It is well known that mass transfer of a solid compound into a liquid phase is characterized by mutual properties of both sides. Solubilization capacity of the liquid phase is primary affected by its composition in inorganic species inducing salting in/out effect evaluated by Setschenow constant, generally defined at 298.15 K. On the other hand, the equilibrium process is highly influenced by polar compatibility issue. Therefore, the study of such transfer is essential in order to set the role of each party participating in the solid-liquid equilibrium. Thus, a comparison of transfer magnitude and feasibility of carbaryl from pure water, to seawater, and lab-made seawater was held. To do so, solubility of the compound was experimented at different temperature in multiple media. Solubility determination is based on the saturation of a specific heated fluid passing through a saturation cell. The solute transported is subsequently trapped in a specific extraction column. Back flashing method is then applied to dissolve the compound. After validation, aqueous solubility of carbaryl was studied as function of temperature ranging from (273.15 to 318.15 K) at atmospheric pressure. In addition, solubility was determined in pure, seawater, and corresponding lab-made water, thus solubility values ranged from 3.57E-06 to 3.49E-05 in pure water, from 3.04E-06 to 2.53E-05 in seawater and from 6.51E-06 to 3.61E-05 in lab-made water. As a result, thermophysical properties of transfer and usage of lab-made water on the mass transfer properties divergence was spotted. The Salting out phenomenon observed for carbaryl was interpreted by the internal pressure theory that suggests the reduction of internal cavities in the presence of salt, making solubilization process more difficult to achieve. Thus, showing an overall endogenic process with a positive Gibbs free energy of transfer that is highly affected by the magnitude of salting out effect and the temperature. The molar entropy of transfer increases versus temperature caused by the disorder of solvent molecules due to the dissolution process.

Toxicity of contaminated soils cannot be assessed only by chemical analyses, therefore bioassays are increasingly used. Widely accepted ecotoxicological methods include organisms from all levels of the food-chain but plant-based ones are usually restricted to germination and growth tests. In our study the toxicity of heavy metal contaminated soil samples were examined not only by germination and bacterial tests of their extracts but also by the measurement of physiological parameters of two plant species (cucumber and wheat) that were grown directly on the contaminated substrate. Changes in chlorophyll concentration, stomatal conductance, fluorescence characteristics, and malondialdehyde (MDA) level (showing oxidative damage to lipids in leaves) undoubtedly indicated the mobilisation and toxic effect of contaminants. The results showed that the sensitivity of plant physiological parameters was higher than that of the extract-based ecotoxicological tests. Whereas these latter could not reveal the toxic effect of the highly contaminated soils the plants have reacted in a more complex way and their physiological parameters have changed significantly in all cases validating their use in such studies. The applied measurements also allow quicker and more reliable testing even under field conditions (stomatal conductance) or the detection of a more complex response if detailed analyses is needed (MDA, fluorescence imaging) thus underlining the importance of plant-based methods.

Several coagulants/flocculants have been studied in order to remove the color and turbidity of raw water, employing natural ones demonstrated advantages in relation to chemicals. Moringa oleifera Lam is a natural polymer that has been gaining prominence in water treatment. It acts as a clarifying agent, providing a cationic protein that destabilizes the particles contained in a liquid medium. The main objective of the present work is to study the efficiency in terms of removing color and turbidity of raw water in order to obtain drinking water. For this purpose, different coagulant solutions were obtained utilizing three solutions of KCl in different concentrations (0.01, 0.1, and 1 M) and pure water combined with M. oleifera Lam seed. Each coagulant solution obtained was studied with concentrations ranging from 50 to 600 ppm of Moringa in solution. The pH was varied (4.0, 6.0, and 8.0) with 25% and 50% sodium hydroxide solution (NaOH) and hydrochloric acid (HCl), respectively. The tests were conducted with the “Jar Test Device” and the efficiency of the process was evaluated regarding the reduction of color and turbidity. The best results were found employing the coagulant solutions extracted with 1 M salt solution, pH 8.0, and different concentrations of coagulant solution. It is important to explain that the best results were in various concentration ranges, as the concentration of protein in solution becomes higher, the greater is its power as a coagulant. The lowest content of protein was found in the solution extracted with water, which consequently had the lowest values of color and turbidity removal.

