Periphyton as an indicator of water quality in the St Lawrence River (Québec, Canada)

The performance of various algal indices to document improvements in water quality across a low nutrient concentration gradient was assessed during 2 years in the St Lawrence River (Quebec, Canada). Water-quality variables and periphyton samples were collected on navigational buoys near Montreal during the spring, summer and fall of 1994 and 1995. Exposure to urban wastewater varied widely within the sector surrounding the island of Montreal, with some areas upstream receiving no direct effluents and areas further downstream receiving treated and untreated wastewater. Faecal coliform concentrations provided a good tracer of effluents and were significantly correlated to nutrient concentrations (r = 0.33-0.72, p < 0.001) and water transparency (r = 0.70, p < 0.001). Despite a strong gradient in faecal coliform concentration (< 2 to > 20 000 UFC/100 ml), algal biomass and diversity did not reflect differences between sites with varying levels of urban wastewater. Taxonomic composition of periphyton communities, particularly the presence of the cyanophyte Plectonema notatum Schmidle, was related (r = 0.48, p = 0.004) to exposure to urban effluents. Variables describing seasonal changes (temperature, Julian day, river discharge, conductivity, NO2-NO3) explained a large fraction of total variance (38-52% of total variance) and thus exerted the predominant influence on algal biomass and species composition in the St Lawrence River. Variables describing the presence of effluents explained 1-22% of the variance in compositional data. Subtle changes in periphyton species composition were the only response to different levels of exposure to urban wastewater in the Montreal area, which represented relatively small differences in comparison to natural seasonal variability.     

Lead concentration increase in the hepatic and gill soluble fractions of European chub (Squalius cephalus)—an indicator of increased Pb exposure from the river water

Purpose

To examine if chronic exposure of feral fish to elevated Pb concentrations in the river water (up to 1???g?L^?1), which are still lower than European recommendations for dissolved Pb in surface waters (7.2???g?L^?1; EPCEU (Official J L 348:84, 2008)), would result in Pb accumulation in selected fish tissues.

Methods

Lead concentrations were determined by use of HR ICP-MS in the gill and hepatic soluble fractions of European chub (Squalius cephalus) caught in the Sutla River (Croatia?CSlovenia).

Results

At the site with increased dissolved Pb in the river water, soluble gill Pb levels (17.3???g?L^?1) were approximately 20 times higher compared to uncontaminated sites (0.85???g?L^?1), whereas the ratio between contaminated (18.1???g?L^?1) and uncontaminated sites (1.17???g?L^?1) was lower for liver (15.5). Physiological variability of basal Pb concentrations in soluble gill and hepatic fractions associated to fish size, condition, sex, or age was not observed, excluding the possibility that Pb increase in chub tissues at contaminated site could be the consequence of studied biotic parameters. However, in both tissues of Pb-exposed specimens, females accumulated somewhat more Pb than males, making female chubs potentially more susceptible to possible toxic effects.

Conclusions

The fact that Pb increase in gill and hepatic soluble fractions of the European chub was not caused by biotic factors and was spatially restricted to one site with increased dissolved Pb concentration in the river water points to the applicability of this parameter as early indicator of Pb exposure in monitoring of natural waters.     

Water quality of the Guadiamar River after the Aznalcóllar spill (SW Spain)

In April 1998, a spill of 6 hm3 of pyritic mud and acidic water was released into the Guadiamar River due to the rupture of the Aznalcóllar tailings dam. Before the spill, the river was already strongly affected by acid mine drainage (AMD). In this study, the water quality of the Guadiamar River is analysed from a periodic sampling started after the spill. Previous data of the water quality have also been obtained. A recovery of the water quality is observed from 2002 on. The distribution of arsenic is opposed to that of the rest of metals, with the lowest concentrations to the north, due to the adsorption and/or coprecipitation on ferric oxyhydroxides. In the southern area, when pH values are close to 8, arsenic desorption occurs. There is a seasonal pattern of the trace metal content evolution, different in the northern and southern zones of the river. In the northern area the highest polluting levels occur in summer, due to a lower dilution of the mining leachates. In the southern area, the highest metal levels occur during the winter, since during the summer metals remain held by surface sorption processes in the hyporheic zone of the river.     

