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The European Union has set targets for cutting carbon emissions by 2020 and Europe''s pump manufacturers are expected to play their part. No one denies that there are substantial energy savings to be achieved and there is a strong debate about which approach would bring the greatest benefits. Here we look at Europump''s response to the proposals. [Copyright &y& Elsevier]

Effects of agricultural intensification and a naturally occurring landslide of asbestos material upon water and sediment quality in a transboundary watershed were investigated. The water and sediments of the Sumas River watershed were analyzed for copper (Cu), zinc (Zn), chromium (Cr), and nickel (Ni) concentrations in 1993/1994 and 2003/2004 and differences within sites over time were examined. Based upon a review of the literature, Cu and Zn were used as indicators of agricultural impacts while Cr and Ni were used as indicators of impacts from an asbestos landslide. Animal unit equivalents (AUEs) were calculated on a per area basis as an indicator of livestock density using detailed statistical census data. Whatman #42 filtered metals, bioavailable metals, and sediment-bound metals (in the <63 μm fraction) were determined at 22 sites along the mainstem and tributaries, including two reference sites. Temperature, pH, and dissolved organic carbon (DOC) were also measured. The bioavailable metal fraction was determined using the diffusive gradient thin film technique (DGT). Sediment-bound results were compared with British Columbia's Interim Sediment Quality Guidelines (ISQGs) and Severe Effects Levels (SELs). A Wilcoxon signed rank test was used to determine if the concentrations of metals changed significantly within sites between 1993/1994 and 2003/2004. Spearman rank correlation analysis was used to determine relationships between trace metals, water quality parameters, and AUEs/hectare. The results indicate that Cu and Zn levels in sediments increased significantly to concentrations above the ISQGs of 35.7 mg/kg and 123 mg/kg, respectively from 1993/1994 to 2003/2004 in streams, where associated land use was dominated by intensive agriculture. Higher AUEs/hectare were significantly correlated with greater bioavailable levels of Zn as well as higher sediment-bound Zn concentrations. Neither Cu nor Cr were detected by the DGTs on any of the sampling occasions. The Cr and Ni sediment concentrations were highest in Swift Creek, the headwater tributary affected by the natural landslide of asbestos material, and decreased in the Sumas River downstream from the point of input. Cr and Ni concentrations have increased in the mid-region of the Sumas River since 1993/1994, suggesting downstream movement of the asbestos material over time. DGT results indicated that bioavailable Zn is significantly positively correlated to sediment-bound Zn and livestock density, and bioavailable Ni is significantly correlated to sediment-bound Ni. [ABSTRACT FROM AUTHOR]

To choose an appropriate dilution ratio to treat woodwaste leachate without inhibition on heterotrophic bacteria, microbial ATP concentration and the rates of heterotrophic leucine incorporation and acetate uptake were compared across surface flow mesocosm wetlands fed with different strengths of influent. Abundances of protozoa and respiring bacteria were investigated in two mesocosm wetlands to elucidate the effects of influent strength on heterotrophic bacteria. The strongest influent or the raw leachate did not show a significant inhibitory effect on leucine incorporation and acetate uptake. Instead, leucine incorporation rates by bacteria in water, epiphytic biofilm and sediment were higher in mesocosm wetlands fed with a stronger influent. There were significantly more respiring planktonic bacteria (451×105 mL−1) and fewer nanoflagellates (3.8×103 mL−1) in the mesocosm fed with a strong influent, while fewer respiring planktonic bacteria (38.7×105 mL−1) and more nanoflagellates (15.4×103 mL−1) in the mesocosm fed with a weak influent. The majority of the total microbial ATP was attributed to sedimentary bacteria, of which >96% were inactive. Heterotrophic activity and its distribution among water, epiphytic biofilm and sediment in the mesocosm wetlands were affected by availability of bacterial substrates and grazing pressure of nanoflagellates. [Copyright &y& Elsevier]

