Effect of carboxylic and thiol ligands (oxalate, cysteine) on the kinetics of desorption of Hg(II) from kaolinite
2011
U Senevirathna, Wasana | Zhang, Hong | Gu, Baohua
Sorption and desorption of Hg(II) on clay minerals can impact the biogeochemical cycle and bio-uptake of Hg in the environment. We studied the kinetics of the desorption of Hg(II) from kaolinite as affected by oxalate and cysteine, representing the ligands with carboxylic and thiol groups of different affinities for Hg(II). The effects of pH (3, 5, and 7), ligand concentration (0.25 and 1.0 mM), and temperature (15°C, 25°C, and 35°C) on the Hg(II) desorption were investigated through desorption kinetics. Our study showed that the Hg(II) desorption was pH dependent. In the absence of any organic ligand, >90% of the previously adsorbed Hg(II) desorbed at pH 3 within 2 h, compared to <10% at pH 7. Similar results were observed in the presence of oxalate, showing that it hardly affected the Hg(II) desorption. Cysteine inhibited the Hg(II) desorption significantly at all the pH tested, especially in the first 80 min with the desorption less than 20%, but the inhibition of the desorption appeared to be less prominent afterwards. The effect of the ligand concentration on the Hg(II) desorption was small, especially in the presence of oxalate. The effect of temperature on the Hg(II) desorption was nearly insignificant. The effect of the organic acids on the Hg(II) sorption and desorption is explained by the formation of the ternary surface complexes involving the mineral, ligand, and Hg(II). The competition for Hg(II) between the cysteine molecules adsorbed on the particle surfaces and in the solution phase probably can also affect the Hg(II) desorption.
显示更多 [+] 显示较少 [-]Presence of Pharmaceuticals and Hormones in Waters from Sewage Treatment Plants
2011
Pedrouzo, Marta | Borrull, Francesc | Pocurull, Eva | Marcé, Rosa Maria
This paper describes the presence of 33 pharmaceuticals and hormones in waters from two sewage treatment plants (STPs) situated in Catalonia, in northeastern Spain. The target compounds were one psychoactive stimulant, one antiepileptic, four analgesics and non-steroidal anti-inflammatories, one lipid regulators, two anti-ulcer agents, nine antibiotics (sulfonamides and macrolides), two beta-blockers, two metabolites, and 11 hormones (free and conjugates). The determination was performed using liquid chromatography coupled to tandem mass spectrometry after enrichment by solid-phase extraction with Oasis HLB sorbent. Most of the pharmaceuticals were found in both influent and effluent samples from the two STPs. The most frequently detected were caffeine, acetaminophen, carbamazepine, diclofenac, ibuprofen, naproxen, sulfamethoxazole, sulfapyridine, sulfathiazole, ranitidine, omeprazole, estrone 3-sulfate, and estradiol 17-glucuronide. Specifically, the highest concentrations found in influents were 19,850Â ng/L (acetaminophen), 9,945Â ng/L (caffeine), 4,215Â ng/L (ibuprofen), 5,695Â ng/L (sulfamethoxazole), and 5,140Â ng/L (sulfathiazole). Most of the pharmaceuticals present in influent waters were found in effluents at lower concentrations. The highest concentrations in effluents were 970Â ng/L (caffeine), 670Â ng/L (sulfamethoxazole), 510Â ng/L (bezafibrate), and 1,032Â ng/L (diclofenac).
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