Triclosan persistence through wastewater treatment plants and its potential toxic effects on river biofilms

Triclosan is a commonly used bactericide that survives several degradation steps in WWTP (wastewater treatment plants) and potentially reaches fluvial ecosystems. In Mediterranean areas, where water scarcity results in low dilution capacity, the potential environmental risk of triclosan is high. A set of experimental channels was used to examine the short-term effects of triclosan (from 0.05 to 500μgL⁻¹) on biofilm algae and bacteria. Environmentally relevant concentrations of triclosan caused an increase of bacterial mortality with a no effect concentration (NEC) of 0.21μgL⁻¹. Dead bacteria accounted for up to 85% of the total bacterial population at the highest concentration tested. The toxicity of triclosan was higher for bacteria than algae. Photosynthetic efficiency was inhibited with increasing triclosan concentrations (NEC=0.42μgL⁻¹), and non-photochemical quenching mechanisms decreased. Diatom cell viability was also affected with increasing concentrations of triclosan. Algal toxicity may be a result of indirect effects on the biofilm toxicity, but the clear and progressive reduction observed in all the algal-related endpoints suggest the existence of direct effects of the bactericide. The toxicity detected on the co-occurring non-target components of the biofilm community, the capacity of triclosan to survive through WWTP processes and the low dilution capacity that characterizes Mediterranean systems extend the relevance of triclosan toxicity beyond bacteria in aquatic habitats.

Does grazing pressure modify diuron toxicity in a biofilm community?

Herbicides affect the structure and functional parameters of fluvial biofilm. Diuron is toxic to primary producers and disrupts endocrine activity. Here, we studied the interaction between this toxicant and several biological compartments in a simple food chain composed of herbivores (the snail Physella [Costatella] acuta) and biofilm. We used indoor experimental channels to which Diuron was added at a realistic concentration (2 mug/L). Bacterial survival and chlorophyll-a and photosynthetic activity were analyzed in the biofilm. We monitored biomass, mortality, reproduction, and motility as end points in the freshwater snail P. acuta. Our results showed that bacterial survival and photosynthetic activity were sensitive to Diuron. Snails were not affected by the herbicide at the concentration tested. No significant interactions between the toxicant and grazers were observed on the biofilm. Reproductive traits, however, were slightly affected, indicating a possible endocrine disruption.

Fluvial biofilms: A pertinent tool to assess beta-blockers toxicity

Among increasingly used pharmaceutical products, beta-blockers have been commonly reported at low concentrations in rivers and littoral waters of Europe and North America. Little is known about the toxicity of these chemicals in freshwater ecosystems while their presence may lead to chronic pollution. Hence, in this study the acute toxicity of 3 beta-blockers: metoprolol, propranolol and atenolol on fluvial biofilms was assessed by using several biomarkers. Some were indicative of potential alterations in biofilm algae (photosynthetic efficiency), and others in biofilm bacteria (peptidase activity, bacterial mortality). Propranolol was the most toxic beta-blocker, mostly affecting the algal photosynthetic process. The exposure to 531microg/L of propranolol caused 85% of inhibition of photosynthesis after 24h. Metoprolol was particularly toxic for bacteria. Though estimated No-Effect Concentrations (NEC) were similar to environmental concentrations, higher concentrations of the toxic (503microg/L metoprolol) caused an increase of 50% in bacterial mortality. Atenolol was the least toxic of the three tested beta-blockers. Effects superior to 50% were only observed at very high concentration (707mg/L). Higher toxicity of metoprolol and propranolol might be due to better absorption within biofilms of these two chemicals. Since beta-blockers are mainly found in mixtures in rivers, their differential toxicity could have potential relevant consequences on the interactions between algae and bacteria within river biofilms.

Bridging levels of pharmaceuticals in river water with biological community structure in the Llobregat River basin (northeast Spain)

A wide range of human pharmaceuticals are present at low concentrations in freshwater systems, particularly in sections of polluted river. These compounds show high biological activity, often associated with a high stability. These characteristics imply a potential impact of these substances on aquatic biota even when present at low environmental concentrations. Low flow conditions in Mediterranean rivers, most of which flow through densely populated areas and are subjected to intensive water use, increase the environmental risk of these emergent compounds. Here, we studied whether pharmaceuticals in river water affect the local benthic community structure (diatoms and invertebrates). For this purpose, we analyzed the occurrence of pharmaceuticals along the Llobregat River and examined the benthic community structure (diatoms and invertebrates) of this system. Some pharmaceutical products in the Llobregat River registered concentrations greater than those cited in the literature. Multivariate analyses revealed a potential causal association between the concentrations of some anti-inflammatories and beta-blockers and the abundance and biomass of several benthic invertebrates (Chironomus spp. and Tubifex tubifex). Further interpretation in terms of cause-and-effect relationships is discussed; however, it must be always taken with caution because other pollutants also may have significant contributions. Combined with further community experiments in the laboratory, our approach could be a desirable way to proceed in future risk management decisions.

