The sensitivity of diatom taxonomy and trait-based endpoints to chemicals has been poorly used so far in Environmental Risk Assessment. In this study, diatom assemblages in outdoor flow-through mesocosms were exposed to thiram (35 and 170 mu g/L), and a hydrocarbon emulsion (HE; 0.01, 0.4, 2 and 20 mg/L). The effects of exposure were assessed for 12 weeks, including 9 weeks post-treatment, using taxonomic structure and diversity, bioindication indices, biological traits, functional diversity indices, indicator classes and ecological guilds. For both chemicals, diversity increased after the treatment period, and responses of ecological traits were roughly identical with an abundance increase of motile taxa tolerant to organic pollution and decrease of low profile taxa. Bioindication indices were not affected. Traits provided a complementary approach to biomass measurements and taxonomic descriptors, leading to a more comprehensive overview of ecological changes due to organic chemicals, including short- and long-term effects on biofilm structure and functioning. (C) 2014 Elsevier Ltd. All rights reserved.

Acidification of lakes and rivers is still an environmental concern despite reduced emissions of acidifying compounds. We analysed trends in surface water chemistry of 173 acid-sensitive sites from 12 regions in Europe and North America. In 11 of 12 regions, non-marine sulphate (SO4*) declined significantly between 1990 and 2008 (−15 to −59 %). In contrast, regional and temporal trends in nitrate were smaller and less uniform. In 11 of 12 regions, chemical recovery was demonstrated in the form of positive trends in pH and/or alkalinity and/or acid neutralising capacity (ANC). The positive trends in these indicators of chemical recovery were regionally and temporally less distinct than the decline in SO4* and tended to flatten after 1999. From an ecological perspective, the chemical quality of surface waters in acid-sensitive areas in these regions has clearly improved as a consequence of emission abatement strategies, paving the way for some biological recovery. | acceptedVersion

International audience | In recent years, there has been increasing concern about the environmental risks of the so called "emerging contaminants (ECs) "in conventional and non conventional water resources. According to the EU NORMAN network ECs are "substances that have been detected in the environment, but which are currently not included in routine monitoring programs at EU level and whose fate, behavior and (eco)toxicological effects are not well understood." ECs originate from a variety of products including human and veterinary pharmaceuticals, industrial chemicals, and personal care products and are continuously discharged into sewer systems. Since degradation rates in conventional sewage treatment plants (STP) are rather low, ECs enter receiving waters through wastewater effluents. During bank filtration, ECs may be transported from river water to groundwater. In addition, if wastewater is used for irrigation of arable land or for artificial aquifer recharge, ECs are transferred into soil and groundwater. Two case studies on the occurrence of ECs in wastewater and river water are presented. The first study demonstrates the occurrence of 1,3-benzothiazole (BT) in river water within the Schwarzbach watershed (Germany) as well as in wastewater influents and effluents from three municipal STPs in Germany. BT mainly originates from sunlight induced direct photolysis of 2-mercaptobenzothiazole which is added as a vulcanization accelerator to rubber compositions in the manufacturing process of the tire industry. Measured BT concentrations in river water were between 58 and 856 ng/L. Concerning the sources, rather similar BT concentrations over a wide range of river discharge indicated that dilution along the mainstream is negligible and, thus, supports the hypothesis that paved surface runoff during rain events is an important BT source, not only for wastewater influent but also for river water. This was supported by detecting the highest BT concentrations at sampling locations close to the dense highway network around the city of Frankfurt. Since BT was also detected in river water collected from locations that were clearly unaffected by wastewater effluent discharge, surface runoff should be considered as a diffuse source of BT in river water. In the second study, treated wastewaters that are used for agricultural irrigation at Oued Souhil area (Tunisia) and artificial aquifer recharge at Korba (Tunisia) as well as river water from the River Meliane (Tunisia) were analyzed for the presence of selected pharmaceuticals. Ibuprofene and its metabolite 2-OH-ibuprofene, diclofenac, oxazepam, atenolol, sulphamethoxazole and carbamazepine were detected in wastewaters. Rather similar concentrations were observed in effluents collected at the STPs outlets and in treated wastewater reused on-site either for irrigation (in Oued souhil) or for aquifer recharge (in Korba) indicated their likely persistence. At Oued Souhil, naproxene, trimethoprim, fenofibric acid, ketoprofene and 1-OH-ibuprofene occurred in effluents and irrigation water with lower concentrations in the latter. All pharmaceuticals, except oxazepam were detected also in river water samples at concentrations between 12 ng/L (trimethoprim) and 1024 ng/L (ibuprofene). From ecotoxicological point of view, the BT concentrations in river water were far below its EC50 value of 4.32 mg/L (Vibrio fischeri). However, BT was reported to inhibit respiratory and nitrification processes on sediment columns while the effect of pharmaceuticals on ecosystems is still an open question. Concerning the occurrence of thousands of ECs, without precise knowledge of their mixture toxicity and the fact that such polar compounds can easily reach groundwater resources after discharge into the aquatic environment, the release of such chemicals has to be reduced in the future. Since belated removal of such compounds from wastewater by additional treatment such as ozonation, UV treatment or activated carbon is expensive, over-application of such ECs and an improper disposal should be avoided.

