Two sampling strategies for an overview of pesticide contamination in an agriculture-extensive headwater stream

Two headwaters located in southwest France were monitored for 3 and 2 years (Auvézère and Aixette watershed, respectively) with two sampling strategies: grab and passive sampling with polar organic chemical integrative sampler (POCIS). These watersheds are rural and characterized by agricultural areas with similar breeding practices, except that the Auvézère watershed contains apple production for agricultural diversification and the downstream portion of the Aixette watershed is in a peri-urban area. The agricultural activities of both are extensive, i.e., with limited supply of fertilizer and pesticides. The sampling strategies used here give specific information: grab samples for higher pesticide content and POCIS for contamination background noise and number of compounds found. Agricultural catchments in small headwater streams are characterized by a background noise of pesticide contamination in the range of 20–70 ng/L, but there may also be transient and high-peak pesticide contamination (2000–3000 ng/L) caused by rain events, poor use of pesticides, and/or the small size of the water body. This study demonstrates that between two specific runoff events, contamination was low; hence the importance of passive sampler use. While the peak pesticide concentrations seen here are a toxicity risk for aquatic life, the pesticide background noise of single compounds do not pose obvious acute nor chronic risks; however, this study did not consider the risk from synergistic “cocktail” effects. Proper tools and sampling strategies may link watershed activities (agricultural, non-agricultural) to pesticides detected in the water, and data from both grab and passive samples can contribute to discussions on environmental effects in headwaters, an area of great importance for biodiversity.     

Occurrence of perchlorate in rice from different areas in the Republic of Korea

Perchlorate concentrations in rice samples from many different provinces, and correlation with surface water contamination, were investigated in the Republic of Korea. Perchlorate levels in the 51 rice samples purchased from local markets ranged from below the detection limit to 1.79?±?0.39 μg/kg with a mean level of 0.21 μg/kg and 7 samples collected from the Nakdong River watershed ranged from 0.38?±?0.1 to 3.23?±?0.47 μg/kg with a mean level of 0.9 μg/kg. The correlation coefficient between perchlorate levels in rice samples from the Nakdong river watershed and the levels in surface water was estimated to be approximately 0.904 in the 95 % confidence interval. These results show that surface water contamination was highly related to the perchlorate pollution of rice in the Republic of Korea.     

Historical trend of nitrogen and phosphorus loads from the upper Yangtze River basin and their responses to the Three Gorges Dam

Excessive inputs of nitrogen and phosphorus (N and P) degrade surface water quality worldwide. Impoundment of reservoirs alters the N and P balance of a basin. In this study, riverine nutrient loads from the upper Yangtze River basin (YRB) at the Yichang station were estimated using Load Estimator (LOADEST). Long-term load trends and monthly variabilities during three sub-periods based on the construction phases of the Three Gorges Dam (TGD) were analyzed statistically. The dissolved inorganic nitrogen (DIN) loads from the upper YRB for the period from 1990 to 2009 ranged from 30.47?×?10⁴ to 78.14?×?10⁴ t, while the total phosphorus (TP) loads ranged from 2.54?×?10⁴ to 7.85?×?10⁴ t. DIN increased rapidly from 1995 to 2002 mainly as a result of increased fertilizer use. Statistics of fertilizer use in the upper YRB agreed on this point. However, the trend of the TP loads reflected the combined effect of removal by sedimentation in reservoirs and increased anthropogenic inputs. After the TGD impoundment in 2003, decreasing trends in both DIN and TP loads were found. The reduction in DIN was mainly caused by ammonium consumption and transference. From an analysis of monthly loads, it was found that DIN had a high correlation to discharges. For TP loads, an average decrease of 4.91 % in October was found when the TGD impoundment occurred, but an increase of 4.23 % also occurred in July, corresponding to the washout from sediment deposited in the reservoir before July. Results of this study revealed the TGD had affected nutrient loads in the basin, and it had played a role in nutrient reduction after its operation.     

