In this study, exposure and ecotoxicity data of six human pharmaceuticals (carbamazepine, clofibric acid, diclofenac, ofloxacin, propranolol, and sulfamethoxazole) were collected, including our own ...experimental data and literature data. From this data collection, the two‐tiered European draft guideline on the environmental risk assessment of human pharmaceuticals was tested. Measured environmental concentrations in effluents from France and in effluents and surface waters from Germany were compared to the predicted environmental concentrations (PECs) in both countries. In a similar manner, predicted no‐effect concentrations (PNECs) derived from acute data and PNECs derived from chronic data were estimated for each pharmaceutical and corresponding PEC/PNEC ratios then were compared in both countries. Globally, results demonstrated that all environmental concentrations (predicted or measured) for each considered pharmaceutical exceeded the 10‐ng/L cutoff value, which requires the implementation of the second‐tier assessment based on ecotoxicity data. Moreover, the six pharmaceuticals showed a relatively limited acute toxicity, and carbamazepine and propranolol were inaccurately identified as having negligible risks under the current European draft procedure. Such results lead to discussion of the actual procedure on pharmaceuticals, especially on the need of appropriate ecotoxicity tests.
In the perspective of a biomonitoring application for assessing genotoxicity of freshwater ecosystems, the Comet assay has recently been developed on spermatozoa in the amphipod
Gammarus fossarum, in ...order to propose a sensitive and reliable genotoxicity biomarker in an ecologically relevant freshwater species. The appropriate use of a genotoxicity biomarker requires good knowledge of its basal level and its natural variability related to intrinsic biotic and environmental abiotic factors. We propose a procedure for which the lowest biomarker variability related to methodological and intrinsic biotic factors is obtained and a reference value of biomarker basal response taking into account its spatio-temporal changes has been defined. A strong impact of spermatogenesis status and exposure time on the response to genotoxicant pressure was observed. These reports led us to select a standard organism, i.e., the mature male gammarid in precopula. No effect of temperature and conductivity on baseline DNA damage was observed in the laboratory for the tested range (6–24
°C and 300/600
μS cm
−1). Similarly, no spatio-temporal change relative to season or the physico-chemical characteristics of the water was recorded during the field survey. On the basis of these results, a reference level with maximal threshold values has been proposed for the standard gammarid.
► The influence of physiological status and abiotic factors on spermatozoa DNA damage was measured. ► We defined a standard procedure for which the lowest biomarker variability is gained. ► No impact of temperature and conductivity on spermatozoa DNA damage base level. ► No spatio-temporal variability relative to season or physico-chemical characteristics of water. ► A reference value of biomarker response taking into account its natural variability is defined.
We present models to link feeding with growth, emergence, and reproduction of the midge Chironomus riparius. These models are based on assumptions about the biology of this species and distinguish ...between males and females. The assumptions are the isomorphism of the chironomidae, the fact that much more energy is used for growth than for maintenance, and the existence of a maximum length for male and female larvae that does not depend on food availability. We supported our assumptions by experimental data and estimated the parameters of the model. We then successfully predicted the length pattern of 2‐d‐old larvae exposed in an artificial sediment to different feeding levels with different starting densities and also linked emergence time and growth pattern. We found our model to be consistent with data from another study and another species (Chironomus plumosus). As for reproduction, the mean number of eggs per mass was described as a linear function of feeding quantity. Our models could be used in sediment risk assessment to choose feeding level, to build effects models, or to predict the effects of toxicants at the population level.
