Showing papers in "Water Air and Soil Pollution in 2009"

Removal of Hexavalent Chromium-Contaminated Water and Wastewater: A Review

Abstract: Cr(VI) is a well-known highly toxic metal, considered a priority pollutant. Industrial sources of Cr(VI) include leather tanning, cooling tower blowdown, plating, electroplating, anodizing baths, rinse waters, etc. This article includes a survey of removal techniques for Cr(VI)-contaminated aqueous solutions. A particular focus is given to adsorption, membrane filtration, ion exchange, and electrochemical treatment methods. The primary objective of this article is to provide recent information about the most widely used techniques for Cr(VI) removal.

Influence of Metal Nanoparticles on the Soil Microbial Community and Germination of Lettuce Seeds

Abstract: Short term influence of silica, palladium, gold and copper nanoparticles on a soil microbial community and the germination of lettuce seeds are investigated in this study at two different concentrations of nanoparticles. Results show a statistically insignificant influence of the nanoparticles in the soil on the number of colony forming units, peak areas of methyl ester of fatty acids in the FAME profile or on the total soil community metabolic fingerprint (P > 0.05). Also, all nanoparticles tested in the study influenced the growth of lettuce seeds as measured through shoot/root ratios of the germinated plant (P < 0.05).

Metal Tolerance, Accumulation and Translocation in Poplar and Willow Clones Treated with Cadmium in Hydroponics

Abstract: To evaluate the phytoremediation capability of some poplar and willow clones a hydroponic screening for cadmium tolerance, accumulation and translocation was performed Rooted cuttings were exposed for 3 weeks to 50 μM cadmium sulphate in a growth chamber and morpho-physiological parameters and cadmium content distribution in various parts of the plant were evaluated Total leaf area and root characteristics in clones and species were affected by cadmium treatment in different ways Poplar clones showed a remarkable variability whereas willow clones were observed to be more homogeneous in cadmium accumulation and distribution This behaviour was further confirmed by the calculation of the bio-concentration factor (BCF) and the translocation factor (Tf) Mean values of all the clones of the two Salicaceae species showed that willows had a far greater ability to tolerate cadmium than poplars, as indicated by the tolerance index (Ti), calculated on the dry weight of roots and shoots of plants As far as the mean values of Tf was concerned, the capacity of willows to translocate was double that of poplars On the contrary, the mean values of total BCF in poplar clones was far higher with respect to those in willows The implications of these results in the selection of Salicaceae clones for phytoremediation purposes were discussed

Silicon Effects on Metal Tolerance and Structural Changes in Maize (Zea mays L.) Grown on a Cadmium and Zinc Enriched Soil

Abstract: Silicon presents a close relationship with the amelioration of heavy metals phytotoxicity. However, mechanisms of Si-mediated alleviation of metal stress remains poorly understood. This work aimed at studying the relationship between the accumulation of Si, Cd, and Zn and the tolerance and structural alterations displayed by maize plants grown on a Cd and Zn enriched soil treated with doses of Si (0, 50, 100, 150, and 200mg kg−1) as calcium silicate (CaSiO3). The results showed that the maize plants treated with Si presented not only biomass increasing but also higher metal accumulation. Significant structural alterations on xylem diameter, mesophyll and epidermis thickness, and transversal area occupied by collenchyma and midvein were also observed as a result of Si application. The deposition of silica in the endodermis and pericycle of roots seems to play an important role on the maize tolerance to Cd and Zn stress.

Photodegradation of Carbamazepine, Ibuprofen, Ketoprofen and 17α-Ethinylestradiol in Fresh and Seawater

Abstract: Photodegradation of four pharmaceuticals (i.e. carbamazepine, ibuprofen, ketoprofen and 17α-ethinylestradiol) in aqueous media was studied using a solar light simulator (Xe lamp irradiation) and sunlight experiments. These experiments were carried out in river and seawater and compared to distilled water. The latter was used to evaluate the direct photodegradation pathways. Irradiation time was up to 400 min and 24 days for the solar light simulator and sunlight assays, respectively. Pharmaceutical photodegradation followed a first-order kinetics and their half-lives calculated in every aqueous matrix. Moreover, the sensitizing effect of DOC was evaluated by comparison with the kinetics obtained in distilled waters. Ketoprofen was rapidly transformed via direct photolysis in all the waters under both sunlight (t 1/2 = 2.4 min) and simulated solar light simulator test (t 1/2 = 0.54 min). Under xenon lamp radiation, ibuprofen and 17α-ethinylestradiol were photodegraded at moderate rate with half-lives from 1 to 5 h. Finally, carbamazepine had the lowest photodegradation rate (t 1/2 = 8–39 h) attributable to indirect photodegradation. Indeed, its elimination was strongly dependent on the DOC concentration present in solution. Finally, several ketoprofen photoproducts were identified and plotted against solar light simulator irradiation time. Accordingly, the photodegradation pathway of ketoprofen was postulated.

