Assessing the effects of tertiary treated wastewater reuse on a Mediterranean river (Llobregat,NE Spain), part III: pathogens and indicators

Purpose  

Need, coupled with advances in water treatment technology, is motivating a growing interest in augmenting drinking water supplies with reclaimed water. Using reclaimed water to increase the flow of the Llobregat River upstream the water catchment site of the complex multi-step drinking water treatment plant of Sant Joan Despí has been considered. The impact of reclaimed water discharges on the load of E. coli, spores of sulphite-reducing clostridia, somatic coliphages, cytopathogenic enteroviruses, and total and infectious Cryptosporidium oocysts in the Llobregat River water was assessed to gain information for funded decisions in potential future emergencies.     

Assessing the effects of tertiary treated wastewater reuse on the presence emerging contaminants in a Mediterranean river (Llobregat,NE Spain)

Purpose  

The Llobregat River, which is characterized by important fluctuations of the flow rates, receives treated waters from WWTPs. During the years 2007 and 2008, the Llobregat River basin suffered from a severe drought which affected the supply of drinking water facilities (DWF) that rely on the exploitation of the river water. The Catalan Water Agency implemented a water reuse experiment with the objective of maintaining the river flow rate at sufficiently high level so as to ensure the supply of raw water to Barcelona’s major DWF.     

Wastewater reuse in Mediterranean semi-arid areas: The impact of discharges of tertiary treated sewage on the load of polar micro pollutants in the Llobregat river (NE Spain)

The presence of sewage-borne micro contaminants in environmental waters is directly related to the discharge of treated effluents from wastewater treatment plants (WWTP) and the flow rate of the receiving river waters. Mediterranean rivers, in particular, are characterized by important fluctuations in the flow rates and heavy pollution pressures resulting from extensive urban, industrial and agricultural activities. This translates into contamination levels in these rivers often higher than those in other larger European basins. The present work provides an overview of the occurrence of five groups of organic contaminants (131 compounds) namely pharmaceuticals, illicit drugs, polar pesticides, estrogens, alkylphenols and related ethoxylates in WWTP tertiary treatment effluents. Data gathered during a period of water reuse carried out in the lower stretch of the Llobregat river (NE Spain), in the surroundings of the town of Barcelona as a consequence of the severe drought that took place along the years 2007-2008 are presented as illustrative example. In general, measured concentrations of the target compounds were in the low to mid ng L⁻¹ range. The total concentration of each compound class downstream to the discharge point was similar or slightly higher than that found upstream. Regarding the loads calculated for each compound, the relative contribution from the river upstream and the tertiary effluent were highly compound depending with no apparent trend. However, estimation of the overall bulk loads for each compound class determined in the Llobregat river showed the following rank order: pharmaceuticals > alkylphenols > pesticides > illicit drugs ? estrogens.     

Assessing decadal changes in rainwater alkalinity at a rural Mediterranean site in the Montseny Mountains (NE Spain)

Annual volume-weighted mean (VWM) concentrations in rainwater collected at La Castanya (LC, Montseny Mountains, NE Spain) were analysed from 1983 to 2000 to study the temporal trends in precipitation chemistry, and the causes behind the changes. A significant positive correlation was found between annual rainwater SO₄²⁻ concentrations at LC and Spanish SO₂ emissions (r=0.73, P=0.0008) both decreasing remarkably during this period. Rainwater alkalinity increased during the period, shifting from negative values at the beginning (VWM in the 5 initial years=−2.7 μeq l⁻¹) to alkaline values in recent years (VWM in the 5 final years=18.0 μeq l⁻¹). Stepwise regression analysis indicated that 88% of the variation of alkalinity could be accounted for by the variability of non-marine Ca²⁺ and non-marine SO₄²⁻, with a more prominent dependence on Ca²⁺.Rains of African provenance were highly enriched in alkalinity and Ca²⁺, but no significant increases in their occurrence were found for the study period. Because of the reported higher dust updraft in northern Africa during years of high North Atlantic Oscillation (NAO) index, we also explored the relationship between rainwater variables associated with an African provenance and NAO. Annual precipitation was inversely related to NAO (r=−0.61, P=0.007). The annual wet deposition of African dust-related elements showed no correlation with NAO, probably because wet deposition of these elements depends on two factors (precipitation and dust updraft) which have opposite behaviour with respect to NAO. We hypothesise that dry deposition of African dust during dry spells (not sampled in this study) might be higher during high NAO-index years.     