The appropriate use of an enzyme activity as a biomarker requires good knowledge of its basal level and its natural variability related to intrinsic biotic and environmental abiotic factors. In view ...of using whole-body acetylcholinesterase (AChE) activity in Gammarus fossarum as a reliable biomarker of exposure to anti-cholinesterase agents in aquatic ecosystems, (i) the effects of the main biotic (sex, reproductive status, and weight) and abiotic (water temperature) factors on the basal activity level of this enzyme were measured in the laboratory and (ii) the spatio-temporal variability of basal enzyme activity was followed in wild populations over a 1-year period. The results show no direct effect of sex. However, significant differences in AChE activity were observed between females depending on gonadal and embryonic development. A strong negative correlation between the AChE activity levels and organism body weight was observed. Indeed, AChE activity decreases drastically during the early life stages and tends to stabilise in larger individuals. These reports led us to select a standard organism (male; weight range, 15-20mg) to minimise inter-individual variability. No effect of temperature on basal AChE activity was observed in the laboratory for the tested range (6-24°C). Similarly, no spatio-temporal change relative to season or the physico-chemical characteristics of the water (such as conductivity and temperature) was recorded during the field survey. On the basis of field-collected data, we defined the standard organism having a reference activity level with minimal and maximal threshold values. Finally, the value of AChE activity normalisation by protein contents is discussed.
The aim of this study was to propose a tool for freshwater environmental genotoxicity assessment using
Gammarus fossarum, a high ecologically relevant species. In a first part, gammarids were caged ...upstream and downstream wastewater treatment plant effluent output. The sensitivity of genotoxic responses of haemocytes, oocytes and spermatozoa was compared using the Comet assay. Spermatozoa appeared to be the most sensitive, suitable and relevant cell type for genotoxicity risk assessment. In a second part, a watershed-scale study was conducted over 2 years to evaluate the applicability of our caging procedure. The genotoxic impact of a contamination was followed, taking into account seasonal variability. DNA damage in spermatozoa exhibited low basal level and low variability in control upstream sites, providing a reliable discrimination of polluted sites. Finally, DNA damage in caged
G. fossarum has been proved to be a sensitive and reproducible tool for freshwater genotoxicity assessment.
► Two different contamination contexts: WWTP effluents and polymetallic contamination. ► DNA damage in caged
Gammarus fossarum is a sensitive tool for freshwater quality assessment. ► Spermatozoa is the most relevant cell type for biomonitoring freshwater genotoxicity. ► Combining biomarker responses with analytical chemistry provides rich ecotoxicological information.
We propose an approach to assess freshwater genotoxicity in the field based on caged
Gammarus fossarum (Crustacea, amphipoda).
Environmental processes and dispersal movements occurring over long distances (10 to 100 km) continually influence local stream fish assemblages. However, electrofishing protocols are classically ...implemented in short reaches (∼1 km) and are not suited for frequent characterization of assemblages over long distances. We developed a new sampling protocol (SPA: snorkelling point abundance) for characterizing fish assemblages over long distances, using series of sampling points, as often applied in electrofishing (PASE: point abundance samples by electrofishing). Nine pairs of PASE and SPA surveys, repeated in a narrow and in a wide stream, were compared. Greater species abundance, occurrence, and richness were found on PASE, but relative species abundance were comparable between protocols. Assemblages were highly variable over time (between-surveys) on both protocols. The spatial structure of point assemblages (within-survey) was consistent between protocols and related to species’ habitat use (depth, current velocity). For several species, the longitudinal distribution of abundance along reaches was comparable between protocols when surveys were pooled. Overall, SPA could be an alternative to electrofishing for analysing spatial structure over long distances.
A 4-day embryo-larval zebrafish test, from blastula stage to hatching included, was developed. The observations of embryo developmental were made at different development stages, for which ...morphological, physiological, and behavioral endpoints were selected and quantified for unexposed and exposed embryos. The sensitivity and the ability of these endpoints to inform about mode of action (MoA) were established in testing three model toxicants with well-known toxic effects (propranolol, malathion, cadmium). Lethal, sublethal (heart rate/edema, spontaneous movements, and hatching rate/time disturbance), and teratogenic effects were detected for all the studied compounds. This bioassay allows characterization of impairments at different biological levels: neuromuscular, physiological, morphological, and behavioral, and brings useful information about the toxic MoA of the chemicals on nontarget organisms. In this sense to answers the chemical industries and international organization (EMEA) requirements for the environmental risk assessment of new chemicals and pharmaceuticals.
