Submarine karstic springs as a source of nutrients and bioactive trace metals for the oligotrophic Northwest Mediterranean Sea.

Groundwater springs in karstified carbonate aquifers are known to transport carbon, nutrients and trace elements to the coastal ocean. The biogeochemical significance of submarine karstic springs and their impact on coastal primary production are often difficult to quantify. We investigated several karstic springs, including the first-order Port-Miou spring, in an urbanized watershed that is also severely impacted by sewage effluent (Calanques of Marseille-Cassis, France). Karstic springs were elevated in major nutrients and bioactive trace metals over Mediterranean seawater, with relatively low concentration ranges. Groundwater NO3- was likely derived from atmosphere-aquifer interactions, while DOC:DON ratios reveal that NO2- and NH4+ was autochthonously produced during mixing between karst groundwater and seawater. Submarine groundwater discharge (SGD) during March 2018 (wet season, baseflow conditions) was 6.7 ± 2.0 m3 s-1 for the entire investigated coastline, determined from simultaneous 224Ra and 226Ra mass balances. The contribution of groundwater PO43-, the major limiting nutrient of the Mediterranean Sea, sustained only 1% of primary production adjacent to sewage outfall, but between 7 and 100% of the local primary production in areas that were not impacted by sewage. Groundwater and seawater Fe:DIN and Fe:DIP ratios suggest that Fe was not a limiting micro-nutrient during the period of study, where bioactive trace metal fluxes were dominated by sewage and atmospheric deposition, although excess Fe from groundwater may locally enhance N fixation. Groundwater solute fluxes may easily vary by a factor of two or more over time because karst aquifers are sensitive to precipitation, as is the case of the regional carbonate karstified aquifer of Port-Miou, highlighting the critical importance of properly characterizing nutrient and trace metal inputs in these coastal environments.

Determination of low-level Radium isotope activities in fresh waters by gamma spectrometry.

A new portable sampling system was developed to extract Radium isotopes from large volumes (up to 300L) of fresh surface- and ground-waters of low Ra-activities (<5mBq/L). Ra is quantitatively adsorbed on a small amount (6.5g) of MnO2-coated acrylic fibers, which are then dried and burned at 600°C in the laboratory. The resulting Mn-oxide powder (about 2cm3 when compacted) is then analyzed through gamma-ray spectrometry which allows measurement of the whole Ra quartet (226Ra, 228Ra, 224Ra and 223Ra) in a single counting of a few days. The usual relative standard combined uncertainties (1σ) are 2-3% for 226Ra, 228Ra and 224Ra; and less than 10% for 223Ra. This method was applied to the analysis of Ra in karstic waters of the Lez aquifer, and surface- and ground-waters of the upper and middle Vidourle watershed (South of France). The analyzed waters have relatively low 226Ra activities (1-4mBq/L) in both cases, regardless of the contrasted geology (Mesozoic limestone vs crystalline Variscan basement), but clearly distinct (228Ra/226Ra) ratios in agreement with the differences in Th/U ratios of the two drained areas. Short-lived Ra isotopes (224Ra and 223Ra) appear to be mainly influenced by near-surface desorption/recoil processes for most of the sampling sites.

Using fluorescence spectroscopy EEM to evaluate the efficiency of organic matter removal during coagulation-flocculation of a tropical surface water (Agbo reservoir).

This study evaluate the use of fluorophores A, C and T fluorescence intensities to access the coagulation efficiency for removing dissolved organic carbon (DOC) in the raw water from Agbo reservoir in Ivory Coast. A coagulation-flocculation was conducted with aluminium sulphate as coagulant and DOC residual and fluorescence intensities were acquired. The consistency of fluorescence data was evaluated to ensure that no inner-effect, quenching or enhanced intensities affect the data. Fluorescence-inferred DOC removal was then calculated in percentage terms from the decrease in organic matter fluorescence intensity for each peak between raw and clarified water and correlated with measured DOC removal. The results indicate a high significant correlation between measured DOC removal and fluorescence-inferred DOC removal calculated for peak A (R(2)=0.91), peak C (R(2)=0.89), peak T (R(2)=0.92) indicating a strong linear relationship between DOC removal and fluorescence intensities. Furthermore, tryptophan-like (peak T) was found to be the least eliminated and thus, may be considered as an indicator of DOC residual after coagulation-flocculation process. This result shows that fluorescence spectroscopy offers a robust analytical technique to be used to evaluate DOM removal efficiency in water treatment.

Organotins in a medium-size Mediterranean basin (the Herault River).