Heavy Metal Pollution in Soils Around the Abandoned Mine Sites of the Iberian Pyrite Belt (Southwest Spain)

Abstract: This paper investigates the pollution load of selected trace elements in 32 soil samples collected around 21 different mining areas of the Iberian Pyrite Belt (Southwest Spain), integrating chemical data with soil parameters to help understand the partitioning and mobility of pollutants. The minesoils are depleted in acid neutralising minerals and show limiting physicochemical properties, including low pH values and very high anomalies of potentially hazardous metals. The total concentrations of As (up to 1,560 mg kg−1) and certain heavy metals (up to 2,874 mg kg−1 Cu, 6,500 mg kg−1 Pb, 6,890 mg kg−1 Zn, 62 mg kg−1 Hg and 22 mg kg−1 Cd) are two orders of magnitude above the soil background values. The close association of Cd and Zn with the carbonate content in lime-amended minesoils suggests metal immobilisation through adsorption and/or co-precipitation mechanisms, after acid neutralisation, whereas As and Pb are similarly partitioned into the soil and mostly associated with iron oxy-hydroxides.

Reuse of Domestic Greywater for the Irrigation of Food Crops

Abstract: As global water resources decline, reuse of domestic greywater for the irrigation of home gardens is quickly becoming widespread in many parts of the world. However, the sanitary implications of reusing greywater to water edible crops remain uncertain. This study examined the benefits and risks associated with domestic greywater reuse for the purposes of vegetable garden irrigation. Untreated (settled only) and treated (settling and slow sand filtration) greywater collected from a family home was analyzed for basic water quality parameters over a period of 8 weeks. During that time, both greywaters were used to irrigate individually potted plots of lettuce, carrots, and peppers in a greenhouse. Tap water was used as control. Upon maturity, plants were harvested and the edible portions tested for fecal coliforms and fecal streptococci, common indicators for the presence of pathogenic microorganisms. Heavy metals were not detected in the greywater, but both fecal coliforms and fecal streptococci were present in high levels, averaging 4 × 105/100 mL and 2,000/100 mL of greywater, respectively. Despite these high counts, no significant difference in contamination levels was observed between crops irrigated with tap water, untreated greywater, and treated greywater. Fecal coliform levels were highest in carrots and fecal streptococcus levels were highest on lettuce leaves. However, contamination levels for all crops were low and do not represent a significant health risk. Plant growth and productivity were unaffected by water quality, owing to the low N, P, and K levels of the greywater. These results reinforce the potential of domestic greywater as an alternative irrigation source.

Distribution of Road Salt Residues, Heavy Metals and Polycyclic Aromatic Hydrocarbons across a Highway-Forest Interface

Abstract: Automobile traffic pollutes roadside environments with a range of contaminants. In this study, we investigate the distribution patterns of different contaminant classes in topsoils across a highway-forest interface north-east of Vienna, Austria, in order to assess spatial pollutant distribution and evaluate the filtering effect of roadside forests. We collected soil samples along transects perpendicular to the highway, and analyzed the soils for road salt residues (Na), total and mobile heavy metals (Pb, Cd, Cu, Zn, Ni, Cr) as well as polycyclic aromatic hydrocarbons (PAHs). Roadside soil pollution was highly heterogeneous. All contaminants followed an exponential-like decrease with distance from the road, reaching background levels at 5 to 10 m from the road curb. Traffic-born heavy metals in the immediate roadside zone tended to be more mobile than heavy metals of predominantly geogenic origin at greater distances from the road; the presence of road salt residues could have contributed to the elevated heavy metal mobility near the road. The forest vegetation acted as filter for PAHs shown by a sharp concentration increase at the forest edge. PAHs are likely transported with airborne soot particles that are scavenged by the wax-coated coniferous needles at our study site.

