Textile industries use large amounts of water in dyeing processes and a wide variety of synthetic dyes. A small concentration of these dyes in the environment can generate highly visible pollution and changes in aquatic ecosystems. Adsorption, biosorption, and biodegradation are the most advantageous dye removal processes. Biodegradation occurs when enzymes produced by certain microorganisms are capable of breaking down the dye molecule. To increase the efficiency of these processes, cell immobilization enables the reuse of the immobilized cells and offers a high degree of mechanical strength, allowing metabolic processes to take place under adverse conditions. The aim of the present study was to investigate the use of Saccharomyces cerevisiae immobilized in activated sugarcane bagasse for the degradation of Acid Black 48 dye in aqueous solutions. For such, sugarcane bagasse was treated with polyethyleneimine (PEI). Concentrations of a 1 % S. cerevisiae suspension were evaluated to determine cell immobilization rates. Once immobilization was established, biodegradation assays for 240 h with free and immobilized yeast in PEI-treated sugarcane bagasse were evaluated by Fourier transform infrared spectrophotometry. The results indicated a probable change in the dye molecule and the possible formation of new metabolites. Thus, S. cerevisiae immobilized in sugarcane bagasse is very attractive for biodegradation processes in the treatment of textile effluents. © 2013 Springer Science+Business Media Dordrecht.

Although degradation data for herbicides are essential in understanding their potential to be contaminants and are indispensable inputs in computer-based modeling of their fate in environment, most available data only concern surface soils. Soil samples, collected at two depths from four representative sites of a 31.4-ha field located in Blue Earth County, MN, USA, were used to determine acetochlor dissipation under laboratory conditions. A field study was also carried out within a 16-ha watershed in Dakota County, MN, USA, where 38 locations were sampled to obtain sample representative of the full range of soil properties found within the watershed. Acetochlor DT50 values ranged from 6.51 to 13.9 days for surface soils and from 20.3 to 26.7 days for subsurface soils. DT90 values were a factor of four times longer than for DT50 values. Field DT50 values for acetochlor dissipation were not significantly different for the 2 years, 5.7 ±2.5 and 7.7±4.5 days. Dissipation was slightly faster in the field as compared to the laboratory; however, the difference seems insignificant in view of the wide range in soil properties inMinnesota. In both studies, acetochlor would be classified as slightly persistent. For acetochlor, laboratory dissipation studies can be considered representative of field dissipation for the soils and climatic conditions in this study. Inclusion of subsoil degradation data in mathematical models used for ground water risk assessment may improve their capability of predicting potential movement of acetochlor to groundwater. © Springer Science+Business Media Dordrecht 2013.

High mercury concentrations in freshwater fish from the Nordic region have been of concern for a long time. Ongoing monitoring of key ecological species occurs in these countries to follow the situation. Here, we investigated spatial and temporal trends in mercury concentrations in European perch (Perca fluviatilis) within the Swedish and Finnish aquatic environments, collated from national monitoring programmes collected between 1974 and 2005 (n = 5,172). Data were length and weight adjusted to remove perch size as a confounding factor. Temporal trend analyses and t tests comparing pre- and post-1996 mercury concentrations for each country (1974-1995; 1996-2005; perch adjusted to 200 g/25 cm), showed a significant decrease in mercury concentration in perch from Sweden (p < 0.001) and a possible increase in mercury concentration in perch from Finland (p < 0.001). No statistically significant geographical trends were seen. Average mercury concentrations exceeded both the current environmental quality standard (EQS) of 20 ng/g wet weight (ww) and a discussed EQS for the Nordic region of 200-250 ng/g ww. Despite large reductions in mercury use and production in these countries, concentrations in perch continue to be higher here than in other European areas, posing a continued environmental risk. © 2013 Springer Science+Business Media Dordrecht.