Abstract: Microbial degradation is the major mechanism for removal of organic carbon from woodwaste leachate in surface flow constructed wetlands. To explore the relations of microbial biomass and heterotrophic production with hydraulic and organic loading rates as well as mass reduction rates, this study examined microbial ATP concentration and leucine incorporation rate in water, epiphytic biofilm and sediment of four surface flow mesocosm wetlands fed at different hydraulic loading rates during two periods with 10× and 3× diluted woodwaste leachate. The hydraulic loading rates from 13 to 49mmd−1 had no effects on microbial biomass and heterotrophic production. The organic loading rates between 32 and 396gCODd−1 m−3 had significant, negative correlations with heterotrophic production rate and microbial biomass of sediment, and positive correlations with heterotrophic production rates of water and epiphytic biofilm. Higher organic loading yields greater substrate availability for planktonic and epiphytic bacteria, and may induce inhibitory effect on sedimentary bacteria. Microbial attachment played an important role in the establishment of epiphytic and sedimentary communities. The reduction rates for chemical oxygen demand (COD), tannin and lignin (T&L), and volatile fatty acids (VFAs) were significantly correlated to the heterotrophic production rates of water, epiphytic biofilm and sediment together. [Copyright &y& Elsevier]

Modification of the acute toxicity of sodium sulphate to Hyalella azteca and Daphnia magna was investigated using exposure water with different levels of water hardness (expressed as CaCO3 equivalents) and calcium-magnesium molar (Ca:Mg) ratios. The influence of Ca:Mg ratios on the toxicity of sodium and potassium chloride to D. magna also was investigated. For both species, the mean lethal concentrations that resulted in mortality of 50% of the sample population (LC50s), expressed as mg SO42-/L, were increased significantly in harder water and in water with higher Ca:Mg ratios. The LC50s for H. azteca increased from 569 to 5,259 mg/L with a change in water hardness from 25 to 250 mg/L. Furthermore, modifying the Ca:Mg ratio from 0.7 to 7.0 at a constant hardness of 100 mg/L significantly increased LC50s from 2,101 to 2,725 mg/L. The LC50s for D. magna were also significantly higher in harder water with LC50s increasing from 1,194 to 3,203 mg/L with a change in water hardness from 25 to 100 mg/L. In addition, modifying the Ca:Mg ratio from 0.7 to 7.0 significantly increased LC50s from 1,194 to 1,985 at a constant hardness of 25 mg/L, and from 3,203 to 4,395 mg/L at a constant hardness of 100 mg/L. No significant change in the toxicity of potassium or sodium chloride to D. magna was observed in waters with higher Ca:Mg ratios. [ABSTRACT FROM AUTHOR]

Laboratory tests were conducted on volatilization, adsorption on silt loam, and on the biological treatability of woodwaste leachate. No significant volatilization was found despite the high concentration of volatile fatty acids. Tannin and lignin adsorption reached equilibration within 78 h. Adsorption at a silt loam:leachate volume ratio of 2:25, equivalent to a 2 cm effective soil layer underlying a 25 cm water column in a surface flow constructed wetland, removed 22–42% tannin and lignin and 6–27% chemical oxygen demand at 23 ºC. Tannin and lignin accounted for the majority of the adsorbed chemical oxygen demand. Adsorption followed the Langmuir isotherm, with an adsorption capacity of 36 mg tannin and lignin/g silt loam. Adsorption efficiency for tannin and lignin at 15 °C was 0.44 times that at 23 °C. An aerated reactor removed 62–67% chemical oxygen demand, 65–67% tannin and lignin, and ≥98% volatile fatty acids. A similar anaerobic reactor removed 28–29% chemical oxygen demand, 13–19% tannin and lignin, and 80–94% volatile fatty acids. In long-term operation, biological degradation would be the major mechanism for organic carbon removal from woodwaste leachate in surface flow constructed wetlands. Sediment adsorption would affect treatment performance mainly during initial and transitional operating periods. [ABSTRACT FROM AUTHOR]

Heterotrophic activities were investigated by measuring ³Hleucine incorporation to bacterial protein and 14C-glucose turnover in surface flow constructed wetlands receiving woodwaste leachate. No significant longitudinal variation was found in heterotrophic activities of bacterioplankton. An open wetland, a vegetated wetland, and a fertilized vegetated wetland were used to examine the effects of vegetation and ammonium nitrate amendment. There was not a significant difference in treatment performance among the three wetlands, except for a significant pH increase and more efficient volatile fatty acids removal in the fertilized wetland. The fertilized wetland had the highest leucine incorporation rate and shortest glucose turnover time accompanied by file lowest glucose mineralization percentage, followed by the open wetland, then the vegetated wetland. Planktonic and sedimentary bacteria contributed to the majority or the total heterotrophic activities; epiphytic bacteria played a minor role. Heterotrophic activities were influenced by the availability of nutrient, electron acceptor, and organic substrate. Water Environ. Res., 78, 671 (2066). [ABSTRACT FROM AUTHOR]