Evaluation of the distribution of fecal indicator bacteria in a river system depending on different types of land use in the southern watershed of the Baltic Sea

The aim of the study was to determine the effects of land use management on changes in the fecal contamination of water in the ?yna River, one of the main lowland watercourses in the southern watershed of the Baltic Sea (northern Poland). A total of 120 water samples were collected in different seasons of 2011 and 2012 at 15 sites where the river intersected forest (FA), agricultural (AA), and urbanized (UA) areas. Fecal indicator bacteria (FIB), the counts of Enterobacteriaceae and Escherichia coli, total bacterial counts (TBCs), and domain Bacteria (EUB338) were determined by culture-dependent and culture-independent methods. Temperature, pH, chemical oxygen demand, dissolved oxygen, total dissolved solids, ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, orthophosphate, and total phosphorus were also determined. The lowest bacterial counts were noted in water samples collected in FA, and the highest in samples collected in UA. Statistically significant differences were determined between bacterial populations across the analyzed land use types and in different sampling seasons. Significant correlations were also observed between the populations of FIB and physicochemical parameters. The results indicate that land use type influenced FIB concentrations in river water. The combined use of conventional and molecular methods improves the accuracy of fecal contamination analyses in river ecosystems.     

Environmental PCBs in Guánica Bay,Puerto Rico: implications for community health

Guánica Bay, located in southwestern Puerto Rico, has suffered oil spills and other pollution discharges since the 1960s. Previous research showed elevated concentrations of polychlorinated biphenyls (PCBs) in coral reef and sediment. This research examined PCB concentrations in sediment and fish. Sediment and fish sampling in the bay was facilitated by community members. This study identified the second highest reported PCB level (129,300 ng/g) in sediment in the USA. Fish samples also showed elevated concentrations (1623 to 3768 ng/g), which were higher than the thresholds of safe levels of PCBs in fish for human consumption. The alarmingly high concentration of PCBs calls for proactive community engagement to bring awareness about contamination of the bay and more extensive sampling to test for the concentration of PCBs in seafood and the people of Guánica. This study also underscores the value of the involvement of local communities during sampling design aimed at identifying hot spots of contaminants.     

Relationship between geographical origin and contents of Pb,Cd, and Cr in honey samples from the state of Paraná (Brazil) with chemometric approach

The aim of this study was to determine the trace elements, Pb, Cd, and Cr in honey samples from eight different regions from the state of Paraná (Brazil), using slurry sampling graphite furnace atomic absorption spectrometry. Chemometric analysis (principal component analysis (PCA)) was applied to classify honey samples according to their levels of the trace elements Pb, Cd, and Cr, which is also related to the geographical origin of honey samples. The mean concentration for the elements followed the order Pb?>?Cr >?>?Cd. The mean values were 200?±?76, 88?±?14, and 4.1?±?4 ng g^?1 for Pb, Cr, and Cd, respectively. It could be verified that honey samples are geographically separated, especially with regard to Pb and Cd contents. Thus, honey can be considered a bioindicator of environmental contamination, suggesting possible contamination in soil, water, and air. This contamination can be related to natural or anthropogenic sources present in the study regions.     

Informal e-waste recycling: environmental risk assessment of heavy metal contamination in Mandoli industrial area,Delhi, India

Nowadays, e-waste is a major source of environmental problems and opportunities due to presence of hazardous elements and precious metals. This study was aimed to evaluate the pollution risk of heavy metal contamination by informal recycling of e-waste. Environmental risk assessment was determined using multivariate statistical analysis, index of geoaccumulation, enrichment factor, contamination factor, degree of contamination and pollution load index by analysing heavy metals in surface soils, plants and groundwater samples collected from and around informal recycling workshops in Mandoli industrial area, Delhi, India. Concentrations of heavy metals like As (17.08 mg/kg), Cd (1.29 mg/kg), Cu (115.50 mg/kg), Pb (2,645.31 mg/kg), Se (12.67 mg/kg) and Zn (776.84 mg/kg) were higher in surface soils of e-waste recycling areas compared to those in reference site. Level exceeded the values suggested by the US Environmental Protection Agency (EPA). High accumulations of heavy metals were also observed in the native plant samples (Cynodon dactylon) of e-waste recycling areas. The groundwater samples collected form recycling area had high heavy metal concentrations as compared to permissible limit of Indian Standards and maximum allowable limit of WHO guidelines for drinking water. Multivariate analysis and risk assessment studies based on total metal content explains the clear-cut differences among sampling sites and a strong evidence of heavy metal pollution because of informal recycling of e-waste. This study put forward that prolonged informal recycling of e-waste may accumulate high concentration of heavy metals in surface soils, plants and groundwater, which will be a matter of concern for both environmental and occupational hazards. This warrants an immediate need of remedial measures to reduce the heavy metal contamination of e-waste recycling sites.     