Influence of Phosphate on the Arsenic Uptake by Wheat (Triticum durum L.) Irrigated with Arsenic Solutions at Three Different Concentrations

Abstract: In this study we have investigated the uptake and distribution of arsenic (As) and phosphate (Pi) in roots, shoots, and grain of wheat grown in an uncontaminated soil irrigated with solutions containing As at three different concentrations (0.5, 1 and 2 mg l−1) and in the presence or in the absence of P fertilization. Arsenic in irrigation water reduced plants growth and decreased grain yield. When Pi was not added (P−), plants were more greatly impacted compared to the plus Pi (P+) treatments. The differences in mean biomass between P− and P+ treatments at the higher As concentrations demonstrated the role of Pi in preventing As toxicity and growth inhibition. Arsenic concentrations in root, shoot and grain increased with increasing As concentration in irrigation water. It appears that P fertilization minimizes the translocation of As to the shoots and grain whilst enhancing P status of plant. The observation that P fertilization minimises the translocation of arsenic to the shoots and grain is interesting and may be useful for certain regions of the world that has high levels of As in groundwater or soils.

Influence of Freshwater Sediment Characteristics on Persistence of Fecal Indicator Bacteria

Abstract: Extended persistence of enteric bacteria in coastal sediments and potential remobilization of pathogens during natural turbulence or human activities may induce an increased risk of human infections. In this study, the effect of sediment characteristics such as particle grain size and nutrient and organic matter contents on the survival of fecal indicator bacteria (FIB) including total coliforms, Escherichia coli, and Enterococcus was investigated. The experimentation was carried out for 50 days in microcosms containing lake water and different contaminated freshwater sediments in continuous-flow and batch conditions. Results of this study revealed: (1) extended FIB survival in sediments up to 50 days, (2) higher growth and lower decay rates of FIB in sediments with high levels of organic matter and nutrients and small (mainly silt) grain size, and (3) longer survival of Enterococcus sp. compared to E. coli and total coliforms. FIB survival in sediments and possible resuspension are of considerable significance for the understanding of permanent microbial pollution in water column and therefore human risk during recreational activities.

Metal Accumulation by Woody Species on Contaminated Sites in the North of France

Abstract: Metal accumulation was investigated in a range of woody species that were planted on Cd-, Zn- and Pb- polluted sites in North of France. The study is unique in that we directly compare a large number of woody species (25). The highest accumulation of Zn and Cd was found in the Salicaceae family members with up to 950 mg Zn kg−1 dry weight (DW) and 44 mg Cd kg−1 DW in leaves of Populus tremula × Populus tremuloides. Zn content was positively correlated with Cd content, both in leaves and stems. Pb concentration was generally low and was species-independent. Oak and birch species accumulated more Mn as compared to other woody species. A seasonal variation in metal accumulation could be found. Although soil compositions and metal bioavailabilities differed amongst the experimental sites chosen in this study, variation of metal concentrations within a given species was small. High bioconcentration factors for poplar and willow suggested the high potential of these species over other woody species for metal accumulation. Taken together, these data suggest that poplar and willow species are good candidates for phytoremediation programmes.

Impact of Acid Mine Drainage (AMD) on Water Quality, Stream Sediments and Periphytic Diatom Communities in the Surrounding Streams of Aljustrel Mining Area (Portugal)

Abstract: Aljustrel mining area is located in the Iberian Pyrite Belt, one of the greatest concentrations of massive sulphide deposits that extends from Lousal (Portugal) to Aznalcollar (Spain). The surrounding streams, Roxo, Agua Azeda and Agua Forte, are influenced by the erosion of the tailing deposits and the input of acid mine drainage (AMD) from the abandoned Aljustrel pyrite mines, recently reopened in 2007. The purpose of this study was to understand how these adverse conditions influenced the stream sediments, water quality and periphytic diatom communities and establish the pre-restoration local conditions to judge the success of rehabilitation program now under way. For stream sediments, the highest metal concentration samples were found at sites F, G and H. Arsenic, Cu, Fe, Pb and Sb detected concentrations, generally exceeded the probable effect concentration values reaching level 4: the highest toxicity level. In surficial water samples of AMD affected sites (F, G and H), low pH values (1.5 to 3.5) and high metal concentrations of As (6,837 μg L−1), Cd (455 μg L−1), Cu (68,795 μg L−1), Fe (1,262,000 μg L−1), Mn (19,451 μg L−1), Pb (136 μg L−1), and Zn (264,377 μg L−1) were found. In these sites, the diversity index (H′) for diatoms was low (0.6 to 2.8) and the dominant taxa were Eunotia exigua (site F, 33.5%) and Pinnularia acoricola (abundances in sites: F, 86.8%; G, 88.5%; and H, 91.1%). In opposition, in less AMD impacted, H′ was high (1.5 to 4.6) and low metal concentrations and high pH were found. Achnanthidium minutissimum was the dominant taxon in (abundances in sites: A, 76.1% and B, 24.39%). Canonical correspondence analysis showed that spatial variation due to mine influence was more important than seasonal variation, which did not show any pattern.