Effects of low concentrations of the phenylurea herbicide diuron on biofilm algae and bacteria

A system of recirculating channels was used in this study to examine the long-term effects (29d) of environmentally realistic concentrations of the herbicide diuron (from 0.07 to 7 microg L(-1)) on biofilm communities. The autotrophic activity of biofilms was affected by this herbicide, as reflected by a marked decrease in the photosynthetic efficiency. Diuron exposure also increased chlorophyll-a content and reduced the biovolume of diatom taxa at low concentrations. The effects on bacteria were also remarkable. Bacterial abundance was reduced after a week of exposure to the herbicide at a range of concentrations. Effects were on the number of live bacteria and on the increase in the leucine-aminopeptidase activity. It is suggested that inputs of herbicides to the river ecosystem at low concentrations may cause a chain of effects in the biofilm, which include inhibitory effects on algae but also indirect effects on the relationships between biofilm components.

Experience with endometrial carcinoma (EC): A population-based study in Tarragona Province (Spain)

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Background: To evaluate outcome, failure patterns, prognostic factors and radiotherapy (RT) toxicity after postoperative RT for EC in Tarragona Province (Spain). Methods: A retrospective population-based review on 232 patients (pts) between 1997 and 2000 from different gynaecological Dpt. and in a single oncologist institution with RT Units. Multivariate analysis of disease-free survival (DFS), overall survival (OS), adjuvant RT, RT toxicity (RTOG), prognostic factors for survival, and the distance in Km to the RT Units. Results: Mean age: 64 years (35–88). Distance to RT Units >70 Km in 15% pts. Median follow-up: 70 months (2–132). FIGO Stage (S): 8.2% IA; 36.2% IB; 19% IC; 7.8% IIA; 6.5% IIB; 7.3% IIIA; 1.3% IIIB; 3.4% IIIC; 2.6% IVA; 2.2 IVB. Pathology: endometrioid 74.5%, papillary 3.9%, serous 3.4%, clear-cell 2.2%, squamous cell 3%, adenosquamous 1.3%, mixed 3.9%. Grade (G): 35.7% G1, 45.3% G2, 19% G3; miometrial invasion: 44.1% >50%, 46% <50%, 9.9% not invasion. Treatment: 1) Surgery in 93.5%, 49.6% lymph nodes dissection. 2) RT in 73.5%: 47% external beam radiotherapy (EBI) and brachytherapy (BT), 9.4% BT alone, 17.1% EBI alone. 3) Chemotherapy in 11.1% and hormonal treatment in 6.9%. 3). Grade 3 and 4 toxicity: 12 (9%) pts, 6 early and 6 late. Relapses: 26/232 (11.6%), S-I: 11/26 (42%), S-II: 1/26 (3.8%), S-III: 5/26 (19.2%), S-IV: 3/26 (11.5%). Metastasis: 28/232 (12.5%). Survivals at 5 years: 1) OS in all stages was 78.8% and 83%, 89.6%, and 76% for SI, SII, and SIII, respectively. 2) DFS was 76.5% for all pts and 82.3%, 86.22%, and 68.24% for SI, SII, and SIII, respectively. Multivariate analysis: significant prognostic factors for poor outcome were age (p < 0.01), lymph nodes dissection (p < 0.001), pathologic subtype (p < 0.001), grade of differentiation (p < 0.001), and deep myometrial invasion (p < 0.005). Conclusions: Survivals, RT toxicity and relapse sites were similar to the other reported series. Predictors of poor outcome were age, lymph nodes dissection, pathology subtype, grade of differentiation, and deep myometrial invasion. Patients of Tarragona Province are in need of a better accessibility to the radiation units.

No significant financial relationships to disclose.

[Staphylococcus aureus bacteremia in Castellón General Hospital (2001-2005)]

OBJECTIVE

The aim of this study was to know the frequency of bacteremias produced by Staphylococcus aureus and the sensibility that strains showed, as well as the clinical characteristics of the patients.