This study reports the first assessment of organotin pollution in the Hérault watershed, a medium size Mediterranean basin. Organotin compounds were analyzed in surface waters, wells supplying drinking water and sewage treatment plants (STPs). In surface and ground waters, a background contamination by total organotin compounds has been identified in the range of 0.51 +/- 0.02-71 +/- 2 ng(Sn) L(-1), which is of the same order of magnitude as those observed in other European areas. Organotins were systematically present in STP influents and sludge. Total or partial elimination of organotin compounds from treated wastewater was observed. STP effluents appeared nevertheless to be a non-negligible source of contamination not only of rivers but also of aquifers tapped for drinking water supply. Tributyltin concentration was higher than the maximum allowable concentration proposed by the European Commission in some surface waters and wells supplying drinking water. This could compromise the water resource and have serious and irreversible consequences for the aquatic eco-system. As it was the case for the ban of antifouling paints, a regulatory regime in decreasing point-source emissions of these harmful compounds used in household products might be applied.

Dissolved and bioavailable contaminants in the Seine river basin.

Diffusive Gradient in Thin Films (DGT) and Semi-Permeable Membrane Devices (SPMDs) were deployed in the Seine river basin in order to assess labile metals and truly dissolved Polycyclic Aromatic Hydrocarbons. We show that the tools are reliable in aquatic environments to assess the speciation of dissolved contaminants and hence provide a good insight into the potential bioavailability of contaminants. The deployment of the DGT and SPMDs in contrasting environments in the Seine river basin allowed distinction to be made of availability of contaminants between headwater streams and much more impacted river reaches and an assessment of bioavailability. At the stations under urban influence, the impact of dissolved organic matter on both copper and PAHs bioavailability is less pronounced than at upstream stations, where humic substances dominate.

Consequences of treated water recycling as regards pharmaceuticals and drugs in surface and ground waters of a medium-sized Mediterranean catchment.

In Mediterranean regions where the population is rapidly growing, the risk of water resource contamination by wastewater is likely to increase. This is the case of the Hérault watershed (south of France), where the presence of treated wastewater in surface and ground waters has been shown in a previous study. To assess the consequence of these wastewater contaminations as regards pharmaceuticals and other organic compounds, 16 common pharmaceuticals (amitryptilin, acetylsalicylic acid, carbamazepine, clenbuterol, diazepam, diclofenac, doxepin, gemfibrozil, ibuprofen, imipramine, ketoprofen, naproxen, nordiazepam, paracetamol, salbutamol, and terbutalin) as well as wastewater related pollutants (caffeine, gadolinium anomaly, and boron) were analyzed in wells pumped for potable water supply and in two wastewater treatment plant (WWTP) effluents. In addition, a monitoring along the Lergue River (the main tributary of the Hérault River) was achieved to assess pharmaceutical behavior in surface waters. Pharmaceuticals and other wastewater-related contaminants are present in several reservoirs tapped for drinking water, confirming wastewater contamination; paracetamol, caffeine, and diclofenac are the most frequently detected. Paracetamol is present at rather high concentrations (up to 11 microg/L and 211 ng/L, respectively, in a wastewater effluent and in a drinking water sample). Though degradable in WWTP, caffeine is commonly encountered in surface waters and detected in highly polluted groundwater. On the contrary, acetylsalicylic acid concentrations are generally low despite a large consumption in France; this is related to its metabolism in humans and rapid degradation in the aquatic environment. The monitoring of pharmaceuticals along the Lergue River shows that dilution is sufficient to decrease pharmaceutical values.

Short-term variability of dissolved trace element concentrations in the Marne and Seine rivers near Paris.

The concentrations of dissolved trace elements (Li, B, Mn, Cu, As, Rb, Sr, Mo, Cd, Ba, Pb) in the Marne and Seine rivers in the Paris urban area were monitored over a 2-year period. The resulting data indicated moderate contamination of waters by the most toxic elements (Cu, As, Cd and Pb). The River Marne upstream and the River Seine downstream of the city of Paris displayed similar concentrations. However higher fluxes of trace elements were observed in the Seine than in the Marne due to their different discharges. Li, B, Rb, Sr and Ba concentrations were correlated with river discharge and concentrations were higher during high river flow. This was interpreted as a dilution by discharge from a major natural or anthropogenic source. Mn, Cu, Mo, Cd and Pb concentrations were not correlated with discharge. Dissolved Mn, Cu and Cd increased rapidly in summer, whereas the concentration of Mo decreased. These variations were attributed to redox processes. During summer when the dissolved oxygen concentrations decrease, Mn, Cu, Cd and Pb are released into solution whereas Mo is immobilised. Like metals, variations in arsenic contents were not linked with discharge. Its similarity with phosphate distribution suggests similar controls involving phytoplankton uptake and release from sediments through organic matter mineralization.

Asthmatics have more nocturnal gasping and reflux symptoms than nonasthmatics, and they are related to bedtime eating.

