Annual pulses of copper-enriched sediment in a North American river downstream of a large lake following the catastrophic failure of a mine tailings storage facility.

Failures of mine tailings storage facilities (TSF) can have profound and long-lasting effects on the downstream receiving environment. Virtually all spills to date have been into river systems without large lakes that may buffer downstream impacts. In August 2014, the failure of the Mount Polley copper (Cu)-gold mine TSF in British Columbia, Canada, released ~25 × 106 m3 of water and solids; globally, this is the second largest TSF spill in history. Over 18 × 106 m3 was delivered to Quesnel Lake, which is ~9 km from the TSF and is the third deepest lake in North America, and a crucial habitat for Pacific salmon and trout populations. We determined the sediment-associated Cu concentrations and fluxes in Quesnel River, downstream of the lake, from August 2014 to February 2021 based on the analysis of >400 samples of sediment, mainly collected using a continuous-flow centrifuge. During each winter since the spill, Cu concentrations in the fluvial sediment in the upper reaches of the river (~35 km from the TSF) were elevated relative to regional background concentrations and samples collected before the spill. Maximum Cu concentrations were ~410 mg kg-1 which exceeds Canadian sediment quality guidelines for the protection of aquatic organisms (197 mg kg-1). Monitoring of Quesnel Lake since the spill shows that these annual pulses in the winter are due to resuspension of unconsolidated tailings and sediments at the bottom of Quesnel Lake, during autumnal lake turnover, which become mixed throughout the water column and subsequently flow into Quesnel River. Results show that while large lakes may buffer downstream aquatic systems from contaminated sediment, they may prolong the environmental impact. These findings are crucial in understanding how lake processes may modify the effects of TSF spills on downstream aquatic systems.

A state-of-the-art model for spatial and stochastic oil spill risk assessment: A case study of oil spill from a shipwreck.

Oil spills are serious environmental issues that potentially can cause adverse effects on marine ecosystems. In some marine areas, like the Baltic Sea, there is a large number of wrecks from the first half of the 20th century, and recent monitoring and field work have revealed release of oil from some of these wrecks. The risk posed by a wreck is governed by its condition, hazardous substances contained in the wreck and the state of the surrounding environment. Therefore, there is a need for a common standard method for estimating the risks associated with different wrecks. In this work a state-of-the-art model is presented for spatial and stochastic risk assessment of oil spills from wrecks, enabling a structured approach to include the complex factors affecting the risk values. A unique feature of this model is its specific focus on uncertainty, facilitating probabilistic calculation of the total risk as the integral expected sum of many possible consequences. A case study is performed in Kattegat at the entrance region to the Baltic Sea to map the risk from a wreck near Sweden. The developed model can be used for oil spill risk assessment in the marine environment all over the world.

Transcriptional Regulation of icaADBC by both IcaR and TcaR in Staphylococcus epidermidis.

S. epidermidis is a primary cause of biofilm-mediated infections in humans due to adherence to foreign bodies. A major staphylococcal biofilm accumulation molecule is polysaccharide intracellular adhesin (PIA), which is synthesized by enzymes encoded by the icaADBC operon. Expression of PIA is highly variable among clinical isolates, suggesting that PIA expression levels are selected in certain niches of the host. However, the mechanisms that govern enhanced icaADBC transcription and PIA synthesis in these isolates are not known. We hypothesized that enhanced PIA synthesis in these isolates was due to function of IcaR and/or TcaR. Thus, two S. epidermidis isolates (1457 and CSF41498) with different icaADBC transcription and PIA expression levels were studied. Constitutive expression of both icaR and tcaR demonstrated that both repressors are functional and can completely repress icaADBC transcription in both 1457 and CSF41498. However, it was found that IcaR was the primary repressor for CSF41498 and TcaR was the primary repressor for 1457. Further analysis demonstrated that icaR transcription was repressed in 1457 in comparison to CSF41498, suggesting that TcaR functions as a repressor only in the absence of IcaR. Indeed, DNase I footprinting suggests IcaR and TcaR may bind to the same site within the icaR-icaA intergenic region. Lastly, we found mutants expressing variable amounts of PIA could rapidly be selected from both 1457 and CSF41498. Collectively, we propose that strains producing enhanced PIA synthesis are selected within certain niches of the host through several genetic mechanisms that function to repress icaR transcription, thus increasing PIA synthesis.IMPORTANCEStaphylococcus epidermidis is a commensal bacterium that resides on our skin. As a commensal, it protects humans from bacterial pathogens through a variety of mechanisms. However, it is also a significant cause of biofilm infections due to its ability to bind to plastic. Polysaccharide intercellular adhesin is a significant component of biofilm, and we propose that the expression of this polysaccharide is beneficial in certain host niches, such as providing extra strength when the bacterium is colonizing the lumen of a catheter, and detrimental in others, such as colonization of the skin surface. We show here that fine-tuning of icaADBC transcription, and thus PIA synthesis, is mediated via two transcriptional repressors, IcaR and TcaR.

