Fluoxetine effects assessment on the life cycle of aquatic invertebrates

International audienceFluoxetine is a serotonin re-uptake inhibitor, generally used as an antidepressant. It is suspected to provoke substantial effects in the aquatic environment. This study reports the effects of fluoxetine on the life cycle of four invertebrate species, Daphnia magna, Hyalella azteca and the snail Potamopyrgus antipodarum exposed to fluoxetine spiked-water and the midge Chironomus riparius exposed to fluoxetine-spiked sediments. For D. magna, a multi-generational study was performed with exposition of newborns from exposed organisms. Effects of fluoxetine could be found at low measured concentrations (around 10 micro g l(-1)), especially for parthenogenetic reproduction of D. magna and P. antipodarum. For daphnids, newborns length was impacted by fluoxetine and the second generation of exposed individuals showed much more pronounced effects than the first one, with a NOEC of 8.9 micro g l(-1). For P. antipodarum, significant decrease of reproduction was found for concentrations around 10 micro g l(-1). In contrast, we found no effect on the reproduction of H. azteca but a significant effect on growth, which resulted in a NOEC of 33 micro g l(-1), expressed in nominal concentration. No effect on C. riparius could be found for measured concentrations up to 59.5 mg kg(-1). General mechanistic energy-based models showed poor relevance for data analysis, which suggests that fluoxetine targets specific mechanisms of reproduction

Évaluation des risques écologiques causés par des matériaux de dragage: roposition d'une approche adaptée aux dépôts en gravière en eau