Heavy metal contamination in sediments of an artificial reservoir impacted by long-term mining activity in the Almadén mercury district (Spain)

Sediments from the Castilseras reservoir, located downstream on the Valdeazogues River in the Almadén mercury district, were collected to assess the potential contamination status related to metals(oids) associated with river sediment inputs from several decommissioned mines. Metals(oids) concentrations in the reservoir sediments were investigated using different physical and chemical techniques. The results were analyzed by principal component analysis (PCA) to explain the correlations between the sets of variables. The degree of contamination was evaluated using the enrichment factor (EF) and the geoaccumulation index (Igeo). PCA revealed that the silty fraction is the main metals(oids) carrier in the sediments. Among the potentially harmful elements, there is a group (Al, Cr, Cu, Fe, Mn, Ni, and Zn) that cannot be strictly correlated to the mining activity since their concentrations depend on the lithological and edaphological characteristics of the materials. In contrast, As, Co, Hg, Pb, and S showed significant enrichment and contamination, thus suggesting relevant contributions from the decommissioned mines through fluvial sediment inputs. As far as Hg and S are concerned, the high enrichment levels pose a question concerning the potential environmental risk of transfer of the organic forms of Hg (mainly methylmercury) from the bottom sediments to the aquatic food chain.     

The assessment of water quality in the Lower Luján River (Buenos Aires,Argentina): phytoplankton and algal bioassays

The monitoring of river phytoplankton and several hydrological, physical and chemical variables, in combination with bioassays using Selenastrum capricornutum Printz, allowed the characterisation of three distinct reaches of the Lower River Luján. The upstream stretch, characterised by the lowest depth and discharge, registered the highest nutrient, dissolved heavy metal and chlorophyll a concentrations in accordance with low phytoplankton diversity and the occurrence of several species typical of organically polluted lowland rivers. A downstream improvement, concomitant to increasing river discharge, is revealed by a progressive decrease of organic pollution parameters even though algal toxicity is registered through bioassays. The water input from the Parana River through the G. Arias Channel plays an important role in the regulation of the limnology of the Lower Luján River. As a result of marked increasing discharge, depth and width, there is a decrease in nutrient concentration and phytoplankton density and an increase in dissolved oxygen concentration. Likewise, algal growth rates in the bioassays showed less toxic effect.     

δ13C variations in tree rings as an indication of severe changes in the urban air quality

Annual growth rings sampled from three free-standing trees (Platanus hybrida sp.), grew in the metropolitan area of Palermo (Italy) and covering a 118 years time span (1880–1998), have been studied for their ¹³C/¹²C carbon isotope ratios. It has been found that the ¹³C/¹²C tree ring record, during the study time interval, decreased of −3.6‰, from −26.4‰ in 1880 to −30‰ in 1998. Such a progressive depletion has been attributed to the addition of anthropogenic ¹³C depleted carbon dioxide to the local atmosphere. The observed ¹³C/¹²C decrease has been used to infer some possible pathways of atmospheric CO₂ change in the study urban area.     

Seasonality of contamination, toxicity, and quality values in sediments from littoral ecosystems in the Gulf of Cádiz (SW Spain)

To seasonally evaluate littoral contamination, toxicity and quality values of sediments from the Gulf of Cádiz, we measured chemical concentrations and conducted toxicity tests in winter and summer and linked these results by means of multivariate analysis. Sediment samples were subjected to two separate, replicated sediment toxicity tests (Microdeutopus gryllotalpa amphipod survival, and Ruditapes philippinarum clam reburial), and to comprehensive sediment chemistry analyses (grain size, organic carbon, 14 heavy metals, and the surfactant linear alkylbenzenesulfonate (LAS)). Only sediments associated with an untreated urban discharge were toxic and related to high levels of surfactant LAS, Ag, and Pb. Multivariate analysis indicated that variables and chemicals associated with geochemical matrix and background levels (specific surface, Fe, Zn, Cu, V, Ni, and Co), chemicals associated with untreated urban discharge sources, and toxicity effects showed no seasonal variability. Only copper concentrations showed seasonal differences, being toxic during the winter and not toxic during summer. Multivariate analysis permits us to derive sediment quality values (SQVs); in terms of concentrations at or below which biological effects were not measured (mg kg(-1) dry sediment), are: LAS, 2.6; lead, 66.8; silver, 0.78; copper, 69.6.     