Spatial and Temporal Variation of Inorganic Nitrogen Wet Deposition to the Yangtze River Delta Region, China

Abstract: Two-year (June 2003–May 2005) precipitation samples were collected from three monitoring sites with similar economy development level in the Yangtze River Delta Region of China to investigate the spatial–temporal variation of inorganic N wet deposition. The results showed that the Yangtze River Delta Region had higher inorganic N wet deposition than the northwestern, northern, or southern China. There was spatial variation of inorganic N wet deposition. The positive relationship between inorganic N deposition and precipitation suggested that rainfall amount might be an important factor influencing the wet deposition of inorganic N. Deposition of inorganic N occurred mainly in the spring and summer season (March–August; 70% of the annual total), which was in accord with seasonal distribution of precipitation. However, a negative logarithmic relation between rainfall and inorganic N concentration in rainwater indicated the dilution effect of rainwater on inorganic N concentration. Distinguished variation of NH4 +/NO3 − ratio in wet deposition existed in the different time scale. NH4 +/NO3 − ratio evidently decreased from 6 in 1980s to 1.2 in 2003/2005 and greatly varied between 0.3 and 9.9 within a year. NH4 +/NO3 − ratio peaked in accordance with nitrogen-fertilizing time during crop growing season. Annual alternate appearance of the 15N-enriched and 15N-depleted periods coincided with the temporal variation of NH4 +/NO3 − ratio, which was closely related to the timing of fertilization and seasonal climate changes, suggesting the effect of NH4 + sources in the wet deposition.

Adsorption of Lead and Cadmium from Aqueous Solution by Using Almond Shells

Abstract: The potential of almond shells was assessed for adsorption of heavy metal ions such as Pb2+ and Cd2+ from aqueous solution. Almond shells were pretreated separately with 0.4 mol/L NaOH, 0.4 mol/L HNO3, and distilled water and their adsorption abilities were compared. Batch adsorption experiments were carried out as a function of the initial ion concentration, pH, and adsorbent dosage. Adsorption isotherms of metal ions on adsorbents were determined and correlated with common isotherm equations such as Langmuir, Freundlich, and BET models. The alkali-modified almond shells had adsorption capacities for Pb2+ from 2 to 9 mg/g and for Cd2+ from 2 to 7 mg/g, which was much higher than acid- and water-pretreated adsorbents. Experimental results showed that the best pH for adsorption was 5–6 and the adsorption values decreased with lowering pH. Isotherm models indicated the best fit for Langmuir model for alkali-modified almond shells. In comparing the parameters of the models, it was observed that the affinity of almond shells for adsorption of lead is stronger than affinity for adsorption of cadmium.

Distribution, Seasonal Variations and Ecotoxicological Significance of Heavy Metals in Sediments of Cross River Estuary Mangrove Swamp

Abstract: The concentrations and distribution of selected heavy metals in epipelic and benthic sediments of Cross River Estuary mangrove swamp were studied to determine the extent of anthropogenic inputs from industrial activities and to estimate the effects of seasonal variations on geochemical processes in this tropical estuarine ecosystem. The analysis shows that the mean concentrations (mg/kg, dw) of Cu, Cr, Fe, Ni, Pb, V and Zn vary from 24.1–32.4, 19.9–27.4, 666.7–943.5, 15.2–30.3, 8.8–24.7, 2.2–6.9 and 140.1–188.9, respectively. An important observation is that, in general, lowest metal concentrations are found during the dry season, compared to wet season. Pollution load index (PLI) and index of geoaccumulation (I geo) revealed overall low values but the enrichment factors (EFs) for Cr, Zn, and V were high, and this reflects the intensity of anthropogenic inputs related to industrial discharge into the estuary. The mean concentrations of Zn, Cu and to some extent Ni exceeded the Effects Range—Low (ERL) and Threshold Effect Level (TEL) values in majority of the samples studied, indicating that there may be some ecotoxicological risk to organisms living in these sediments. The inter-element relationship revealed the identical source of elements in the sediments of the studied area. The concentration of heavy metals reported in this work will be useful as baselines for comparison in future sediment quality studies.