Pharmaceuticals on a sewage impacted section of a Mediterranean River (Llobregat River,NE Spain) and their relationship with hydrological conditions

Introduction  

Mediterranean rivers are characterized by a high flow variability, which is strongly influenced by the seasonal rainfall. When water scarcity periods occur, water flow, and dilution capacity of the river is reduced, increasing the potential environmental risk of pollutants. On the other hand, floods contribute to remobilization of pollutants from sediments. Contamination levels in Mediterranean rivers are frequently higher than in other European river basins, including pollution by pharmaceutical residues. Little attention has been paid to the transport behavior of emerging contaminants in surface waters once they are discharged from WWTP into a river. In this context, this work aimed to relate presence and fate of emerging contaminants with hydrological conditions of a typical Mediterranean River (Llobregat, NE Spain).     

Pilot survey of a broad range of priority pollutants in sediment and fish from the Ebro river basin (NE Spain)

Priority organic pollutants were investigated in sediments and fish collected along the Ebro river basin (NE Spain) to evaluate their occurrence, transport and bioavailability. Sediments were collected in 18 sites and two species of fish were captured in nine sites according to the availability in each area. The sampling sites covered industrial, urban and agricultural areas. Four methods were used to detect 20 organochlorine compounds (OCs), 8 polycyclic aromatic hydrocarbons, 3 organotin compounds, 2 alkylphenols and 40 polybrominated diphenyl ethers (PBDEs) from purified extracts. The contamination pattern was site specific and no downstream increase in concentration of pollutants was observed but rather a generalized low level diffuse pollution. Target compounds were detected in sediments at 0.01 to 2331 microg/kg dry weight, and only OCs and PBDEs were accumulated in benthopelagic fish. Toxicological assessment was performed according to predicted environmental levels and revealed sites where adverse effects could occur.     

Distribution of endocrine disruptors in the Llobregat River basin (Catalonia, NE Spain)

The Llobregat basin is a Mediterranean fluvial system with major agricultural, urban and industrial impacts. We combined chemical quantification by liquid chromatography–mass spectrometry with electrospray interface (LC-ESI-MS) and the recombinant yeast assay (RYA) assays to estimate the loads of endocrine disrupting compounds (EDCs) along the basin. Chemical analysis revealed maximum concentrations (at μg l⁻¹ level) of alkylphenols at the lower course of the Llobregat River, which correlated with high levels of estrogenic activity detected by RYA. Analysis by RYA and LC-ESI-MS of influent and effluent waters from four sewage treatment plants (STP) discharging into the basin showed the removal of 80–95% of EDCs by STP treatment. Chemical analysis data and RYA data showed a quasi-linear correlation, demonstrating the complementariness of both methods. Our data suggest that the concentrations of the analysed compounds were enough to explain the total estrogenicity of water and STP samples from the Llobregat basin.     

Distribution of endocrine disruptors in the Llobregat River basin (Catalonia,NE Spain)

The Llobregat basin is a Mediterranean fluvial system with major agricultural, urban and industrial impacts. We combined chemical quantification by liquid chromatography–mass spectrometry with electrospray interface (LC-ESI-MS) and the recombinant yeast assay (RYA) assays to estimate the loads of endocrine disrupting compounds (EDCs) along the basin. Chemical analysis revealed maximum concentrations (at μg l⁻¹ level) of alkylphenols at the lower course of the Llobregat River, which correlated with high levels of estrogenic activity detected by RYA. Analysis by RYA and LC-ESI-MS of influent and effluent waters from four sewage treatment plants (STP) discharging into the basin showed the removal of 80–95% of EDCs by STP treatment. Chemical analysis data and RYA data showed a quasi-linear correlation, demonstrating the complementariness of both methods. Our data suggest that the concentrations of the analysed compounds were enough to explain the total estrogenicity of water and STP samples from the Llobregat basin.     

Impact assessment of a large river on the sediments and fish from its continental shelf: using Solea solea as sentinel in the Ebro river mouth (NW Mediterranean,Spain)

Environmental Science and Pollution Research - Many studies have been carried out along mighty rivers with heavily industrialized watersheds to evaluate pollutants and their effects on freshwater...     