Abstract: Four surface-flow mesocosm wetlands were operated at different hydraulic retention times during two periods to treat diluted woodwaste leachate that was acidic, of very high oxygen demand, and toxic. Temperature, dissolved oxygen, and redox potential decreased with increasing water depth. However, there was no significant vertical variation in microbial biomass. No significant development in biomass of planktonic microorganisms was found over 6 weeks of initial operation. It took <1–6 weeks for maturation of the biofilm on submerged plant surfaces and the sedimentary microbial community. Mass reduction efficiencies of chemical oxygen demand, and tannin and lignin increased significantly with hydraulic retention time when 10% leachate was fed with tap water. When a more recalcitrant influent was fed, there was a slight increase of reduction efficiency with increasing hydraulic retention time. Reduction rates increased linearly with mass loading rates up to 0.4kgm−3 d−1 chemical oxygen demand and 0.13kgm−3 d−1 tannin and lignin. Precipitation and evapotranspiration had profound impacts on the overall performance and its variability. Mass balance-based operating data of wetlands with a mature microbial community are required for proper performance assessment. [Copyright &y& Elsevier]

Developments aimed at transforming initial teacher education in France since the early 1990s are examined and a contribution is made to the debate about the key factors involved. The discussion is contextualised in earlier discussions in JET and in relation to the new reforms for teacher education proposed by the Minister of Education. [ABSTRACT FROM AUTHOR]

Discusses the characteristics and aquatic impacts of combined sewer overflows (CSO) in Greater Vancouver, British Columbia. CSO distribution, discharge and characteristics; Fate and impacts of CSO contaminants.

World Pumps has always had a close association with Europump, which has been serving and promoting the European pump industry since the 1950s. Here, Ken Hall, president, and Guy Van Doorslaer, secretary general of Europump give the background to this special relationship. [Copyright &y& Elsevier]

The sorption behaviour of alpha- and beta-endosulfan in soil organic matter was investigated using standard soil humic acid (HA) and soil fulvic acid (FA) with a modified solubility enhancement method and a dialysis bag technique. For HA, all the experiments were conducted at an ionic strength of 0.001 mol/L, in both the presence and absence of calcium and at an ionic strength of 0.01 mol/L. For FA, the experiments were conducted at two ionic strengths: 0.001 mol/L (with calcium) and 0.01 mol/L. This study is the first to describe the striking differences in the sorption behaviours of the two stereoisomers of endosulfan in HA and in FA. The sorption coefficients of alpha-endosulfan in HA and FA were significantly higher than those of beta-endosulfan. Beta-endosulfan has comparable sorption coefficients (1.5–5.4 L/g) in HA and in FA. Ionic strength and the presence of calcium have no significant effect on the sorption of beta-endosulfan in HA. However, calcium can significantly (p=0.01) enhance the solubility of alpha-endosulfan in HA. Changes in ionic strength by one order of magnitude also affect the solubility of alpha-endosulfan in HA. The sorption coefficients of alpha-endosulfan in HA (10–36 L/g) were greater than those in FA (9–14 L/g). The chirality of the alpha-isomer was hypothesised to be the primary reason behind its higher sorption in soil organic matter relative to the beta-isomer. In the presence of dissolved HA and FA found in natural soil environments, solubility of endosulfan can be increased by five times than the aqueous solubility of endosulfan without HA and FA. [ABSTRACT FROM AUTHOR]

