This paper evaluates the use of a PBS/PBAT biodegradable rope to reduce the environmental impact of fishing gear lost at sea. The study aims to better understand the degradation mechanisms that the rope and its monofilaments may encounter due to the long term exposure to seawater. The monofilaments were immersed in natural seawater for up to 18 months, and rope samples were also immersed to study aging at a larger scale and evaluate the ability of a modelling tool to predict initial and aged states of the rope. At low temperatures, no loss of properties was observed for the monofilament and rope. However, at higher temperatures, biodegradation and hydrolysis processes were observed, leading to a faster loss of properties in the monofilament compared to the rope. The modelling tool provided conservative predictions due to severe mechanical test conditions of aged monofilament and a degradation gradient within the rope structure.

International audience | In rural areas, nitrate concentrations in surface waters most often originate from the leaching of excess N fertilizer in agricultural lands, whereas forested catchments often have good water quality. However, Douglas-fir plantations may induce nitrogen cycle unbalances which may lead to an excess of nitrate production in the soil. We hypothesize that the excess of production of nitrate in the soil and nitrate leaching to streamwater is greater in catchments planted with Douglas fir. We used paired catchments in both France and Luxembourg with different land covers (Douglas-fir, Spruce, Deciduous, Grassland and clearcut) which were monitored over a 3-5 year period in order to assess the effect of Douglas-fir plantations on the chemical composition of surface water. Nitrate concentration in the soil and groundwater were also monitored. The results show that nitrate concentrations in streams draining Douglas-fir catchments were two to ten times higher than in streams draining other land covers, but were similar to the clearcut catchment. Nitrate concentrations under Douglas-fir in groundwater (up to 50 mg L-1) and in the soil were also higher than under all other land covers. Soil nitrate concentration was related to stream nitrate concentration. This suggests that soil processes, through excessive nitrate production under Douglas-fir, are driving the nitrate concentration in the stream water and our hypothesis of a transfer of a fairly large proportion of this excessive production from the soil to the stream is supported. This study also shows that nitrate concentrations in surface and ground waters in rural areas could also originate from Douglas fir forested catchments. The impact of Douglas-fir is nevertheless reduced downstream through a dilution effect: mixing tree species at the catchment scale could thus be a solution to mitigate the effect of Douglas-fir on nitrate concentration in surface waters.

Water quality has recently emerged as one of the utmost severe ecological problems being faced by the developing countries all over the world, and Bangladesh is no exception. Both surface and groundwater sources contain different contaminants, which lead to numerous deaths due to water-borne diseases, particularly among children. This study presents one of the most comprehensive reviews on the current status of water quality in Bangladesh with a special emphasis on both conventional pollutants and emerging contaminants. Data show that urban rivers in Bangladesh are in a critical condition, especially Korotoa, Teesta, Rupsha, Pashur, and Padma. The Buriganga River and few locations in the Turag, Balu, Sitalakhya, and Karnaphuli rivers have dissolvable oxygen (DO) levels of almost zero. Many waterways contain traces of NO3, NO2, and PO4-3 pollutants. The majority of the rivers in Bangladesh also have Zn, Cu, Fe, Pb, Cd, Ni, Mn, As, and Cr concentrations that exceed the WHO permissible limits for safe drinking water, while their metal concentrations exceed the safety threshold for irrigation. Mercury poses the greatest hazard with 90.91% of the samples falling into the highest risk category. Mercury is followed by zinc 57.53% and copper 29.16% in terms of the dangers they pose to public health and the ecosystem. Results show that a considerable percentage of the population is at risk, being exposed to contaminated water. Despite hundreds of cryptosporidiosis cases reported, fecal contamination, i.e., Cryptosporidium, is totally ignored and need serious considerations to be regularly monitored in source water.

