Microsurgical limb reconstruction in the non-concordant patient.

Substance misuse is common in patients undergoing limb reconstruction secondary to open fractures and fracture related infection. This group risk breaching the social contract with their treating team through reduced engagement with perioperative care. Potential problems include limited social support, intravenous access, analgesia and withdrawal. These factors may negatively influence the range of treatments offered to this group. We aimed to establish the prevalence and outcomes of the problematically non-concordant cohort in our limb reconstruction population, who we aim to treat equitably even where non-concordance is suspected pre-operatively. A retrospective study was performed using our prospectively collected free flap limb reconstruction database from December 2021-October 2023. Patient electronic health records were reviewed for demographics, perioperative details and outcomes. Eighty patients were identified, with 8 identified as problematically non-concordant (10%). All patients had a background of substance abuse; smoking (100%), alcohol (75%), IVDU (63%). Pre-operative non-concordance included absconding (43%), staff abuse (57%) and refusal of care (57%). Post-operative non-concordance included smoking (75%), mobilisation against instructions (75%), absconding (63%). No patients had free flap failure. Inpatient stay varied from 8-83 days, average 28.50% of patients did not attend follow-up. The expanding horizon of microsurgery means complex reconstruction is offered to a greater range of patients. Surgical teams should ensure that this service is offered equitably, individualising treatment plans to achieve the best outcomes. Risk of non-concordance is usually evident pre-operatively. We advise early involvement of substance misuse teams, discharge support and an understanding team to achieve good outcomes.

Reference interval for the C-ACT activated clotting time test in healthy dogs using a water bath and manual assessment of clot formation.

AIMS: To establish a reference range for the canine C-ACT activated clotting time (ACT) test using a water bath and visual clot assessment technique. METHODS: Healthy, privately owned dogs (n = 48) were prospectively recruited to the study. Blood samples were collected via direct jugular venipuncture for complete blood count, serum biochemistry analysis and measurement of prothrombin time (PT) and activated partial thromboplastin time (aPTT). Five animals with major abnormalities or who became agitated during phlebotomy were excluded. For the 43 remaining animals, 2 mL of blood was collected via the cephalic vein and added directly to a C-ACT tube that was shaken vigorously before being placed in a water bath at 37°C. Tubes were visually assessed for clot formation and C-ACT was recorded in seconds when the magnet within the tube lodged in the clot. RESULTS: The nonparametric reference interval (capturing the central 95% of the data) was 50-80 seconds, with a 90% CI for the lower limit of 50-55 seconds and a 90% CI for the upper limit of 75-80 seconds. The C-ACT ACT test had a positive correlation with aPTT (0.42; 95% CI = 0.13-0.64). There was no evidence of a correlation between C-ACT ACT and age, weight, PT, haematocrit, white blood cell count, platelet count or total protein. CONCLUSIONS AND CLINICAL RELEVANCE: The results of this study suggest that the normal reference interval for ACT in dogs using C-ACT tubes in a 37°C water bath is 50-80 seconds. Care should be taken extrapolating the results of this study to the general population, as the smaller study design had less control for confounders than a larger study. However, when using the described analytical methods, C-ACT tube ACT test results >80 seconds should be considered prolonged in dogs and should prompt further investigation.

Elective cricothyrotomy in a dog with transient laryngeal paralysis secondary to Australian paralysis tick (Ixodes holocyclus) envenomation.

The tube cricothyrotomy (CTT) has recently been introduced to small animal medicine as a viable surgical airway access procedure; however, there are no reports documenting its clinical use. The author's objective is to describe the clinical application, complications, and management of an elective CTT in a dog. Furthermore, the characteristics of CTT that may be clinically advantageous over temporary tube tracheostomy (TT) will be discussed. A 2-year-old female spayed German shepherd dog required mechanical ventilation (MV) due to unsustainable work of breathing as a result of tick paralysis and aspiration pneumonia. After successful weaning from MV, the dog was diagnosed with laryngeal paralysis. A surgical airway was performed using CTT to allow extubation and patient management whilst conscious. Complications included frequent tube suctioning due to accumulation of airway secretions in the tube and a single dislodgement event. The dog made an uneventful recovery with complete stoma healing by the second intention within 15 days. To the authors' knowledge, this is the first clinical report of an elective CTT performed to successfully manage upper airway obstruction in the dog. Its efficacy, clinical management and patient outcome are described.

Bone mineral density in high-level endurance runners: Part B-genotype-dependent characteristics.