In this study, arsenate removal by apricot stone-based activated carbon (IAC) modified with iron (oxy-hydr)oxides was carried out. For this purpose, hybrid adsorbents based on Fe²⁺-loaded activated carbon (IAC–Fe(II)) and Fe³⁺-loaded activated carbon (IAC–Fe(III)) were synthesized by precipitation method. A three-level, three-factor Box–Behnken experimental design combined with response surface methodology (RSM) was employed to find the optimum combination of process parameters for maximizing the As(V) adsorption capacity of activated carbon-based iron-containing hybrid adsorbent. Three important operation parameters, namely, initial pH of solution (3.0–7.0), temperature (25–65 °C), and initial As(V) concentration (0.5–8.5 mg L⁻¹), were chosen as the independent variables, while the As(V) adsorption capacities of hybrid adsorbents were designated as dependent variables. Lack of fit test showed that the quadratic model provided the best fit to experimental data for both adsorbents with the highest coefficients of determination (R ²), adjusted R ², and p-values for lack of fit. The standardized effects of the independent variables and their interactions were tested by analysis of variance and Pareto chart. The model F-values (F IAC–Fₑ₍II₎=330.39 and F IAC–Fₑ₍III₎=36.19) and R ² values (R ² IAC–Fₑ₍II₎=0.9977 and R ² IAC–Fₑ₍III₎=0.9789) of second-order polynomial regression equations indicated the significance of the regression models. Optimum process conditions for As(V) adsorption onto IAC–Fe(II) were 63.68 °C, pH 3.10, and 8.4 mg L⁻¹ initial arsenic concentration, while 25.22 °C, pH 3.07, and 8.28 mg L⁻¹ initial As(V) concentration were found to be optimum conditions for IAC–Fe(III).

Quality of the essential commodity, water, is being compromised by contaminants originating from anthropogenic sources, industrial activities, agriculture, etc. Water scarcity and severe droughts in many regions of the world also represent a significant challenge to availability of this resource. Domestic rainwater harvesting, which involves collection and storage of water from rooftops and diverse surfaces, is successfully implemented worldwide as a sustainable water supplement. This review focuses on chemical and microbial qualities of domestic rainwater harvesting, with a particular focus on sources of chemical pollution and major pathogens associated with the water source. Incidences of disease linked to consumption and utilization of harvested rainwater are also discussed. In addition, various procedures and methods used for disinfection and treatment of harvested rainwater, such as implementation of filter systems (activated carbon, slow sand filtration, etc.), heat treatment, and chlorination, among others, are also presented.

The successive alkalinity-producing passive system (SAPPS) located in Gangneung, South Korea was designed to treat acid mine drainage. The performance of SAPPS has been monitored intensively for 3 years at the component level (influent, settling pond A, the successive alkalinity-producing system (SAPS), settling pond B, constructed wetland, and effluent). This study evaluated the ability of SAPPS to remove acidity and iron from influents at flow rates ranging from 17 to 160 m3/day. The concentration of soluble Fe total was the highest, and the pH was the lowest at low flow rates (≤61 m3/day). When flow rates were over 80 m3/day, concentrations decreased and Fetotal was removed primarily at the SAPS stage. For flow rates of less than 61 m3/day, Fetotal was removed at the SAPS stage as well as in settling pond B and at the constructed wetland. Hydraulic retention times of 1 and 2 days were found to be appropriate and economical for use with the SAPS stage and for settling pond B and the constructed wetland, respectively The treatment of acid mine drainage by conventional SAPPSs is limited by the availability of alkaline materials. However, the new proposed system can address this weakness through the provisioning of a suitable alkalinity supply. © 2013 Springer Science+Business Media Dordrecht.

Analytical measurements are commonly used to screen for toxicity or lack of toxicity from sediment-associated copper. Comparisons of analytical measurements with toxicological responses can be useful for determining the practicality of analytical measurements for assessing the toxicity of copper in sediments. The purpose of this research was to determine the utility of method detection limits (MDLs; i.e., minimum concentration of an analyte such as copper that can be measured with 99 % confidence with a specific analytical method and matrix) to predict the bioavailability of copper in five different sediments. The specific objectives of this research were to (1) select and characterize five sediments with different characteristics, (2) amend and measure a range of copper concentrations in the five sediments to determine MDLs and bioavailability of copper amendments in those sediments, (3) discern relationships with sediment characteristics to MDLs and bioavailability of copper in the five sediments, and (4) compare MDLs and observed toxicity to Hyalella azteca Saussure as an indicator of copper bioavailability in the five sediments. The lowest copper concentrations that elicited an observable adverse effect ranged from 15 to 550 mg Cu/kg, and the MDLs ranged from 1.5 to 6 mg Cu/kg. The MDLs and measured copper concentrations were not adequately predictive of the bioavailability and toxicity of copper in the five sediments. No adverse effects were observed for H. azteca exposed for 10 days to the sediment from California with simultaneously extractable metals > acid-volatile sulfides. Since the lowest observed effects concentrations of copper in the five sediments ranged two orders of magnitude, the National Oceanic and Atmospheric Administration screening values (threshold and probable effect levels) were not predictive of H. azteca responses to the copper-amended sediments.