Early gain in pain reduction and hip function, but more complications following the direct anterior minimally invasive approach for total hip arthroplasty: a randomized trial of 100 patients with 5 years of follow up.

Background and purpose - The minimally invasive direct anterior (DA) approach for total hip arthroplasty (THA) is supposed to reduce surgical tissue trauma. We hypothesized that patients operated with the DA technique would have less postoperative pain and better hip function compared with a group operated with a conventional direct lateral (DL) approach. Patients and methods - 100 patients with hip osteoarthritis scheduled for THA were equally randomized to surgery through either DA or DL. Pain was assessed on a VAS scale, hip function with TUG, 10mWT, HHS, and quality of life with EQ-5D. Patients were followed up after the first 3 days, 8 weeks, and at 1 and 5 years postoperatively. Results - The DA group registered less pain with activity on the second day (VAS 42 vs. 55), performed TUG 6 seconds faster on the third day and had 8 points higher HHS and higher EQ-5D index (0.86 vs 0.78) at 8 weeks; all differences were statistically significant. No clinically relevant differences between groups in pain, hip function, or quality of life were seen at 1 or 5 years. 7 surgical approach related complications appeared in the DA group, none in the DL. Interpretation - The results indicate that the presumably less traumatic approach results in reduced immediate postoperative pain and better hip function and higher quality of life in the early postoperative period. However, this positive effect is not seen at later time points. Instead, complications appear to be over-represented, thus questioning the use of the method.

Copper release rate needed to inhibit fouling on the west coast of Sweden and control of copper release using zinc oxide.

How zinc oxide influences copper release has been tested and the lowest release rate of copper from various combinations of copper and zinc in a paint matrix evaluated, whilst still deterring macrofouling, including barnacles and bryozoans. Copper (I) oxide was added to a generic AF paint in 0, 8.5, 11.7 or 16.3 wt% copper oxide in combination with 0, 10 or 20 wt% zinc oxide and applied on PMMA panels. The results show that zinc influences the release rate of copper. When 10 and 20 wt% zinc was added, the total amount of copper released significantly increased by on average 32 and 47% respectively. All treatments that included copper were successful in deterring macrofouling, including the treatment with the lowest average Cu release rate, ie 4.68 µg cm-2 day-1.

In situ release rates of Cu and Zn from commercial antifouling paints at different salinities.

Antifouling paints are environmentally risk assessed based on their biocidal release rates to the water phase. In situ release rates of copper (Cu) and zinc (Zn) were derived for five commercial paints in two recreational marinas with different salinities (5 and 14 PSU) using an X-Ray Fluorescence spectrometer (XRF). Salinity was found to significantly affect the Cu release, with twice the amount of Cu released at the higher salinity, while its influence on the Zn release was paint-specific. Site-specific release rates for water bodies with salinity gradients, e.g. the Baltic Sea, are therefore necessary for more realistic risk assessments of antifouling paints. Furthermore, the in situ release rates were up to 8 times higher than those generated using standardized laboratory or calculation methods. The environmental risk assessment repeated with the field release rates concludes that it is questionable whether the studied products should be allowed on the Swedish market.

Expert elicitation for deriving input data for probabilistic risk assessment of shipwrecks.

