Water samples were collected from 50 streams in an area of accelerating shale gas development in the eastern U.S.A. The geochemical/isotopic characteristics show no correlation with the five categories of Marcellus Shale production. The sub-watersheds with the greatest density of Marcellus Shale development have also undergone extensive coal mining. Hence, geochemical/isotopic compositions were used to understand sources of salinity and effects of coal mining and shale gas development in the area. The data indicates that while some streams appear to be impacted by mine drainage; none appear to have received sustained contribution from deep brines or produced waters associated with shale gas production. However, it is important to note that our interpretations are based on one time synoptic base flow sampling of a few sampling stations and hence do account potential intermittent changes in chemistry that may result from major/minor spills or specific mine discharges on the surface water chemistry.

At a 50-year-old coal mine drainage barrens in central Pennsylvania, USA, we evaluated the biogeochemistry of acidic, Fe(III)oxy(hydr)oxide precipitates in reclaimed plots and compared them to untreated precipitates in control areas. Reclaimed plots supported successional vegetation that became established after a one-time compost and lime treatment in 2006, while control plots supported biological crusts. Precipitates were sampled from moist yet unsaturated surface layers in an area with lateral subsurface flow of mine drainage above a fragipan. Fe(II) concentrations were three- to five-fold higher in reclaimed than control precipitates. Organically bound Fe and amorphous iron oxides, as fractions of total Fe, were also higher in reclaimed than control precipitates. Estimates of Fe-reducing and Fe-oxidizing bacteria were four- to tenfold higher in root-adherent than both types of control precipitates. By scaling up measurements from experimental plots, total Fe losses during the 5-yr following reclamation were estimated at 45 t Fe ha−1 yr−1.

In the artificial reservoir of the Isahaya reclaimed land, Nagasaki, Japan, algal blooms have become an annual event, dominated primarily by the microcystin (MC) producing cyanobacteria Microcystis aeruginosa. Although the majority of MCs are either degraded by bacteria or washed out to sea, some remain in the sediment of the reservoir and bay throughout the year. As a result, they also accumulate in aquatic organisms (mullet, oyster, etc.) that inhabit the reservoir and surrounding areas, as well as midge flies that spend their larval period in the bottom of the reservoir. Accordingly, MCs also accumulate in the predators of these organisms, allowing the toxin to spread from the hydrosphere to terrestrial ecosystems. The most effective method for resolving this potentially dangerous condition is to introduce seawater into the reservoir by opening the drainage gates at high tide.

The aim of the paper was to evaluate 23 catchment factors that determine total phosphorus and total nitrogen load to the Baltic Sea. Standard correlation analysis and clustering were used. Both phosphorus and nitrogen loads were found to be positively related to the number of pigs and the human population associated with wastewater treatment plants (WWTPs) per km2, while the number of cattle and agricultural area were found to influence nitrogen rather than phosphorus load, and the area of forests is negatively related to loads of both nutrients. Clustering indicates an overall north–south pattern in the spatial co-occurrence of socio-ecological factors, with some exceptions discussed in the paper. Positive steps in the Baltic Sea region have already been taken, but much remains to be done. The development of coherent response policies to reduce eutrophication in the Baltic Sea should be based on a comprehensive knowledge base, an appropriate information strategy and learning alliance platform in each drainage river catchments.

Water samples collected in 1995 and 2007 from the Shinano and Agano rivers were examined to determine the types and concentrations of pesticides and their effects on tap water in typical rice production areas of Japan. Tap water originating from the Shinano River was also sampled in 2007, in Niigata City, Japan. Pesticides were present in the river and tap water throughout the year. Comparison of 13 pesticides common to both 1995 and 2007 series revealed that the frequency of individual pesticide occurrence and concentrations were decreasing. Riverine pesticides were classified into five groups according to the period of their appearance and changes in concentration. Pesticides were detected at the time of application to, and drainage from, paddy fields. Pesticide concentrations in tap water showed notable decline following rapid sand-filtration combined with granular activated carbon. The detection index (DI) for tap water and Shinano River water did not exceed a value of 1. Herbicides contributed most to the DI.

The study presented here focuses on the use of monolayer covers for reclaiming two acid-generating tailings sites located in Quebec, Canada. One of these covers is made of non-acid-generating tailings, and the other is made of a silty sand (till). The covers are part of the closure plans that aim at controlling acid mine (rock) drainage at these two sites. Reactive tailings and cover material samples were collected in situ and characterised in the laboratory. Large-size columns (230 cm in height) were set up to evaluate the hydrogeological and geochemical response of the tailings and cover systems. Monthly wetting and drying cycles were repeated over nearly 2 years to simulate climatic conditions. Water content, suction, and oxygen concentrations were monitored, and chemical analyses were performed on the leachate collected at the base during each cycle to follow the evolution of water quality, in terms of pH and concentrations of sulfates and metals. In addition, small columns (45 cm in height) were also set up, with a similar testing program, to assess the hydrogeochemical behaviour of exposed tailings. The specific objective of this experimental program was to evaluate the hydrogeological and geochemical behaviour of the tailings-cover systems under controlled conditions. The results indicate that, for the imposed conditions, the monolayer covers became significantly desaturated, thus insufficiently limiting the oxygen diffusion flux. Consequently, these covers do not efficiently prevent sulfide oxidation within the tailings. The implications of these results are also discussed.