Climate change is expected to affect hydrologic and thermal regimes of river ecosystems. During dry periods when river flows decrease and water temperatures increase, the hyporheic zone (HZ) can ...provide a refuge to surface aquatic invertebrates and enhance the resilience capacity of riverine ecosystems. However, shifts from up‐ to downwelling flow conditions in the HZ could jeopardise this capacity.
Using laboratory mesocosms and high‐resolution fibre‐optic distributed temperature sensing, we explored the combined effects of five different increased surface water temperature treatments (from 15 to 27°C at 3°C intervals) and the direction of water exchange on the ability of Gammarus pulex (Crustacea: Amphipoda: Gammaridae) to migrate into the HZ as a response to warming. We determined the survival rates of this ubiquitous hyporheic dweller and its rates of consumption of alder (Alnus glutinosa; Betulaceae) leaf litter in the HZ.
Results showed that at increasing surface water temperature, leaf‐litter breakdown was observed at a greater depth in the sediments under downwelling flow conditions, that is, G. pulex migrated deeper into the HZ compared with upwelling conditions, resulting in greater survival rates (64 ± 11 vs. 44 ± 10%). However, under both upwelling and downwelling conditions, we found evidence for potential use of the hyporheic zone as a thermal refuge for G. pulex. Below sediment depths of 25 cm, temperatures remained low (<22°C) even when surface waters were at 27°C, so temperatures deep in the hyporheic zone never exceeded critical thermal thresholds for G. pulex.
This study provides evidence that alterations to the direction of groundwater–surface water exchange can alter the capacity of the HZ to provide a refuge for benthic invertebrates, thereby affecting the resilience of river communities to warming under climate change.
Mollusk species have been shown to be sensitive to various endocrine disrupting compounds (EDC) at environmentally relevant concentrations. Waste water treatment plant (WWTP) effluents are a major ...source of potential or known EDC in the aquatic environment. The aim of this study was to develop an
in situ exposure method using the New Zealand mudsnail
Potamopyrgus antipodarum (Molluska, Hydrobiidea) to assess the impact of water quality on the life traits of this species, by focusing on its reproduction. The impact of three WWTP discharges on three different receiving rivers was studied. The effects of WWTP effluent on adult survival, weight, reproduction and vertebrate-like sex-steroid levels in snails were monitored for three to four weeks. Although the physicochemical and hydrological parameters varied greatly between the rivers, the caging experiments allowed us to detect significant impairment of the life traits of snails when exposed downstream of the WWTPs discharge. While adult survival was not affected by exposure, reproduction was significantly impacted downstream from the WWTP effluent discharges (60–70% decrease of embryos without shells after three to four weeks exposure) independently of the river. Modulations of steroid levels proved to be an informative parameter with an increase of testosterone downstream of the discharges, and increases and decreases of 17β-estradiol levels according to site. The endpoints used proved to be an adapted method for field exposures and allowed the discrimination between upstream and downstream sites.
Recently, we built a model to link feeding input with growth, emergence, and reproduction of the midge Chironomus riparius exposed to an artificial sandy sediment. This model is based on assumptions ...about both feeding behavior and use of energy. Here, we show how it can be used for toxicity tests with natural sediments to understand and model the influence of sediment characteristics. We measured growth, emergence, and reproduction of chironomids exposed in beakers to four unpolluted natural sediments and three feeding conditions (no feeding, 0.2 mg Tetramin®/larva/d, and 1.4 mg Tetramin/larva/d) and compared the results with data obtained on our artificial sandy sediment. Sediment characteristics had lower influence on growth than feeding level, but their influence could not be neglected. First, we could distinguish between sandy sediments and other sediments. This difference resulted in a significant delay of about 18 h in the growth curves. Second, in case of food limitation, chironomids could use the organic materials in the sediment, provided that the C:N ratio of the sediment was less than 14. Our model proved to be able to incorporate those two phenomena. As for reproduction, we observed a better reproduction (measured in number of eggs per mass) for natural sediments than for artificial sediments. We showed that this difference could be due to the lipid content of the natural sediments.
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