METHOD

We retrospectively studied cases of S. aureus bacteremia detected in our hospital from 2001 to 2005 and also reviewed medical histories from patients during 2005.

RESULTS

A total of 295 cases of S. aureus bacteremia were detected in this study. Annual distributions of the cases were as follows: 35, 54, 62, 64 and 80. By gender, 62.7 % related to males and 37.3 % to females. A total of 58.6 % of the patients were admitted to medical services and 49 % were older than 65 years. Regarding resistance, 34 % of the strains showed resistance to oxacillin, 33 % to ciprofloxacin, 41 % to erythromycin and 4.4 % to gentamicin. In one-third of the patients, S. aureus was isolated in other samples, the catheter being the most common. A total of the 73.5 % of the patients had some baseline disease and the most frequent predisposing factor was the intravascular catheter. The bacteremias were nosocomial-acquired in 73.5 % of the cases.

CONCLUSIONS

In our hospital, S. aureus bacteremia and oxacillin resistance has been increasing over the years of this study.

Longitudinal development of chlorophyll and phytoplankton assemblages in a regulated large river (the Ebro River)

The distribution of chlorophyll and phytoplankton communities were compared to nutrient concentrations and hydrological parameters along the main stretch of the river Ebro. A progressive increase in planktonic chlorophyll was observed from the upper reaches to the middle section of the river. Chlorophyll reached a maximum (60-80 microg L(-1)) in the meandering section (downstream of the city of Zaragoza), where nutrient inputs (both N and P) and the residence time of the water are very high. In this meandering section phytoplankton assemblages consisted of large centric diatoms and Scenedesmus sp.pl. These longitudinal patterns were interrupted by the presence of three large reservoirs in the lower section of the river. In the section below the reservoirs, the shorter residence water time, the presence of the invasive zebra mussel, and the massive macrophyte development may explain the historical decrease in chlorophyll-a (from 20-45 microg L(-1) in the 1990s to the present 2-5 microg L(-1)). Phytoplankton densities were extremely poor in this section of the river, where large colonial Coelastrum sp.pl. and Pediastrum sp.pl. were the most characteristic taxa.

Relevance of polymeric matrix enzymes during biofilm formation

Extracellular polymeric substances (EPS) contribute to biofilm stability and adhesion properties. The EPS matrix might also be a site for free extracellular enzyme activity; however, little is known about participation of enzyme activity in EPS during biofilm formation. In this study, we analyzed the activities of beta-glucosidase, leu-aminopeptidase, and beta-glucosaminidase during the colonization of artificial substrata (glass tiles) in a stream distinguishing enzyme activity in EPS matrix (matrix-enzymes) and total biofilm extracellular enzyme activity. The 1-h incubation of a biofilm suspension and cation-exchange resin followed by centrifugation seems appropriate to extract the matrix fraction (supernatant) and measure matrix enzymes (including free and linked to EPS) in freshwater biofilms, although there is a methodological limitation for using a biofilm suspension instead of an undisrupted biofilm. Total biofilm activities and matrix-enzyme activities showed similar capabilities to decompose organic matter compounds, with a greater capacity for peptide decomposition (leu-aminopeptidase) than for polysaccharides (beta-glucosidase), and a low decomposition of chitin and peptidoglycan (beta-glucosaminidase). Matrix-enzyme activity increased with colonization time, but more slowly than that of total enzyme activity. At the beginning of the colonization experiment (days 1-4) matrix enzymes accounted for 65-81% of total biofilm enzyme activity. Higher proportion of polysaccharides in EPS versus total biofilm, and higher matrix-enzyme activities per microgram of polysaccharides in the EPS were measured during the first 1-3 days of biofilm formation, indicating a high rate of enzyme release into the matrix during this period. Relative contribution of matrix-enzyme activities decreased as biofilm matures, but was maintained at 13-37% of total enzyme activity at the 42- to 49-day-old biofilm. These enzymes, retained and conserved in the EPS, may contribute to community metabolism. When analyzing extracellular enzymes in biofilms, the contribution of matrix enzymes must be considered, especially for young biofilms.