The Lea Navigation in the north-east of London, a canalized reach of the River Lea, is affected by episodes of very low levels of dissolved oxygen. The problem was detected by the Environment Agency from the confluence with Pymmes Brook (which receives the final effluent of Deephams sewage treatment works) to the Olympic site (Marshgate Lane, Stratford). In this study, possible causes and sources of the poor water quality in the Lea Navigation were investigated using algal bioassays and detailed spatial seasonal mapping of the physico-chemical parameters collected in situ. Results showed chronic pollution and identified polar compounds in the river water and high bacterial concentrations as possible causes of low dissolved oxygen levels. This study confirmed the negative impact of Deephams sewage treatment works (via Pymmes Brook) on the water quality of the Lea. However, whilst the Environment Agency had previously focused on the pollution created by the sewage treatment works, results showed evidence of other sources of pollution; in particular, Stonebridge Brook was identified as an uncontrolled source of pollution and untreated wastewater. This study demonstrates the value of conducting combined methodologies and detailed monitoring. Other possible sources include Old Moselle Brook, diffuse pollution from surface run-off, boat discharges and other undetected drainage misconnections.

Detention basins are valuable facilities for urban storm water management, from both the standpoint of flood control and the trapping of pollutants. Studies performed on storm water have shown that suspended solids often constitute the main vector of pollutants (heavy metals, polycyclic aromatic hydrocarbon (PAH), etc.). In order to characterise the ecotoxicity of urban sediments from storm water detention basins, the sediments accumulated over a 6-year period were sampled at five different points through the surface of a large detention basin localised in the east of Lyon, France. A specific ecotoxicological test battery was implemented on the solid phase (raw sediment) and the liquid phase (interstitial water of sediments). The results of the study validated the method formulated for the ecotoxicological characterization of urban sediments. They show that the ecotoxicological effect of the sediments over the basin is heterogeneous and greater in areas often flooded. They also show the relationship between, on one hand, the physical and chemical characteristics of the sediments and, on the other hand, their ecotoxicity. Lastly, they contribute to a better understanding of the dynamics of the pollution close to the bottom of detention basins, which can be useful for improving their design. The results of this research raise particularly the issue of using oil separators on the surface of detention basins.

The paper presents the role of spontaneous vegetation on the hydraulic performance of an infiltration basin. The objective of the research was more particularly to study this role of different types of spontaneous vegetation found in situ in an infiltration basin near Lyon. The saturated hydraulic conductivity of three areas covered by Phalaris arundinacea, Polygonum mite, Rumex crispus and similar non-vegetated zones was compared. Eight field campaigns were carried out from July 2010 to May 2011 in order to compare the performance of each type of vegetation and its evolution over time. The results suggest a positive impact of vegetation on hydraulic performance in particular in summer during the growth of the plants. The hydraulic conductivity in this period was twice to four times higher than in bare areas or in vegetated zones during the plant rest periods. Some species were also found more appropriate to limit clogging (Phalaris arundinacea) likely due to its specific structure and growth process.

Fresh water scarcity is an increasing problem worldwide. Strategies to alleviate water scarcity include the use of low-quality water for irrigation. The risk of groundwater contamination by pollutants in this water is affected by soil heterogeneity and preferential flow. These risk factors can be assessed by measuring the spatio-temporal redistribution of uniformly applied water and solutes. We placed a soil monolith (height 29 cm) from an Australian vineyard on a 100-cell multi-compartment sampler (MCS). At this vineyard, treated wastewater is used in response to the severe shortage of water in the summer. We studied the leaching risk associated with heterogeneous or preferential flow by irrigating the soil column with 24 applications to simulate one year. We applied simulated rainfall as well as wastewater (which contained chloride) during summer while relying on rainfall only in winter. We compared the chloride leaching with the leaching of bromide, which was applied during one of the applications as a pulse. During the entire simulated year, leaching of solutes from the monolith was measured. The results indicate that the assumption of uniform flow would underestimate the risk for the fresh groundwater reserves: 25 % of the solutes are transported though 6 % of the soil’s cross-section. The spatial distribution of drainage and solute leaching varied little during the experiment. Consequently, the mass flux density pattern of the bromide pulse was comparable to that of the repeatedly applied chloride. However, the MCS data suggested lateral ‘escape’ from chloride to non-mobile areas, which means in the long run, considerable quantities of these solutes can build up in areas that do not receive irrigation water.