The necessity of having a process in place for adequate risk assessment of shipwrecks that pose a threat to the marine environment is today internationally acknowledged. However, retrieving the desired data for such a risk assessment can prove challenging. One means of addressing this problem is to make use of experts' knowledge and experience. The purpose of this paper is therefore to present and analyse data for risk assessment of shipwrecks derived by expert elicitation. The main outcome is the experts' estimations of (i) the generic probability of an opening in a shipwreck due to the occurrence of a number of activities and (ii) estimations of the degree to which site-specific and wreck-specific indicators affect the probability of opening. Results show that the derived information is applicable in probabilistic shipwreck risk assessment and that the VRAKA framework now contains needed information for integrating generic and site-specific information using Bayesian updating.

Induced tolerance in situ to chronically PAH exposed ammonium oxidizers.

Sediment was sampled in the vicinity of a long-term source of Polycyclic Aromatic Hydrocarbons (PAHs) to evaluate whether tolerance can be induced in situ. Total PAH concentrations as well as the bioavailable PAHs were measured, and for nine PAHs the pore water concentration could be calculated. An induced tolerance in the ammonium oxidizing community was detected at the site with highest PAH concentration and tolerance was strongest, although not significantly, correlated to bioavailable alkylated PAHs. In addition, the tolerant microbial community showed a significant lower baseline capability for nitrification with an on average 35% reduction compared to the other sites. Meiofaunal community structure differed between all sites, and the difference was significantly correlated to bioavailable alkylated PAHs and PAH31 concentrations. The results suggest that in order to judge magnitude of long-term effects, the bioavailable fraction is to be preferred, and when possible as estimation of the freely dissolved concentration.

Validation of reoperations due to infection in the Swedish Hip Arthroplasty Register.

BACKGROUND: Complete or almost complete recording of reoperations is essential to enable a correct interpretation of data in arthroplasty registers. The completeness of recordings due to infection is unknown in the Swedish Hip Arthroplasty Register (SHAR). We therefore used a combination of data from the Swedish Prescribed Drug Register (SPDR) and studies of medical records to validate the data of reoperations due to infection in the SHAR. METHODS: All patients registered for a primary Total Hip Replacement (THR) in the SHAR between July 1, 2005 and December 31, 2008 were selected for the study (45,531 patients with 49,219 THRs) and were matched with the SPDR. All patients with a minimum of 4 weeks of continuous outpatient antibiotic treatment within 2 years after their primary THR (1,989 patients, with 2,219 THRs) were selected for a medical records review to find the THRs reoperated due to infection. RESULTS: 599 (1.3%) of the THRs had been reoperated within 2 years after the index operation and in 47.4% of these the prosthesis had been revised or extracted. 400 of the THRs were registered for a reoperation in the SHAR resulting in a completeness of 67%. CONCLUSIONS: The completeness of registration due to early infection after THR questions whether the SHAR reoperation data can be used in order to evaluate changes in postoperative infection rates.

A fault tree model to assess probability of contaminant discharge from shipwrecks.

Shipwrecks on the sea floor around the world may contain hazardous substances that can cause harm to the marine environment. Today there are no comprehensive methods for environmental risk assessment of shipwrecks, and thus there is poor support for decision-making on prioritization of mitigation measures. The purpose of this study was to develop a tool for quantitative risk estimation of potentially polluting shipwrecks, and in particular an estimation of the annual probability of hazardous substance discharge. The assessment of the probability of discharge is performed using fault tree analysis, facilitating quantification of the probability with respect to a set of identified hazardous events. This approach enables a structured assessment providing transparent uncertainty and sensitivity analyses. The model facilitates quantification of risk, quantification of the uncertainties in the risk calculation and identification of parameters to be investigated further in order to obtain a more reliable risk calculation.

Patient-reported outcome is influenced by surgical approach in total hip replacement: a study of the Swedish Hip Arthroplasty Register including 42,233 patients.