Atmospheric deposition of organochlorine pesticides by precipitation in a coastal area

Wet deposition fluxes of organochlorine pesticides (OCPs) were determined for rain samples collected in a coastal area of Turkey. Seventeen precipitation samples were collected over a 1-year period from 2008 to 2009. Rainwater was accumulated at the beginning of rain events using real time monitoring. Atmospheric concentrations were also measured in parallel with deposition samples. Both atmospheric concentrations and deposition fluxes were determined as particle and gas phases. The particle phase and dissolved phase deposition fluxes were 794.26?±?756.70 ngm^?2 day^?1 and 800.77?±?672.63 ngm^?2 day^?1, respectively. The washout ratios for OCP compounds were calculated separately for the particle and dissolved phases using the atmospheric concentrations and rain concentrations. The minimum washout ratio for the particle phase was 2339.47 for Endrin aldehyde, whereas the maximum washout ratio was 497593.34 for Methoxychlor. The maximum washout ratio for the dissolved phase was 247523.89 for Endosulfan beta, whereas the minimum washout ratio was 10169.69 for p,p′-DDT. The dry deposition velocities ranged from 0.01 to 1.67 cms^?1. The partitioning of wet deposition between the particle and dissolved phases was 50 % in terms of total OCP deposition.     

Geochemical and mineralogical characterization of a neutral, low-sulfide/high-carbonate tailings impoundment, Markušovce, eastern Slovakia

Tailings deposits generated from mining activities represent a potential risk for the aquatic environment through the release of potentially toxic metals and metalloids occurring in a variety of minerals present in the tailings. Physicochemical and mineralogical characteristics of tailings such as total concentrations of chemical elements, pH, ratio of acid-producing to acid-neutralizing minerals, and primary and secondary mineral phases are very important factors that control the actual release of potentially toxic metals and metalloids from the tailings to the environment. The aims of this study are the determination of geochemical and mineralogical characteristics of tailings deposited in voluminous impoundment situated near the village of Marku?ovce (eastern Slovakia) and identification of the processes controlling the mobility of selected toxic metals (Cu, Hg) and metalloids (As, Sb). The studied tailings have unique features in comparison with the other tailings investigated previously because of the specific mineral assemblage primarily consisting of barite, siderite, quartz, and minor sulfides. To meet the aims, samples of the tailings were collected from 3 boreholes and 15 excavated pits and subjected to bulk geochemical analyses (i.e., determination of chemical composition, pH, Eh, acid generation, and neutralization potentials) combined with detailed mineralogical characterization using optical microscopy, X-ray diffraction (XRD), electron microprobe analysis (EMPA), and micro-X-ray diffraction (μ-XRD). Additionally, the geochemical and mineralogical factors controlling the transfer of potentially toxic elements from tailings to waters were also determined using short-term batch test (European norm EN 12457), sampling of drainage waters and speciation–equilibrium calculations performed with PHREEQC. The tailings mineral assemblage consists of siderite, barite, quartz, and dolomite. Sulfide minerals constitute only a minor proportion of the tailings mineral assemblage and their occurrence follows the order: chalcopyrite?>?pyrite?>?tetrahedrite?>?arsenopyrite. The mineralogical composition of the tailings corresponds well to the primary mineralization mined. The neutralization capacity of the tailings is high, as confirmed by the values of neutralization potential to acid generation potential ratio, ranging from 6.7 to 63.9, and neutral to slightly alkaline pH of the tailings (paste pH 7.16–8.12) and the waters (pH 7.00–8.52). This is explained by abundant occurrence of carbonate minerals in the tailings, which readily neutralize the acidity generated by sulfide oxidation. The total solid-phase concentrations of metal(loid)s decrease as Cu?>?Sb?>?Hg?>?As and reflect the proportions of sulfides present in the tailings. Sulfide oxidation generally extends to a depth of 2 m. μ-XRD and EMPA were used to study secondary products developed on the surface of sulfide minerals and within the tailings. The main secondary minerals identified are goethite and X-ray amorphous Fe oxyhydroxides and their occurrence decreases with increasing tailings depth. Secondary Fe phases are found as mineral coatings or individual grains and retain relatively high amounts of metal(loid)s (up to 57.6 wt% Cu, 1.60 wt% Hg, 23.8 wt% As, and 2.37 wt% Sb). Based on batch leaching tests and lysimeter results, the mobility of potentially toxic elements in the tailings is low. The limited mobility of metals and metalloids is due to their retention by Fe oxyhydroxides and low solubilities of metal(loid)-bearing sulfides. The observations are consistent with PHREEQC calculations, which predict the precipitation of Fe oxyhydroxides as the main solubility-controlling mineral phases for As, Cu, Hg, and Sb. Waters discharging from tailings impoundment are characterized by a neutral to slightly alkaline pH (7.52–7.96) and low concentrations of dissolved metal(loid)s (<5–7.0 μg/L Cu, <0.1–0.3 μg/L Hg, 5.0–16 μg/L As, and 5.0–43 μg/L Sb). Primary factors influencing aqueous chemistry at the site are mutual processes of sulfide oxidation and carbonate dissolution as well as precipitation reactions and sorption onto hydrous ferric oxides abundantly present at the discharge of the impoundment waters. The results of the study show that, presently, there are no threats of acid mine drainage formation at the site and significant contamination of natural aquatic ecosystem in the close vicinity of the tailings impoundment.     