Alteration of acetylcholinesterase activity in Semele solida (MOLLUSCA: SEMELIDAE) as a biochemical response to coastal anthropogenic impact

Acetylcholinesterase (AChE) activity was analyzed as a molecular marker indicative of exposure to organophosphorus pesticide residues in individuals of the endemic clam species Semele solida in selected coastal locations of Chile's VIII Region. AChE activity was assayed in clams from (i) Penco Beach near the mouth of the Andalién River (Concepción Bay), (ii) Lenga Beach, near the mouth of the Lenga Estuary (San Vicente Bay), and (iii) Coliumo Beach, near the mouth of the Coliumo Estuary (Coliumo Bay). We also analyzed variations in protein content of clam hemolymph, and variability in the activity of AChE in relation to the sizes of the individual clams sampled. Collection of the clams was done using routine methods, during the spring of 2005, the period during which the use of pesticides is typically intensified in the surrounding forestry and agriculture. The results showed no significant correlation of AChE activity with either the size of the clam, or with the concentration of proteins in the hemolymph. The lowest AChE activity was observed in clams from mouth of the Andalién River (187.5 ± 34.9 Umin^?1) which was significantly less than that measured in specimens collected near the mouth of the Coliumo Estuary and the mouth of the Lenga Estuary. A very close relation was observed between the degree of anthropogenic inputs, ocean dynamics, and alterations in AChE activity in S. solida. This clam appears to be a useful indicator species, and AChE activity a sensitive marker for the presence of xenobiotics.     

Alteration of acetylcholinesterase activity in Semele solida (MOLLUSCA: SEMELIDAE) as a biochemical response to coastal anthropogenic impact

Acetylcholinesterase (AChE) activity was analyzed as a molecular marker indicative of exposure to organophosphorus pesticide residues in individuals of the endemic clam species Semele solida in selected coastal locations of Chile's VIII Region. AChE activity was assayed in clams from (i) Penco Beach near the mouth of the Andalién River (Concepción Bay), (ii) Lenga Beach, near the mouth of the Lenga Estuary (San Vicente Bay), and (iii) Coliumo Beach, near the mouth of the Coliumo Estuary (Coliumo Bay). We also analyzed variations in protein content of clam hemolymph, and variability in the activity of AChE in relation to the sizes of the individual clams sampled. Collection of the clams was done using routine methods, during the spring of 2005, the period during which the use of pesticides is typically intensified in the surrounding forestry and agriculture. The results showed no significant correlation of AChE activity with either the size of the clam, or with the concentration of proteins in the hemolymph. The lowest AChE activity was observed in clams from mouth of the Andalién River (187.5 +/- 34.9 Umin(-1)) which was significantly less than that measured in specimens collected near the mouth of the Coliumo Estuary and the mouth of the Lenga Estuary. A very close relation was observed between the degree of anthropogenic inputs, ocean dynamics, and alterations in AChE activity in S. solida. This clam appears to be a useful indicator species, and AChE activity a sensitive marker for the presence of xenobiotics.     

Factors affecting the organochlorine pollutant load in biota of a rice field ecosystem (Ebro Delta, NE Spain)

The concentrations of PCBs, DDTs, HCHs, HCB and OCS were determined in sediments and associated biota, both invertebrates (Physella acuta, Hirudo medicinalis, chironomid larvae, Hydrous pistaceus, Helochares lividus) and vertebrates (Rana perezi), in a temporary aquatic system, a rice field in the Ebro Delta (NE Spain). The qualitative and quantitative distribution of organochlorine compounds in sediments and aquatic biota has been explained by two mechanisms: equilibrium partitioning and/or biomagnification through the trophic web. Nevertheless, bioaccumulation processes are by far more complex, since several biotic and abiotic factors contribute to the observed pollutant loads in the organisms. In this respect, the biological characteristics of the organisms considered (e.g. species, age, lipid contents, feeding habits, etc.), as well as ecological factors (e.g. the habitat of the species and vertical distribution), have been shown to account for the organochlorine levels observed.     