Abstract: The gold ore mined by artisanal and small-scale miners in Portovelo-Zaruma, Ecuador, is processed in custom mills. Miners can choose between Chilean-mill processing centers, where the ore is ground, concentrated and amalgamated, or “Chancha” Centers, where the whole ore is amalgamated. By weighing mercury before and after all unit operations involved in the amalgamation process, it was possible to determine mercury losses. Analyses in eight centers indicated that 51–59% of mercury introduced into the amalgamation process is recovered when miners squeeze the excess mercury. Around 29% of total mercury is lost when miners burn amalgam and gold is melted, and 15% is lost with the tailings. When only gravity concentrates are amalgamated, 1.4% of mercury entering the process is lost with tailings, whereas 29.5% is lost when the whole ore is amalgamated. Approximately 1.5 tonnes/annum of mercury is released in Portovelo-Zaruma, from which 70% is evaporated and 30% is released with tailings. Mercury-contaminated tailings are leached with cyanide in agitated tanks. A large majority of the processing centers dispose the final tailings with mercury and cyanide into the Calera River and Amarillo River. Mercury dissolved with cyanide likely becomes more bioavailable than metallic mercury. A campaign for reducing mercury emissions must focus on the use of individual retorts – mercury pollution control devices – and the elimination of whole ore amalgamation. [Copyright &y& Elsevier]

Abstract: Percolation of rainfall through woodwaste piles leaches natural chemicals from the wood residuals that can have adverse impacts on the environment. A study was conducted on a woodwaste storage site, adjacent to the Lower Fraser River, near Mission, BC, Canada. The objective of this research was to evaluate the effectiveness of constructed wetland for treatment of this woodwaste leachate. The leachate was characterized by high oxygen demand, tannin and lignin, and volatile fatty acids (VFAs), but low pH and nutrients. Diluted leachate passed through six pilot-scale wetland cells, four planted with cattail (Typha latifolia) and two unplanted controls, with a hydraulic retention time of 7 days and an average depth of 40cm. Nutrient addition and pH adjustments were made to improve contaminant removal. Reductions in contaminants were consistently achieved, with average removals for BOD, COD, VFAs and tannin and lignin of 60, 50, 69 and 42%, respectively. Climatic conditions had an impact on the performance of the constructed wetland. Further operation of the system will help to elucidate the seasonal fluctuations. Aging of the constructed wetland system increased the treatment performance. [Copyright &y& Elsevier]

Molybdenum is generally reported in the literature to be acutely lethal to various fish species at relatively high concentrations (70 to >2000 mg/L). The toxicity of molybdenum to fertilized rainbow trout eggs and alevins (EA), however, is controversial as different bioassays demonstrate a wide toxicity range (0.73 to >90 mg/L Mo). A duplication of a previous study using similar water chemistry along with the standard bioassay protocol demonstrated that molybdenum was not acutely toxic to the early life stages of rainbow trout over 32 d up to a maximum molybdenum concentration of 400 mg/L. An additional bioassay exposing early life stages of rainbow trout to a maximum molybdenum concentration of 1500 mg/L for 32 d did not cause sufficient mortality to allow an LC50 to be calculated. [ABSTRACT FROM AUTHOR]

At a time of rapid development in the role of teaching assistants and of corresponding increase in their numbers, studies of how TAs and teachers collaborate are particularly welcome. In this article, Sue Pearson, Gary Chambers and Ken Hall explore the potential of video recordings as a tool in joint professional development. [ABSTRACT FROM AUTHOR]

The article looks at strategies for increasing the data storage capacity of hard disks, focusing on array-reader-based magnetic recording (ARMR) using joint signal processing of more than one readback stream to achieve greater areal density capability (ADC) on the disk. The authors describe their development of a drive-tap-based evaluation platform for ARMR. Topics include the error margin for write failures and two-dimensional (2-D) magnetic recording (TDMR).