ALGAL RESPONSE TO NUTRIENT ENRICHMENT IN FORESTED OLIGOTROPHIC STREAM(1)

Nutrient input in streams alters the density and species composition of attached algal communities in open systems. However, in forested streams, the light reaching the streambed (rather than the local nutrient levels) may limit the growth of these communities. A nutrient-enrichment experiment in a forested oligotrophic stream was performed to test the hypothesis that nutrient addition has only minor effects on the community composition of attached algae and cyanobacteria under light limitation. Moderate nutrient addition consisted of increasing basal phosphorus (P) concentrations 3-fold and basal nitrogen (N) concentrations 2-fold. Two upstream control reaches were compared to a downstream reach before and after nutrient addition. Nutrients were added continuously to the downstream reach for 1 year. Algal biofilms growing on ceramic tiles were sampled and identified for more than a year before nutrient addition to 12 months after. Diatoms were the most abundant taxonomic group in the three stream reaches. Nutrient enrichment caused significant variations in the composition of the diatom community. While some taxa showed significant decreases (e.g., Achnanthes minutissima, Gomphonema angustum), increases for other taxa (such as Rhoicosphenia abbreviata and Amphora ovalis) were detected in the enriched reach (for taxonomic authors, see Table 2). Epiphytic and adnate taxa of large size were enhanced, particularly during periods of favorable growth conditions (spring). Nutrients also caused a change in the algal chl a, which increased from 0.5-5.8 to 2.1-10.7 μg chl · cm(-2) . Our results indicate that in oligotrophic forested streams, long-term nutrient addition has significant effects on the algal biomass and community composition, which are detectable despite the low light availability caused by the tree canopy. Low light availability moderates but does not detain the long-term tendency toward a nutrient-tolerant community. Furthermore, the effects of nutrient addition on the algal community occur in spite of seasonal variations in light, water flow, and water chemical characteristics, which may confound the observations. [Table: see text].

Effect of climate on the trophic structure of temperate forested streams. a comparison of Mediterranean and Atlantic streams

Climate affects many aspects of stream ecosystems, although the presence of riparian forests can buffer differences between streams in different climatic settings. In an attempt to measure the importance of climate, we compared the seasonal patterns of hydrology, input and storage of allochthonous organic matter, and the trophic structure (abundance of algae and macroinvertebrates) in two temperate forested streams, one Mediterranean, the other Atlantic. Hydrology played a leading role in shaping the trophic structure of both streams. Frequency and timing of floods and droughts determined benthic detritus storage. Inputs and retention of allochthonous organic matter were higher in the Atlantic stream, whereas chlorophyll concentration was lower because of stronger light limitation. Instead, light availability and scour of particulate organic matter during late winter favoured higher chlorophyll concentration in the Mediterranean stream. As a result, in the Mediterranean stream grazers were more prevalent and consumers showed a higher dependence on autotrophic materials. On the other hand, the Atlantic stream depended on allochthonous materials throughout the whole study period. The overall trophic structure showed much stronger seasonality in the Mediterranean than in the Atlantic stream, this being the most distinctive difference between these two types of temperate streams. The different patterns observed in the two streams are an indication that climatic differences should be incorporated in proper measurements of ecosystem health.

Monitoring the effect of chemicals on biological communities. The biofilm as an interface

Biofilms can be regarded as early warning systems for detection of the effects of toxicants on aquatic systems, because they have been successfully used for detection of other environmental stressors (e.g. pH, salinity, organic pollution). A variety of methods is used for detection of the effects of toxicants by use of biofilms. The methods range from structurally-based to functionally-based, and from in vitro-based to systemic approaches. Physiological approaches may be appropriate for detection of acute effects. Among these methods, photosynthesis is more related to the effect of toxicants affecting algal communities, directly or indirectly, and extracellular enzyme activity is less specific. Selecting one or the other may depend on the suspected direct effect of the toxicant. Integrated studies have revealed the relevance of toxicants to top-down or bottom-up regulation of the biofilm community. Persistent or chronic effects should affect other biofilm indicators, for example growth or biomass-related factors (e.g. chlorophyll), or community composition. Among these, community composition might better reflect the effects of the toxicant(s), because this may cause a shift from a sensitive to a progressively tolerant community. Community composition-based approaches do not usually adequately reflect cause-effect relationships and require complementary analysis of properties affected in the short-term, for example physiological properties. The current array of methods available must be wisely combined to disentangle the effects of chemicals on biofilms, and whether these effects are transient or persistent, to successfully translate the chemical action of toxicants into the effect they might have on the river ecosystem.