Impact of dredged urban river sediment on a Saronikos Gulf dumping site (Eastern Mediterranean): sediment toxicity,contaminant levels,and biomarkers in caged mussels

Impacts of chemical contaminants associated with dumping of dredged urban river sediments at a coastal disposal area in Saronikos Gulf (Eastern Mediterranean) were investigated through a combined approach of sediment toxicity testing and active biomonitoring with caged mussels. Chemical analyses of aliphatic hydrocarbons (AHs), polycyclic aromatic hydrocarbons (PAHs), Cu, and Zn in combination with the solid phase Microtox® test were performed on sediments. Concentrations of PAHs, AHs, Cu, and Zn as well as multiple biomarkers of contaminant exposure and/or effects were measured in caged mussels. Sediments in the disposal and neighboring area showed elevated PAHs and AHs concentrations and were characterized as toxic by the solid-phase Microtox® test during and after dumping operations. Biomarker results in the caged mussels indicated sublethal effects mainly during dumping operations, concomitantly with high concentrations of PAHs and AHs in the caged mussel tissues. Cu and Zn concentrations in sediments and caged mussels were generally not elevated except for sediments at the site in the disposal area that received the major amount of dredges. High PAHs and AHs levels as well as sublethal effects in the caged mussels were not persistent after termination of operations. The combined bioassay–biomarker approach proved useful for detecting toxicological impacts of dredged river sediment disposal in sediments and the water column. Nevertheless, further research is needed to evaluate whether sediment toxicity will have long-term effects on benthic communities of the disposal area.     

The impact of an industrial effluent on the water quality,submersed macrophytes and benthic macroinvertebrates in a dammed river of Central Spain

This research was conducted in the middle Duratón River (Central Spain), in the vicinity of Burgomillodo Reservoir. An industrial effluent enters the river 300 m downstream from the dam. Fluoride and turbidity levels significantly increased downstream from the effluent, these levels being to some extent affected by differential water releases from the dam. The community of submersed macrophytes exhibited slighter responses and, accordingly, lower discriminatory power than the community of benthic macroinvertebrates, this indicating that metrics and indices based on macroinvertebrates may be more suitable for the biological monitoring of water pollution and habitat degradation in dammed rivers receiving industrial effluents. However, in relation to fluoride bioaccumulation at the organism level, macrophytes (Fontinalis antipyretica and Potamogeton pectinatus) were as suitable bioindicators of fluoride pollution as macroinvertebrates (Ancylus fluviatilis and Pacifastacus leniusculus). Fluoride bioaccumulation in both hard and soft tissues of these aquatic organisms could be used as suitable bioindicator of fluoride pollution (even lower than 1 mg F⁻ L⁻¹) in freshwater ecosystems. Echinogammarus calvus exhibited a great sensitivity to the toxicity of fluoride ions, with a 96 h LC₅₀ of 7.5 mg F⁻ L⁻¹ and an estimated safe concentration of 0.56 mg F⁻ L⁻¹. The great capacity of E. calvus to take up and retain fluoride during exposures to fluoride ions would be a major cause of its great sensitivity to fluoride toxicity. It is concluded that the observed fluoride pollution might be partly responsible for the absence of this native amphipod downstream from the industrial effluent.     

Distribution and biological impact of dioxin-like compounds in risk zones along the Ebro River basin (Spain)

The aim of this investigation was to evaluate the environmental impact associated to PCDDs/Fs and dioxin-like PCBs in the Ebro River basin. Sediments and fish from several species were sampled at three sites with different historical pollution records, including the Barbastro area with different industrial activities, and the Flix and Monzón sites, associated to heavy organochlorine compound pollution. Seventeen toxic PCDDs/Fs and 12 dioxin-like PCBs were analyzed by GC-MS. The results obtained indicated significant accumulation of dioxin-like PCBs, but not PCDDs/Fs, in sediments and fish at the Flix site compared to the other sites. Concomitantly, cytochrome p450 1A (CYP1A) expression, a known indicator for pollution by dioxins and dioxin-like PCBs, was significantly elevated in barbel (Barbus graellsii) from the Flix site, compared to the population from the Barbastro site. CYP1A expression correlated with the concentration of dioxin-like PCBs in the fish fat, whereas no significant correlation was found with PCDDs/Fs concentrations. Our data suggest a significant biological impact at the Flix site, closely related to the presence of dioxin-like PCBs, whereas the PCDDs/Fs contribution to this impact appears to be non-significant, at least in the studied sites.     