Remediation of anthracene from soil was faster in the topsoil than in the lower layers. It was not clear whether this was due to a higher anthracene bioavailability or an increased microbial degradation in the topsoil layer. Therefore, an arable soil was contaminated with 500 mg anthracene kg⁻¹ dry soil, and its removal was monitored with an exhaustive technique and with n-butanol to determine its bioavailability in three layers. Additionally, part of the contaminated soil was stored aerobically for 112 days (considered the aged soil), and the anthracene was monitored thereafter. After 112 days, 360 mg anthracene kg⁻¹ was removed from the soil, but its dissipation was not affected by the layer, depth, and fluctuations in water content or the interaction between. In the aged soil stored for 112 days, only 170 mg anthracene kg⁻¹ was removed. In the subsequent incubation of the aged soil, 273 mg anthracene kg⁻¹ was removed within 28 days, and after 112 days, no contaminant was detectable in the soil. An additional experiment confirmed the hypothesis that simply mixing the soil accelerated the removal of anthracene. Mixing the soil every 7 days removed all anthracene from the soil within 28 days, while in the undisturbed soil, 301 mg anthracene kg⁻¹ was still extractable. It can be concluded that mixing the soil accelerated the removal of anthracene, but fluctuations in water content did not. The anthracene extracted with n-butanol was not related to the amount removed and is thus not a good indicator of bioavailability of anthracene in soil.

Input/output budgets for cadmium (Cd), lead (Pb) and mercury (Hg) in the years 1997–2011 were monitored and determined for 14 small forest-covered catchments across Europe as part of the Integrated Monitoring program on the effects of long-range pollutants on ecosystems. Metal inputs were considered to derive from bulk deposition, throughfall and litterfall. Outputs were estimated from run-off values. Litterfall plus throughfall was taken as a measure of the total deposition of Pb and Hg (wet + dry) on the basis of evidence suggesting that, for these metals, internal circulation is negligible. The same is not true for Cd. Excluding a few sites with high discharge, between 74 and 94 % of the input Pb was retained within the catchments; significant Cd retention was also observed. High losses of Pb (>1.4 mg m⁻² year⁻¹) and Cd (>0.15 mg m⁻² year⁻¹) were observed in two mountainous Central European sites with high water discharge. All other sites had outputs below or equal to 0.36 and 0.06 mg m⁻² year⁻¹, respectively, for the two metals. Almost complete retention of Hg, 86–99 % of input, was reported in the Swedish sites. These high levels of metal retention were maintained even in the face of recent dramatic reductions in pollutant loads.

Emissions of volatile organic compounds (VOCs) were studied from three heavily polluted rivers (Huijiang, Nancun, and Zengbian Rivers) in Guangzhou, South China. A total of 49 species of VOCs were identified. Nancun River had the highest concentration of total VOCs (TVOCs), which ranged from 1,467 to 5,522 μg m⁻³. Trichloroethene, benzene, toluene, ethylbenzene, m/p-xylene, o-xylene, styrene, and 1,3,5-trimethylbenzene were the main pollutants. The levels of VOCs evaporated from the three rivers exhibited different patterns. Correlations between the concentrations of major VOCs were established and found to be statistically significant, except for o-xylene. The ratios of toluene/benzene, ethylbenzene/benzene, and xylene/benzene were estimated and found to be higher than widely reported in the literature. TVOC fluxes in the three rivers were calculated to be the range from 24.8 to 765 μg m⁻² h⁻¹. This study provides a regional background for the emission inventories of VOCs from heavily polluted rivers in southern China and provides resource managers with important information to guide remediation and policy concerning VOC emissions to the environment.