International audience | In rural areas, nitrate concentrations in surface waters most often originate from the leaching of excess N fertilizer in agricultural lands, whereas forested catchments often have good water quality. However, Douglas-fir plantations may induce nitrogen cycle unbalances which may lead to an excess of nitrate production in the soil. We hypothesize that the excess of production of nitrate in the soil and nitrate leaching to streamwater is greater in catchments planted with Douglas fir. We used paired catchments in both France and Luxembourg with different land covers (Douglas-fir, Spruce, Deciduous, Grassland and clearcut) which were monitored over a 3-5 year period in order to assess the effect of Douglas-fir plantations on the chemical composition of surface water. Nitrate concentration in the soil and groundwater were also monitored. The results show that nitrate concentrations in streams draining Douglas-fir catchments were two to ten times higher than in streams draining other land covers, but were similar to the clearcut catchment. Nitrate concentrations under Douglas-fir in groundwater (up to 50 mg L-1) and in the soil were also higher than under all other land covers. Soil nitrate concentration was related to stream nitrate concentration. This suggests that soil processes, through excessive nitrate production under Douglas-fir, are driving the nitrate concentration in the stream water and our hypothesis of a transfer of a fairly large proportion of this excessive production from the soil to the stream is supported. This study also shows that nitrate concentrations in surface and ground waters in rural areas could also originate from Douglas fir forested catchments. The impact of Douglas-fir is nevertheless reduced downstream through a dilution effect: mixing tree species at the catchment scale could thus be a solution to mitigate the effect of Douglas-fir on nitrate concentration in surface waters.

International audience | Recently, Comte et al. (2022) re-examined the natural degradation of chlordecone (CLD) in the soils of the French West Indies (FWI) by introducing an additional ‘dissipation parameter’ into the WISORCH model developed by Cabidoche et al. (2009). Recent data sets of CLD concentrations in FWI soils obtained by Comte et al. enabled them optimizing the model parameters, resulting in significantly shorter estimates of pollution persistence than in the original model. Their conclusions jeopardize the paradigm of a very limited degradation of CLD in FWI soils, which may lead to an entire revision of the management of CLD contamination. However, we believe that their study is questionable on several important aspects. This includes potential biases in the data sets and in the modeling approach. It results in an inconsistency between the estimated dissipation half-life time (DT50) of five years that the authors determined for CLD and the fate of CLD in soil from the application period 1972–1993 until nowadays. Most importantly, a rapid dissipation of CLD in the field as proposed by Comte et al. is not sufficiently supported by data and estimates. Hence, the paradigm of long-term persistence of CLD in FWI soils is still to be considered.

Sound emissions from human activities represent a pervasive environmental stressor. Individual responses in terms of behaviour, physiology or anatomy are well documented but whether they propagate through nested ecological interactions to alter complex communities needs to be better understood. This is even more relevant for freshwater ecosystems that harbour a disproportionate fraction of biodiversity but receive less attention than marine and terrestrial systems. We conducted a mesocosm investigation to study the effect of chronic exposure to motorboat noise on the dynamics of a freshwater community including phytoplankton, zooplankton, and roach as a planktivorous fish. In addition, we performed a microcosm investigation to test whether roach’s feeding behaviour was influenced by the noise condition they experienced in the mesocosms. Indeed, compared to other freshwater fish, the response of roach to motorboat noise apparently does not weaken with repeated exposure, suggesting the absence of habituation. As expected under the trophic cascade hypothesis, predation by roach induced structural changes in the planktonic communities with a decrease in the main grazing zooplankton that slightly benefited green algae. Surprisingly, although the microcosm investigation revealed persistent alterations in the feeding behaviour of the roach exposed to chronic noise, the dynamics of the roach-dominated planktonic communities did not differ between the noisy and noiseless mesocosms. It might be that roach’s individual response to noise was not strong enough to cascade or that the biological cues coming from the conspecifics and the many planktonic organisms have diverted each fish’s attention from noise. Our work suggests that the top-down structuring influence of roach on planktonic communities might be resilient to noise and highlights how extrapolating impacts from individual responses to complex communities can be tricky.

