Environmental and energy performances of a water network system (WNS) utilizing water reuse are compared to those of a conventional water system (CWS) supplying only freshwater from the perspective of an entire economy and life cycle. Environmental input-output analysis (EIOA) is used to evaluate their air pollutant emissions and energy consumptions. The global warming potential and the emissions of carbon monoxide and of volatile organic compounds from the WNS are less than those from the CWS because of the decrease in the consumption of industrial water, while the emissions of sulfur dioxide and of nitrogen oxides and energy consumption from the WNS are greater because of the increase in electricity consumption for pumping. For perfectly environmentally-friendly water reuse, electricity consumption should be constrained or optimized in water network synthesis, and primary energy mix for electricity generation should be shifted towards renewable energy.

This laboratory-scale study investigated initially the potential of heavy metal removal from a metal-finishing wastewater using fly and bottom ash from a power plant as coagulants. It was found that the maximum heavy metal content in the ash-sludge mix was obtained at a fly ash-to-bottom ash ratio of 1.5:1 and a stirring time of 3 h, which resulted in heavy metal removal (i.e., Cr, Ni, Cu, Zn, Cd, and Pb) in excess of 99%, with effluent concentrations below the corresponding regulatory standards of Thailand. Furthermore, the feasibility of using fly ash as an admixture to stabilize and solidify the ash-sludge mix generated previously was explored. Results indicated that the stabilization/solidification process can achieve a high level of heavy metal removal efficiency from the ash-sludge mix. The optimum ratio regarding chromium leaching was found to be 1:0.75:0.75 (cement:fly ash:ash-sludge). In addition, the compressive strength and the chromium leaching concentration of the solidified sludge were within acceptable levels for secure landfill disposal and/or use as a construction material.

Regressions of aluminum against potentially toxic elements in the sediments of freshwater aquatic systems in Louisiana were used to distinguish natural variability from anthropogenic pollution when elemental concentrations exceeded screening effects levels. The data were analyzed using geometric mean model II regression methods to minimize, insofar as possible, bias that would have resulted from the use of model I regression. Most cadmium concentrations exceeded the threshold effects level, but there was no evidence of an anthropogenic impact. In Bayou Trepagnier, high concentrations of Cr, Cu, Pb, Ni, and Zn appeared to reflect anthropogenic pollution from a petrochemical facility. In Capitol Lake, high Pb concentrations were clearly associated with anthropogenic impacts, presumably from street runoff. Concentrations of potentially toxic elements varied naturally by as much as two orders of magnitude; hence it was important to filter out natural variability in order to identify anthropogenic effects. The aluminum content of the sediment accounted for more than 50% of natural variability in most cases. Because model I regression systematically underestimates the magnitude of the slope of the regression line when the independent variable is not under the control of the investigator, use of model II regression methods in this application is necessary to facilitate hypothesis testing and to avoid incorrectly associating naturally high elemental concentrations with human impacts.

This study assessed the arsenic and heavy metal contaminations of agricultural soils around the tin and tungsten mining areas in Dai Tu district in northern Vietnam. Among the examined elements, high total contents of As and Cu were found in the agricultural fields at both tin and tungsten mining sites. Although the major part of the accumulated As and Cu were bound by various soil constituents such as Fe and Mn oxides, organic matter, and clay minerals, increases in water soluble As and Cu were observed, especially for the paddy fields. The results suggest that, in the studied area, As and Cu dispersion from their pollution sources into farmlands is mainly via fluvial transportation of mine waste through streams that cross the paddy fields around the tin mining area, and soil erosion at the tea fields located at lower positions of the slope in the tungsten mining area.

