Diet quality and NSAIDs promote changes in formation of prostaglandins by an aquatic invertebrate.

We used the freshwater insect Hydropsyche sp. to investigate the impact of diets lacking arachidonic acid (ARA) and an environmentally relevant mixture of NSAIDs (Ibuprofen, Ketoprofen, Diclofenac and Naproxen at a nominal concentration of all compounds together 16.75 µg L-1) on their metabolism of ARA and prostaglandins (PGs). The organisms were exposed for 16 days to four different treatments: a reference (FF), a diet lacking ARA (O), to NSAIDs in water (FFN) and to the combination of the two factors (ON). Mortality, biomass and bioconcentration of pharmaceuticals were investigated. The ARA and PGs levels in the organisms were monitored by utilising a targeted metabolomics approach. NSAIDs or dietary constraints did not produce significant differences in biomass or mortality of Hydropsyche sp. among treatments. In organisms exposed to NSAIDs, all pharmaceuticals were detected, except for Ketoprofen. Metabolomic approach determined the presence of PGH2, PGE1 and PGD1. Levels of ARA diminished significantly in those organisms in treatment ON. The levels of PGs responded negatively to the absence of ARA in diet: PGH2 diminished significantly with respect to the reference in treatment O while PGE1 diminished significantly in treatment ON. Regarding the effects of NSAIDs on ARA metabolism, our results suggest that it was sensitive to NSAIDs, but effects were weak and did not imply a general decrease in the PGs. We confirmed that ARA was the main substrate for the synthesis of PGs in Hydropsyche sp, their absence or poor levels of ARA in diet, produced changes in the PG levels.

Exposure to single and binary mixtures of fullerenes and triclosan: Reproductive and behavioral effects in the freshwater snail Radix balthica.

Emerging pollutants occur in complex mixtures in rivers and have the potential to interact with freshwater organisms. The chronic effects of nominal exposure to 3 µg/L of fullerenes (C60) and 1 µg/L of triclosan (TCS) alone and in a binary mixture, were evaluated using the freshwater snail Radix balthica. Pollutants accumulation, reproductive output and feeding behavior were selected as sublethal endpoints. After 21 days of exposure, we did not observe interactive effects between TCS and C60 on the studied endpoints, except for the accumulation of C60 in R. balthica in TCS + C60 treatment, which was lower than when the fullerenes were alone. Neither TCS nor C60 caused significant effects on reproduction, expressed as number of eggs per individual, but an increase in the clutch size was observed in treatments with TCS at the third week of exposure, independently of the presence of C60 (16.15 ± 1.67 and 18.9 ± 4.01 eggs/egg mass in TCS and TCS + C60 treatments, respectively, vs. 13.17 ±â€¯4.01 in control). The presence of C60 significantly enhanced the grazing activity of R. balthica during the first seven days (4.95 ±â€¯1.35 and 3.91 ±â€¯0.59% of the area grazed per individual in C60 and TCS + C60 treatments, respectively, vs 2.6 ±â€¯0.39% in control). The accumulation of TCS was quite similar in treatments where this pollutant was present (BAF ≈ 1007 L/kg d.w.); however, the accumulation of C60 was higher when the nanoparticles were alone (BAF = 254.88 L/kg d.w.) than when it was in the binary mixture (BAF = 7.79 L/kg d.w). Overall, although TCS has been listed as an endocrine disrupter compound, no significant effects on reproduction were observed in the assayed conditions. Regarding C60, the limited effects on feeding activity and the low BAF obtained in this experiment indicate that fullerenes do not have ecological consequences of relevance at the studied environmental concentrations in freshwater snails.

Impact of copper sulfate application at an urban Brazilian reservoir: A geostatistical and ecotoxicological approach.

A landscape ecotoxicology approach was used to assess the spatial distribution of copper in the recent bottom sediment (surficial sediment) of a Brazilian subtropical reservoir (the Guarapiranga reservoir) and its potential ecotoxicological impacts on the reservoir ecosystem and the local society. We discuss the policies and procedures that have been employed for the management of this reservoir over the past four decades. Spatial heterogeneity in the reservoir was evaluated by means of sampling design and statistical analysis based on kriging spatial interpolation. The sediment copper concentrations have been converted into qualitative categories in order to interpret the reservoir quality and the impacts of management policies. This conversion followed the Canadian Water Framework Directive (WFD) ecotoxicological concentration levels approach, employing sediment quality guidelines (SQGs). The SQG values were applied as the copper concentration thresholds for quantitative-qualitative conversion of data for the surficial sediment of the Guarapiranga. The SQGs used were as follows: a) interim sediment quality guideline (ISQG), b) probable effect level (PEL), and c) regional reference value (RRV). The quantitative results showed that the spatial distribution of copper in the recent bottom sediment reflected the reservoir's management policy and the copper application protocol, and that the copper concentrations varied considerably, ranging from virtually-zero to in excess of 3gcopper/kgds. The qualitative results demonstrated that the recent bottom sediment was predominantly in a bad or very bad condition, and could therefore have impacts on the local society and the ecosystem. It could be concluded that the management policy for this reservoir was mainly determined by the desire to minimize short-term costs, disregarding long-term socioeconomic and environmental consequences.

Assessing the impact of chemical pollution on benthic invertebrates from three different European rivers using a weight-of-evidence approach.

The aim of this study was to combine different lines of evidence on the impact of chemical pollution on benthic invertebrate communities in three European river basins (Elbe, Scheldt, and Llobregat). The study integrates chemical analyses, a battery of different sediment toxicity tests, and field data from soft-sediment meio- and macrobenthic fauna within a sediment-quality triad in which chironomids, oligochaetes, and nematodes are identified on the species level. The use of TU (toxic units) and msPAF (multi-substance potentially affected fraction) in an approach assessing the chemical impact as well as the integration of sediment toxicity tests with bacteria (Vibrio fischeri), benthic invertebrates (Caenorhabditis elegans, Potamopyrgus antipodarum, Lumbriculus variegatus, Chironomus riparius), and fish embryos (Danio rerio), together with univariate and non-parametric multivariate statistical analyses of the biological data revealed significant differences between unpolluted and polluted sites in all three river basins. To combine the different results obtained in the sediment-quality triad, a scoring system was successfully developed based on a simple algorithm. This system provides an easily understandable scheme for non-experts among decision makers and water managers.

Effects of indomethacin and propranolol on Chironomus riparius and Physella (Costatella) acuta.

New analytical methods are available for detecting novel xenobiotic compounds in freshwater systems. Pharmaceuticals are suspected of having effects on freshwater biota at very low concentrations, although the nature of these effects remains unclear. Previous data from the Llobregat River revealed a positive statistical relationship between the biomass of benthic macroinvertebrates and the presence of certain non-steroidal anti-inflammatory drugs (NSAIDs) and beta-blockers. Here, experiments were conducted with the midge Chironomus riparius and the freshwater snail Physella (Costatella) acuta in sediments and water, respectively. The sediments and water were treated with the pharmaceuticals propranolol and indomethacin, with the aims of assaying the effects of these compounds on the organisms and testing the statistical relationships observed in field. The variables measured were survival; C. riparius biomass; and the carbon/nitrogen ratio, lipid content and fertility of freshwater snails. Indomethacin in treated sediments induced an increase in C. riparius biomass, whereas propranolol inhibited growth, albeit at marginal statistical significance. By contrast, indomethacin in water had no effect on any of the parameters measured in P. acuta.

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.