Flow regulation effects on the hydrogeochemistry of the hyporheic zone in boreal rivers.

River-aquifer interfaces are essential for ecosystem functioning in terms of nutrient exchange and biological habitat, but are greatly threatened world-wide. This study examined geochemical aspects of river-aquifer interaction in one regulated and one unregulated boreal river in Northern Sweden to determine whether the geochemical functioning of the hyporheic zone is affected by hydrological alterations, e.g. regulated river discharge and river-aquifer connectivity. In the unregulated Kalix River, the hyporheic pore water was well-oxygenated with orthogonal fluxes (≈0.6-0.7 m d(-1)) and acted as a sink for Fe, Mn, Al, NH4, and Ca, with fractional losses of 95%, 92%, 45%, 31%, and 15%, respectively. A corresponding elevation in the concentrations of these elements in the hyporheic sediment was observed, with higher saturation indices of Fe-, Mn-, and Al-bearing secondary minerals in hyporheic waters. In the regulated Lule River, hydraulic connectivity at the river-aquifer interface was altered by the presence of a clogging layer (0.04 m d(-1)). In addition, the river discharge oscillated daily, severely reducing exchange flows across the riverbed (<0.01 m d(-1)). As a result, the hyporheic pore water was suboxic, with elevated concentrations of filtered Fe and Mn (fractional increases of ≈3700% and ≈2500%, respectively) and other solutes (NH4, Si, S, Ca). A conceptual model revealed functional differences between geochemical features of the hyporheic zone of regulated and unregulated rivers. Overall, the results showed that hyporheic processes are altered along regulated rivers, with resulting impacts on the geochemistry of riverine, riparian and related marine ecosystems.

Geochemical investigations of sulfide-bearing tailings at Kristineberg, northern Sweden, a few years after remediation.

In the Kristineberg mining area in northern Sweden, massive, pyrite-rich Zn Cu ores are intercalated in ca. 1.9 Ga volcano-sedimentary rocks. Investigations of a tailings impoundment remediated by means of both till coverage and raising the groundwater table have been undertaken. The aim of the study was to characterise the tailings with respect to mineralogy, the chemical composition of both the tailings and the pore water, and to try to identify the significant reactions that may have occurred before and after remediation. It was found that the oxidation front had reached down to depths of between approximately 0.1 and 1.15 m before remediation. The oxidation of sulfides has produced high concentrations of some metals in the pore water; up to 26, 16, 4.1, 2.7 and 82 mg/l have been measured for Al, Mn, Fe and Zn, respectively. Concentrations of metals such as Cd, Co, Cu, Ni and Pb are lower, with average concentrations of 18.4, 83.8, 45, 79.6 and 451 microg/l, respectively. Higher concentrations of major elements such as Ca, Fe, Mn, Mg and S have been measured at depth in pore water than at shallower levels. This is probably caused by flush out of elements after remediation and vertical transport from the upper parts before remediation. The pH is relatively high, approximately 5.5 at most depths in the tailings, except in and around the former oxidation zone where it is lower, and where the highest dissolved concentrations of elements such as As, Cd, Co, Cu, Pb and Zn occur. This is probably due to the release of metals secondarily retained below the oxidation front prior to the remediation. Since the groundwater table is raised, the groundwater reaches the retained metals, which leads to desorption of metals and dissolution of secondary minerals.

The character of the suspended and dissolved phases in the water cover of the flooded mine tailings at Stekenjokk, northern Sweden.

Studies of the suspended and dissolved phases of the pond water, material collected from sediment traps, and surficial sediments/tailings from the flooded tailings pond at Stekenjokk have been performed. The aim was to characterise the material, to study the seasonal variations and to quantify possible resuspension of the tailings in the pond. The element concentrations in the pond at Stekenjokk seem to be largely controlled by processes controlling the precipitation and dissolution of Mn- and Fe-oxyhydroxides in both the water column and in the surficial tailings. Physiochemical processes such as weathering of silicates on the surrounding mountain slopes or dykes contributes both dissolved elements and detrital particles. The suspended phase consists of detrital silicate material as well as Fe- and Mn-oxyhydroxides. The average heavy metal concentrations are high, e.g. 0.42% Cu, 0.15% Pb and 3.1% Zn, which is probably due to sorption onto Fe- and Mn-oxyhydroxides. The suspended phase is richer in Fe, and particularly Mn, during the winter. The suspended phase resembles the material collected in sediment traps and the material in the surficial sediments. The pond water is well mixed during the ice-free season. The dissolved heavy metal concentrations are generally rather low with, e.g. maximum concentrations of 2.03 micrograms/l Cu, 0.23 microgram/l Pb and 268 micrograms/l Zn during the winter. Higher dissolved concentrations are found below the ice-cover above the sediment surface during the winter, caused by diffusion of elements from the sediment-water interface up into the pond water. Most of the metals occurring in the pond are dissolved and resuspension of tailings is negligible.

