The partial phase transformation of nanometer TiO₂ powder from anatase phase to rutile phase was realized by heat-treatment and a new TiO₂ photocatalyst which could be excited by visible light was obtained. The heat-treated TiO₂ powder at different stage of transition crystal was characterized and monitored by XRD, TEM, FT-IR and UV-vis DRS methods. The test of photocatalytic activity of the heat-treated TiO₂ powder was carried out by the photocatalytic degradation of rhodamine B and acid orange II dyes, respectively, in aqueous solution under visible light irradiation. The results indicate that the nanometer TiO₂ photocatalyst heat-treated at 500°C for 60 min shows the highest photocatalytic activity, that is, it can effectively degrade the rhodamine B and acid orange II under visible light irradiation. The remarkable improvement of photocatalytic activity of heat-treated TiO₂ powder at 500°C for 60 min was mainly illustrated by the formation of special interphase between rutile and anatase phases, which not only restrains the recombination of photogenerated electrons and holes, but also reduces the adsorbability of nanometer anatase TiO₂ powder properly for various dyes. Additionally, the effects of dye-assisting chemicals such as Na₂CO₃ and NaCl on the photocatalytic degradation were also studied.

The applicability of magnetic susceptibility measurements was tested for the detection of industrial pollution by fly ash in topsoil in a beech stand in the vicinity of a steel factory at Široka near Oravskyỳ Podzámok (Slovakia). The first trial measurements already showed that there is at least one spot near the trunk of each tree in which the susceptibility is significantly higher than anywhere else beneath the crown of the same tree. Detailed measurements showed that the susceptibility anomaly is associated with stemflow, and extends to some distance on the slope side of the trunk. Elsewhere beneath the crowns, at spots unaffected by stemflow, the variation of susceptibility is moderate. Samples were collected systematically from the topsoil around five trees in the beech stand, and another one elsewhere exposed to direct flow of fly ash from Široka. The results of measurements of low and high frequency susceptibility allow to conclude that in the beech stand where the ground is effectively shielded by the canopy from direct precipitation of pollution particles, all susceptibility values unaffected by stemflow are dominated by fine-grained magnetic particulates having formed by biogenic processes during pedogenesis, while those pertaining to the stemflow zone are dominated by larger multidomain particles conveyed to the ground in the stemflow. So, in this particular environment, it is the stemflow and its effect that makes magnetic pollution detectable by using susceptibility parameters. The case of the site exposed to direct precipitation of pollution particles is different in that that every susceptibility value irrespective of being small or large is dominated by large multidomain pollution particles. The heavy metal concentration of the soils investigated is elevated with respect to background levels of the Geochemical atlas of Slovakia, and have strong positive relationship, basically established by the effect of stemflow, with magnetic susceptibility. Without the stemflow effect the variation either in susceptibility or heavy metal concentration would not be sufficient to recognise existing relationships between them in the topsoil of the beech stand selected for the present study.

The US fleet of coal-fired power plants, with generating capacity of just over 300 GW, is known to be a major source of domestic mercury (Hg) emissions. To address this, in March 2005, the Environmental Protection Agency (EPA) promulgated the Clean Air Mercury Rule (CAMR) to reduce emissions of mercury from these plants. It is generally believed that most of the initial (Phase I) mercury reductions will come as a co-benefit of existing controls used to remove particulate matter (PM), SO₂, and NO X . Deeper reductions in emissions (as required in Phase II of CAMR) may require the installation of mercury-specific control technology. Duct injection of activated carbon sorbents is the mercury-specific control technology that has been most widely studied and has been demonstrated over a wide range of coal types and combustion conditions. The effectiveness of the mercury control options (both “co-benefit control” and “mercury-specific control”) is significantly impacted by site-specific characteristics such as the combustion conditions, the configuration of existing air pollution controls, and the type of coal burned. This paper identifies the role of coal properties and combustion conditions in the capture of mercury by fly ash and injected sorbents.

During the seasons 2003/04, 2004/05 and 2005/06, a study was made of the evolution of runoff as well as soil and available P and K losses in the sediment carried away in a conventional till system--that most used at the present time--and in a no till system with added pruning remains in an olive grove of the picual variety located in Torredonjimeno (Jaén, Spain). A group of microplots for sediment collection in a randomized complete block design was established. The samples were collected in the field after each storm. In the study period, a total of 21 storms were recorded, with a precipitation of 450 mm in 2003/04, 179 mm in 2004/05 and 388 mm in 2005/06. The erosivity of the rainfall was characterized and the cover percentage in the plots throughout the time was determined. The establishment of pruning remains reduced soil loss with respect to conventional tillage (CT) in the 3 years (72%). Likewise, the available P loss greatly declined in the study (46.4%) under conservation agriculture. The reduction in available K loss (72.4%) was much greater than that of available P. The close relationship between both variables and sediment production also stands out. Runoff was the parameter on which the pruning remains had the least influence with only an 11% average reduction.

A gully pot is often cleaned with the help of an eductor truck, which uses hydrodynamic pressure and a vacuum to loosen and remove the solids and standing liquid from a gully pot. This paper considers the polycyclic aromatic hydrocarbons (PAH) content in the gully pot mixture (water and sediment) after it has been discharged from the eductor truck. The results show that most PAH was attached to particles, and the dissolved phase represented approximately 22% of the total water concentration. No significant difference was found for the water phase between a housing area and a road, whereas a significant difference was found for NAP, ACE, FL, ANT, FLR, PYR, BaF, and BPY in the sediment at a 95% confidence level. Source identification showed that the PAH in the gully pot mixture came from mixed sources. Both the water and sediment phase exceed all or some of the compared guidelines. The result from this paper shows that not only the sediment needs to be discussed, but also the water phase created during the maintenance of different BMPs.