Cadmium Uptake From Soil by Maize With Intercrops

Abstract: A pot experiment was conducted to study the effect of 7 intercrops on Cd uptake by maize. The intercrops included cowpea (V. unguiculata (L.) Walp.), purple haricot (L. purpureus (L.) Sweet.), chickpea (C. arietinum L.), alfalfa (M. sativa L.), teosinte (E. mexicana Schrad.), amaranth (A. paniculatus L.) and rape (B. napus L.). The results showed that most legumes substantially increased Cd uptake by maize during vegetative growth. Leaf tissue of maize grown with legumes averaged 5.05 mg kg−1 higher Cd than that grown with nonlegumes, or 2.42 mg kg−1 higher than the control. However, the effect of intercrops on Cd uptake by maize became small during reproductive growth. Since chickpea resulted in a relatively large maize bioconcentration factor of 2.0 and large transfer factor of 0.55, it is regarded as the most valuable intercrop for enhancing Cd extraction from soil by maize. The results suggest that intercropping might be a feasible practice in facilitating phytoremediation.

Photocatalytic Degradation of Azo Dye Reactive Orange 16 by TiO2

Abstract: Photocatalytic degradation of hydrolyzed reactive orange 16 (RO16) using titanium dioxide (TiO2) was analyzed in our study. The effects of various parameters, such as photocatalyst amount, RO16 concentration, light intensity, and temperature on photocatalytic degradation were investigated. Decolorization of hydrolyzed RO16 resulted in an decreasing of toxicity (EC50 = 76.54 ± 2.16). It was found that the decolorization efficiency was 87% after 20-min reaction and 100% after 80-min reaction. The total mineralization was 70% after 20 min and nearly 100% after 120 min, respectively. The results indicate that color degradation was faster than the decrease of total organic carbon. The photocatalytic degradation process was well described by first-order reaction. The final mineralization product was acetamide and the intermediate products were identified by gas chromatography–mass spectroscopy.

Reduction of Hexavalent Chromium in Soil and Ground Water Using Zero-Valent Iron Under Batch and Semi-Batch Conditions

Abstract: Chemical remediation of soil and groundwater containing hexavalent chromium (Cr(VI)) was carried out under batch and semi-batch conditions using different iron species: (Fe(II) (sulphate solution); Fe0G (granulated elemental iron); ZVIne (non-stabilized zerovalent iron) and ZVIcol (colloidal zerovalent iron). ZVIcol was synthesized using different experimental conditions with carboxymethyl cellulose (CMC) and ultra-sound. Chemical analysis revealed that the contaminated soil (frank clay sandy texture) presented an average Cr(VI) concentration of 456 ± 35 mg kg−1. Remediation studies carried out under batch conditions indicated that 1.00 g of ZVIcol leads to a chemical reduction of ∼280 mg of Cr(VI). Considering the fractions of Cr(VI) present in soil (labile, exchangeable and insoluble), it was noted that after treatment with ZVIcol (semi-batch conditions and pH 5) only 2.5% of these species were not reduced. A comparative study using iron species was carried out in order to evaluate the reduction potentialities exhibited by ZVIcol. Results obtained under batch and semi-batch conditions indicate that application of ZVIcol for the “in situ” remediation of soil and groundwater containing Cr(VI) constitutes a promising technology.

A Simple Feedforward Neural Network for the PM10 Forecasting: Comparison with a Radial Basis Function Network and a Multivariate Linear Regression Model

Abstract: The problem of air pollution is a frequently recurring situation and its management has social and economic considerable effects. Given the interaction of the numerous factors involved in the raising of the atmospheric pollution rates, it should be considered that the relation between the intensity of emission produced by the polluting source and the resulting pollution is not immediate. The aim of this study was to realise and to compare two support decision system (neural networks and multivariate regression model) that, correlating the air quality data with the meteorological information, are able to predict the critical pollution events. The development of a back-propagation neural network is presented to predict the daily PM10 concentration 1, 2 and 3 days early. The measurements obtained by the territorial monitoring stations are one of the primary data sources; the forecasting of the major weather parameters available on the website and the forecasting of the Saharan dust obtained by the “Centro Nacional de Supercomputacion” website, satellite images and back trajectories analysis are used for the weather input data. The results obtained with the neural network were compared with those obtained by a multivariate linear regression model for 1 and 2 days forecasting. The relative root mean square error for both methods shows that the artificial neural networks (ANN) gives more accurate results than the multivariate linear regression model mostly for 1 day forecasting; moreover, the regression model used, in spite of ANN, failed when it had to fit spiked high values of PM10 concentration.

