Use of USLE/GIS Methodology for Predicting Soil Loss in a Semiarid Agricultural Watershed

The Universal Soil Loss Equation (USLE) is an erosion model to estimate average soil loss that would generally result from splash, sheet, and rill erosion from agricultural plots. Recently, use of USLE has been extended as a useful tool predicting soil losses and planning control practices in agricultural watersheds by the effective integration of the GIS-based procedures to estimate the factor values in a grid cell basis. This study was performed in the Kazan Watershed located in the central Anatolia, Turkey, to predict soil erosion risk by the USLE/GIS methodology for planning conservation measures in the site. Rain erosivity (R), soil erodibility (K), and cover management factor (C) values of the model were calculated from erosivity map, soil map, and land use map of Turkey, respectively. R values were site-specifically corrected using DEM and climatic data. The topographical and hydrological effects on the soil loss were characterized by LS factor evaluated by the flow accumulation tool using DEM and watershed delineation techniques. From resulting soil loss map of the watershed, the magnitude of the soil erosion was estimated in terms of the different soil units and land uses and the most erosion-prone areas where irreversible soil losses occurred were reasonably located in the Kazan watershed. This could be very useful for deciding restoration practices to control the soil erosion of the sites to be severely influenced.     

Distribution of PAHs in Surface Soils from Petroleum Handling Facilities in Calabar

The level of concentrations of polycyclic aromatic hydrocarbons (PAHs) in surface soils from petroleum handling facilities (kerosene tank, generating plant, petrol stations, mechanic workshops, leaking pipeline and air port fuel dump) from Calabar metropolis southeastern Nigeria was determined by gas chromatography/ mass spectrometry. The results show that total polycyclic aromatic hydrocarbons (PAHs) varied from 1.80 to 334.43 mg/kg with a mean of 50.31 mg/kg. The lowest value of 1.80 mg/kg was obtained from petrol station while the highest value of 334.43 mg/kg was obtained from facility characterised by petrol stations and mechanic workshops. The ratio of phenanthrene/anthracene and fluoranthene/pyrene, varied from 0.43 to 27.72 and from 0.14 to 17.76 respectively. These ratios indicate various sources for the PAH. The two to three ring PAHs are the most abundant. Based on the PAH ratios and content alone it is not possible to distinguish between contribution from motor vehicle exhaust, gasoline spillage, used engine oil or petroleum production. However, considering the area of the study, it is very likely that the major source of soil contamination is originating from petroleum product.     

Ozone pre-treatment as improver of PAH removal during anaerobic digestion of urban sludge

Polycyclic aromatic hydrocarbons are ubiquitous persistent pollutants. They may accumulate in sludge during wastewater treatment because of their low biodegradability and their hydrophobic characteristics. Combination of ozonation and anaerobic digestion may be efficient to remove PAHs naturally present in sludge. The objective of this study was to investigate the impact of ozone pre-treatment, with and without surfactant addition, on the anaerobic degradation of 12 PAHs (from low to high molecular weight). Under anaerobic digestion without ozonation pre-treatment, the highest removals were obtained for the lightest PAHs (3-aromatic rings). Ozonation pre-treatment of sludge allowed to increase biodegradability or bioavailability of each PAH, and the PAH removals were well correlated to the PAH solubility. Finally, addition of tyloxapol before sludge ozone pre-treatment had antagonist effects on PAH removal during anaerobic digestion: negative impact on anaerobic ecosystem activity and improvement of PAH bioaccessibility (particularly the PAHs with the highest octanol water partition coefficients).     

Effect of pre-treatment and supporting media on Ni(II), Cu(II), Al(III) and Fe(III) sorption by plant root material

In this work Paspalum notatum root material was used to elucidate the influence of acid leaching pre-treatment and of sorption medium on metal adsorption. Ground P. notatum root was leached with 0.14M HNO(3). Leached root material (LRM) and non-leached root material (NLRM) were employed to flow sorption of Ni(II), Cu(II), Al(III) and Fe(III) in 0.5M CH(3)COONH(4) medium at pH 6.5. For LRM the sorption was also studied in 0.5M KNO(3) medium. The acid pre-treatment increased the sorption capacity (SC) for all ions studied. For the KNO(3) medium, Cu(II) and Fe(III) sorption was higher than in CH(3)COONH(4) and the type of the Ni(II) isotherm's model changed. The Freundlich model was the most representative isotherm model to describe metallic ions sorption. The (1)H NMR spectra showed differences between LRM and NLRM and the acid-basic potentiometric titration elucidated that acid-leaching procedure affected the root material sorption sites once only two predominant sorption sites were found for LRM (phenolic and amine, both able cations sorption) and five sorption sites (two carboxylic, amine and two phenolic) were founded for NLRM.     