To clarify nitrogen (N) sources, the overall N budget in a forested watershed in Kanagawa Prefecture, Central Japan was estimated by measuring dissolved inorganic N (DIN; NH₄ ⁺ + NO₃ ⁻ + NO₂ ⁻) from Nov 2004 through Oct 2005. The estimated N budget (-1.43 kg N ha⁻¹ year⁻¹) showed that the N output rate (stream water N) was higher than the N input rate (bulk deposition N) in the watershed. The annual NO₂ ⁻ and NO₃ ⁻ input rates were 0.02 and 1.99 kg N ha⁻¹ year⁻¹, respectively. NH₄ ⁺ was the predominant source in this forested watershed, accounting for 71% (4.99 kg N ha⁻¹ year⁻¹) of DIN input rate. In addition, this study estimated rainfall pH, air temperature, and wind direction, which were considered as controlling factors related to the atmospheric deposition rate of NH₄ ⁺. This study showed that the rainfall NH₄ ⁺ was inversely proportional to the initial pH of the rainfall, which was calculated by adding the amount of H⁺ consumed by the dissociation process of NH₃₍aq₎ to the measured rainfall pH. This result implies that acid rain can elevate the solubility of NH₃₍g₎ and the dissociation capacity of NH₄ ⁺ throughout the process of precipitation. Also, this study provides strong evidence that the high NH₄ ⁺ deposition rate is mainly derived from NH₃₍g₎ emitted from livestock wastes under the NH₃ transport condition of warm summer and favorable wind direction.

Metal dispersal in the Danube and Maritsa drainage basins resulting from metal mining activities in Bulgaria has been assessed through the collection of 611 samples of river water, river channel and floodplain sediment, and mine waste from over 218 sites. Concentrations of Cd, Cu, Pb, and Zn in river water were found to be highest in close proximity to locations of Cu and Pb-Zn mining regions in the Maritsa catchment. Downstream dispersal of solute metals in these catchments, and into the River Danube, was found to be limited by physical dilution and a well-buffered pH environment. Dispersal of contaminant metals in channel and floodplain sediment was found to be extensive. Contamination was particularly severe in the Rivers Timok and Iskar (Danube catchment) and the Topolnitsa, Chepelarska, and Arda Rivers (Maritsa catchment) and creates the potential of transboundary dispersal of contaminant metals.

Significant quantities of the broiler chicken (Gallus gallus domesticus) litter produced in the USA are being applied to pasture lands. The traditional surface- broadcast application of animal manure onto permanent pasture, however, may lead to high concentration of nutrients and pathogenic microorganisms near the soil surface that could be transported off site by runoff water. Subsurface banding of poultry litter has the potential to reduce nutrient and pathogen losses through runoff. However, this has not been thoroughly investigated. In this study, we used rainfall simulations to examine the effect of broiler litter application methods on the longevity of nutrient and Escherichia coli losses in runoff by successive runoff events. Runoff plots were constructed on Hartsells fine sandy loam (Typic Hapludults) soil with permanent Kentucky 31 tall fescue (Festuca arundinacea) pasture in Crossville, AL. Treatments included two methods of litter application (surface broadcast and subsurface banding), commercial fertilizer, and control (no litter or fertilizer applied). To evaluate the longevity of nutrient losses, simulated rainfall (110 mm h⁻¹) was applied to each plot on days 1, 7, and 14 following litter and fertilizer applications. Total P (TP), inorganic N, and E. coli concentrations were all significantly greater in runoff from broadcast litter application than the subsurface litter banding treatments. The TP losses from broadcast litter applications averaged 6.5 times those from subsurface litter applications. About 81% of the runoff TP concentration was in the form of dissolved reactive phosphorus for both litter application methods. The average losses of NO₃-N and total suspended solids from subsurface litter banding plots were 358 g ha⁻¹ and 68 kg ha⁻¹ compared to 462 and 60 kg ha⁻¹ for the broadcast method, respectively. This study shows that subsurface banding of broiler litter into perennial grassland can substantially reduce nutrient and pathogen losses in runoff compared to the traditional surface-broadcast practice.

The loads and sources of heavy metals (Cd, Co, Cu, Mn, Mo, Ni, Pb, V, and Zn) in the midstream of Tama River were evaluated on the basis of their chemical analyses in ordinary and stormwater runoff from July 2007 to November 2008. Tama River is one of the three major rivers flowing into Tokyo Bay. The total annual water discharges differed largely for 2007 and 2008, depending on the scales of typhoon rainfalls and other heavy rainfalls in each year. The concentrations of the metals other than Mo in the river did not change markedly at a flow rate of less than approximately 200 m³ s⁻¹, but at higher flow rates, the concentrations of all the metals increased linearly with the increase in the log of flow rate (r ² = 0.94-0.99). The annual loads of heavy metals for 2007 and 2008 were estimated using regression equations between the above parameters and the hourly flow rate data for each year. For the metals other than Mo, the contribution of the loads at higher flow rates (>200 m³ s⁻¹) was much larger than that at lower flow rates (<200 m³ s⁻¹), showing the importance of the particulate loads (primarily crustal materials) during storm runoff following typhoon rainfalls and other heavy rainfalls. In contrast, the loads of Mo at lower flow rates accounted for major portions (56-78%) of the total loads, because of a relatively small contribution of particulate load during storm runoff. The contribution of the loads of Mo, Zn, Cd, Cu, and Ni at lower flow rates to the annual loads was larger than that of other metals. It was found that the concentrations of these metals in ordinary runoff are strongly affected by the discharge of treated water from sewage treatment plants which are located along the catchment. Thus, treated water from sewage treatment plants may be the primary source contributing to the present pollution of Mo, Zn, Cd, Cu, and Ni in Tokyo Bay.