Nitrogen and Phosphorus Remediation by Three Floating Aquatic Macrophytes in Greenhouse-Based Laboratory-Scale Subsurface Constructed Wetlands

Abstract: In the greenhouse and container nursery production industry there is potential for runoff of nitrogen (N) and phosphorus (P), which may contaminate surface and groundwater. Since the 1950s constructed wetlands (CWs), as a simple, low-technology method, have been shown to effectively treat agricultural, industrial, and municipal wastewater. We investigated the N and P attenuating potential of three floating hydrophytes planted in a laboratory-scale subsurface flow (SSF) CW system. Over an 8-week period plants were supplied with N and P (0.39 to 36.81 mg·L−1 N and 0.07 to 6.77 mg·L−1 P) that spanned the rates detected in nursery runoff between the discharge and inflow locations of a commercial nursery currently employing CWs. Whole plant dry weight was positively correlated with N and P supplied. Highest N recovery rates were exhibited by water hyacinth (Eichhornia crassipes [Mart.] Solms.) and water lettuce (Pistia stratiotes L.). P recovery rates were similar for water hyacinth, water lettuce, and dwarf redstemmed parrotfeather (Myriophyllum aquaticum [Vell.] Verdc.). These floating hydrophytes can be cultivated in a SSF CW to remediate runoff losses of N and P. The possibility exists for integrating them into a polycultural remediation system that includes emergent aquatic macrophytes for processing and polishing nursery/greenhouse wastewater.

Distribution and Accumulation of Copper and Cadmium in Soil–Rice System as Affected by Soil Amendments

Abstract: The effects of seven amendments on the distribution and accumulation of copper and cadmium in a soil–rice system were investigated using a pot experiment. Results showed that application of limestone, calcium magnesium phosphate (Ca–Mg–P fertilizer), calcium silicate (silicon fertilizer), Chinese milk vetch, pig manure, and peat significantly decreased the concentrations of Cu and Cd in rice roots by 24.8–75.3% and 9.7–49.9%, respectively. However, no significant difference was observed between zinc sulfate (zinc fertilizer) and the control treatment. The concentrations of Cu and Cd in different parts of rice followed the order: root > straw > grain, and all amendments restrained the transfer of Cu and Cd from rice root to stem. Copper and Cd concentrations in rice stems at the tillering stage were the highest, and then decreased from the tillering stage to the heading stage. However, they increased again at the ripening stage. The results also showed that application of amendments changed Cu and Cd solubility in soil and decreased their bioavailability, which resulted in the reduction of Cu and Cd uptake by rice. Significant correlations between the concentrations of Cu and Cd in soil solutions and in rice stems were found. The result demonstrated that limestone has the best efficiency among all the amendments used in reducing Cu and Cd contamination to rice production.

Polycyclic Aromatic Hydrocarbons in Intertidal Marine Bivalves of Sunderban Mangrove Wetland, India: An Approach to Bioindicator Species

Abstract: The paper presents the first comprehensive account of congener profiles of polycyclic aromatic hydrocarbons (PAHs) in intertidal bivalve mollusks [Meretrix meretrix, Macoma birmanica, and Sanguilonaria (Soletellina) acuminata] of Sunderban mangrove wetland (India). The main aim of this work was to use the bivalves as bioindicators of the contamination of the 16 USEPA PAH. The PAH profile in bivalves is largely dominated by a petrogenic fingerprint, with over-imposition of pyrolytic PAH sources, as evidenced by diagnostic molecular ratios. Bioaccumulation factors (BAF) of individual compounds from the sediments were calculated, and it reveals overall higher values in the visceral mass of the bivalves. S acuminata showed significantly higher levels of PAHs, especially the high molecular weight (HMW) PAHs, compared to the other two species as a sensitive indicator of trace organic stress in future monitoring programs.

Sources of Elevated Chloride in Local Streams: Groundwater and Soils as Potential Reservoirs

Abstract: Several recent reports document increasing concentrations of chloride in surface waters of northeastern and midwestern North America. These patterns, together with high summertime baseflow concentrations, suggest the possibility of short-term retention of winter-applied chloride within catchments. This study examined the potential of groundwater and soils to act as reservoirs of Cl within the watershed of a small rural stream in New York that has shown a doubling of Cl over the past two decades and almost constant concentrations across seasons. Groundwater samples were obtained from 20 private drinking wells distributed around the catchment to determine whether concentrations were at or greater than surface waters and so could act as a source to the stream. In 16 of the 20 wells, chloride concentrations were lower (mean of 16 samples = 4.10 mg Cl/L (standard deviation = 4.8)) than concurrent streamwater concentrations (mean of eight locations sampled on two dates = 28.9 (5.8)). Four wells, however, showed higher concentrations ranging from 35 to 230 mg Cl/L suggesting either point source contamination or very heterogeneous groundwater chloride sources. Soil cores from the catchment were irrigated in the laboratory with a NaCl solution for 2 weeks followed by 2 weeks irrigation with a chloride-free solution. Chloride concentrations in core leachates were lower than in the irrigation solution during the first 2 weeks indicating some retention of Cl within the cores. After cores were irrigated with chloride-free water, leachate concentrations declined but would not reach streamwater concentrations until the equivalent of 15 cm of precipitation was added to the core.