Abstract: In many countries, such as Brazil, Colombia, Ecuador, Indonesia, Venezuela and Zimbabwe, amalgamated tailings are leached with cyanide to recover remaining gold. This paper describes a recently completed study conducted at seven gold processing centers in Portovelo-Zaruma, Southern Ecuador, which involved consultation with local miners. The objective of the study was to understand the behaviour of mercury (with a focus on mercury loss) in artisanal gold mining operations through the evaluation of two cyanidation processes (Merrill-Crowe and Carbon-in-pulp), using a participatory approach. In order to assess the kinetics of mercury dissolution in cyanide, a bottle roll test was conducted in the laboratory. In the Merrill-Crowe cyanidation process, an average of 24.2% of metallic mercury was determined to be trapped at the bottom of the agitation tanks; 33.1% of mercury is lost in association with solid material and 11.7% is lost in solution. Approximately 31.0% of mercury in solution is sent to the zinc precipitation cells from which 27.8% is precipitated on the zinc shavings, with 3.23% remaining in solution. The mercury precipitated on to the zinc is lost to the atmosphere when the shavings are burned at 900 °C. In the Carbon-in-pulp (CIP) leaching system, 11.2% of the mercury is lost with the solid tailings; 31.6% of the mercury is associated with fine particles in suspension and 50.8% is likely dissolved. About 2.68% is trapped at the bottom of the tank and 3.72% is absorbed by the activated carbon. The bottle roll test revealed that mercury dissolution is directly proportional to cyanide concentration. At 10 g/ton of cyanide, approximately 42% of mercury was leached, whereas all gold was solubilized. During this study, miners recognized the risk associated with the cyanidation of mercury-rich tailings, and were aware of how much mercury is discharged to local streams and to the atmosphere. The active participation of miners in this study has led to the strengthening of their knowledge and awareness of mercury contamination, and has enhanced their understanding of the nature of the problem, as well as the weaknesses and strengths of the system they operate. [Copyright &y& Elsevier]

The population of anoxygenic phototrophic bacteria in the aerobic zone of the meromictic Mahoney Lake was investigated using classical microbiological methods. This bacterial community was found to be very rich and diverse. Thirty-one new strains of the obligately aerobic phototrophic bacteria, and two new purple nonsulfur strains, were isolated in pure cultures and preliminarily characterized. The isolates contain a variety of carotenoids, bacteriochlorophyll a incorporated into pigment protein complexes, and are morphologically and physiologically diverse. These properties indicate a diversity of adaptations to the stratified environments of this meromictic lake. Phylogenetically all isolated strains belong to the α subclass of Proteobacteria. [Copyright &y& Elsevier]