Response of microcrustacean communities from the surface—groundwater interface to water contamination in urban river system of the Jarama basin (central Spain)

In order to evaluate the water quality at the surface/groundwater interface (hyporheic zone), the pattern of microcrustacean assemblages in response to environmental stress caused by urban industrial contamination was studied in the Jarama River basin (central Spain) during high water discharges (March and April 2011). The clustering of biological variables and the concentration of urban contaminants in hyporheic waters showed that pristine hyporheic waters have moderate species diversity (two to seven species) and dominance of k strategist stygobites, whereas excessively contaminated sites are devoid by crustaceans. An intermediate level of disturbance in hyporheic waters is associated with a peak of species taxonomic diversity (four to nine species) and proliferation of r strategist more tolerant species. Typical species found in hyporheic zone, e.g., Paracyclops imminutus (Copepoda, Cyclopoida), Cryptocandona vavrai (Ostracoda) and Herpetocypris chevreuxi (Ostracoda), were good indicators of high concentrations of Cr, Mn, Ni, Cd, Pb and VOCs; whereas the stygobites do not show any significant correlation. The effectiveness of hyporheic crustaceans as efficient bioindicators for assessing the current ecological status of river ecosystems is emphasised.     

Diurnal variation in the concentration of α- and β-pinene in the landes forest (France)

The study deals with the identification and the determination of the main monoterpenes (α- and β-pinene) released by the pines in the Landes Forest in France. The measurements were taken after preconcentration using TENAX-GC and thermal desorption. The diurnal variation of atmospheric concentration of α- and β-pinene is established; it is less than 0.5 ppbV in the daytime and varies from 2 to 4 ppbV in the night-time. These variations are explained by the fact that the photochemical reactions and the turbulence phenomena to which the terpenes are exposed change quite radically from day to night. The terpene concentration, higher at 5 m than at 25 m, would seem to confirm the existence of a terpene source at ground level.     

Determination and evaluation of cadmium, lead and nickel in greenhouse soils of Almería (Spain)

This study determines total levels of three (Cd, Pb and Ni) potentially toxic trace elements in western Almería (Spain) greenhouse surface soil horizons using microwave digestion; it establishes the geochemical baseline concentration, and it investigates possible relationships between soil properties and elemental concentrations. The results show that the soil concentration of these heavy metals is lower than mentioned in the European and Spanish normative, but they are higher than those reported by other authors working on agricultural soils. The obtained geochemical baseline concentrations (mg kg(-1)) were: Cd 0.4-0.8, Pb 2.5-89.9 and Ni 16.1-30.7. Using the upper baseline criterion, 88% of greenhouse soils have relatively higher content of heavy metals because of their Cd, Pb and Ni concentration. Moreover, soil properties are related to heavy metals contents suggesting that among Cd, Pb and Ni have a similar origin and those total metal concentrations are controlled primarily by soil compositions.     

Evaluation of surface water quality using an ecotoxicological approach: a case study of the Piracicaba River (São Paulo, Brazil)

A long-term study was conducted to evaluate Piracicaba River water (São Paulo state, Brazil) using different methodologies and organisms. During 1 year (February 2011 to January 2012), water samples were collected monthly at six different locations and exposed under laboratory conditions to the microcrustaceans Ceriodaphnia dubia and Ceriodaphnia silvestrii for 7 days and to the fish Danio rerio for 4 days to evaluate effects on reproduction and on gill morphology, respectively. Physical–chemical parameters of the water were also measured. Physical–chemical characteristics demonstrated decreasing water quality from upstream to downstream of the river. Effects on the reproduction of C. dubia and C. silvestrii were observed in 3 months (February and March 2011 and January 2012) and occurred in samples collected close to industrialized cities like Americana and Piracicaba. Evaluation of the gills showed normal function of the organ during all months, except in February, September, and October for some locations.     

Mercury species accumulation and trophic transfer in biological systems using the Almadén mining district (Ciudad Real,Spain) as a case of study

The impact of mercury (Hg) pollution in the terrestrial environments and the terrestrial food chains including the impact on human food consumption is still greatly under-investigated. In particular, studies including Hg speciation and detoxification strategies in terrestrial animals are almost non-existing, but these are key information with important implications for human beings. Therefore, in this work, we report on Hg species (inorganic mercury, iHg, and monomethylmercury, MeHg) distribution among terrestrial animal tissues obtained from a real-world Hg exposure scenario (Almadén mining district, Spain). Thus, we studied Hg species (iHg and MeHg) and total selenium (Se) content in liver and kidney of red deer (Cervus elaphus; n?=?41) and wild boar (Sus scrofa; n?=?16). Similar mercury species distribution was found for both red deer and wild boar. Major differences were found between tissues; thus, in kidney, iHg was clearly the predominant species (more than 81 %), while in liver, the species distribution was less homogeneous with a percentage of MeHg up to 46 % in some cases. Therefore, Hg accumulation and MeHg transfer were evident in terrestrial ecosystems. The interaction between total Se and Hg species has been evaluated by tissue and by animal species. Similar relationships were found in kidney for both Hg species in red deer and wild boar. However, in liver, there were differences between animals. The possible underlying mechanisms are discussed.     