Nutrient Removal in Pilot-Scale Constructed Wetlands Treating Eutrophic River Water: Assessment of Plants, Intermittent Artificial Aeration and Polyhedron Hollow Polypropylene Balls

Abstract: Seven experimental pilot-scale subsurface vertical-flow constructed wetlands were designed to assess the effect of plants [Typha latifolia L. (cattail)], intermittent artificial aeration and the use of polyhedron hollow polypropylene balls (PHPB) as part of the wetland substrate on nutrient removal from eutrophic Jinhe River water in Tianjin, China. During the entire running period, observations indicated that plants played a negligible role in chemical oxygen demand (COD) removal but significantly enhanced ammonia–nitrogen (NH4–N), nitrate–nitrogen (NO3–N) total nitrogen (TN), soluble reactive phosphorus (SRP) and total phosphorus (TP) removal. The introduction of intermittent artificial aeration and the presence of PHPB could both improve COD, NH4–N, TN, SRP and TP removal. Furthermore, aerated wetlands containing PHPB performed best; the following improvements were noted: 10.38 g COD/m2 day, 1.34 g NH4–N/m2 day, 1.04 g TN/m2 day, 0.07 g SRP/m2 day and 0.07 g TP/m2 day removal, if compared to non-aerated wetlands without PHPB being presented.

Aerosol Inorganic Ions in a Semiarid Region on the Southeastern Spanish Mediterranean Coast

Abstract: PM2.5 and PM10 samples were collected in the urban atmosphere of Elche (southeastern Spain) between December 2004 and November 2005. The samples were analyzed for mass and water-soluble inorganic ions (Na+, $${\text{NH}}^{{\text{ + }}}_{{\text{4}}}$$ , K+, Ca2+, Mg2+, Cl−, $${\text{NO}}^{{\text{ - }}}_{{\text{3}}}$$ and $${\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}}$$ ) with the aim of investigating the influence of the climatic and geographic features of a coastal semiarid area on the contribution of these species to PM levels. Secondary inorganic ions ( $${\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}}$$ , $${\text{NO}}^{{\text{ - }}}_{{\text{3}}}$$ , $${\text{NH}}^{{\text{ + }}}_{{\text{4}}}$$ ) were the major components in the fine fraction (PM2.5), accounting for 40% of the total mass. The relationship between non-marine $${\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}}$$ and $${\text{NH}}^{{\text{ + }}}_{{\text{4}}}$$ indicated that fine sulfate particles were completely neutralized by ammonium. In the coarse fraction (PM10–2.5), nitrate (as NaNO3 and Ca(NO3)2), together with crustal (CaCO3) and marine species (NaCl) accounted for almost 50% of the total mass. Fine sulfate and coarse nitrate showed summer maximums. In contrast, the concentrations of fine $${\text{NO}}^{{\text{ - }}}_{{\text{3}}}$$ were lowest in the warm period. Ammonium presented both winter and summer maximums. The levels of marine ions, except for coarse Cl−, were highest in summer when the dominant wind flow is from the sea. No significant seasonal variations were observed for coarse Ca2+ and $${\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}}$$ . The concentrations of all inorganic ions increased during Saharan dust events, in particular, fine $${\text{NH}}^{{\text{ + }}}_{{\text{4}}}$$ and $${\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}}$$ and coarse $$NO_3^ - $$ . Coarse calcium was proved not to be a good tracer for this type of episode in our region since the average levels of this cation are elevated and the relative increase in its concentrations during African events was not as high as expected.

Biofiltration for Reducing Methane Emissions from Modern Sanitary Landfills at the Low Methane Generation Stage

Abstract: The performance of a lab-scale model biofilter system was investigated to treat CH4 gas emitted from modern sanitary landfills using landfill cover soil as the filter bed medium. From the batch experiment to measure the influence of moisture content and temperature of the filter medium on CH4 removal capacity of a biofilter system, the optimum moisture content and temperature were found to be 10–15% by weight and 25–35°C, respectively. From the model biofilter experiment to measure the influence of inlet CH4 concentration and landfill gas inflow rate on CH4 removal capacity of a biofilter system, it was found that the removal percentage of CH4 increased as the inlet CH4 concentration decreased. Up to a landfill gas inflow rate of 1,000 mL min−1 (empty bed retention time = 7.7 min), the CH4 removal efficiency of the biofilter was able to reach 100%. Up to CH4 loading rate of 278.5 g CH4 m−3 h−1, the ratio of elimination capacity to CH4 loading rate was 1 while they were 0.68 and 0.34 at CH4 loading rate of 417.8 and 557.1 g CH4 m−3 h−1, respectively. The CH4 removal by biofilter was also confirmed by measuring the change of temperature and moisture content of the filter medium in the model biofilter. The results demonstrated that the installation of a properly managed biofilter system should be effective to reduce atmospheric CH4 emissions from modern sanitary landfills at the low CH4 generation stage.

