Evaluation of natural and anthropogenic influences on the Guadalquivir River (Spain) by dissolved heavy metals and nutrients

Metal concentrations and pathological responses of wild native fish exposed to sewage discharge in a Mediterranean river

The requirements of the Water Framework Directive suggest the need for further research to test and develop sensitive tools that will allow freshwater managers to detect impacts on fish communities. Diagnostic refinement often encompasses the use of lethal diagnostic tools that are incompatible with the conservation of native ichthyofauna. Here we determine the metal concentration and the pathological response of Squalius laietanus exposed to sewage discharges in the Ripoll river (north-eastern Spain), and compare these findings with our previous studies on Barbus meridionalis using lethal and non-lethal diagnostic tools. Metals concentrations (Zn, Cu, Pb, Hg, Fe, Cd and Ni) were determined in liver and muscle. A complete blood cell profile (haematocrit, haemoglobin, differential leukocyte count, erythrocytic nuclear abnormalities, erythrocytes in division and the development stage of erythrocytes) was used as a non-lethal diagnostic tool to determine early warning signs of disease in these two fish species. As the reference range for these haematological variables is lacking, liver histology, calculation of body condition (CF) and organosomatic indices (HSI and GSI) were employed to support the findings of the blood analyses. Compared to our previous results on B. meridionalis, S. laietanus appeared to have fewer pathological responses than B. meridionalis under the environmental conditions measured and the fish size range examined in this study. Both species showed a similar bioaccumulation pattern, but B. meridionalis stored high Hg and Cu concentrations in muscle and liver, respectively. Hg, Cu and Pb concentrations in fish tissues exceeded the thresholds of European and Spanish legislation. Our findings pinpoint the potential suitability of the blood variables determined in the health diagnoses of these species. Further research will be necessary to establish the natural variability of these and other haematological variables to convert haematology into a sensitive and useful non-lethal diagnostic tool in wild fish populations.

Monitoring of trace metals and pharmaceuticals as anthropogenic and socio-economic indicators of urban and industrial impact on surface waters

The research focuses on the monitoring of trace metals and pharmaceuticals as potential anthropogenic indicators of industrial and urban influences on surface water. This study includes analysis of tracers use for the indication of water pollution events and discussion of the detection method of these chemicals. The following criteria were proposed for the evaluation of indicators: specificity (physical chemical properties), variability (spatial and temporal), and practicality (capacity of the sampling and analytical techniques). The combination of grab and passive water sampling (i.e., diffusive gradient in the thin film and polar organic chemical integrated samplers) procedure was applied for the determination of dissolved and labile trace metals (Ag, Cd, Cr, Cu, Ni, Pb, and Zn) and pharmaceuticals (carbamazepine, diazepam, paracetamol, caffeine, diclofenac, and ketoprofen). Samples were analyzed using inductively coupled plasma mass spectrometry (MS; trace metals) and liquid chromatography-tandem MS electrospray ionization+/- (pharmaceuticals). Our results demonstrate the distinctive spatial and temporal patterns of trace elements distribution along an urban watercourse. Accordingly, two general groups of trace metals have been discriminated: "stable" (Cd and Cr) and "time varying" (Cu, Zn, Ni, and Pb). The relationship Cd >> Cu > Ag > Cr ≥ Zn was proposed as an anthropogenic signature of the industrial and urban activities pressuring the environment from point sources (municipal wastewaters) and the group Pb-Ni was discussed as a relevant fingerprint of the economic activity (industry and transport) mainly from non-point sources (runoff, atmospheric depositions, etc.). Pharmaceuticals with contrasting hydro-chemical properties of molecules (water solubility, bioaccumulation, persistence during wastewater treatment processes) were discriminated on conservative, labile, and with combined properties in order to provide information on wastewater treatment plant efficiency, punctual events (e.g., accidents on sewage works, runoff), and uncontrolled discharges. Applying mass balance modeling, medicaments were described as relevant socio-economic indicators, which can give a picture of main social aspects of the region.