The effects of surgical approach in total hip replacement on health-related quality of life and long-term pain and satisfaction are unknown. From the Swedish Hip Arthroplasty Register, we extracted data on all patients that had received a total hip replacement for osteoarthritis through either the posterior or the direct lateral approach, with complete pre- and one-year post-operative Patient Reported Outcome Measures (PROMs). A total of 42 233 patients met the inclusion criteria and of these 4962 also had complete six-year PROM data. The posterior approach resulted in an increased mean satisfaction score of 15 (sd 19) vs. 18 (sd 22) (p < 0.001) compared with the direct lateral approach. The mean pain score was 13 (sd 17) vs. 15 (sd 19) (p < 0.001) and the proportion of patients with no or minimal pain was 78% vs. 74% (p < 0.001) favouring the posterior approach. The patients in the posterior approach group reported a superior mean EQ-5D index of 0.79 (sd 0.23) vs. 0.77 (sd 0.24) (p < 0.001) and mean EQ score of 76 (sd 20) vs. 75 (sd 20) (p < 0.001). All observed differences between the groups persisted after six years follow-up. Although PROMs after THR in general are very good regardless of surgical approach, the results indicate that some patients operated by the direct lateral approach report an inferior outcome compared with the posterior approach. The large number of procedures and the seemingly sustained differences make it likely these findings are clinically relevant.

Arginine deiminase in Staphylococcus epidermidis functions to augment biofilm maturation through pH homeostasis.

Allelic replacement mutants were constructed within arginine deiminase (arcA1 and arcA2) to assess the function of the arginine deiminase (ADI) pathway in organic acid resistance and biofilm formation of Staphylococcus epidermidis 1457. A growth-dependent acidification assay (pH ∼5.0 to ∼5.2) determined that strain 1457 devoid of arginine deiminase activity (1457 ΔADI) was significantly less viable than the wild type following depletion of glucose and in the presence of arginine. However, no difference in viability was noted for individual 1457 ΔarcA1 (native) or ΔarcA2 (arginine catabolic mobile element [ACME]-derived) mutants, suggesting that the native and ACME-derived ADIs are compensatory in S. epidermidis. Furthermore, flow cytometry and electron paramagnetic resonance spectroscopy results suggested that organic acid stress resulted in oxidative stress that could be partially rescued by the iron chelator dipyridyl. Collectively, these results suggest that formation of hydroxyl radicals is partially responsible for cell death via organic acid stress and that ADI-derived ammonia functions to counteract this acid stress. Finally, static biofilm assays determined that viability, ammonia synthesis, and pH were reduced in strain 1457 ΔADI following 120 h of growth in comparison to strain 1457 and the arcA1 and arcA2 single mutants. It is hypothesized that ammonia synthesis via the ADI pathway is important to reduce pH stress in specific microniches that contain high concentrations of organic acids.

PAH effects on meio- and microbial benthic communities strongly depend on bioavailability.

The effects of anthropogenic pollutants in dissimilar habitats can vary depending on differences in bioavailability. The factors determining bioavailability are not yet fully understood. This study was performed to evaluate whether analysis of total PAH concentrations in sediments is a satisfactory measurement to indicate environmental effects or if bioavailability is needed to be taken into account. We have here performed a 60-day experiment, where nominal PAH concentrations of 1,300 µg/kg sediment were added to three different marine sediments. Meiofaunal and microbial communities were analyzed for alterations in community response at 30 and 60 days. Results showed that bioavailability of PAHs varied between the three different sediments. Nonetheless, the petroleum addition gave rise to significant negative effects on all three sediments at both time points. The two direct measurements of toxicity on the microbial community, potential nitrification and denitrification, displayed a lower effect of the PAH addition in the muddy sediment at both time points, compared to the other two sediment types. No effects were seen in the analysis of meiofaunal community structure. Measurements of PAH bioavailability in the three sediment types concurred with the results from the microbial community, revealing a lower bioavailability in the muddy sediment compared to the other two sediment types, 34% compared to sandy and 18% compared to organic at day 0. At day 60 it was 61% lower compared to sandy and 20% lower compared to organic. The negative effects of the PAH addition on the microbial nitrogen cycle were in six out of eight cases best correlated to the amount of alkylated bioavailable PAH in the sediments, and thus microbial nitrogen cycle is a possible good indicator for assessing PAH-induced stress. The results presented here have implications for risk analysis studies of petroleum-contaminated marine sediments; consequently, sediment characteristics and its effects on bioavailability are important to include. In addition, these results add to the understanding that bioavailability measurements of PAHs are a more correct assessment compared to measurements of total PAH concentrations, and need to be included when estimating effects of PAHs in marine benthic communities.

