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.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA | Midge larvae (Chironomus riparius) were exposed to sediments from a deposition sampled at a site along the Rhône River (France) downstream of an industrial site releasing various perfluorinated chemicals. This sediment is characterized by high concentrations of perfluoroundecanoic acid (PFUnA) and perfluorotridecanoic acid (PFTrDA) and a low perfluorooctane sulfonate (PFOS) concentration. Concentrations of 23 perfluoroalkyl compounds, including C4eC14 carboxylate acids, C4eC10 sulfonates, and seven precursors, were analyzed in overlying and pore water, sediment, and larvae. Midge larvae accumulated carboxylate acids (C11eC14), PFOS, and two precursors (perfluorooctane sulfonamide: FOSA and 6:2 fluorotelomer sulfonic acid, 6:2 FTSA). These substances accumulated mainly during the fourth instar larvae exponential growth phase. Accumulation of 6:2 FTSA, PFUnA, and PFOS occured via trophic and tegumentary routes. Other compounds mainly accumulated from food. Kinetics followed a partition model, from which uptake and elimination constants were derived.

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.

International audience

Effets des pollutions atmosphériques sur les cultures et la forêt. Journée scientifique sur la pollution atmosphérique et les impacts sanitaires

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

A multi-scale methodology was used to characterize the long-term behavior and chemical stability of a CeO2-based nanocomposite used as UV filter in wood stains. ATR-FTIR and 13C NMR demonstrated that the citrate coated chelates with Ce(IV) through its central carboxyl- and its α-hydroxyl- groups at the surface of the unaged nanocomposite. After 42 days under artificial daylight, the citrate completely disappeared and small amount of degradation products remained attached to the surface even after 112 days. Moreover, the release/desorption of the citrate layer led to a surface reorganization of the nano-sized CeO2 core observed by XANES (Ce L3-edge). Such a surface and structural transformation of the commercialized nanocomposite could have implications in term of fate, transport, and potential impacts towards the environment.

Occupational and experimental studies have revealed the organs most affected by dimethylformamide (DMF) are liver and gastrointestinal tract. However, few studies have focused on the potential effect of outdoor pollution of DMF. This study examined the health risk of hospitalization due to digestive system disease by time series studies in a case city Longwan, China. The urine metabolite of DMF was correlated well with DMF exposure concentration (EC). A 101.0-μg/m3 (interquartile range) increase in the two-day moving average of DMF EC was associated with a 1.10 (1.01 ˜ 1.20), 1.22 (1.10 ˜ 1.35), and 1.05 (0.90 ˜ 1.22) increase in hospitalization for total digestive system diseases, liver disease, and gastrointestinal tract disease, respectively. The exposure-dose response between DMF and the relative risk of liver disease was linear only below 350 μg/m3. These findings highlight a previously unrecognized health problem related to VOCs released into the outdoor environment.

Application of passive samplers is demonstrated for assessment of temporal and spatial trends of dissolved polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and priority metals in the middle stretch of the Danube river. Free dissolved concentrations of PAHs, measured using SPMD samplers, ranged from 5 to 72 ng L−1. Dissolved PCBs in water were very low and they ranged from 5 to 16 pg L−1. Concentration of mercury, cadmium, lead and nickel, measured using DGT samplers, were relatively constant along the monitored Danube stretch and in the range <0.1, <1–20, 18–74, and 173–544 ng L−1, respectively. Concentrations of PAHs decreased with increasing temperature, which reflects the seasonality in emissions to water. This has an implication for the design of future monitoring programs aimed at assessment of long term trends. For such analysis time series should be constructed of data from samples collected always in the same season of the year.