Atmospheric influence on the distribution of organic pollutants in the Guadalquivir River estuary, SW Spain

In the lower Guadalquivir river basin, a system stressed by a wide variety of anthropogenic activities, eight pesticides (four triazines, two chloroacetanilide herbicides, one organochlorine, and one organophosphorus insecticide); and four emerging pollutants (two personal care products, one organophosphorous flame retardant, and one xanthine alkaloid) were analyzed in river water during a 2-year monitoring program, and after rain episodes. Samples were extracted using the solid phase extraction (SPE) technique prior to determination of compounds using gas chromatograph coupled to a mass spectrometer detector. Except for caffeine, recoveries were mostly above 80 %, while limits of detection and quantification were in the low nanograms per liter level (except for dimethoate). Terbuthylazine, simazine (triazine herbicides), and dimethoate (organophosphorus insecticide), present in agrochemicals, were predominant in the river water, although concentrations were below the quality standards established by the EU Water-Framework-Directive. A general trend to increase concentration was observed after rain events, in particular for pesticides, possibly as a consequence of surface runoff.

Metal bioaccumulation in the Mediterranean barbel (Barbus meridionalis) in a Mediterranean river receiving effluents from urban and industrial wastewater treatment plants

Although sewage treatment plants (STPs) play a crucial role in maintaining the water quality and flow of Mediterranean rivers, particularly during drought periods, few studies have addressed their impact on aquatic fauna. Here we analyzed the role of STPs as a source of metals in the Ripoll River, a heavily urbanized and industrialized watercourse with a long history of anthropogenic disturbance. For this purpose, we measured iron, mercury, cadmium, zinc, lead, nickel and copper accumulation in the liver and muscle of the Mediterranean barbel, Barbus meridionalis and also the concentrations of these metals in the river water. Industrial and urban sewage treatment plants are source of metals in Ripoll River but the former mainly increases Zn and Ni values. Significant differences in metal bioaccumulation between reference and polluted sites were detected. Nevertheless, there was only a significant positive relationship between bioaccumulation of Cu and Hg, and their concentration in water. In addition, the lead concentration in fish was not clearly associated with the presence of STPs. On the basis of morphometric parameters, the hepato-somatic index was the only one denoting significant differences between polluted and references sites. Given that fish are key elements in food webs, recreational fishing is practice in this area and that river water is used for agricultural purposes, we recommend long-term studies to analyze the impact of metal pollution in this river.

A chemometric approach to the evaluation of atmospheric and fluvial pollutant inputs in aquatic systems: the Guadalquivir River estuary as a case study

To establish the quality of waters it is necessary to identify both point and non-point pollution sources. In this work, we propose the combination of clean analytical methodologies and chemometric tools to study discrete and diffuse pollution caused in a river by tributaries and precipitations, respectively. During a two-year period, water samples were taken in the Guadalquivir river (selected as a case study) and its main tributaries before and after precipitations. Samples were characterized by analysing nutrients, pH, dissolved oxygen, total and volatile suspended solids, carbon species, and heavy metals. Results were used to estimate fluvial and atmospheric inputs and as tracers for anthropic activities. Multivariate analysis was used to estimate the background pollution, and to identify pollution inputs. Principal Component Analysis and Cluster Analysis were used as data exploratory tools, while box-whiskers plots and Linear Discriminant Analysis were used to analyse and distinguish the different types of water samples.

Analysis and evaluation of the source of heavy metals in water of the River Changjiang

In order to analyze and evaluate different trace metals on surface water of the Changjiang River, concentrations of dissolved trace metals (Cu, Ni, Fe, Co, Sc, Al, Zn, Pb, Cd, Se, As, Cr, and Hg), major elements (Ca and Mg), and nutrient (NO3- were measured. Samples were taken at 76 positions along Changjiang River in flood and dry seasons during 2007-2008. Spatial distributions identified two main large zones mainly influenced by mineral erosion (sites 1-22) and anthropogenic action (sites 23-76), respectively. Principal component analysis (PCA) and hierarchical cluster analysis were used to identify the variance distinguishing the origin of water. Four significant components were extracted by PCA, explaining 74.91% of total variable. Cu, Ni, Fe, Co, Sc, Al, Ca, and Mg were mainly associated with the weathering and erosion of various rocks and minerals, while an anthropogenic source was identified for Cd and As. Although erosion was one source of Pb and Zn, they were also input by atmospheric deposition and industrial pollutions. NO3- and Se were mainly associated with agriculture activities. However, Hg and Cr showed different sources. CA confirmed and completed the results obtained by PCA, classifying the data into two large groups representing different areas. Group 1 referred to the upper reaches which represented samples mainly corresponding to natural background areas. Group 2 referred to the middle and lower reaches including samples under anthropogenic influence. Meanwhile, group 2 was subdivided into three new groups, representing agricultural, industrial, and various artificial pollution sources, respectively.