On a global scale, pathogenic contamination of drinking water poses the most significant health risk to humans, and there have been countless numbers of disease outbreaks and poisonings throughout history resulting from exposure to untreated or poorly treated drinking water. However, significant risks to human health may also result from exposure to nonpathogenic, toxic contaminants that are often globally ubiquitous in waters from which drinking water is derived. With this latter point in mind, the objective of this commission paper is to discuss the primary sources of toxic contaminants in surface waters and groundwater, the pathways through which they move in aquatic environments, factors that affect their concentration and structure along the many transport flow paths, and the relative risks that these contaminants pose to human and environmental health. In assessing the relative risk of toxic contaminants in drinking water to humans, we have organized our discussion to follow the classical risk assessment paradigm, with emphasis placed on risk characterization (see Figure 1). In doing so, we have focused predominantly on toxic contaminants that have had a demonstrated or potential effect on human health via exposure through drinking water. In the risk assessment process, understanding the sources and pathways for contaminants in the environment is a crucial step in addressing (and reducing) uncertainty associated with estimating the likelihood of exposure to contaminants in drinking water. More importantly, understanding the sources and pathways of contaminants strengthens our ability to quantify effects through accurate measurement and testing, or to predict the likelihood of effects based on empirical models. Understanding the sources, fate, and concentrations of chemicals in water, in conjunction with assessment of effects, not only forms the basis of risk characterization, but also provides critical information required to render decisions regarding regulatory initiatives, remediation, monitoring, and management. Our discussion is divided into two primary themes. First we discuss the major sources of contaminants from anthropogenic activities to aquatic surface and groundwater and the pathways along which these contaminants move to become incorporated into drinking water supplies. Second, we assess the health significance of the contaminants reported and identify uncertainties associated with exposures and potential effects. Loading of contaminants to surface waters, groundwater, sediments, and drinking water occurs via two primary routes: (1) point-source pollution and (2) non-point-source pollution. Point-source pollution originates from discrete sources whose inputs into aquatic systems can often be defined in a spatially explicit manner. Examples of point-source pollution include industrial effluents (pulp and paper mills, steel plants, food processing plants), municipal sewage treatment plants and combined sewage-storm-water overflows, resource extraction (mining), and land disposal sites (landfill sites, industrial impoundments). Non-point-source pollution, in contrast, originates from poorly defined, diffuse sources that typically occur over broad geographical scales. Examples of non-point-source pollution include agricultural runoff (pesticides, pathogens, and fertilizers), storm-water and urban runoff, and atmospheric deposition (wet and dry deposition of persistent organic pollutants such as polychlorinated biphenyls "PCBs" and mercury). Within each source, we identify the most important contaminants that have either been demonstrated to pose significant risks to human health and/or aquatic ecosystem integrity, or which are suspected of posing such risks. Examples include nutrients, metals, pesticides, persistent organic pollutants (POPs), chlorination by-products, and pharmaceuticals. Due to the significant number of toxic contaminants in the environment, we have necessarily restricted our discussion to those chemicals that pose risks to human health via exposure through drinking water. A comprehensive and judicious consideration of the full range of contaminants that occur in surface waters, sediments, and drinking water would be a large undertaking and clearly beyond the scope of this article. However, where available, we have provided references to relevant literature to assist the reader in undertaking a detailed investigation of their own. The information collected on specific chemicals within major contaminant classes was used to determine their relative risk using the hazard quotient (HQ) approach. Hazard quotients are the most widely used method of assessing risk in which the exposure concentration of a stressor, either measured or estimated, is compared to an effect concentration (e.g., no-observed-effect concentration or NOEC). A key goal of this assessment was to develop a perspective on the relative risks associated with toxic contaminants that occur in drinking water. Data used in this assessment were collected from literature sources and from the Drinking Water Surveillance Program (DWSP) of Ontario. For many common contaminants, there was insufficient environmental exposure (concentration) information in Ontario drinking water and groundwater. Hence, our assessment was limited to specific compounds within major contaminant classes including metals, disinfection byproducts, pesticides, and nitrates. For each contaminant, the HQ was estimated by expressing the maximum concentration recorded in drinking water as a function of the water quality guideline for that compound. There are limitations to using the hazard quotient approach of risk characterization. For example, HQs frequently make use of worst-case data and are thus designed to be protective of almost all possible situations that may occur. However, reduction of the probability of a type II error (false negative) through the use of very conservative application factors and assumptions can lead to the implementation of expensive measures of mitigation for stressors that may pose little threat to humans or the environment. It is important to realize that our goal was not to conduct a comprehensive, in-depth assessment of risk for each chemical; more comprehensive assessments of managing risks associated with drinking water are addressed in a separate issue paper by Krewski et al. (2001a). Rather, our goal was to provide the reader with an indication of the relative risk of major contaminant classes as a basis for understanding the risks associated with the myriad forms of toxic pollutants in aquatic systems and drinking water. For most compounds, the estimated HQs were <1. This indicates that there is little risk associated with exposure from drinking water to the compounds tested. There were some exceptions. For example, nitrates were found to commonly yield HQ values well above 1 in many rural areas. Further, lead, total trihalomethanes, and trichloroacetic acid yielded HQs >1 in some treated distribution waters (water distributed to households). These latter compounds were further assessed using a probabilistic approach; these assessments indicated that the maximum allowable concentrations (MAC) or interim MACs for the respective compounds were exceeded <5% of the time. In other words, the probability of finding these compounds in drinking water at levels that pose risk to humans through ingestion of drinking water is low. Our review has been carried out in accordance with the conventional principles of risk assessment. Application of the risk assessment paradigm requires rigorous data on both exposure and toxicity in order to adequately characterize potential risks of contaminants to human health and ecological integrity. Weakness rendered by poor data, or lack of data, in either the exposure or effects stages of the risk assessment process significantly reduces the confidence that can be placed in the overall risk assessment. Overall, while our review suggested selected instances of potential risks to human health from exposure to contaminants in drinking water, we also noted a distinct paucity of information on exposure levels for many contaminants in this matrix. We suggest that this represents a significant limitation to conducting sound risk assessments and introduces considerable uncertainty with respect to the management of water quality. In this context, future research must place greater emphasis on targeted monitoring and assessment of specific contaminants (e.g., pharmaceuticals) in drinking water for which there is currently little information. This could be conducted using a tiered risk approach, beginning with, for example, a hazard quotient assessment. Potentially problematic compounds identified in these preliminary assessments would then be subjected to more comprehensive risk assessments using probabilistic methods, if sufficient data exist to do so. On this latter point, adequate assessment of potential risks for many contaminants in drinking water is currently limited by a paucity of toxicological information. Generating this important information is a critical research need and would reduce the uncertainty associated with conducting risk assessments. [ABSTRACT FROM AUTHOR]