Covers of the nuclear waste repository are of great significance to the long-term safe storage and disposal of nuclear wastes. Capillary barriers have proven to be effective to resist the downward water seeping into the underlying nuclear wastes, especially in dry climate, and have been widely used worldwide. Infiltrating water is removed from the fine layer by evaporation or transpiration or through percolation into the coarse layer, which plays a critical role in preventing the water from further infiltration in the bulk wastes. In this paper, laboratory infiltration tests were conducted with an organic glass box, filled with fine-grained quartz sand in which a layer of coarse-grained quartz sand was emplaced horizontally or at various slopes (10° and 20°), and the capillary barrier effect under various conditions (different thickness, slop of coarse-grained quartz sand layer, and sprinkling intensity) was investigated in detail. The results show that the thickness of the underlying coarse layer plays a critical role in governing the performance of the capillary barrier. The efficiency of capillary barrier increases with increasing thickness and/or slope of the coarse layer, but decreases with increasing sprinkling intensity. For a sprinkling intensity of 20 mm/day, a 30-mm-thick coarse layer even emplaced horizontally can achieve 100% water diversion. In addition, a visible tracer test was performed with an inert red dyestuff to trace the streamlines; the results indicate that even with a 7-mm-thick coarse layer, the capillary barrier can offer marked ability to prevent water from percolating into the coarse layer. The findings could be useful for improving engineered uses of capillary barriers at waste repository sites.

In 1996, dichlorodiphenyltrichloroethane (DDT) pollution of industrial origin was discovered in Lake Maggiore. It was caused by industrial effluents on a tributary of the River Toce, one of the major affluents of the lake in correspondence of Pallanza Bay. This event is the worst case of environmental pollution that has occurred in Western countries in the last 25 years, not due to agricultural use of DDT, but because of an accidental industrial discharge. Heavy polychlorinated biphenyls (PCBs) pollution was also noticed in 2002, with concentration levels three to seven times higher than those measured in other Italian subalpine lakes. In this study, the current DDT and PCBs contamination levels were assessed according to their presence in zebra mussel (Dreissena polymorpha) specimens sampled in the last 5 years (2003-2008) in eight sampling stations of Lake Maggiore, chosen to cover the entire perimeter of the basin. Moreover, for two stations (Baveno and Pallanza-Villa Taranto) located inside and outside Pallanza Bay, respectively, it is possible to make comparisons starting from 1996. The results obtained show how Lake Maggiore is still an ecosystem with a severe environmental risk, more than 10 years after the original insecticide discharge. DDT contamination continues to evolve, and natural events, like lake overturn, floods, and heavy rains, can have a great influence on the insecticide levels in the lake. By contrast, PCB contamination is absolutely negligible, even if the peak of pollution revealed in 2002 seems to indicate that these pollutants are still present in large quantities in the Lake Maggiore watershed.

Tamarind fruit shell was used as a low-cost biosorbent for the removal of methylene blue from aqueous solution. The various factors affecting adsorption, such as agitation, pH, initial dye concentration, contact time, and temperature, were investigated. The dye adsorption capacity was strongly dependent on solution pH as well as temperature. The Langmuir isotherm model showed good fit to the equilibrium adsorption data, and the maximum adsorption capacity obtained was 1.72 mg g⁻¹ at 303 K. The kinetics of adsorption followed the pseudo-second-order model and the rate constant increased with increase in temperature, indicating endothermic nature of adsorption. The Arrhenius equation was used to obtain the activation energy (E a) for the adsorption system. The activation energy was estimated to be 19.65 kJ mol⁻¹. Thermodynamic parameters such as Gibbs free energy (ΔG ⁰), enthalpy (ΔH ⁰), and entropy (ΔS ⁰) were also investigated. Results suggested that adsorption of methylene blue onto tamarind fruit shell was a spontaneous and endothermic process. The present investigation suggests that tamarind fruit shell may be utilized as a low-cost adsorbent for methylene blue removal from aqueous solution.