International audience | Bisphenol (BP) structural analogues of BPA are widely used. Previous studies showed similar effects of BPA and BPS on reproduction in several species including human. We hypothesised that the similar effects of several bisphenols (BPs) could accumulate in granulosa cells (GCs) and affects steroidogenesis. This study investigated the effects of seven BP analogues and their equimolar cocktail on human granulosa cells (hGC) and assessed BPA, BPS, BPF and BPAF level exposures in the follicular fluid of 277 women undergoing Assisted Reproductive Technology. The hGCs were recovered after women oocyte punctures and treated with the seven BP analogues (BPS, BPA, BPAF, BPF, BPAP, BPE and BPB) or their equimolar cocktail of 7 × 1.43 or 7 × 7.14 μM for each of the seven BPs, the sum of BPs reaching 10 (" ∑ BPs 10 μM"), or 50 μM (" ∑ BPs 50 μM"), respectively. Oestradiol and progesterone secretion, cell proliferation, viability and expression of steroidogenic enzymes were investigated. Progesterone secretion was decreased by 6 BPs 10 μM and the cocktail " ∑ BPs 10 μM", (− 17.8 to − 41.3%) and by all seven BPs 50 μM and " ∑ BPs 50 μM" (− 21.8 to − 84.2%). Oestradiol secretion was decreased only by 50 μM BPAF and BPAP (− 37.8% and − 44%, respectively), with corresponding decreases in CYP17A1 and CYP19A1 gene expression. Cellular proliferation was decreased after treatment with 50 μM BPAF (− 32.2%), BPAP (− 29%), BPB (− 24%) and the equimolar cocktail " ∑ BPs 50 μM" (− 33.1%). BPB (50 μM) and the cocktail " ∑ BPs 50 μM" increased HSD3B2 mRNA expression. At least one BP was detected in 64 of 277 (23.1%) women follicular fluids. Similar effects of the seven BPs or their cocktail were observed on progesterone secretion and/or on cell proliferation, suggesting cumulative effects of BPs. Our results highlight the urge to consider all BPs simultaneously and to further investigate the potential additive or synergistic effects of several BPs. ☆ This paper has been recommended for acceptance by Wen Chen.

International audience | Pollinators have to cope with a wide range of stressful, not necessarily lethal factors limiting their performance and the ecological services they provide. Among these stressors are pesticides, chemicals that are originally designed to target crop-harming organisms but that also disrupt various functions in pollinators, including flight, communication, orientation and memory. Although all these functions are crucial for reproductive individuals when searching for mates or nesting places, it remains poorly understood how pesticides affect reproduction in pollinators. In this study, we investigated how a widely used fungicide, boscalid, affects reproduction in honey bees (Apis mellifera), an eusocial insect in which a single individual, the queen, fulfills the reproductive functions of the whole colony. Boscalid is a succinate dehydrogenase inhibitor (SDHI) fungicide mainly used on rapeseed flowers to target mitochondrial respiration in fungi but it is also suspected to disrupt foraging-linked functions in bees. We found that immature queen exposure to sublethal, field relevant doses of boscalid disrupted reproduction, as indicated by a dramatic increase in queen mortality during and shortly after the nuptial flights period and a decreased number of spermatozoa stored in the spermatheca of surviving queens. However, we did not observe a decreased paternity frequency in exposed queens that successfully established a colony. Queen exposure to boscalid had detrimental consequences on the colonies they later established regarding brood production, Varroa destructor infection and pollen storage but not nectar storage and population size. These perturbations at the colony-level correspond to nutritional stress conditions, and may have resulted from queen reduced energy provisioning to the eggs. Accordingly, we found that exposed queens had decreased gene expression levels of vitellogenin, a protein involved in egg-yolk formation. Overall, our results indicate that boscalid decreases honey bee queen reproductive quality, thus supporting the need to include reproduction in the traits measured during pesticide risk assessment procedures.

International audience | Aflatoxin B1 (AFB1) is the most potent natural carcinogen among mycotoxins. Versicolorin A (VerA) is a precursor of AFB1 biosynthesis and is structurally related to the latter. Although VerA has already been identified as a genotoxin, data on the toxicity of VerA are still scarce, especially at low concentrations. The SOS/umu and miniaturised version of the Ames test in Salmonella Typhimurium strains used in the present study shows that VerA induces point mutations. This effect, like AFB1, depends primarily on metabolic activation of VerA. VerA also induced chromosomal damage in metabolically competent intestinal cells (IPEC-1) detected by the micronucleus assay. Furthermore, results from the standard and enzyme-modified comet assay confirmed the VerA-mediated DNA damage, and we observed that DNA repair pathways were activated upon exposure to VerA, as indicated by the phosphorylation and/or relocation of relevant DNA-repair biomarkers (γH2AX and 53BP1/FANCD2, respectively). In conclusion, VerA induces DNA damage without affecting cell viability at concentrations as low as 0.03 μM, highlighting the danger associated with VerA exposure and calling for more research on the carcinogenicity of this emerging food contaminant.