Une procédure d'évaluation des risques pour l'écosystème aquatique engendrés par un dépôt de matériaux de dragage dans une gravière type a été élaborée, et testée avec des échantillons de sédiments d'un canal du Nord-Est de la France. La procédure comporte une étape d'évaluation sommaire des risques, à partir de quotients des concentrations mesurées par les critères de danger correspondants, et une étape d'évaluation détaillée où des essais de toxicité et de lixiviation en colonnes sont mis en œuvre. Le scénario testé retient trois hypothèses, qui concernent (a) les effets sur les peuplements d'invertébrés benthiques, représentés notamment par Hyalella azteca et Chironomus riparius, (b) les effets sur les peuplements d'organismes pélagiques, représentés par Chlorella vulgaris, Ceriodaphnia dubia, et Brachionus calyciflorus, et (c) la pollution de la nappe alluviale associée. Différentes modalités d'exposition (essais normalisés, microcosmes) ont été testées. Dans le contexte particulier des trois sédiments étudiés, ces hypothèses se sont avérées plus ou moins discriminantes, la pollution de la nappe étant la plus sensible. Des améliorations de la procédure doivent être envisagées qui concernent à la fois la formulation des hypothèses (risques à court et long terme sur les organismes pélagiques), et les protocoles d'essai, tant pour les organismes du sédiment (rôle de la nourriture notamment) que pour les essais de lixiviation en colonnes.When contaminated by metals or synthetic organic compounds, dredged sediments may have negative impacts on receiving ecosystems. Therefore, there is a need for an operational risk assessment approach. Such a framework is proposed for dredged material deposits in open gravel quarries, which is a rather common means of disposal in France. The first step of the assessment relies upon chemical characterisation of the sediments; the resulting concentrations are divided by "probable effect concentrations" and pooled together, in order to calculate a global hazard quotient. According to the value of this quotient, several decisions can be taken: (a) undertake a detailed risk assessment, (b) dispose of the materials without further constraints, or (c) in case of uncertainty, do some biological testing (with Hyalella azteca and Chironomus riparius) in order to allow decisions. The second step is a detailed ecological risk assessment. Three different assessment endpoints have been proposed, which are (1) the deposit should have no effect on the structure and abundance of benthic invertebrates in the quarry, (2) it should have no long term effect on pelagic species, and (3) it should not cause groundwater pollution, as such quarries are in fact cross sections of shallow alluvial groundwater aquifers. A fourth assessment endpoint should be introduced, regarding health risks for recreational uses, including fishing, but this endpoint was not implemented in the current version of the approach. The analysis phase includes aquatic bioassays (bacteria - Metplate TM-, algae, microcrustaceans Ceriodaphnia dubia, rotifers Brachionus calyciflorus), and leaching assays in columns under ascendant flow.The proposed approach was tested with 3 sediments from a canal located in the north-eastern region of France. Microcosm assays were introduced in parallel to the proposed tests, in order to explore alternatives to standardised bioassays. According to their hazard quotient, the 3 sediments showed a contamination gradient; one of them should not have entered the detailed risk assessment phase, while another would have been further tested with H. azteca and C. riparius. In that case, this latter sediment would not have entered the detailed phase either, as it was not toxic to these species. However, the detailed risk assessment approach was applied to the three sediments, so as to test completely the relevance of the framework.The three sediments were not significantly toxic to either C. riparius or H. azteca. However, some effects were observed in microcosms, including genotoxicity to molluscs. In this case, no risk characterisation could be made. Pore waters extracted from the three sediments were not toxic or slightly toxic to bacteria, algae, and C. dubia; an EC10 value could be determined only for B. calyciflorus. Therefore, due to exposure calculations, it seems there is a risk to pelagic species. However, as 3 bioassays out of 4 were negative or inconclusive, a refinement step would seem to be necessary. The highest concentrations of cadmium, copper, chromium, nickel and zinc were measured in the first lixiviates of the most contaminated sediment. Yet, even in that case, the total extracted fraction remained less than 10% of the total load. This fraction was below 1% for the other sediments, whatever the metal. Maximum concentrations and predicted concentrations at 1 year were compared to drinking water standards. This comparison showed a real risk of degrading groundwater quality for that most contaminated sediment, and a transient risk due to cadmium and nickel for the following one on the contamination gradient.Considering these results, the design of the first step of the proposed assessment approach may be discussed, as one sediment which would not have been assessed in depth according to its hazard quotient did show a risk to pelagic species. This discrepancy underlines the fact that some sediment toxicity may exist below the lowest threshold. As it would be unrealistic to enter systematically into detailed risk assessments, the proposed thresholds in the decision diagram must be pragmatic compromises rather than absolutely safe boundaries. Moreover, protocol improvements are needed for sediment toxicity bioassays. Chronic endpoints are preferable, as they are more sensitive and more relevant. Another issue is related to the role of additional food: not adding food may increase the apparent toxicity, but the sediment organic content, which is an alternative food source, may also be a contaminant carrier. Furthermore, the second assessment endpoint (risk to pelagic species) should be reformulated, as it includes in fact two different questions. Short-term risks related to the deposition phase could be assessed with standardised bioassays like C. dubia survival and reproduction and algal growth, while longer term risks related to contaminant diffusion could be assessed with microcosms. Genotoxic effects were observed at rather high levels, as compared to published results. This result stresses the interest of introducing sensitive and early markers in the risk assessment process, although their real meaning for ecosystems is not yet fully elucidated. Finally, the leaching tests in columns are not completely satisfactory, as the column filling implies that one must first dry the sediments, which will alter their structure. Other application trials along with field validation studies should be carried out prior to the introduction of this scenario in operational or regulatory frameworks