Despite many studies of the N₂O emission, there is a lack of knowledge on the role of subsoil for N₂O emission, particularly in sandy soils. To obtain insight into the entrapment, diffusion, convection and ebullition of N₂O in the soil, the N₂O concentration in the soil atmosphere was measured over a period of 1 year in 4 lysimeters (agricultural soil monoliths of 1 m2 x 2 m) at 30, 50, 80, 155, and 190 cm depth with altogether 86 gas probes. Additionally the N₂O emission into the atmosphere was measured in 20 closed chambers at the soil surface. Concurrently the soil temperature and soil water content were recorded in order to quantify their effects on the fate of N₂O in the soil. Results of the continuous measurements between January and December 2006 were: N₂O concentrations were highest in the deeper soil; maximum concentration was found at a depth of 80 cm, where the water content was high and the gas transport reduced. The highest N₂O concentration was recorded after 'special events' like snowmelt, heavy rain, fertilization, and grubbing. The combination of fertilization and heavy rain led to an increase of up to 2,700 ppb in the subsoil.

The commonly used plastic softener, di (2-ethylhexyl) phthalate (DEHP), also a known Endocrine Disrupting Compound, was found contaminated in various aquatic environments, including river water in Thailand. The data of adsorption kinetics from this study indicated that DEHP can adsorb onto pure bentonite and natural suspended sediment with average adsorption rate constants of 0.0056 and 0.0039 min⁻¹ respectively. The average distribution coefficients between suspended particles and water found in this study for pure bentonite and natural suspended sediment were 0.045 and 0.043 l g⁻¹ respectively. Although the studies were carried out in pH 4.0, 7.0 and 10.0, there were no obvious influences of pH on adsorption rates and distribution coefficients of DEHP onto both pure bentonite and natural suspended particles. The desorption rate was very small and was estimated to be less than 0.03 μg min⁻¹. The results indicated that suspended sediment could become a long term release of DEHP and facilitate the transport of DEHP mainly due to fast adsorption rate and relatively high adsorption capacity.

Although the area of urban river sediment quality has received increasing attention over the last 10 years, the presence of contaminated sediments in urban rivers and the potential risk to public health it poses has yet to be rigorously addressed within the urban river restoration context. This is an issue of particular concern at the current time, as the opening-up of urban rivers is being strongly promoted by many legislative and non-legislative bodies as a multi-benefit approach to tackling a range of urban challenges; from decreasing the risk of flooding to increasing the quality-of-life in urbanised areas. This paper brings together these two contrasting concepts; urban rivers as pollutant sinks and sources (presentation of data on urban river sediment quality) and urban rivers as sites of flood alleviation, amenity, recreation and wildlife value (review of the drivers and initiatives behind the increasing implementation of urban river rehabilitation schemes). In light of this combined assessment, the urgent need for a risk assessment of restored urban river sites to establish whether the presence of contaminated sediments poses a risk to public health is strongly recommended. Should such a risk be demonstrated, a tiered approach to supporting the identification and pro-active management of these risks is proposed as a way to inform and enable, rather than to prevent, the safe and appropriate use of the increasing number of urban river restoration schemes being implemented.

Nonylphenol is the primary breakdown product of nonylphenol ethoxylates, a certain class of nonionic surfactants. Nonylphenol has been found to be toxic to aquatic organisms and has been suspected of being harmful to humans due to its xenoestrogenic properties. Although there are known releases of nonylphenol to the environment, there is a lack of data describing the extent of biodegradation. This study thus focuses on much needed information on the biodegradation kinetics of nonylphenol. Oxygen uptake, cell growth and nonylphenol removal data were collected using batch reactors in an electrolytic respirometer. Nonylphenol removal, cell growth and substrate removal rates were modeled by the Monod, Haldane, Aiba, Webb, and Yano equations. The differential equations were solved by numerical integration to simulate cell growth, substrate removal, and oxygen uptake as a function of time. All models provided similar results with the Haldane model providing the best fit. The values of the kinetic parameters and the activation energy for nonylphenol were determined. These values can be used for predicting fate and transport of nonylphenol in the environment. The validity of applying each model to the biodegradation of nonylphenol was analyzed by computing the R ² values of each equation.

Four sand pit lakes, at the Rio de Janeiro Sand Mining District, were monitored from November 2003 to November 2005, in order to characterize their hydrogeochemistry aiming to provide information to their possible use as fishponds at the end of mining activities. The results show diluted waters (low electrical conductivity) with low pH (<4) and relatively high sulfate and aluminum concentrations. The major water components (in particular Fe, Mn, SiO₂, Al and SO₄) are related to water acidity, since it controls solubility of aluminum silicate minerals and Mn and Fe oxides. Fe, Mn and Al availability in these waters are probably associated to organic colloids formation. On the other hand, the SiO₂ content, as well as the decrease of sand mining in rainy season, may partially control Al availability by the formation of hydroxi-aluminum silicates. These geochemical processes together with the interruption of sand mining in the rainy season and the dilution of sand pit lakes water by rainwater can support the use of these pit lakes as fishpond for aquaculture.