The sensitivity of copepods to ocean acidification (OA) and warming may increase with time, however, studies >10 days and on synergistic effects are rare. We therefore incubated late copepodites and females of two dominant Arctic species, Calanus glacialis and C. hyperboreus, at 0 °C at 390 and 3000 µatm pCO2 for several months in fall/winter 2010. Respiration rates, body mass and mortality in both species and life stages did not change with pCO2. To detect synergistic effects, in 2011 C. hyperboreus females were kept at different pCO2 and temperatures (0, 5, 10 °C). Incubation at 10 °C induced sublethal stress, which might have overruled effects of pCO2. At 5 °C and 3000 µatm, body carbon was significantly lowest indicating a synergistic effect. The copepods, thus, can tolerate pCO2 predicted for a future ocean, but in combination with increasing temperatures they could be sensitive to OA.

peer reviewed

Conséquences des pollutions atmosphériques sur l'agriculture et la forêt. Séminaire Agriculture et pollution de l’air

International audience

The authors thank the "Ville numérique" and "OPUR" research programmes, IFSTTAR and École des Ponts ParisTech/Cerea for their financial support, SIVOA for providing the data on the catchment and DRIEA for providing the traffic data. | International audience | Methods for simulating air pollution due to road traffic and the associated effects on stormwater runoff quality in an urban environment are examined with particular emphasis on the integration of the various simulation models into a consistent modelling chain. To that end, the models for traffic, pollutant emissions, atmospheric dispersion and deposition, and stormwater contamination are reviewed. The present study focuses on the implementation of a modelling chain for an actual urban case study, which is the contamination of water runoff by cadmium (Cd), lead (Pb), and zinc (Zn) in the Grigny urban catchment near Paris, France. First, traffic emissions are calculated with traffic inputs using the COPERT4 methodology. Next, the atmospheric dispersion of pollutants is simulated with the Polyphemus line source model and pollutant deposition fluxes in different subcatchment areas are calculated. Finally, the SWMMwater quantity and quality model is used to estimate the concentrations of pollutants in stormwater runoff. The simulation results are compared to mass flow rates and concentrations of Cd, Pb and Zn measured at the catchment outlet. The contribution of local traffic to stormwater contamination is estimated to be significant for Pb and, to a lesser extent, for Zn and Cd; however, Pb is most likely overestimated due to outdated emissions factors. The results demonstrate the importance of treating distributed traffic emissions from major roadways explicitly since the impact of these sources on concentrations in the catchment outlet is underestimated when those traffic