The use of enhanced-flushing technologies has emerged as a promising technique for the remediation of sites contaminated with immiscible liquids. An important aspect for the effective remediation of these sites depends on the physical heterogeneity of the subsurface and the related distribution of immiscible liquid present within porous media. Recent interest has developed in using mass flux-based approaches to evaluate remediation success and performance for immiscible liquid-contaminated sites. The unique focus of these experiments was to evaluate trichloroethene (TCE) mass flux behavior and mass removal effectiveness for various solubilization agents when the distribution of immiscible liquid is uniform. In order to accurately compare the performance of each enhanced-solubilization agent, the distribution of immiscible liquid must be consistent and uniform. Previous dissolution experiments have typically relied upon injecting immiscible liquid into the porous media which can result in nonuniform immiscible liquid distribution causing nonideal dissolution and mass flux behavior (i.e., immiscible liquid fingering and bypass flow). Homogeneous 20/30 quartz sand was thoroughly mixed with a predetermined amount of immiscible liquid TCE and packed into columns to ensure that uniform distributions of residually saturated TCE (S N = 8-11%) were created. These columns were then flushed with a specific enhanced-solubilization flushing agent to initiate dissolution. Of the four enhanced-solubilization used, the lower solubilization power flushing agents (i.e., cyclodextrins) resulted in more ideal TCE mass flux behavior in which mass flux is maximized and maintained during the majority of the flushing experiment. A strong positive correlation (R ² = 0.92) exists between enhancement factor and mass flux ideality which may suggest that these systems were in fact uniformly distributed with immiscible liquid. In order to appropriately evaluate and compare the effectiveness of specific solubilization agents, it is important to consider mass flux behavior in conjunction with elution behavior and mass removal efficiency.

Annually, sawmills and other wood-processing factories generate a significant amount of scrap materials which are sent to landfills or incinerated. The amount of residue generated in Australia annually is estimated at 200,000 tonnes. A research project conducted at RMIT University explored utilizing these waste materials as particleboard furnish. The research team has now established a methodology for making particleboard in the laboratory using 100% hardwood sawmill residues, developing a particleboard product made in the laboratory which has acceptable mechanical properties and density profiles in accordance with the Australian Standards. However, this board product has some perceived issues which have been hindering ready commercial uptake. The current product requires a 10% higher resin load, has a 10% higher board density, and requires 10% longer pressing times compared to normal softwood particleboard. The paper presents an analysis of the current production process of particleboard to investigate the economic feasibility of particleboard production using hardwood sawmill residues. A major challenge in the analysis is converting the environmental benefit of utilizing large quantities of sawmill residue to a monetary term. Investigation of the global impact of particleboard by considering emission of carbon dioxide to the atmosphere is also included. A comparison is presented between different methods of disposing wood residues to understand the environmental benefit of using hardwood residue in particleboard.

Mesostructured iron oxyhydroxide (FeO x ) and iron oxyhydroxide-phosphate (FeO x P) composites were organized using dodecylsulfate surfactant as a template. X-ray diffraction studies depicted a lamellar structure of the product. Ion exchange and solvent extraction methods were employed for the removal of the surfactant. Carboxylate ions exchanged lamellar type mesostructured material reorganized to a wormhole-like mesoporous material when heated under N₂ atmosphere. Surfactant was completely removed by carboxylate ions as observed by the Fourier transform infrared spectra. High surface area acetate-exchanged FeO x (230 m² g⁻¹) was obtained after the surfactant removal from the composite (2.8 m² g⁻¹). Surface area of acetate-exchanged FeO x P was the highest (240 m²g⁻¹) after the removal of the surfactant. Local structure of iron species of FeO x was investigated by X-ray absorption fine structure spectroscopy. Further, Fe···Fe bond appeared at 3.21-3.25 Å with coordination number 2-3, showing a high degree of un-saturation of Fe···Fe bonds. As compared with bulk iron oxyhydroxide and iron-intercalated montmorillonite, the mesoporous iron materials were highly effective for arsenic removal from low concentrations of aqueous solutions. Furthermore, mesoporous iron materials were stable in aqueous phase.

In order to recover and reuse water in the Kraft mill process, evaluation of separate streams is required to identify toxic compounds or microcontaminants. The stage E1 Kraft effluent, corresponding to the first extraction step of the bleaching Kraft mill process, provides the main toxic compounds found in the final process effluent. This paper uses the toxicity identification evaluation (TIE) procedure for the physicochemical and ecotoxicological characterization of the E1 Kraft effluent. To distinguish the most important toxic compounds, a physicochemical characterization and Phase I of the TIE procedure were performed. The acute toxic effect of the E1 Kraft effluent and treated fraction was performed on Daphnia magna. Results show that untreated E1 Kraft effluent exerts an acute toxic effect on D. magna (24 h LC₅₀ = 27.6%), where the E1 Kraft effluent is characterized by pH 10.5, chemical organic demand (COD) 1,348.8 mg/l, and biological organic demand (BOD₅) 397.5 mg/l, while total phenolic compounds and color are 853.7 mg/l and 0.204 1 x 1 cm, respectively. Additionally, Cu⁺² (0.51 mg/l) and Fe⁺² (0.64 mg/l) were detected. With respect to different treatments, our results indicate that activated carbon, anionic and cationic exchange treatments were able to reduce more that 45% of E1 Kraft effluent's acute toxicity and that the ethylenediaminetetraacetic acid treatment was able to reduce the E1 Kraft effluent's acute toxicity to around 75% and the Cu⁺² concentration to 0.019 mg/l. Moreover, specific analysis of heavy metals and organic compounds by GC-MS show that the main compound responsible for the toxicity was Cu⁺², whose tolerance level on D. magna of the 0.12 mg/l.

