In order to quickly assess the transfer of radioactive cesium after a nuclear incident, it is useful to know the main biospheric parameters influencing this transfer. A suitably simplified heuristic formula for the Cs transfer is helpful for further application in a Geographic Information System (GIS). In order to determine the most relevant parameters given their huge variability in nature, samples of 150 aquatic plants and the corresponding sediments of 26 diverse aquatic locations such as lakes, ponds, and disconnected parts of rivers were measured for 137Cs, 134Cs, and 40K radioactivity one year after the nuclear disaster of Chernobyl. Sediments were characterized by determination of weight loss after heating, extractable Cs and K, pH(KCl), particle size distribution, content of clay minerals, and similar biospheric, chemical, and physical parameters. As a general concept, the procedure of uptake of radioactive cesium was subdivided into the two following steps: “resorption of cesium fallout by soil” and “uptake of soil cesium by plants”. Results for the resorption by soil show strong dependence on the percentage of dry matter and on the content of muscovite (mica) in the sediment. The uptake in plants, however, depends mostly on the content of 137Cs in the sediment itself, on the content of montmorillonite (weathered mica) and on the transfer factor of 40K which indicates the potassium affinity of the 30 different collected plant species. These findings can serve to quickly and practically assess the transfer factor across larger geographic regions in an evidence-based manner. Suitable IT tools for such space-related estimations are Geographic Information Systems or Virtual Globes such as Google Earth.

Nanocomposite of CeO₂–SnO₂ containing different CeO₂ contents was prepared by coprecipitation process. The material obtained was characterized by X-ray diffraction and N₂ adsorption–desorption isotherms. Its photocatalytic activity was tested in the degradation of azo dye of leather, Direct Black 38, in aqueous solution under sunlight. The photocatalytic activity of the coupled CeO₂–SnO₂ oxide ranged depending on the CeO₂ contents. The optimum amount of CeO₂ for the synthesis of CeO₂–SnO₂ was 7 wt.% since the nanoparticles showed high photocatalytic activity in the degradation of the dye, similar to that of the TiO₂–P25 photocatalyst. The kinetics of photocatalytic degradation and total organic carbon removal under sunlight were found to follow a first-order rate law. The results indicated that CeO₂–SnO₂ can be used for the removal of dyes from wastewater.

Four devices developed for measuring settling velocity distributions of combined sewer overflow (CSO) solids were applied to dry and wet weather flow samples from an urban area serviced by combined sewers (Welland, ON, Canada). The settling column-based methods (the Aston, Brombach and US Environmental Protection Agency columns) produced comparable results indicating minimal differences in settleability of dry and wet weather samples. The elutriation apparatus, which assessed settling velocities in a flowing medium, indicated higher settleabilities than the column methods. This was attributed to enhanced opportunities for particle coalescence in the flowing medium, which should better approximate actual sedimentation conditions. While the elutriation apparatus also indicated larger differences in settleabilities between dry and wet weather samples than the column methods, this difference was not statistically significant. Experimental distributions of particle settling velocities were approximated by a mathematical function, which was then used to estimate partial settling of total suspended solids (TSS) with settling velocities smaller than the clarifier overflow rate. The TSS removal target of 50%, which is applicable to CSOs in Ontario, could be met for overflow rates ranging from 4.7 to 6.8 m/h, for dry and wet weather flows, respectively, based on the average settling velocities measured. Experimental data collected in the study indicate that the design of CSO storage and settling facilities is affected, among other factors, by both the apparatus used to assess CSO settleability and the inter-event variability of CSO settling characteristics.