Commonly occurring plant species on metal-contaminated soils and noncontaminated soils adjoining Kanpur Tanneries, Uttar Pradesh, India were surveyed for arbuscular mycorrhizal association. In the present study, pH, electric conductivity (E.C.), organic carbon, macronutrients (available phosphorus, available potassium), micronutrients (Cu and Zn), and toxic metals (Cr, Cd, Pb) were higher in metal-contaminated site compared to noncontaminated site. These factors were also significantly different between metal-contaminated and noncontaminated soils. High E.C. along with toxic concentrations of metals like Cr, Cd, and Pb may have acted as selection pressure for vegetation cover, making the metal-contaminated site hostile for cultivation purpose. The study recorded Arum type of arbuscular mycorrhiza. The highest mean total root colonization levels in metal-contaminated and noncontaminated soils were 100% (Parthenium sp.) and 34.16% (Parthenium sp.), respectively. Maximum mean spore density in metal-contaminated and noncontaminated soils was 19 spores rhizosphere soil⁻¹ (Parthenium sp.) and nine spores rhizosphere soil⁻¹ (Desmostachya bipinnata and Cynodon sp.), respectively. Studies revealed that for a particular plant species, the root colonization levels and spore density (except Cynodon sp.) were higher in contaminated soil compared to noncontaminated soils. A total of six species of arbuscular mycorrhizal fungi belonging to two genera viz., Glomus and Scutellospora were recovered during the study. Species richness of arbuscular mycorrhizal fungi was maximum in the noncontaminated site compared to the metal-contaminated site. This result suggests that continuous exposure of plants and associated arbuscular mycorrhizal fungi to heavy metals can result in tolerant species which can be used for phytoremediation.

The high radioactivity and trace elements in drinking water are common concerns for human health. The aim of this study was to investigate the eligibility of groundwater for drinking purpose in terms of both radioactivity and trace element contents in Eskisehir Region (Turkey). The study area is located in a highly populated residential area where water supply is mostly met from groundwater. The area is about 20,000 km², where igneous, metamorphic, and sedimentary rocks are exposed. The 209 water samples collected from 84 water resources (including thermal waters) were analyzed with respect to major ions, trace elements, and radioactivity (gross alpha and gross beta) during both in wet and dry seasons. Based on the analysis results, trace elements in 49 samples of 84 water resources were over the limits of Code TS 266 1997 (Turkish Drinking Water Standards) and WHO 1993 standards. Particularly, Fe, Mn, Al, As, Ba, Zn, Cr, Cu, and B ion concentrations exceeded the limits. The gross alpha values in 18 locations and gross beta values in three locations also exceeded the limits of aforementioned standards in terms of radioactivity (gross alpha = 0.1 Bq L⁻¹; gross beta = 1 Bq L⁻¹). Furthermore, water radioactivity levels were close to the allowable limits in 33 water resources. The obtained results explicitly indicate that there is a strong relationship between the higher radioactivity-trace element contents and geochemical composition of rocks, which controls the radioactivity and trace element concentrations present in the aquifer.

PM2.5 and PM10 samples were collected in the urban atmosphere of Elche (southeastern Spain) between December 2004 and November 2005. The samples were analyzed for mass and water-soluble inorganic ions (Na⁺, [graphic removed] , K⁺, Ca²⁺, Mg²⁺, Cl⁻, [graphic removed] and [graphic removed] ) with the aim of investigating the influence of the climatic and geographic features of a coastal semiarid area on the contribution of these species to PM levels. Secondary inorganic ions ( [graphic removed] , [graphic removed] , [graphic removed] ) were the major components in the fine fraction (PM2.5), accounting for 40% of the total mass. The relationship between non-marine [graphic removed] and [graphic removed] indicated that fine sulfate particles were completely neutralized by ammonium. In the coarse fraction (PM10-2.5), nitrate (as NaNO₃ and Ca(NO₃)₂), together with crustal (CaCO₃) and marine species (NaCl) accounted for almost 50% of the total mass. Fine sulfate and coarse nitrate showed summer maximums. In contrast, the concentrations of fine [graphic removed] were lowest in the warm period. Ammonium presented both winter and summer maximums. The levels of marine ions, except for coarse Cl⁻, were highest in summer when the dominant wind flow is from the sea. No significant seasonal variations were observed for coarse Ca²⁺ and [graphic removed] . The concentrations of all inorganic ions increased during Saharan dust events, in particular, fine [graphic removed] and [graphic removed] and coarse [graphic removed] . Coarse calcium was proved not to be a good tracer for this type of episode in our region since the average levels of this cation are elevated and the relative increase in its concentrations during African events was not as high as expected.