Analgesia in tonsillectomy: a double-blind study on pre and post-operative treatment with diclofenac.

The efficacy and tolerability of diclofenac suppositories given pre and/or post-operatively were investigated in a randomized double-blind study on 99 patients undergoing tonsillectomy. In one group, 50 mg diclofenac was given 1 h preoperatively, followed by 50 mg directly after the operation. In another group, diclofenac 100 mg was given only immediately post-operatively. A significantly lower consumption of rescue analgesics (paracetamol and/or pethidine) was found in the group treated preoperatively with diclofenac and the average time until first demand of rescue analgesics was significantly longer compared to the group given diclofenac post-operatively only. The tolerance was good and no serious bleeding complications occurred in either group. In the treatment of post-operative pain after tonsillectomy, the combination of pre and post-operative administration of diclofenac suppositories resulted in significantly lower consumption of rescue analgesics and is thus preferable to administration solely post-operatively.

A multicentre study of loratadine, clemastine and placebo in patients with perennial allergic rhinitis.

This multicentre, double-blind, randomized parallel-group study compared 3 weeks' treatment with either loratadine (Clarityn) 10 mg once daily, or clemastine (Tavegyl) 1 mg twice daily, and placebo in outpatients with active perennial allergic rhinitis. 155 patients were evaluated for efficacy and safety. Grading of four nasal and three non-nasal symptoms, rhinoscopy signs, and therapeutic response was performed on treatment days 6, 13, and 20. Patients recorded daily symptoms and possible adverse experiences in a diary, also indicating when symptoms of active rhinitis were relieved. Loratadine and clemastine were statistically significantly superior to placebo throughout the study (P less than 0.05), based on assessment of patients' nasal and eye symptoms, patients' diary scores, rhinoscopy signs of symptoms, and onset of relief. The loratadine group showed a statistically significantly (P less than 0.05) faster onset of relief of symptoms compared with the group treated with clemastine. Concerning nasal stuffiness, loratadine was significantly (P less than 0.05) superior to clemastine after 1 week's treatment. Reports of adverse reactions showed that significantly (P less than 0.05) more patients complained of sedation in the clemastine than in the loratadine group. Regarding other adverse experiences and laboratory tests, the three treatment groups were statistically comparable (P less than 0.05). The study showed that compared with placebo both loratadine and clemastine were effective in relieving nasal and eye symptoms in patients with perennial allergic rhinitis. Loratadine was safe and well tolerated and was significantly less sedative than clemastine; loratadine may therefore possess an advantage in clinical use in the treatment of perennial allergic rhinitis.

Treatment of hay fever with loratadine--a new non-sedating antihistamine.

The efficacy and safety of loratadine, a new orally active specific H1-receptor blocking antihistamine with poor penetration into the CNS, was evaluated in a double blind comparative study. One hundred and seven hay fever patients, sensitive to birch pollen, were randomized into three parallel groups receiving loratadine 40 mg once daily, clemastine 1 mg twice daily, or placebo during the birch pollen season. Both active treatments showed reduction of symptoms in comparison with placebo, but the results were more pronounced with loratadine treatment, which significantly reduced the overall allergic condition as well as all separate allergic rhino-conjunctivitis symptoms except nasal stuffiness. Compared with placebo the sedation rate was significantly higher with clemastine treatment (P less than 0.05) but not with loratadine. Loratadine was thus concluded to be efficacious in hay fever treatment with a sedation rate not differing from placebo.

A comparison of three injectable corticosteroids for the treatment of patients with seasonal hay fever.

Three injectable corticosteroids, betamethasone dipropionate, beta-methasone disodium phosphate and betamethasone acetate, and methylprednisolone acetate, were compared for onset and duration of action in patients with severe seasonal allergic rhinoconjunctivitis. The sixty patients who were entered into the trial had been well-studied in our allergy clinic. They were assigned, on the basis of a random number code, to treatment with one of the corticosteroids. Following a single intramuscular injection with one of the preparations, plasma cortisol and blood glucose concentrations also were compared at days 1, 2--3, 5--7 and 14. All three preparations improved the nasal symptoms. There were no individual differences with respect to onset or to duration of action. However, there were some differences in the effects on endogenous cortisol production and on blood glucose levels. Two of the preparations, betamethasone dipropionate and methylprednisolone acetate, suppressed endogenous cortisol for more than 14 days, while betamethasone phosphate/acetate did not suppress cortisol beyond 12 days. Beta-methasone dipropionate produced a moderate increase in blood glucose concentrations for the first two days after administration; betamethasone phosphate/acetate caused an increase for one day and methylprednisolone acetate had no effect.