Assessment of the Salinization Process at the Coastal Area with Hydrogeochemical Tools and Geographical Information Systems (GIS): Selçuk Plain, Izmir, Turkey

Abstract: The salinization process was investigated with hydrogeochemical tools to evaluate the origin of salinity in the Selcuk Plain. Na/Cl and Cl/Br molar ratios of coastal zone that covers an alluvial aquifer, karstic discharges, and a wetland are similar to the local seawater ratio. According to mixing ratios, seawater addition can reach 9–18% in both seasons at the coastal zone especially in karstic springs that are a kind of seawater–freshwater mixing points. A thematic map of the Salinization zone was constructed for the Selcuk Plain using geographical information system tools with different parameters such as major ion ratios, EC values, mixing ratios, and sodium adsorption ratio values. High correlation between Cl and Br, B, Li and Sr explains the salinization process that comes from marine intrusion. The δ 18O and δD composition of water samples varies between −6.7‰ and −2.9‰; −37‰ and −20‰, respectively. The coastal zone waters are plotted on the mixing line due to the effects of the salinization process in the plain.

Use of Enrichment Factors for the Assessment of Heavy Metal Contamination in the Sediments of Koumoundourou Lake, Greece

Abstract: Lake Koumoundourou is a shallow meromictic lake located ∼11 km NW of Athens. It is surrounded by various industries and oil refineries, which contaminate the lake by oil spills and leakage. Moreover, the lake receives freshwater from underwater springs, plus drainage from industrialized catchment and Athens landfill. Potential contamination of the lakes’ sediments in heavy metals and metalloids was assessed by means of enrichment factors (EFs) estimated against local preindustrial core sediment; elements were normalized to loss on ignition. EFs revealed that surface sediments were enriched in Pb (×10.2), Cu (×6.7), V (×5.1), Ni (×4.1), and other heavy metals. The use of EFs is recommended as a reliable method for heavy metal contamination assessment, provided that (1) element contents are corrected following a careful normalization procedure, (2) local preindustrial sediment is used as reference, and (3) reference sediment should be unaffected by diagenetic alterations.

The Environmental Impact of the Platinum Group Elements (Pt, Pd, Rh) Emitted by the Automobile Catalyst Converters

Abstract: The present paper deals with an extensive review of literature concerning the platinum group elements (PGEs), and their impact on the environment. The increased number of cars and vehicles fitted with catalytic converters, has been linked with the wide spread in the environment of the PGEs, i.e. Pt, Pd and Rh. Numerous studies present compelling evidence that the catalytic converters, do not only minimize the pollution caused by the car exhaust fumes, but also they release in the environment particulate matter containing the above noble elements, which accumulate in the soil, and plants, or remain suspended in the air, being transported to large distances. Indeed, the concentration of these noble elements in the soil and plants has increased significantly during the last 10–15 years, especially along the road side of high ways. Assessment of the PGEs health risk was originally based on measuring the body fluid in Pt, Pd and Rh content of occupationally involved people, as well as of the general population. Recent results based on cellular studies show that the PGEs are related to respiratory sensitization, allergic reactions, dermatitis, urticaria, damage of the epithelial lung cells, asthma, rhinoconjuctivitis, lymphocyte proliferation and cytokine release and possibly to cancer. In spite of the progress attained, more work is necessary for an accurate health risk assessment.

Kinetics and Energetics of Azo Dye Decolorization by Pycnoporus sanguineus

Abstract: Trypan Blue, an azo dye, was decolorized using the self-immobilizing fungal biomass of Pycnoporus sanguineus. The extent and the rate of dye decolorization were directly proportional to the initial dye concentration (20–60 mg L−1) and the reaction temperature (25–45°C). Mass transfer within and outside the pellets did not limit dye degradation. The apparent kinetics of the decolorization reaction followed a first-order behavior. Activation energy for the biological decolorization was calculated at 23 kJ mol−1. The decolorization process was endothermic with the enthalpy and entropy values calculated at 45.6 kJ mol−1 and 146 J mol−1 K−1, respectively. Based on the value of Gibbs free energy change, the decolorization reaction under the conditions studied was non-spontaneous below 39°C but was spontaneous at higher temperatures.