Evaluating the needs of risk assessment methods of potentially polluting shipwrecks.

Shipwrecks deteriorate and the probability of a release of oil increases with time on the sea floor. The potential leakage is a risk to the marine environment and may also have social and economic consequences. The purpose of this study was to evaluate existing methods for risk assessment of shipwrecks and suggest a generic risk assessment framework. A risk assessment is necessary for providing decision support on remediation actions and thus enabling an efficient use of available resources. Existing risk assessment methods aimed for assessing shipwrecks were evaluated by comparison to relevant parts of an international standard on risk management. The comparison showed that existing methods lack several key components of risk assessment procedures. None of the evaluated methods provide a comprehensive risk assessment for potentially polluting shipwrecks and few take into account uncertainty and sensitivity. Furthermore, there is a need to develop risk assessment methods considering long-term effects of continuous release of oil into the marine environment. Finally, a generic comprehensive framework for risk assessment of shipwrecks is suggested.

Meiofaunal and bacterial community response to diesel additions in a microcosm study.

Effects of low PAH-containing diesel were studied in a 60-day microcosm experiment at PAH concentrations 130, 1300 and 13,000µg/kg sediment. Nutrient fluxes, potential nitrification and meiofaunal community composition were analysed at three time points. Changed ∑NOx-fluxes indicated reduced sediment nitrification in Medium and High with time, in agreement with lowered potential nitrification rates in all treatments. Reduction in silicate and phosphate fluxes over time suggested severe effects on activity of meiofauna. Reduced activity increased the anoxic sediment layer, which could have contributed to the changed ∑NOx-fluxes. There were significant differences in meiofaunal community composition after 30 and 60days in Medium and High. Changes were due to increasing numbers of harpacticoids and the foraminiferan group Rotaliina, as well as decreasing numbers of Nematodes and the foraminiferan group Reophax. In spite of the low PAH-level, small additions of this diesel can still have pronounced effects on meiofaunal and bacterial communities.

Adverse reaction to metal release from a modular metal-on-polyethylene hip prosthesis.

A 70-year-old man with an uncemented metal-on-polyethylene total hip prosthesis underwent revision arthroplasty 33 months later because of pain, swelling and recurrent dislocation. There appeared to be corrosion and metal release from the prosthetic head, resulting in pseudotumour formation and severe local soft-tissue destruction. The corrosion occurred at the junction between the titanium-molybdenum-zirconium-iron taper and the cobalt-chrome-molybdenum head, but the mechanism was unproven.

Oxygen-depleted surfaces: a new antifouling technology.

A novel, non-toxic strategy to combat marine biofouling is presented. The technology is paint with additions of up to 43% of industrial protein. Through microbial degradation of the protein component, an oxygen-depleted layer rapidly forms in a 0.2 mm layer close to the paint surface. With the present paint formulations, a stable, O(2)-depleted layer can persist for 16 weeks. Barnacle larvae (cyprids) did not settle on panels where oxygen saturation was <20%, and cyprids were killed when exposed to O(2)-free water for more than 1 h. It is also shown that the O(2)-depleted layer will rapidly reform (within 15 min) after exposure to turbulent flow. Field exposure of panels for 16 weeks showed that paint with protein reduced fouling by barnacles and bryozoans by 80% and close to 100%, respectively. The results suggest that this novel technology may be developed into a non-toxic alternative to copper-based antifouling paints, especially for pleasure boats in sensitive environments. There is clearly potential for further development of the paint formulation, and a full-scale test on a boat-hull suggested that service-life under realistic operations needs to be improved.

Decreased IgG production but increased MIP-1beta expression in collagen-induced arthritis in C-C chemokine receptor 5-deficient mice.