Spatial distribution of mercury in topsoil from five regions of China

The concentrations and distributions of mercury (Hg) in topsoil from four provinces and one municipality in China were investigated. A total of 1,254 samples were collected and analyzed. The average concentrations of Hg were 0.064 mg kg^?1 for Liaoning Province, 0.100 mg kg^?1 for Jiangsu Province, 0.110 mg kg^?1 for Zhejiang Province, 0.154 mg kg^?1 for Sichuan Province, and 0.098 mg kg^?1 for Chongqing Municipality. Although differences were found among the ranges of Hg concentrations, the average values for each region were similar with other published data. The concentrations of Hg in topsoil varied largely upon the sampling locations. More than 80 % of the soil samples from Liaoning Province, Jiangsu Province, Zhejiang Province, and Chongqing Municipality, were ranked Grade I by the China Environmental Quality Standard for Soils, which can be considered as not contaminated by Hg. The concentrations of Hg in 0.3–0.4 % of soils collected from Jiangsu Province, Zhejiang Province and Chongqing Municipality exceeded the limitation for Grade III, indicating the contamination of Hg in these sites. The sources and potential risks of Hg in these sites should be brought to attention and further investigated.     

Hexabromocyclododecanes in soils and plants from a plastic waste treatment area in North China: occurrence,diastereomer- and enantiomer-specific profiles,and metabolization

Plastic waste is a source of organic contaminants such as hexabromocyclododecanes (HBCDs). HBCDs have been found to cause developmental and reproductive toxicity; it is important to investigate the occurrence and metabolization of HBCDs in the soil environments with plastic waste contamination. This work analyzed HBCDs and their metabolites in soil and plant samples collected from Xinle and Dingzhou—the major plastic waste recycling centers in North China. Results showed that total HBCD concentrations in soils followed the order: plastic waste treatment site (11.0–624 ng/g) > roadside (2.96–85.4 ng/g) ≥ farmland (8.69–55.5 ng/g). HBCDs were detected in all the plant samples with total concentrations ranging from 3.47 to 23.4 ng/g. γ-HBCD was the dominant congener in soils, while α-HBCD was preferentially accumulated in plants. Compositions of HBCD isomers in soils and plants were significantly different (P < 0.05) among sampling sites and among plant species. HBCDs in farmland soil and all plant samples exhibited high enantio-selectivity based on the enantiomeric fractions (EFs). Furthermore, metabolites of pentabromocyclododecenes (PBCDEs) were frequently identified in soils, and mono-OH-HBCDs were the most common ones in plants. This study for the first time provides evidences of HBCD contamination in the soil-plant system caused by plastic waste, their stereo-selectivity, and metabolization behavior, improving our understanding of the environmental behavior and fate of HBCDs.     