This work aims to identify and characterize heavy metal contamination in a fluvial system from Cartagena–La Unión mining district (SE Spain). In order to assess the dynamics of transport and the accumulation of heavy metals, sediments, surface water and vegetation, samples along “El Avenque” stream were collected. The former direct dumps of wastes and the presence of tailing ponds adjacent to the watercourse have contributed to the total contamination of the stream. Total Cd (103 mg kg−1), Cu (259 mg kg−1), Pb (26,786 mg kg−1) and Zn (9,312 mg kg−1) in sediments were above the limits of European legislation, being highest where tailing ponds are located. Bioavailable metals were high (3.55 mg Cd kg−1, 6.45 mg Cu kg−1, 4,200 mg Pb kg−1 and 343 mg Zn kg−1) and followed the same trend than total contents. Metals in water were higher in sampling points close to ponds, exceeding World Health Organization guidelines for water quality. There is a direct effect of solubilisation of sediment metals in water with high contents of SO 4 2− , product of the oxidation of original sulphides. The mobility of metals varied significantly with shifts in pH. Downstream, available and soluble metals concentrations decreased mainly due to precipitation by increments in pH. As a general pattern, no metal was bioaccumulated by any tested plant. Thus, native vegetation has adopted physiological mechanisms not to accumulate metals. This information allows the understanding of the effect of mining activities on stream contamination, enforcing the immediate intervention to reduce risks related to metals’ mobility.

Characterization of spatial variation of heavy metals in urban soils is essential to identify pollution sources and potential risks to humans and the environment. While heavy metals concentration in soils depends also on the nature of bedrock and on abiotic and biotic factors, it can be argued that nowadays, due to increasing human activities, it is determined mainly by anthropogenic sources. We determined concentrations and spatial distribution of heavy metals, with particular focus on those potentially toxic (As, Cr, Pb, V, and Zn), in urban and peri-urban soils of Cosenza-Rende (southern Italy). One hundred forty-nine samples of topsoil (0–10 cm) were collected and analyzed for 36 elements by X-ray fluorescence spectrometry and inductively coupled plasma mass spectrometry (ICP-MS). In addition, 18 samples of rocks were collected on outcrops of whole area and analyzed by ICP-ES and ICP-MS. Geostatistical methods were used to map the concentrations of major oxides and several minor elements. Heavy metals in the analyzed samples showed a wide range of concentrations, primarily controlled by the geochemical composition of bedrock, with the notable exceptions of Cu, Pb, and Zn, whose concentrations are heavily affected by land use and anthropogenic pollution in urban areas. Geochemical analysis and spatial distribution showed that high concentrations of potentially toxic elements are found in soils near major roads, indicating that anthropogenic factors determine the anomalies in these areas.

Microbiologically contaminated water severely impacts public health in low-income countries, where treated water supplies are often inaccessible to much of the population. Groundwater represents a water source that commonly has better microbiological quality than surface water. A 2-month intensive flow and quality monitoring programme of a spring in a densely settled, unsewered parish of Kampala, Uganda, revealed the persistent presence of high chloride and nitrate concentrations that reflect intense loading of sewage in the spring’s catchment. Conversely, thermotolerant coliform bacteria counts in spring water samples remained very low outside of periods of intense rainfall. Laboratory investigations of mechanisms responsible for this behavior, achieved by injecting a pulse of H40/1 bacteriophage tracer into a column packed with locally derived granular laterite, resulted in near-total tracer adsorption. X-ray diffraction (XRD) analysis showed the laterite to consist predominantly of quartz and kaolinite, with minor amounts (<5%) of haematite. Batch studies comparing laterite adsorption capacity with a soil having comparable mineralogy, but with amorphous iron oxide rather than haematite, showed the laterite to have a significantly greater capacity to adsorb bacteriophage. Batch study results using pure haematite confirmed that its occurrence in laterite contributes substantially to micro-organism attenuation observed and serves to protect underlying groundwater.

Lime was investigated as a soil amendment to decrease phosphorus (P) loss in runoff from two Delaware sandy loam soils, one high and one low in P. Soils were limed at three rates (control and target pH values of 6 and 6.8, respectively), packed into runoff boxes (2,000 cm²) and received simulated rainfall (80 mm h⁻¹ for 30 min). Lime showed potential to decrease P loss in runoff, but its effectiveness was soil specific and dependant on other management factors also. Lime decreased dissolved reactive P (DRP) and dissolved organic P (DOP) loss by 20–25 and 52–93 %, respectively, for the high-P soil and particulate P (PP) by 13 % for the low-P soil. The majority of P lost in runoff was DOP (3–29 %) or PP (64–96 %). Lime increased PP losses from the finer-textured soil following P application, indicating that increased P sorption can lead to increased losses if P is sorbed to more erodable particles. Initial soil P status was more important than liming in determining P loss. While amendments may decrease P losses in the short term, addressing nutrient imbalances at the field scale is clearly necessary in the long term. Losses increased significantly following inorganic P application. Although P was sorbed rapidly, with less than 2 % of added P removed in runoff, mean concentrations in excess of 700 μg l⁻¹ DRP, 2,500 μg l⁻¹ OP and 6,500 μg l⁻¹ PP were recorded for both soils immediately following P application.