Selected trace metals were determined in stormwater runoff and sediments of the highly urbanized Brunette watershed in Metro-Vancouver. Surface sediment samples from three tributaries and a lake between 1974 and 1998 were analyzed for total and acid-extractable trace metals. Metal bioavailability was also investigated using Chelex-100 resin. Sediment geochemistry was determined by sequential extraction. Total trace metal concentrations decreased as stormwater moved through the hydrologic gradient of stormwater runoff, headwater stream to outflow river. The percentage of dissolved metals increased downstream largely due to disposition. Higher concentrations of particle-associated trace metals were flushed in stormwater runoff as the rainfall and total suspended solids transport increased. The highest trace metal levels were found in the lower reaches of a creek before entering the lake and in the lake where organic matter accumulated. Copper was associated with the organic/sulphur sediment components, whereas iron and manganese were mainly mineral-bound. Zinc concentrated in the easily acid reducible phase, augmented by increasing traffic and development. At least half of the sediment-bound lead was associated with the easily acid reducible and organic/sulphur-bound phases with an overall decrease as lead has been phased out as a gasoline additive.

Metal accumulation was investigated in a range of woody species that were planted on Cd-, Zn- and Pb- polluted sites in North of France. The study is unique in that we directly compare a large number of woody species (25). The highest accumulation of Zn and Cd was found in the Salicaceae family members with up to 950 mg Zn kg⁻¹ dry weight (DW) and 44 mg Cd kg⁻¹ DW in leaves of Populus tremula × Populus tremuloides. Zn content was positively correlated with Cd content, both in leaves and stems. Pb concentration was generally low and was species-independent. Oak and birch species accumulated more Mn as compared to other woody species. A seasonal variation in metal accumulation could be found. Although soil compositions and metal bioavailabilities differed amongst the experimental sites chosen in this study, variation of metal concentrations within a given species was small. High bioconcentration factors for poplar and willow suggested the high potential of these species over other woody species for metal accumulation. Taken together, these data suggest that poplar and willow species are good candidates for phytoremediation programmes.

Photodegradation of four pharmaceuticals (i.e. carbamazepine, ibuprofen, ketoprofen and 17α-ethinylestradiol) in aqueous media was studied using a solar light simulator (Xe lamp irradiation) and sunlight experiments. These experiments were carried out in river and seawater and compared to distilled water. The latter was used to evaluate the direct photodegradation pathways. Irradiation time was up to 400 min and 24 days for the solar light simulator and sunlight assays, respectively. Pharmaceutical photodegradation followed a first-order kinetics and their half-lives calculated in every aqueous matrix. Moreover, the sensitizing effect of DOC was evaluated by comparison with the kinetics obtained in distilled waters. Ketoprofen was rapidly transformed via direct photolysis in all the waters under both sunlight (t ₁/₂ = 2.4 min) and simulated solar light simulator test (t ₁/₂ = 0.54 min). Under xenon lamp radiation, ibuprofen and 17α-ethinylestradiol were photodegraded at moderate rate with half-lives from 1 to 5 h. Finally, carbamazepine had the lowest photodegradation rate (t ₁/₂ = 8-39 h) attributable to indirect photodegradation. Indeed, its elimination was strongly dependent on the DOC concentration present in solution. Finally, several ketoprofen photoproducts were identified and plotted against solar light simulator irradiation time. Accordingly, the photodegradation pathway of ketoprofen was postulated.