Influence of sediment acidification on the bioaccumulation of metals in Ruditapes philippinarum

BACKGROUND, AIM AND SCOPE

The influence of pH (range 6.5-8.5) on the uptake of Zn, Cd, Pb, Cu, Ni, Cr, Hg, and As by juveniles of the clam Ruditapes philippinarum was examined in order to understand whether variation in sediment pH has significant repercussions on metal bioaccumulation.

MATERIALS AND METHODS

Clams were exposed to sediments collected in three locations in the Gulf of Cadiz (Huelva, Guadalquivir and Bay of Cadiz) and to contaminated particles derived from an accidental mining spill in Spain.

RESULTS

With a notable exception of metal Cd, the concentration of metals within clams significantly increased (p < 0.1) when sediment pH was lowered by one or two units. Moreover, the magnitude of this effect was dependent on the type of sediment contamination.

DISCUSSION

Lower pH increases metal solubility and reduces or invert the metal sorption of metals to sediments. Increases in free metal ions in water favors metal uptake by clams, hence pH is an important factor controlling the mobility of these metals within sediments and their subsequent bioaccumulation within biota. Although sediment-water exchange of Cd can increase with acidification, this excess may be counterbalanced by the presence of ligands in seawater preventing the uptake by organism. Besides chlorines, Cd has also an affinity with carbonates and other ligands present in sea water. These Cd-carbonate complexes may reduce the bioavailable to organisms.

CONCLUSIONS

These results highlight the potential implications of sediment acidification, either due to the storage excess of organic matter or to the forced capture of CO(2), on the increasing metal availability to benthic organisms.

RECOMMENDATIONS AND PERSPECTIVES

This kind of studies should be increased to address the influence of acidification in the behavior, bioavailability, toxicity, and risk assessment of contaminants associated with sediments either above sub-seabed geological formations in marine environments or in high enriched by organic matter in estuarine areas. Recently, the capture of CO(2) in marine environments has been approved and started; it is necessary to address the potential impacts associated with leakages or other events occurring during the procedure of injection and storage of CO2.

Genotoxic analysis in aquatic environment under influence of cyanobacteria, metal and radioactivity

The micronucleus (MN) and nuclear abnormality (NA) tests were employed to evaluate the genotoxic potential of the Lucrecia dam (RN, Brazil) located in a semi-arid region and influenced by crop irrigation and irregular rainfall. The analyses of these water samples demonstrated the presence of several cyanobacteria as well as metals and radioactivity. The Nile Tilapia (Oreochromis niloticus) was used for micronucleus and nuclear abnormality assays and analysis of metal concentrations in gills and liver samples. Genotoxic assays in source water fish showed a significant increase in the frequency of nuclear damage (MN and NA) in relation to the negative control group. In conclusion, the results obtained with water surface and biological samples from the Lucrecia dam suggest that this important water resource contains a number of chemical and microbiological pollutants with genotoxic potential and that these substances may be compromising the species inhabiting this ecosystem. Particular care must be taken to prevent further degradation of this water supply. Capsule: A battery of assay was successfully applied to assess the water quality of Lucrecia dam from a Northeastern region of Brazil.

Multi-source water pollution in a highly anthropized wetland system associated with the estuary of Huelva (SW Spain)

Major ions, nutrients, trace elements and pesticides distribution were studied in a coastal wetland heavily impacted by human development in Spain. Past land use has altered the local hydrodynamics leading to the partitioning of the ecosystem into a tideland subject to marine influence, and an artificial freshwater reservoir created by stream impoundment. The tideland stretch is flooded twice a day with a heavy metal plume that emerges from the mine-polluted estuary of Huelva and propagates landward depicting the same dispersal trend of major seawater ions. Additionally, the tidal channel receives acid discharges from industrial point sources that contribute to metal enhancement. The impounded area and stream tributaries are affected by agrochemicals runoff (nitrate, phosphate, pendimethalin, simazine, diuron and therbuthylazine) from surrounding agricultural lands. The tidal regime plays a crucial role in the transport and dispersion of pollutants, except in the artificial reservoir where freshwater exhibits a seasonal mineralization pattern.