Collagen-induced arthritis (CIA) is a widely used model of human rheumatoid arthritis (RA) characterized by chronic inflammation of the synovial joints. The pathogenesis of RA and CIA has not been completely defined, but both involve the recruitment of leukocytes and lymphocytes to the joints and Th1-type cell mediated autoimmune responses. The C-C chemokine receptor 5 (CCR5) is preferentially expressed on Th1 cells and has been strongly implicated in inflammatory process through trafficking of leukocytes and lymphocytes into the sites of inflammation. We investigated the role of the CCR5 in CIA using CCR5 knockout mice (CCR5-/-) in which we analyzed the consequences of CCR5 deficiency for the immune response and inflammation. We found that CCR5-/- mice showed a significant reduction in the incidence of CIA after collagen II (CII)-immunization as compared to wild-type (CCR5+/+) mice. The reduced incidence seen in CCR5-/- mice was associated with these animals having significantly lower IgG levels, especially IgG2a and IgG2b antibodies against CII, as well as an obviously augmented IL-10 production in splenocytes. Overproduction of MIP-1beta in CCR5-deficient mice after CII-immunization may contribute partially to the occurrence of arthritis.

Effects of heavy drinking, binge drinking, and family history of alcoholism on regional brain metabolites.

BACKGROUND: The main goals are to investigate the effects of chronic active heavy drinking on N-acetylaspartate (NAA) and other metabolites throughout the brain and to determine whether they are affected by family history (FH) of alcoholism and long-term drinking pattern. METHODS: Forty-six chronic heavy drinkers (HD) and 52 light drinkers (LD) were recruited from the community and compared on measures of regional brain structure using magnetic resonance imaging and measures of common brain metabolites in gray matter (GM) and white matter (WM) of the major lobes, subcortical nuclei, brainstem, and cerebellum using short-echo time magnetic resonance spectroscopic imaging. Regional atrophy-corrected levels of NAA, myoinositol (mI), creatine, and choline-containing metabolites were compared as a function of group, FH of alcoholism, and bingeing. RESULTS: Frontal WM NAA was lower in FH-negative HD than FH-positive HD and tended to be lower in women than men. Creatine-containing metabolites in parietal GM were higher in HD than LD. FH-negative compared with FH-positive HD also had more mI in the brainstem and tended to have lower NAA and more mI in frontal GM. Although parietal GM NAA was not significantly lower in HD than LD, it was lower in non-binge drinkers than bingers. Frontal WM NAA was lower in HD than LD, with the difference driven by a small number of women, FH-negative HD, and older age. Lower frontal WM NAA in HD was associated with lower executive and working memory functions and with lower P3b amplitudes at frontal electrodes. CONCLUSIONS: Community-dwelling HD who are not in alcoholism treatment have brain metabolite changes that are associated with lower brain function and are likely of behavioral significance. Age, FH, and binge drinking modulate brain metabolite abnormalities. Metabolite changes in active HD are less pronounced and present with a different spatial and metabolite pattern than reported in abstinent alcoholics.

Galanin in adjuvant arthritis in the rat.

OBJECTIVE: To study the concentration changes of galanin in the ankles and spinal cord and to detect the distribution of galanin in different tissues in arthritic rats. METHODS: Adjuvant arthritis was induced by intradermal injection of Mycobacterium butyricum in Freund's incomplete adjuvant at the base of the tail. The concentrations of galanin were measured by radioimmunoassay (RIA) and the distributions of galanin were detected by immunoelectron microscopy (iEM). RESULTS: Measurements were taken on Day 28 after injection. RIA results showed that the concentration of galanin was significantly lower in the ankles and spinal cords of rats with adjuvant arthritis compared to controls. Our iEM results showed a heterogeneous distribution of galanin labelling in different cells and tissue compartments. In arthritic rats, we observed decreased galanin labelling in the sciatic nerve and in macrophage-like cells in the synovial membrane and increased labelling in monocyte lineage cells, polymorphonucleated lineage cells in the bone marrow, fibroblasts in the periosteum, osteoclasts and osteocytes, and lower labelling in osteoblasts compared to controls. CONCLUSION: Galanin is involved in the response to inflammation in adjuvant arthritis and might play a role in the regulation of inflammation and nociception. These findings are in accordance with a biological role of galanin in the development of inflammatory arthritis.