Occurrence of polybrominated diphenyl ethers (PBDEs) and 2,2’,4,4’,5,5’-hexabromobiphenyl (BB-153) in water samples from the Diep River, Cape Town, South Africa

Until recently, studies reporting the concentrations of polybrominated diphenyl ethers (PBDEs) as well as polybrominated biphenyls (PBBs) are generally scarce in the literature. Consequently, this study was aimed to investigate the occurrence and concentrations of certain PBDE congeners (BDE 28, 47, 100, 99, 154, 153, 183 and 209) and BB 153 in river water samples collected bi-monthly from the Diep River. The routine analyses of the target compounds were performed using a high-capillary GC–microelectron capture detection, while their structural elucidation was assessed using GC-TOF-MS technique. The overall mean concentrations of the sum of the eight PBDE congeners were 2.60, 4.83 and 4.29 ng/L for the upstream, point of discharge and downstream sampling points, respectively. Similarly, the overall mean concentrations of BB 153 were 0.25, 4.85 and 1.56 ng/L for the upstream, point of discharge and downstream sampling points, respectively. BDE 47 was the dominant congener found in these samples contributing between 19 and 26 % to the total PBDEs across the sampling points. The statistical analyses performed on the results obtained showed that all the congeners, except BDE 209 in certain instances, had strong positive correlations with one another, thus suggesting that these contaminants could be emanating from the same source. In this study, potential sources of these pollutants other than WWTP discharges into the investigated river were also identified. However, the relatively high concentrations of the target compounds found at the point of discharge sampling point coupled with the large volume of treated effluent being discharged suggested that the contributions from this source could be very significant over time.     

Evidence of excessive releases of metals from primitive e-waste processing in Guiyu, China

Guiyu, China is infamous for its involvement in primitive e-waste processing and recycling activities. Freshwater samples were collected in and outside of Guiyu for dissolved metal analysis. It was found that dissolved metal concentrations were higher in Lianjiang and Nanyang River within Guiyu than the reservoir outside of Guiyu. Lianjiang was enriched with dissolved As, Cr, Li, Mo, Sb and Se, while Nanyang River had elevated dissolved Ag, Be, Cd, Co, Cu, Ni, Pb and Zn. Temporal distributions of the metals suggested recent discharges of metals attributable to a strong acid leaching operation of e-waste, where dissolved Ag, Cd, Cu and Ni (0.344+/-0.014, 0.547+/-0.074, 87.6+/-3.0 and 93.0+/-1.4 microg/L, respectively) were significantly elevated. Pb isotopic composition of dissolved Pb confirmed that more than one non-indigenous Pb were present in Lianjiang and Nanyang River. In summary, it was evident that the riverine environment of Guiyu was heavily impacted by e-waste related activities.     

Evaluation of transport and storage of 60Co, 134Cs, 137Cs and 65Zn by river sediments in the lower Susquehanna River

The Peach Bottom Atomic Power Station (PBAPS) has contributed measurable quantities of radioactivity to Conowingo Reservoir, an impoundment of the lower Susquehanna River. As part of an ongoing radiological assessment program, concentrations of plant-related radionuclides in sediments have been monitored in spring and fall since 1980. Mass balance estimates derived from grab samples of surface sediments (< 10 cm) indicate that less than 20% of reactor released (60)Co, (65)Zn, (134)Cs and (137)Cs is present in these sediments. Significant seasonal variations in radionuclide trapping efficiency by the reservoir are not apparent. Deep core samples (c. 200 cm) confirm that some, but not all, of this surface sediment radionuclide inventory remains within the reservoir-trapped in discrete locations by subsequent sediment accumulation. The remaining radionuclide mass, in dissolved or particle-associated form, appears to be transported downstream, through Conowingo Dam, to upper Chesapeake Bay. The detection of PBAPS-derived radionuclides in the sediments of upper Chesapeake Bay, primarily the Susquehanna Flats, confirms the transport of these radionuclides from the lower Susquehanna River.     