Temporal and spatial variations of water quality in the Jinshui River of the South Qinling Mts., China

Water pollution has become a growing threat to human society and natural ecosystems in recent decades, increasing the need to better understand the spatial and temporal variabilities of pollutants within aquatic systems. This study sampled water quality at 12 sampling sites from October 2006 to August 2008 in the Jinshui River of the South Qinling Mts., China. Multivariate statistical techniques and gridding methods were used to investigate the temporal and spatial variations of water quality and identify the main pollution factors and sources. Two-way analysis of variance (ANOVA) showed that 25 studied water quality variables had significant temporal differences (p<0.01) and spatial variability (p<0.01). Using cluster analysis, the 12 sampling sites were classified into three pollution level groups (no pollution, moderate pollution, and high pollution) based on similarity of water quality variables. Factor analysis determined that 80.4% of the total variance was explained by five factors, that is, salinity, trophicity, organic pollution, oxide-related process, and erosion. The gridding methods illustrated that water quality progressively deteriorated from headwater to downstream areas. The analytical results suggested that the water pollution primarily resulted from domestic wastewater and agricultural runoff, and provided critical information for water resource conservation in mountainous watersheds of the South Qinling Mts., China.

Anthropogenic influence on surface water quality of the Nhue and Day sub-river systems in Vietnam

In order to investigate the temporal and spatial variations of 14 physical and chemical surface water parameters in the Nhue and Day sub-river systems of Vietnam, surface water samples were taken from 43 sampling sites during the dry and rainy seasons in 2007. The results were statistically examined by Mann-Whitney U-test and hierarchical cluster analysis. The results show that water quality of the Day River was significantly improved during the rainy season while this was not the case of the Nhue River. However, the river water did not meet the Vietnamese surface water quality standards for dissolved oxygen (DO), biological oxygen demand (BOD(5)), chemical oxygen demand (COD), nutrients, total coliform, and fecal coliform. This implies that the health of local communities using untreated river water for drinking purposes as well as irrigation of vegetables may be at risk. Forty-three sampling sites were grouped into four main clusters on the basis of water quality characteristics with particular reference to geographic location and land use and revealed the contamination levels from anthropogenic sources.

Identification of coastal water quality by statistical analysis methods in Daya Bay, South China Sea

In this paper, cluster analysis (CA), principal component analysis (PCA) and the fuzzy logic approach were employed to evaluate the trophic status of water quality for 12 monitoring stations in Daya Bay in 2003. CA grouped the four seasons into four groups (winter, spring, summer and autumn) and the sampling sites into two groups (cluster DA: S1, S2, S4-S7, S9 and S12 and cluster DB: S3, S8, S10 and S11). PCA identified the temporal and spatial characteristics of trophic status in Daya Bay. Cluster DB, with higher concentrations of TP and DIN, is located in the western and northern parts of Daya Bay. Cluster DA, with the low Secchi, is located in the southern and eastern parts of Daya Bay. The fuzzy logic approach revealed more information about the temporal and spatial patterns of the trophic status of water quality. Chlorophyll a, TP and Secchi may be major factors for deteriorating water quality.

Evaluation of spatial and temporal variation in water quality by pattern recognition techniques: A case study on Jajrood River (Tehran, Iran)