Review on the acute Daphnia magna

Executive summary : One of the most internationally used bioassays for toxicity screening of chemicals and for toxicity monitoring of effluents and contaminated waters is the acute toxicity test with daphnid crustaceans, and in particular that performed with Daphnia magna. Standard methods have been developed for this assay that were gradually endorsed by national and international organisations dealing with toxicity testing procedures, in view of its application within a regulatory framework. As for all toxicity tests, the organisms used for the acute D. magna assay have to be obtained from live stocks which are cultured in the laboratory on live food (micro-algae). Unsurprisingly the various standard protocols of this particular assay differ – at least to a certain extent – with regard to the test organism culturing conditions. In addition, some technical aspects of the toxicity test such as the effect criterion (mortality of immobility), the exposure time, the type of dilution water, etc., also vary from one standard to another. Although this particular assay is currently used in many countries, the technical and biological problems inherent in year-round culturing and availability of the biological material and the culturing/maintenance costs of live stocks restrict its application to a limited number of highly specialised laboratories. This fundamental bottleneck in toxicity testing triggered investigations which brought forward the concept of “microbiotests” or “small-scale” toxicity tests. “Culture/maintenance free” aquatic microbiotests with species of different phylogenetic groups were developed in the early 1990s at the Laboratory for Environmental Toxicology and Aquatic Ecology at the Ghent University in Belgium. These assays which were given the generic name “Toxkits”, are unique in that they employ dormant stages (“cryptobiotic eggs”) of the test species, which can be stored for long periods of time and “hatched” at the time of performance of the assays. One of these microbiotests is the Daphtoxkit F magna, which is currently used in many laboratories worldwide for research as well as for toxicity monitoring purposes. The microbiotest technology has several advantages in comparison to the “traditional” tests based on laboratory cultures, especially its independence of the stock culturing burden. However, the acceptance (or possible non-acceptance) of performing assays with test organisms obtained from “dormant eggs” should be clearly dictated by the “sensitivity” and “precision” criteria of the former assays in comparison to the latter. The first part of this review therefore thoroughly reviews the scientific literature and of data obtained from various laboratories for assays performed with either D. magna test organisms obtained from lab cultures or hatched from dormant eggs. Attention has focused on data of quality control tests performed on reference chemicals, and in particular on potassium dichromate (K2Cr2O7) for which an acceptability range of 0.6–2.1 mg·L–1 has been set in ISO standard 6341 for the 24 h EC50 of the acute D. magna assay. Mean EC50s, standard deviations and variation coefficients were calculated from the collected data, all of which are presented in tables and figures and discussed in detail. The major conclusions drawn from the analysis of the large number of quality control (QC) data on the acute D. magna toxicity test are that : (1) Virtually all results from assays performed with Daphnias taken from lab cultures or with Daphnia microbiotests are within the acceptability range set by ISO standard 6341 for the reference chemical potassium dichromate. (2) The mean 24 h EC50s of the Daphnia microbiotests performed in different laboratories are within the range of the mean EC50s of the assays based on lab cultures, and the variation coefficients (20 to 30%) are similar. (3) The precision – in terms of the long term in house variability – of the quality control Daphnia microbiotests is as good as that of the QC tests based on lab cultures. The review further reports on intra-laboratory sensitivity comparison studies performed during the last 15 years on pure chemicals and on natural samples, with both laboratory cultured organisms and Daphnias hatched from dormant eggs. These studies carried out in different laboratories showed EC50 correlation coefficients of 0.86 to 0.98, corroborating a similar sensitivity of the two types of test organisms. The third part of the review reports and analyses data on proficiency ringtests on the acute D. magna assay which have been organised in different countries since 2002 with either reference chemicals or with natural samples, and in which part of the laboratories performed their assays with Daphnia microbiotests and others with lab cultured Daphnias. The conclusions drawn from all the ringtests indicate that the sensitivity of Daphnia neonates hatched from dormant eggs is similar to that of test organisms taken from lab cultures and that in most cases the precision of the Daphnia microbiotest is superior to that of the assays based on lab cultures. The review finally addresses the issue of possible sensitivity differences of Daphnias hatched from dormant eggs which are produced by different D. magna strains. From these investigations it appeared that the EC50s from assays performed with Daphnias hatched from dormant eggs of different strains did not differ significantly from those from assays undertaken with daphnids from lab cultures. The obvious advantages of Daphnia microbiotests over tests with Daphnias stemming from lab cultures have led to the worldwide use of these culture/maintenance free and low cost small-scale assays in both research and toxicity monitoring. The Daphnia microbiotest is in current use in several countries for toxicity testing in a regulatory framework, and recent calculations indicate that about 10 000 acute D. magna assays are now performed annually with neonates hatched from dormant eggs. The use of dormant eggs to obtain test organisms independently of stock culturing has recently also been accepted in international standards for toxicity testing. ISO standard 20665 (2008) related to the determination of chronic toxicity with Ceriodaphnia dubia, and ISO standard 20666 (2008) for the determination of the chronic toxicity with Brachionus calyciflorus in 48 h, both indicate that the assays can be conducted with organisms hatched from dormant eggs. On the basis of the extensive scientific evidence provided in this review that is justifiably supported by the two ISO methods mentioned above, the authors therefore recommend that the use of Daphnias hatched from dormant eggs should also be incorporated in national and international standards, as an alternative to the use of Daphnias taken from laboratory cultures