Airborne particulate matter around the Cathedral of Burgos (Castilla y León,Spain)

A methodology to collect and analyse atmospheric particulate matter has been developed at the Cathedral of Burgos (Spain). Particles were collected in a portable particle sampler on carbon layers and stone surfaces. The analyses were undertaken under SEM-EDX by means X-ray mapping and Featurescan (a program for the automated characterisation of particles). To determine their possible sources, particles collected in the sampler and on carbon layers were classified according to their composition, mainly by cluster analysis. Then, they were compared with those deposited on stone surfaces. This classification is useful when a plan of preventive conservation for monuments is to be undertaken. In general, no important differences are observed between the chemical composition of particles directly collected from the atmosphere and those deposited on different substrates. Fine particles present the highest sulphur contents (almost 100%), while calcium is the major element in the medium and coarse particles. Other abundant elements are silicon, chlorine and phosphorus. The number of iron-rich particles is small. The study of the material deposited on carbon layers and stone substrates has confirmed the presence of gypsum in all cases.     

Groundwater chemistry of the Okélobondo uraninite deposit area (Oklo, Gabon): two-dimensional reactive transport modelling

The stability of uranium-bearing minerals in natural environments is of interest to evaluate the feasibility of radioactive waste repositories. The uraninite bodies, UO2(s), in the Oklo district (Gabon) are the result of a natural fission process, which took place 1970 Ma ago. These deposits can be regarded as natural analogues for spent fuel. One of the uraninite bodies, the Okélobondo deposit, is located at a depth of 300 m. Groundwater samples from boreholes located at shallow depths (100-200 m) show neutral to basic pH, anoxic conditions (Eh = 0.10 to -0.05 V) and are saturated with respect to uraninite. In contrast, deeper samples collected in the vicinity of the ore body are oxidising (Eh = 0.32-0.47 V), slightly basic (pH = 7.0-8.5) and undersaturated with respect to uraninite. These oxidising conditions at depth, if present under repository conditions, may affect the stability of uranium oxide. In order to improve our understanding of the observed site geochemistry, the available information on the lithology and groundwater flow was integrated in a reactive transport model. The chemical composition and the pH-Eh values of the water sampled above and in the western side of the Okélobondo deposit can be explained by the interaction of meteoric recharge with pelites, dolomites and sandstones. The dissolution of Fe(II)-silicates and the oxidation of the Fe(II)-aqueous species maintained the pH-Eh distribution along the Fe(2+)-Fe(OH)3(am) equilibrium, with the result that uraninite does not dissolve. This may explain the lower uranium content in the water samples from pelites and dolomites above the Okélobondo deposit. The high Mn/Fe ratio and the high pH-Eh values of the water sampled at depth, close to the Okélobondo deposit, suggest a control by the Mn(2+)-MnOOH(s) equilibrium. This control is attributed to the dissolution of a large rhodochrosite, MnCO3(s), and manganite, MnOOH(s) deposit in the recharge area on the eastern side.     

Occurrence of perfluorinated compounds in water and sediment of L’Albufera Natural Park (València,Spain)

Purpose  

Perfluorinated compounds (PFCs) are widely distributed from industrialized to remote locations throughout the world. This study demonstrates the spatial distributions of PFCs in water and sediments from the L’Albufera Natural Park (Valencia, Spain).     