In this paper, principal component analysis (PCA) and hierarchical cluster analysis (CA) methods have been used to investigate the water quality of Jajrood River (Iran) and to assess and discriminate the relative magnitude of anthropogenic and "natural" influences on the quality of river water. T, EC, pH, TDS, NH(4), NO(3), NO(2), Turb., T.Hard., Ca, Mg, Na, K, Cl, SO(4), SiO(2) as physicochemical and TC, FC as biochemical variables have been analyzed in the water samples collected every month over a three-year period from 18 sampling stations along a 50 km section of Jajrood River that is under the influence of anthropogenic and natural changes. Exploratory analysis of experimental data has been carried out by means of PCA and CA in an attempt to discriminate sources of variation in water quality. PCA has allowed identification of a reduced number of mean 5 varifactors, pointing out 85% of both temporal and spatial changes. CA classified similar water quality stations and indicated Out-Meygoon as the most polluted one. Ahar, Baghgol, Rooteh, Befor Zaygan, Fasham, Roodak and Lashgarak were identified as affected by organic pollution. A Scree plot of stations in the first and second extracted components on PCA also gave us a classification of stations due to the similarity of pollution sources. CA and PCA led to similar results, though Out-Meygoon was identified as the most polluted station in both methods. Box-plots showed that PCA could approximately demonstrate temporal and spatial variations. CA gave us an overview of the problem and helped us to classify and better explain the PCA results.

Genotoxicity assessment in aquatic environment impacted by the presence of heavy metals

The aim of this study was to access the genotoxic potential of Extremoz Lake waters in Northeastern Brazilian coast, using the Allium cepa system, piscine micronucleus test and comet assay. In addition, heavy metal levels were quantified by atomic absorption flame spectrometry. The results of the A. cepa system showed significant changes in the frequency of chromosome aberrations and in the mitotic index compared to negative control. No significant changes were observed in micronuclei frequency in the erythrocytes of Oreochromis niloticus. The comet assay showed a statistically significant alteration in the level of DNA breaks of O. niloticus. Chemical analysis detected an increase in heavy metal levels in different sampling periods. These results point out a state of deterioration of water quality at Extremoz Lake, caused by heavy metal contamination and genotoxic activity. It is recommended to establish a monitoring program for the presence of genotoxic agents in this water lake.

Ranking sediment samples from three Spanish estuaries in relation to its toxicity for two benthic species: the microalga Cylindrotheca closterium and the copepod Tisbe battagliai

The present study assesses the sediment toxicity levels of three Spanish estuaries, as well as the suitability of two microorganisms, the benthic microalga Cylindrotheca closterium and the harpacticoid copepod Tisbe battagliai, as test organisms in whole-sediment toxicity assays. The sensitivity of both species to potentially polluted sediments was compared. Three sites at the southwest of the Iberian Peninsula were chosen: the Ría of Huelva, the Guadalquivir Estuary, and the Bay of Algeciras. Inhibition data were based on growth for C. closterium and fecundity for T. battagliai. No toxicity was recorded for the microalga in the Guadalquivir Estuary and the Bay of Algeciras. However, for T. battagliai, inhibition of fecundity was approximately 50% in those zones, indicating higher sensitivity. Samples from stations in the Ría of Huelva were the most toxic of all those assayed; inhibition values higher than 90% were obtained for both organisms. The highest values for total metal concentrations such as arsenic (As), cadmium (Cd), copper (Cu), iron (Fe), lead (Pb), tin (Sn), and zinc (Zn) were found in the Ría of Huelva, which can be classified as severely impacted. The Guadalquivir Estuary and the Bay of Algeciras can be considered moderately impacted. In general, both methodologies are suitable for application in ecotoxicological studies.

Multivariate statistical study of organic pollutants in Nanjing reach of Yangtze River

Multivariate statistical approach was used to identify the source apportionment of 25 semi-volatile compounds (SVOCs) in surface water in Nanjing reach of Yangtze River, China. Surface water samples were collected from six sites in January 2007. Concentrations of SVOCs were determined by gas chromatography equipped with a mass spectrometry detector (GC-MS). Cluster analysis (CA) and principal component analysis-multiple linear regression (PCA-MLR) were used for evaluation of contamination status, distribution and source apportionment. The results of CA showed that the six sites in this study could be divided into two significant groups, i.e. low and high pollutant groups. PCA-MLR results suggested that four source types were identified, explaining about 84.5% of the total variance. Of four sources, industrial and domestic sewage sources contributed 43.5-64.8% of various SVOCs in six sites, precipitance and runoff sources 4.22-42.87%, shipping sources 4.22-23.49%, and other miscellaneous sources 1.05-8.97%. These results indicated that point source pollutants affected the water quality of this region. High correlation coefficient (R(2)=0.973) between the measured and predicted concentrations of SVOCs suggested the applicability of the PCA-MLR for estimation of source contribution to the SVOCs in water.