Pesticide pressure and fish farming in barrage pond in Northeastern France Part I: site characterization and water quality

Purpose

Fish farming in barrage pond is a rearing system commonly used worldwide. Obtaining good water quality is essential to improve sustainability of these ecosystems, both for health of fish consumers and environmental considerations. However, ponds are often located in agricultural landscape, but few study reports impact of pesticide pressure on these ecosystems. This study characterizes five sites in Northeastern France. This work establishes an initial framework for pesticide monitoring with the aim to improve understanding of the fate of pesticides in ponds.

Methods

This framework is based on surveys indicating managements and Geographical Information System (GIS) for five ponds and their watersheds (sites: C-0, C-25, C-45, C-75 and C-85) and completes with some analysis of a large spectrum of pesticide residues in surface waters.

Results

Watersheds show a gradient of crop proportion ranging from 0% to 82% of the watershed area, mainly rapeseed, wheat, barley and maize. Ponds were representative of local Northeastern France management. Many pesticides, and also nutrients, were measured in water with concentrations varying between sites and seasons. The sum of quantified molecules ranged from 0.17 ??g/l for site C-0 (March) to 8.81 ??g/l for site C-25 (October). Concentrations of metaldehyde, quinmerac, isoproturon and bentazon were sometimes above 1 ??g/l.

Conclusions

There is a strong connection between pond and watershed, due to water supply throughout the fish production cycle. Sites with small pond/big watershed are the most exposed to acute contamination a few days after spraying because water discharges are not diluted.     

Utilization of long duration high-volume sampling coupled to SPME-GC-MS/MS for the assessment of airborne pesticides variability in an urban area (Strasbourg,France) during agricultural application

Atmospheric samples have been collected between 14 March and 12 September 2012 on a 2-week basis (15 days of sampling and exchange of traps each 7 days) in Strasbourg (east of France) for the analysis of 43 pesticides. Samples (particle and gas phases) were separately extracted using Accelerated Solvent Extraction (ASE) and pre-concentrated by Solid Phase Micro-Extraction (SPME) before analysis by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). Four SPME consecutive injections at distinct temperatures were made in order to increase the sensitivity of detection for the all monitored pesticides. Currently used detected pesticides can be grouped in four classes; those used in maize crops (acetochlor, benoxacor, dicamba, s-metolachlor, pendimethalin, and bromoxynil), in cereal crops (benoxacor, chlorothalonil, fenpropimorph, and propiconazole), in vineyards (tebuconazole), and as herbicides for orchards, meadows of green spaces (2,4-MCPA, trichlopyr). This is in accordance with the diversity of crops found in the Alsace region and trends observed are in accordance with the period of application of these pesticides. Variations observed permit also to demonstrate that the long time sampling duration used in this study is efficient to visualize temporal variations of airborne pesticides concentrations. Then, long time high-volume sampling could be a simple method permitting atmospheric survey of atmospheric contamination without any long analysis time and consequently low cost.     

Experimental exposure of juvenile savannah monitors (Varanus exanthematicus) to an environmentally relevant mixture of three contaminants: effects and accumulation in tissues

Using varanids as indicators of pollution in African continental wetlands was previously proposed. The present study aimed at understanding experimentally how monitors absorb and accumulate pollutants and how they are affected. The relevance of non-destructive sampling was also evaluated. Savannah monitors (Varanus exanthematicus) were orally exposed during 6 months to a mixture of lead, 4,4′-dichlorodiphenyltrichloroethane (4,4′-DDT) and chlorpyrifos-ethyl (CPF) or to the vehicle only. Proportionally to their mass, exposed monitors received the same dose: 20 then 10 mg lead?kg^?1, 2 then 0.5 mg CPF?kg^?1 and 4 mg 4,4′-DDT?kg^?1. Individuals surviving contamination were euthanized after 4 or 6 months of experiment. Tissues were analysed for lead by atomic absorption spectrophotometry and for DDT and CPF by gas chromatography. Exposed monitors absorbed all three pollutants but only lead (essentially in bone, tail tips and phalanxes) and 4,4′-DDT plus its main metabolites (essentially in fat and liver) accumulated. CPF killed ten individuals. Clear correlations occurred between the total quantity of lead or 4,4′-DDT administered and concentrations in tissues. Tail tips and skin samples are recommended non-destructive indicators for lead and organochlorine pesticides contamination, respectively. This work confirms that monitors can be used as relevant indicators of environmental pollution by lead and organochlorine pesticides. Although varanids withstand heavy lead and DDT contamination, our results suggest that CPF can be lethal at very low doses to the herpetofauna and emphasize the importance of considering all taxa in impact assessment studies, including reptiles.     