Macroinvertebrate community as a biological indicator of ecological and toxicological factors in Lake Saint-François (Québec)

To assess the potential of the macroinvertebrate community for monitoring variation in the environmental quality of large rivers, the response of littoral macrobenthos in Lake Saint-Fran?ois, a fluvial lake of the St Lawrence River (Québec) are described. First, the composition of total macroinvertebrate communities and important taxonomic groups as well as the biotic ICI-SL index in 16 littoral stations varying in sedimentology, water chemistry and contamination are described to define indicator species groups and environmental quality ranks. Thereafter, the relative contribution of ecological and toxicological factors in explaining the variation observed in macroinvertebrate assemblages and biotic index were quantified using partial canonical correspondence analysis. Cluster analyses based on taxonomic composition separated five groups of stations where macroinvertebrate assemblages varied in density, composition and tolerance to pollution. The ICI-SL biotic index varied from 7.2 to 27.2 with a mean value of 19 +/- 6. The ICI-SL values determined for the macroinvertebrate communities in Lake Saint-Fran?ois did not reflect an important deterioration in environmental quality, and there was some agreement between the environmental quality ranking of the stations expressed either by the ICI-SL index or the community cluster analysis. Water conductivity and phosphorus concentration, followed by macrophyte types (Chara, Ceratophyllum) and sediment grain size, were the most significant ecological variables to explain variation in macroinvertebrate communities and derived ICI-SL index in Lake Saint-Fran?ois. Among the toxicological factors, metals in water (Fe, Cr, Pb, Mn, Zn) and sediment (Mn, Pb, Se), as well as the composite indices of metal and organic contamination (water CI, sediment CI, sediment total PAHs) were the most important factors. The contamination factors selected in our models represented contaminant sorption processes rather than direct toxicological effects. The lack of clear relationships between contaminants and macroinvertebrate variables reflected the relative low level of contamination in the stations sampled in Lake Saint-Fran?ois. There were some interactions between toxicological and ecological variables that should be considered in the planning of sampling and interpretation of biomonitoring studies. However, the large amount of unexplained variance (49.2-86.6%) in the CCA models underlined the limitations of the use of the indices of macroinvertebrate community structure that were assessed in this study for biomonitoring purposes in the absence of a contrasting pollution gradient.     

Characterization of dioxin-like contamination in soil and sediments from the ��hot spot�� area of petrochemical plant in Pancevo (Serbia)

Purpose

Combinatorial bio/chemical approach was applied to investigate dioxin-like contamination of soil and sediment at the petrochemical and organochlorine plant in Pancevo, Serbia, after the destruction of manufacturing facilities that occurred in the spring of 1999 and subsequent remediation actions.

Materials and methods

Soil samples were analyzed for indicator polychlorinated biphenyls (PCBs) by gas chromatography/electron capture detection (GC/ECD). Prioritized soil sample and sediment samples from the waste water channel were analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). Microethoxyresorufin o-deethylase (Micro-EROD) and H4IIE?Cluciferase bioassays were used for monitoring of dioxin-like compounds (DLC) and for better characterization of dioxin-like activity of soil samples.

Results

Bioanalytical results indicated high dioxin-like activity in one localized soil sample, while the chemical analysis confirmed the presence of large quantities of DLC: 3.0?×?10⁵ ng/g d.w. of seven-key PCBs, 8.2 ng/g d.w. of PCDD/Fs, and 3.0?×?10⁵ ng/g d.w. of planar and mono-ortho PCBs. In the sediment, contaminant concentrations were in the range 2?C8 ng/g d.w. of PCDD/Fs and 9?C20 ng/g d.w. of PCBs.

Conclusions

This study demonstrates the utility of combined application of bioassays and instrumental analysis, especially for developing and transition country which do not have capacity of the expensive instrumental analysis. The results indicate the high contamination of soil in the area of petrochemical plant, and PCDD/Fs contamination of the sediment from the waste water channel originating from the ethylene dichloride production.     

Patinas developed in environmental burial conditions: the Neolithic steles of Reguers de Seró (Lleida,Spain)

Background, aim and scope  

Weathering patinas in rocks are the result of interaction processes between rock surfaces and atmosphere, biosphere and soil. Therefore, their textural and mineral composition is strongly related to environmental and bioactivity conditions. Whereas the development of weathering patinas in atmospheric conditions is well documented (e.g. typical Mediterranean patina), only very few studies focus on their formation in a burial environment. Our study of patinas developed on the tumular structure of Reguers de Seró deals with the knowledge of burial patinas from a textural and mineralogical point of view. The aims of this study include: (1) the characterisation of the rock used in this megalithic monument as well as inferences regarding the origin of the raw material; (2) the evaluation of the patinas developed on the surface of the carved steles; and (3) the discussion of the environmental conditions (atmospheric or burial) that favoured the development of the patinas.