The southern sector of the Guadiana River basin (GRB) drains the central-western part of the Iberian Pyrite Belt, an area with many polymetallic sulfide deposits and residues of mining activities that under oxidizing conditions generate an acidic leachate with large quantities of sulfates, metals, and metalloids in solution. These acidic leachates seep into the fluvial system contaminating the surface water bodies and increasing the contamination risk for local populations and riparian habitats. The present study was carried out both in Portugal and Spain with the main aim of identifying the principal contamination sources that produce acid mine drainage (AMD) in the southern part of the GRB and to evaluate the seasonal variations of water quality affected by AMD. The physicochemical parameters determined in the field (temperature, electrical conductivity, pH, redox potential, and dissolved oxygen) are discussed and interpreted together with the hydrochemical analysis of surface water samples collected at 79 points of observation. The data show a strong seasonal variation of surface water quality with poorer water quality standards during the dry season. It is also possible to observe that there is a natural decrease in pollution levels with increasing distance from the pollution source (mining areas). Acidic leachates are gradually neutralized as they drain away from the mining areas depositing Fe-(Cu-Al) bearing secondary minerals. There is also an important contaminant load reduction in the estuary area as a result of the mixing process with seawater. This contributes to a loss of the metals in solution due to both dilution and precipitation, as a result of pH increase.

The dynamic removal of cadmium from aqueous solutions by natural and surfactant-modified Mexican zeolitic rocks (clinoptilolite-heulandite type) in fixed bed column systems was investigated. The performances of fixed bed columns were described through the breakthrough curves obtained from column experiments and the values of column parameters predicted as a function of bed height. The column adsorption data were evaluated in terms of the bed adsorption capacity and the efficiency of the process. The experimental results fitted well the bed depth service time model (BDST) for both adsorbents, and the empty bed residence time model (EBRT) was used to optimize column operating conditions. The surface modification of the zeolitic rock with surfactant affected the removal of cadmium in fixed bed systems. Moreover, a column experiment with surfactant modified zeolitic rock previously saturated with 4-chlorophenol was carried out and the results showed that this saturation had a negative effect on the performance of the column.

The Sulphur Bank Mercury Mine (SBMM), active intermittently from 1873-1957 and now a USEPA Superfund site, was previously estimated to have contributed at least 100 metric tons (10⁵ kg) of mercury (Hg) into the Clear Lake aquatic ecosystem. We have confirmed this minimum estimate. To better quantify the contribution of the mine in relation to other sources of Hg loading into Clear Lake and provide data that might help reduce that loading, we analyzed Inputs and Outputs of Hg to Clear Lake and Storage of Hg in lakebed sediments using a mass balance approach. We evaluated Inputs from (1) wet and dry atmospheric deposition from both global/regional and local sources, (2) watershed tributaries, (3) groundwater inflows, (4) lakebed springs and (5) the mine. Outputs were quantified from (1) efflux (volatilization) of Hg from the lake surface to the atmosphere, (2) municipal and agricultural water diversions, (3) losses from out-flowing drainage of Cache Creek that feeds into the California Central Valley and (4) biotic Hg removal by humans and wildlife. Storage estimates include (1) sediment burial from historic and prehistoric periods (over the past 150-3,000 years) from sediment cores to ca. 2.5m depth dated using dichloro diphenyl dichloroethane (DDD), ²¹⁰Pb and ¹⁴C and (2) recent Hg deposition in surficial sediments. Surficial sediments collected in October 2003 (11 years after mine site remediation) indicate no reduction (but a possible increase) in sediment Hg concentrations over that time and suggest that remediation has not significantly reduced overall Hg loading to the lake. Currently, the mine is believed to contribute ca. 322-331 kg of Hg annually to Clear Lake, which represents ca. 86-99% of the total Hg loading to the lake. We estimate that natural sedimentation would cover the existing contaminated sediments within ca. 150-300 years.

In Tabasco the petroleum industry pollutes soil recurrently by oil spills. We analysed Pb, V, Ni and Cr concentrations in water samples, and total metal contents and metal fractions in soil samples of contaminated and non-contaminated soils and in sediments. Besides, we determined Eh, pH, DOC and major ions in water and Eh, pH, Corg in soils and sediments. Sediments contained considerably larger heavy metal (HM) concentrations than soils. Local background concentrations of V, Ni and Cr in soils are larger than global means and oil spillages have not added these metals in quantities that exceed the natural variation. Spillage of formation water increases Pb concentrations in soils, particularly in mobile fractions. The contribution of the oil industry to HM loads is diluted by large fluvial water and sediment discharges and difficult to assess by comparison of total metal contents. Therefore, easily mobile metal fractions are much better indicators.

The legacy of Chernobyl is not the only nuclear accident likely to confront Turkish territory, which is not far from other insecure power plants, especially the Metsamor. The main purpose of this study was to examine the possible impacts to Turkish territory of a hypothetical accident at the Metsamor Nuclear Plant. The research was performed based on two different methodologies: First, a 10-day trajectory analysis was carried out a set of long-term (30 years) meteorological data; second, a tracer study was performed using the MM5T online model for the selected episode. Trajectory and tracer studies showed that an accident at the Metsamor Nuclear Power Plant would influence all of Turkey. Furthermore, vulnerable regions in Turkey after the Chernobyl disaster were demonstrated as a new and first attempt in this study.

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.