Continuous monitoring of conventional parameters to assess receiving water quality in support of combined sewer overflow abatement plans.

As part of its long-term control plan for combined sewer overflow (CSO) abatement, the city of Buffalo, New York, maintained a network of Hydrolab Datasondes (Hydrolab-Hach Company, Loveland, Colorado) to assess receiving water-quality effects by continuously logging dissolved oxygen, pH, temperature, conductivity, and turbidity. Although the effect of individual CSOs could be visualized, turbidity levels entering the Buffalo River from the upper watershed often were greater than from CSO discharges. Turbidity data showed that the Buffalo River was a net-sediment sink. Low dissolved oxygen levels were observed in the summer during dry weather, baseflow, and watershed-wide storms and CSO events. Some CSOs did not produce dissolved oxygen sags in the receiving waters, but others did. This information, together with the sampling done for organic and inorganic contaminants, can aid the decisionmaking process when prioritizing outfalls for abatement work and provides a baseline against which receiving water-quality improvements can be measured.     

Leaching of heavy metals and alkylphenolic compounds from fresh and dried sewage sludge

Reusing sewage sludge as a soil fertiliser has become a common alternative to disposal. Although this practice has a few benefits, it may contribute to the medium- and long-term contamination of the trophic chain because sewage sludge may contain heavy metals and organic contaminants. As the leaching of contaminants may depend on the sludge pre-treatment, the leaching of heavy metals (Cu, Ni, Pb, Zn and Cr) and alkylphenolic compounds (APCs) (octylphenol (OP), nonylphenol (NP), nonylphenol-mono-ethoxylate (NP₁EO)) was investigated in five fresh and 40 °C dried sewage sludge samples from north-eastern Spain. FT-IR analyses and full-scan GC-MS chromatograms showed that sludge drying changed the nature of organic compounds leading to changes in their solubility. Moreover, sludge drying led to a higher relative contribution of dissolved organic carbon than the particulate organic carbon in the leachates. Leaching of Pb, Zn and Cr was below 5 % in both fresh and dried sludge samples, whereas Cu and Ni leached at rates up to 12 and 43 %, respectively, in some of the dried sludge samples. The leaching yields of OP, NP and NP₁EO ranged from 1.3 to 35 % for fresh samples, but they decreased from 0.8 to 3.4 % in dried samples. The decrease in the leachability of APCs observed in dried sludge samples might be attributed to the fact that these compounds are associated with particulate organic matter, with significantly lower concentration or even absent in dried sludge than in fresh sludge samples. Therefore, it is recommended to dry the sludge before its disposal.     

Groundwater quality in Imphal West district, Manipur, India, with multivariate statistical analysis of data

The aim of this paper was to analyze the groundwater quality of Imphal West district, Manipur, India, and assess its suitability for drinking, domestic, and agricultural use. Eighteen physico-chemical variables were analyzed in groundwater from 30 different hand-operated tube wells in urban, suburban, and rural areas in two seasons. The data were subjected to uni-, bi-, and multivariate statistical analysis, the latter comprising cluster analysis (CA), principal component analysis (PCA), and factor analysis (FA). Arsenic concentrations exceed the Indian standard in 23.3 % and the WHO limit in 73.3 % of the groundwater sources with only 26.7 % in the acceptable range. Several variables like iron, chloride, sodium, sulfate, total dissolved solids, and turbidity are also beyond their desirable limits for drinking water in a number of sites. Sodium concentrations and sodium absorption ratio (SAR) are both high to render the water from the majority of the sources unsuitable for agricultural use. Multivariate statistical techniques, especially varimax rotation of PCA data helped to bring to focus the hidden yet important variables and understand their roles in influencing groundwater quality. Widespread arsenic contamination and high sodium concentration of groundwater pose formidable constraints towards its exploitation for drinking and other domestic and agricultural use in the study area, although urban anthropogenic impacts are not yet pronounced.