Comparing the response of biochemical indicators (biomarkers) and biological indices to diagnose the ecological impact of an oil spillage in a Mediterranean river (NE Catalunya, Spain)

Three biomarkers of hydrocarbon exposure, liver 7-ethoxyresourfin-O-deethylase activity (EROD), fluorescent hydrocarbon compounds (FACs) in bilis, and the liver antioxidant enzyme catalase (CAT) were examined in the autochthonous fish species Barbus meridionalis collected in the river Fluvià (NE Catalunya, Spain) after an oil spillage. Four different locations were sampled, including the impacted site, upstream and downstream sites and a reference site. Biomarker responses were compared with diatom and macroinvertebrate community assemblage metrics (Specific Pollution Sensitivity index - IPS, and Iberian Biological Monitoring Working Party - IBMWP, respectively). Chemical analyses denoted that polycyclic aromatic hydrocarbon levels in sediment were much higher at the impacted site than in downstream reaches. Four fold increase of EROD activity together with increased levels of biliary FACs in barbs collected at the spilled site indicated exposure of inhabiting fish to the oil. Additionally, CAT activity was significantly depressed (four fold) when compared to other stations, thus suggesting that fish collected from the impacted sites could be more susceptible to suffer oxidative stress. Biological indices (particularly that of the diatom community IPS) showed slight significant effects between control and impacted sites, indicating that more tolerant taxa were favoured because of the oil spillage. These results support the need to include biochemical responses measured in local species in monitoring programmes aimed to diagnose specific pollution effects in stressed river ecosystems.

Influence of phosphate on the response of periphyton to atrazine exposure

After indications from the literature that nutrient concentrations may modify the toxicity of herbicides to natural periphyton communities, this study aims to provide experimental proof for atrazine. In this microcosm experiment, phosphate (P) addition did not ameliorate atrazine toxicity to periphyton. Three weeks of P addition did not increase atrazine tolerance (measured as EC50 in acute toxicity tests), whereas exposure to atrazine under conditions that were either P-limited or non-P-limited clearly reduced the development of algal biomass. Long-term exposure to atrazine induced tolerance of the community to the herbicide, and this was not influenced by P addition. Tolerance induction in this microcosm experiment has been compared with previously published field data from the same area of study and indicates that tolerance induction by atrazine may take place under atrazine exposure in streams as well as in microcosms.

Cosmetic outcome of breast conservative treatment for early stage breast cancer

PURPOSE

To evaluate the cosmetic outcome of breast conservative therapy and to examine the degree of agreement between the patients' and oncologists' ratings. We also analyze the influence of several factors on cosmesis.

METHODS AND MATERIALS

We retrospectively evaluated 145 patients with primary breast cancer treated by local excision and radiotherapy between January 2000 and May 2001. Cosmetic outcome was evaluated by doctors and patients and was scored as excellent, good, fair or poor.

RESULTS

73% of patients rated cosmesis as excellent or good while the percentage was 71% when rated by radiation oncologists. The degree of cosmesis concordance evaluated by oncologists and patients was low (kappa = 0.3). In our study the variables which significantly influence on the cosmetic outcome were concomitant adjuvant chemotherapy (p = 0.04) and radiation therapy boost, either by electron beam or brachytherapy (p = 0.013).

CONCLUSION

The cosmetic outcome of breast conserving therapy was good. There was a similar rating by the patient and radiation oncologist, but the level of concordance between patients and doctors was low. Factors that significantly influence the cosmesis appear to be concomitant adjuvant chemotherapy and radiation therapy boost.

The nematode community in cyanobacterial biofilms in the river Llobregat, Spain

Abstract

The aim of our study was to understand the role of the nematode community in a cyanobacterial-dominated biofilm located in the river Llobregat, NE Spain. This biofilm was mainly composed of oscillatorial species and diatoms. Fractions of these mats can become detached from the substrata and become free-floating, dispersing downstream and acquiring different structural and physiological properties. Both cyanobacterial biofilms, attached and free-floating, were compared with another benthic biofilm that occurred in the reach of the river that was studied. The nematode diversity was restricted, and was dominated by Chromadorita leuckarti, Diplogaster rivalis, Plectus parvus, Neotobrilus diversipapillatus, Monhystera spp., Dorylaimus sp. and Mononchus sp. Nematode density and biomass were significantly greater in the free-floating biofilm (maximum values of 752 ind/cm2 and 171.3 μgC/cm2). Different trophic and sexual strategies were observed. The free-floating biofilm showed higher abundances of juveniles and a high proportion of gravid females. A positive correlation was observed between cyanobacterial density and the abundance of juveniles or adults of the commonest nematode species, indicating their potential as food resources.