Biochemical responses in Salmo salar muscle following exposure to ethynylestradiol and tributyltin

This study investigated the effects of nominal concentrations of two endocrine-disrupting chemicals (EDCs) on fish physiology. The effects of the synthetic pharmaceutical estrogen ethynylestradiol (EE(2)) and the antifoulant tributyltin (TBT) were investigated in exposure studies with immature Atlantic salmon, Salmo salar. Fish were exposed for 7 days to waterborne EE(2), TBT, or a combination of both. The activities of lactate dehydrogenase (LDH), acetylcholinesterase (AchE) and glutathione S-transferase (GST), and lactate and glycogen content were determined in samples of fish muscle. Fish exposed to EE(2) for 3 days responded rapidly with increasing AchE and GST activities and increasing lactate content. These responses were limited to the first 3 days of exposure and had disappeared by day 7, indicating that the fish had adapted to EE(2) exposure. Compared to the controls, TBT increased AchE and LDH activity, inhibited GST activity and had no effect on lactate content. When mixed, the highest concentration of EE(2) increased the effect of TBT on lactate content. However, fish exposed to a lower concentration of EE(2) in combination with TBT had the lowest lactate content. Effects on AchE and LDH activities were smaller when TBT was combined with EE(2) compared to TBT alone. This suggests that TBT and EE(2) influence biochemical processes in fish muscle, acting on different organizational levels, by antagonistic and synergistic mechanisms.     

Biodegradability of alkylates as a sole carbon source in the presence of ethanol or BTEX

The biodegradability of alkylate compounds in serum bottles was investigated in the presence and absence of ethanol or benzene, toluene, ethylbenzene, and p-xylene (BTEX). The biomass was acclimated to three different alkylates, 2,3-dimethylpentane, 2,4-dimethylpentane and 2,2,4-trimethylpentane in porous pot reactors. The alkylates were completely mineralized in all three sets of experiments. They degraded more slowly in the presence of BTEX than in their absence because BTEX inhibited the microbial utilization of alkylates. However, in the presence of ethanol, their slower biodegradation was not related to inhibition by the ethanol. Throughout the experiments alkylates, ethanol, and BTEX concentrations did not change in the sterile controls.     

Future climate scenarios and rainfall--runoff modelling in the Upper Gallego catchment (Spain)

Global climate change may have large impacts on water supplies, drought or flood frequencies and magnitudes in local and regional hydrologic systems. Water authorities therefore rely on computer models for quantitative impact prediction. In this study we present kernel-based learning machine river flow models for the Upper Gallego catchment of the Ebro basin. Different learning machines were calibrated using daily gauge data. The models posed two major challenges: (1) estimation of the rainfall-runoff transfer function from the available time series is complicated by anthropogenic regulation and mountainous terrain and (2) the river flow model is weak when only climate data are used, but additional antecedent flow data seemed to lead to delayed peak flow estimation. These types of models, together with the presented downscaled climate scenarios, can be used for climate change impact assessment in the Gallego, which is important for the future management of the system.     

Challenges in quantifying biosphere-atmosphere exchange of nitrogen species

Recent research in nitrogen exchange with the atmosphere has separated research communities according to N form. The integrated perspective needed to quantify the net effect of N on greenhouse-gas balance is being addressed by the NitroEurope Integrated Project (NEU). Recent advances have depended on improved methodologies, while ongoing challenges include gas-aerosol interactions, organic nitrogen and N(2) fluxes. The NEU strategy applies a 3-tier Flux Network together with a Manipulation Network of global-change experiments, linked by common protocols to facilitate model application. Substantial progress has been made in modelling N fluxes, especially for N(2)O, NO and bi-directional NH(3) exchange. Landscape analysis represents an emerging challenge to address the spatial interactions between farms, fields, ecosystems, catchments and air dispersion/deposition. European up-scaling of N fluxes is highly uncertain and a key priority is for better data on agricultural practices. Finally, attention is needed to develop N flux verification procedures to assess compliance with international protocols.     

Geochemical fractions of copper in soil chronosequences of selected European floodplains

The influence of soil formation on copper sorption is documented based on chronosequences of soils from three river floodplains in Europe (Danube, Ebro and Elbe). Sequential extraction was used to fractionate copper in original and spiked soils in order to study the long-term and short-term behaviour of copper retention. Copper partitioning among defined geochemical fractions was mainly determined by soil pH and the contents of carbonates, organic matter and Fe-/Mn-oxides and hydroxides. Copper extracted with NH(2)OH.HCl correlated well with the contents of crystalline Fe-oxides and hydroxides, demonstrating increasing retention capacity with progressing soil development. Copper retained in original soils was found in more strongly bound fractions, whereas sorption of freshly added copper was primarily influenced by the presence of carbonates. Beyond the effect of progressing soil formation, variations in organic carbon contents due to different land use history affected the copper retention capacity of the investigated soils.     

Occurrence of alkylphenolic substances in a Great Lakes coastal marsh, Cootes Paradise, ON, Canada

Occurrence and fate of alkylphenols (APs), known endocrine disruptors, were investigated in a Great Lakes coastal wetland, Cootes Paradise, ON. The wetland, which receives discharges from a Wastewater Treatment Plant (WTP) and several Combined Sewer Overflows (CSOs), is an important spawning ground for fish and crucial habitat for other fauna. Elevated concentrations of nonylphenol ethoxylates (NPEs) and their degradation product nonylphenol (NP) were found in water and sediment samples near the sources. Since transfer of APs through the food chain is of concern, we compared their concentrations in invertebrates from clean and contaminated sites. The results reveal transfer of alkylphenolics from sediments to biota and their accumulation in the invertebrate tissue, particularly the highly hydrophobic 4-NP, whose concentrations ranged from 1.9 to 6.3 microg g(-1). To our knowledge, this is the first study to evaluate AP concentrations in tissue of benthic invertebrates under real environmental conditions.