Chronic effects of ivermectin chronic effects of ivermectin on daphnia magna and ceriodaphnia dubia: between-species and between-strains comparisons

International audienc

Evaluation de l'écotoxicité des rejets industriels et urbains et de la contamination du milieu récepteur : application à la Moselle à l'amont de Nancy

An integrated study of the quality of part of the Moselle river was conducted. It includes the evaluation of the intrinsic toxicity of industrial waste and in situ measurements of the impacts. A correlation is demonstrated between waste toxicity and in situ impacts. The effluents were then classified as a function of the toxic hazards and the exposition risks they presented. / Une étude intégrée de la qualité d'un tronçon de la Moselle a été effectuée. Elle comprend l'évaluation de la toxicité intrinsèque de rejets industriels et la mesure des impacts in situ. Une corrélation satisfaisante est mise en évidence entre la toxicité des rejets et les impacts in situ. Les effluents ont pu être classés en fonction des dangers toxiques et des risques d'exposition qu'ils présentent

Ecotoxicological and chemical characterization of municipal wastewater treatment plant effluents

The toxicology and the chemical quality of three municipal wastewater effluents have been studied. Acute and sub-chronic bioassays were carried out. We also measured the induction of the hepatic ethoxy resorufin-O-deethylase enzymatic activity (EROD) of fish exposed to the effluents. Chemical analysis allowed to identify the most frequent substances detected in the effluents. From chemical data and results of bioassays we conclude that ammonia concentration explains a part of the lethal toxicity. But chronic toxicity tests carried out with whole effluents or extracted chemical fractions showed that organic pollutants detected in the effluents could also cause long-terme effect. All the tested effluents induced fish EROD activity. The instream invertebrates monitoring confirmed the municipal wastewater treatment plant impact on the receiving water. / La qualité chimique et écotoxicologique (au moyen de bioessais aigus et chroniques) de trois stations d'épuration urbaines a été déterminée. La mesure de l'activité enzymatique EROD a été réalisée sur des truites exposées aux effluents en laboratoire. Les analyses physico-chimiques ont permis d'identifier les substances les plus fréquemment présentes dans ces effluents. Après les résultats biologiques et chimiques, l'ammoniac explique la toxicité aigue constatée. Néanmoins des effets à long terme sont significativement mesurés, soit sur l'effluent total, soit sur certaines fractions organiques. Tous les échantillons testés induisent une induction de l'activité EROD. Les effets toxiques mesurés en laboratoire sont confirmés par des observations sur les populations d'invertébrés in situ

Chronic effects of ivermectin chronic effects of ivermectin on daphnia magna and ceriodaphnia dubia: between-species and between-strains comparisons

International audienc

Effets chroniques de l'ivermectine chez Daphnia magna et Ceriodaphnia dubia: comparaisons inter-espèces et inter-souches

International audienceThe parasiticide ivermectin is widely used due to its high efficiency against endo- and ectoparasites in livestock. Local aquatic ecosystems can thus be contaminated, but few data are available to quantify chronic effects of ivermectin on non-target aquatic organisms. The aim of our study is to understand how ivermectin affects survival, growth and reproduction of two cladoceran species: Daphnia magna (one Japanese and one European strain) and Ceriodaphnia dubia. Hence, chronic toxicity tests were carried out. Survival and the number of neonates per litter were daily recorded, and adult length was measured at the end of the test. The first data analyses showed that ivermectin had a significant effect on all processes, but that differences occurred between species and between strains. The European strain of D. magna was more sensitive than the Japanese one, and the effects appeared earlier but were lower for C. dubia than D. magna