The efficiency of the photocatalytic degradation of the herbicide quinmerac in aqueous TiO2 suspensions was examined as a function of the type of light source, TiO2 loading, pH, temperature, electron acceptors, and hydroxyl radical (.OH) scavenger. The optimum loading of catalyst was found to be 0.25 mg mL−1 under UV light at pH 7.2, with the apparent activation energy of the reaction being 13.7 kJ mol−1. In the first stage of the reaction, the photocatalytic degradation of quinmerac (50 μM) followed approximately a pseudo-first order kinetics. The most efficient electron acceptor appeared to be H2O2 along with molecular oxygen. By studying the effect of ethanol as an .OH scavenger, it was shown that the heterogeneous catalysis takes place mainly via .OH. The results also showed that the disappearance of quinmerac led to the formation of a number of organic intermediates and ionic byproducts, whereas its complete mineralization occurred in about 120 min. The reaction intermediates (7-chloro-3-methylquinoline-5,8-dione, three isomeric phenols hydroxy-7-chloro-3-methylquinoline-8-carboxylic acids, and 7-chloro-3-(hydroxymethyl)quinoline-8-carboxylic acid) were identified and the kinetics of their appearance/disappearance was followed by LC–ESI–MS/MS. Tentative photodegradation pathways were proposed and discussed. The study also encompassed the effect of quality of natural water on the rate of removal of quinmerac.

Water monitoring results of the Danjiangkou Reservoir indicated that total nitrogen and total phosphorus concentrations are high and therefore worse than required for central drinking water supplies. Nutrients including nitrogen and phosphorus accumulated in the bank cultivated land were greater than those contained within the river estuary sediment as well as in the reservoir bay sediment. This implies that high concentrations of loosely exchangeable phosphorus (166.53 mg/kg) in cultivated land could, after the completion of the dam heightening project, easily lead to the development of algal blooms. Serious water and soil loss occurring in the reservoir area will promote the transportation of non-point source pollution mainly caused by untreated agricultural domestic wastewater, chemical fertilizer and livestock farming, which accounted for more than 50% of the total basin’s nutrient input loads. Ecological control techniques were therefore the first choice for nutrient reduction and water quality guarantee in the Danjiangkou Reservoir. In order to guide the ecological restoration process, leading international ecological methodologies were summarized and compared, taking into consideration aspects of engineering, as well as ecological, biological, environmental and economic advantages and disadvantages. Finally, novel ecological filtration and a purification dam were designed for eutrophication control.

Solution pH is among the most important parameters that influence heavy metal biosorption. This work presents a kinetic study of the effects of pH on chromium biosorption onto Cupressus lusitanica Mill bark from aqueous Cr(VI) or Cr(III) solutions and proposes a mechanism of adsorption. At all assayed contact times, the optimum pH for chromium biosorption from the Cr(III) solution was 5.0; in contrast, optimum pH for chromium biosorption from the Cr(VI) solution varied depending on contact time. The kinetic models that satisfactorily described the chromium biosorption processes from the Cr(III) and Cr(VI) solutions were the Elovich and pseudo second-order models, respectively. Diffuse reflectance infrared Fourier transform spectroscopy studies suggest that phenolic compounds present on C. lusitanica Mill bark play an important role in chromium biosorption from the Cr(III) solution. On the other hand, chromium biosorption from the Cr(VI) solution involved carboxyl groups produced on the bark by redox reactions between oxygen-containing groups and Cr(VI), and these were in turn responsible for the biosorption of Cr(III) produced by Cr(VI) reduction.