Spatial distribution and sources of perfluorochemicals in the NW Mediterranean coastal waters (Catalonia, Spain)

This study provides the first evidence of the sources and loads of perfluorochemicals (PFCs) to the NW Mediterranean Sea. Five PFCs were analyzed in 45 seawater samples collected along the Catalan coast. Total PFCs ranged from 0.07 to 13.0 ng/l, being the levels higher in ports than in coastal waters. To determine the sources of PFCs, 8 wastewater treatment plants (WWTPs) effluents and 6 rivers discharging to the sea were also analyzed. WWTP effluents contained total PFCs levels ranging from 3.47 to 132 ng/l but due to the relatively low discharge flows, they contributed to 34.7 g/d to the sea. Total PFCs in rivers ranged from 2.24 to 21.9 ng/l and were the principal PFCs contributors to the sea. Overall, a total load of 190 g/d of PFCs are discharged to the NW Mediterranean coast. The effects and risk of PFCs discharges to the Mediterranean basin are discussed.     

Occurrence and fate of alkylphenols and alkylphenol ethoxylates in sewage treatment plants and impact on receiving waters along the Ter River (Catalonia, NE Spain)

The partitioning of alkylphenols in the dissolved and particulate matter of influents, effluents, accumulation onto sludge and the impact of sewage treatment plant upon receiving waters was studied along the Ter River basin (Catalonia, NE Spain). A solid-phase extraction or pressurized liquid extraction followed by liquid chromatography-mass spectrometry was developed and permitted to determine target compounds with high efficiency in waters, particulate material and sludge. Nonylphenol mono- and diethoxylate, nonylphenol and octylphenol partitioned preferably upon particulate matter and sludge, whereas long chain NPE(3-15)O prevailed in the dissolved phase and was released by effluents. Within the treatment process, a net accumulation of alkylphenols in sludge was found, producing up to 148g/t/month. The removal efficiency of alkylphenols was of 37-90% and depended on the treatment. Assessment on the fate of these contaminants within STPs is discussed in terms of flow rates, biological oxygen demand and tons of sludge produced.     

First evidence of polybrominated diphenyl ether (flame retardants) effects in feral barbel from the Ebro River basin (NE, Spain)

Polybrominated diphenyl ethers (PBDEs) are chemicals of environmental concern due to their lipophilic, persistent and bioaccumulable characteristics as well as for their potential endocrine disrupting role. Former studies carried out in a tributary of the Cinca river (Ebro basin, NE Spain) revealed high levels of PBDEs in fish due to the discharges of effluents rich in PBDEs coming from a nearby industrial park in Barbastro. In this study, several biomarkers of pollutants exposure were measured in barbel, Barbus graellsii, before (upstream) and after (downstream) the main industrial site (Barbastro) in the Vero river. The results evidenced an enhanced hepatic phase I and II metabolism (measured as reductases, glutathione S transferase and uridinediphospho-glucuronosyltransferase), and of the antioxidant enzyme glutathione peroxidase. Conversely, fishes collected from downstream reaches had their phase I CYP1A dependent ethoxyresorufin O-deethylase, antioxidant diaphorase and brain cholinesterase activities depleted. In addition, the histological study of the liver and kidney of these fish evidenced an increase of the number and size of macrophage aggregates in most individuals collected downstream. Bivariate correlated analyses showed that the above mentioned biomarkers were correlated to measured PBDE congeners, thus indicating that the observed biological effects were unlikely to be related to other environmental factors than PBDEs. Overall, the measured biochemical and histological markers provide new evidence that in field exposed fish, PBDEs levels were associated with high activities of phase I and II metabolic enzymes, oxidative stress in liver, neurotoxicity in brain and histopathological effects in both liver and kidney.     

Application of the Microtox test and pollution indices to the study of water toxicity in the Albufera Natural Park (Valencia, Spain)

The toxic effects of waters collected from irrigation channels in a Mediterranean wetland (Albufera Natural Park, Valencia, Spain) were tested with the Microtox assay and compared with six pollution indices (PIs) defined from analytical parameters. Chemical oxygen demand (COD), biological oxygen demand (BOD), nutrients, heavy metals and pesticides were measured. The bioassay result (concentrations of the water sample (% V/V) that reduced light emission to 10%, 20% and 50%, EC10, EC20 and EC50, respectively (ECs)) was compared with the PIs. This comparison has demonstrated a general agreement between ECs and PIs, except in the case of irrigation channels affected by herbicides used in rice farming (molinate and thiobencarb). No pronounced inhibition was detected in the bioluminescence in relation to the eutrophic parameters in the irrigation waters for EC50 values, indicating that this parameter does not suffice to detect eutrophic waters. Data derived from irrigation water pollution and bioassay were assembled by multivariate statistical techniques (principal component analysis). These components were associated with various contamination sources.