OBJECTIVES: Certain pulmonary diseases are now recognized as possible complications of gastroesophageal reflux (GER) disease. To further clarify the relationship between GER and asthma, we determined the prevalence, nature, and patterns of reflux symptoms in consecutive asthmatics and a well-defined patient population control group. METHODS: Two hundred and sixty-one asthmatic outpatients with well-documented asthma were interviewed in person using an extensive questionnaire. To avoid selection bias, we (a) used no selection criteria other than asthma, (b) interviewed every identified asthmatic from either the outpatient general medical clinic or pulmonary clinic (and excluded the gastroenterology clinic), and (c) excluded asthmatics referred because of gastrointestinal symptoms. A control group comprised 218 consecutive outpatients chosen from the same general medical clinics in which the asthmatics were enrolled. Interviews were conducted by one of two investigators. RESULTS: The control and asthmatic groups were similar with regard to age, gender, ethnicity, and consumption of tobacco and alcohol. There were major significant differences between the asthmatics and controls with regard to the age of onset of pulmonary and reflux symptoms, prevalence of eating before bedtime, prevalence of reflux symptoms, the quality of reflux symptoms, and the factors that promote and relieve reflux symptoms. Heartburn, regurgitation, and dysphagia were present in 71%, 45%, and 22% of asthmatics compared with 51%, 30%, and 5% of controls (p < 0.001). Three times as many asthmatics as controls had heartburn occurring throughout the day and night (OR; 95% CI: 19.5; 4.5-85.7), and three times as many asthmatics as controls had sudden nocturnal awakening with reflux symptoms and reflux-associated pulmonary symptoms that occurred simultaneously with the reflux symptoms (p < 0.001). Within the asthma group, reflux symptoms were similar in those who required and those who did not require continuous bronchodilator therapy. In these asthmatics, however, those requiring continuous bronchodilator therapy (more severe asthma) developed pulmonary and GER symptoms at a significantly older age. Eating before bedtime was recognized by significantly more asthmatics than controls as a promoter of serious nocturnal GER symptoms (4.5; 2.7-7.7). In terms of patient awareness, one-third of the asthmatics with heartburn had previously considered a relationship between their reflux symptoms and their asthma. CONCLUSION: Compared to nonasthmatics, asthmatics have significantly more frequent and more severe day and night GER symptoms and significantly more of the pulmonary symptoms (nocturnal suffocation, cough, or wheezing) so often attributed to GER. The habit of eating before bedtime appears in asthmatics to have serious and life-threatening consequences.

Asthmatics with gastroesophageal reflux: long term results of a randomized trial of medical and surgical antireflux therapies.

OBJECTIVE: In short term studies, asthma symptoms and pulmonary function have been reported to improve during and after medical treatment or surgical correction of gastroesophageal reflux (GER). In this study, we aimed to determine whether prolonged treatment of GER altered the long term natural history of asthma in asthmatics with GER. METHODS: A total of 62 patients with both GER and asthma entered a randomized study of antireflux treatments for at least 2 yr: 24 controls (antacids as needed); 22 medical (ranitidine 150 mg t.i.d.); and 16 surgical (Nissen fundoplication). Asthma was defined as a previous diagnosis of asthma with discrete attacks of wheezing and 20% reversibility in airway disease. GER was defined as an abnormal ambulatory 24-h esophageal pH test and macroscopic or microscopic evidence of GER disease. Overall clinical status, asthma symptom scores, and pulmonary medication requirements were recorded monthly. Peak expiratory flow rates were recorded up to seven times per day for 1 wk of each month throughout the years. Pulmonary function, esophageal manometry, and endoscopy with biopsy were repeated yearly. RESULTS: The 62 patients were followed for up to 19.1 yr. In the surgical group, but not in the medical or control groups, there was an immediate and sustained reduction in acute nocturnal exacerbations of wheezing, coughing, and dyspnea. By the end of 2 yr, improvement, marked improvement, or cure in the overall asthma status occurred in 74.9% of the surgical group, 9.1% of the medical group and 4.2% of the control group, whereas the overall status worsened in 47.8% of the control group, 36.4% of the medical group, and 12.5% of the surgical group (p < 0.001, surgical vs medical and control). The mean asthma symptom score of the surgical group improved 43%, compared with less than 10% in the medical and control groups (p = 0.0009). As determined by changes in peak expiratory flow rates, there was no statistically significant difference in pulmonary function during the 2-yr period or during regularly scheduled follow-up. There was no difference in medication requirements among the groups. There was no difference between the groups in overall survival. CONCLUSION: In patients with both GER and asthma, antireflux surgery (but not medical therapy with ranitidine 150 mg t.i.d.) has minimal effect on pulmonary function, pulmonary medication requirements, or survival, but significantly improves asthma symptoms and overall clinical status.

Occurrence of an anthropogenic gadolinium anomaly in river and coastal waters of southern France.

This study reports a pronounced positive Gd anomaly in a small river and in the largest French Mediterranean lagoon. Along the studied catchment, this anomaly is also present in the effluents of the municipal sewage treatment plants, suggesting an anthropogenic origin for the Gd excess. The anomaly corresponds to a distinct increase of Gd concentrations (up to 19 pmol/l) in the river and around 5.4 pmol/l in the lagoon. The excess flux of Gd is compatible with the medical use of water soluble Gd complexes as contrasting agent in magnetic resonance imaging.