PURPOSE: Inter-individual variability in bone mineral density (BMD) exists within and between endurance runners and non-athletes, probably in part due to differing genetic profiles. Certainty is lacking, however, regarding which genetic variants may contribute to BMD in endurance runners and if specific genotypes are sensitive to environmental factors, such as mechanical loading via training. METHOD: Ten single-nucleotide polymorphisms (SNPs) were identified from previous genome-wide and/or candidate gene association studies that have a functional effect on bone physiology. The aims of this study were to investigate (1) associations between genotype at those 10 SNPs and bone phenotypes in high-level endurance runners, and (2) interactions between genotype and athlete status on bone phenotypes. RESULTS: Female runners with P2RX7 rs3751143 AA genotype had 4% higher total-body BMD and 5% higher leg BMD than AC + CC genotypes. Male runners with WNT16 rs3801387 AA genotype had 14% lower lumbar spine BMD than AA genotype non-athletes, whilst AG + GG genotype runners also had 5% higher leg BMD than AG + GG genotype non-athletes. CONCLUSION: We report novel associations between P2RX7 rs3751143 genotype and BMD in female runners, whilst differences in BMD between male runners and non-athletes with the same WNT16 rs3801387 genotype existed, highlighting a potential genetic interaction with factors common in endurance runners, such as high levels of mechanical loading. These findings contribute to our knowledge of the genetic associations with BMD and improve our understanding of why some runners have lower BMD than others.

Does Trans-radial Longitudinal Compression Influence Myoelectric Control?

BACKGROUND: Existing trans-radial prosthetic socket designs are not optimised to facilitate reliable myoelectric control. Many socket designs pre-date the introduction of myoelectric devices. However, socket designs featuring improved biomechanical stability, notably longitudinal compression sockets, have emerged in more recent years. Neither the subsequent effects, if any, of stabilising the limb on myoelectric control nor in which arrangement to apply the compression have been reported. METHODOLOGY: Twelve able-bodied participants completed two tasks whilst wearing a longitudinal compression socket simulator in three different configurations: 1) compressed, where the compression strut was placed on top of the muscle of interest, 2) relief, where the compression struts were placed either side of the muscle being recorded and 3) uncompressed, with no external compression. The tasks were 1) a single-channel myoelectric target tracking exercise, followed by 2), a high-intensity grasping task. The wearers' accuracy during the tracking task, the pressure at opposing sides of the simulator during contractions and the rate at which the limb fatigued were observed. FINDINGS: No significant difference between the tracking-task accuracy scores or rate of fatigue was observed for the different compression configurations. Pressure recordings from the compressed configuration showed that pressure was maintained at opposing sides of the simulator during muscle contractions. CONCLUSION: Longitudinal compression does not inhibit single-channel EMG control, nor improve fatigue performance. Longitudinal compression sockets have the potential to improve the reliability of multi-channel EMG control due to the maintenance of pressure during muscle contractions.

Outcome Measures Used to Assess Hand Activity in Amputee and Intact Populations: a Literature Review.

BACKGROUND: The human hand is critical in assisting with activities of daily living (ADL). Amputation of the hand can affect a person physically, socially and psychologically. Knowledge of outcome measures used to assess upper limb activity of intact and amputee populations may aid in guiding research to develop applicable measurement tools specific to the amputee population. Tools could aid developments in prosthetic design and prescription, which benefit both users and healthcare researchers. OBJECTIVES: This literature review examined outcome measurement tools used with non-amputee and amputee populations to assess hand activity. The objectives were to identify which characteristics of hand activity are captured by currently available measurement tools. METHODOLOGY: Searches were conducted using PubMed, Cochrane and ProQuest for studies investigating hand activity for amputee and non-amputee populations. A total of 15 studies were included. PRISMA guidelines were used to assist with study selection. Data extraction and narrative synthesis were carried out. FINDINGS: A total of 32 outcome measures were found. Frequently used tools were: Box and Block Test, Swedish Disabilities of the Arm Shoulder and Hand Questionnaire, and range of motion. Studies employed a combination of 2 to 12 tools. Themes extracted were: importance of function and quality of life, the need for realistic tasks, and the need for outcome measures specific of the population. CONCLUSION: There is a gap in research surrounding outcome measurement tools used to assess hand activity in the amputee population. A combination of outcome measures are required to obtain insight into the hand activities of intact and amputee populations. Function and quality of life are important aspects to consider when describing hand activity.

BSHI/BTS guidance on crossmatching before deceased donor kidney transplantation.

All UK H&I laboratories and transplant units operate under a single national kidney offering policy, but there have been variations in approach regarding when to undertake the pre-transplant crossmatch test. In order to minimize cold ischaemia times for deceased donor kidney transplantation we sought to find ways to be able to report a crossmatch result as early as possible in the donation process. A panel of experts in transplant surgery, nephrology, specialist nursing in organ donation and H&I (all relevant UK laboratories represented) assessed evidence and opinion concerning five factors that relate to the effectiveness of the crossmatch process, as follows: when the result should be ready for reporting; what level of donor HLA typing is needed; crossmatch sample type and availability; fairness and equity; risks and patient safety. Guidelines aimed at improving practice based on these issues are presented, and we expect that following these will allow H&I laboratories to contribute to reducing CIT in deceased donor kidney transplantation.

Bone mineral density in high-level endurance runners: part A-site-specific characteristics.

PURPOSE: Physical activity, particularly mechanical loading that results in high-peak force and is multi-directional in nature, increases bone mineral density (BMD). In athletes such as endurance runners, this association is more complex due to other factors such as low energy availability and menstrual dysfunction. Moreover, many studies of athletes have used small sample sizes and/or athletes of varying abilities, making it difficult to compare BMD phenotypes between studies. METHOD: The primary aim of this study was to compare dual-energy X-ray absorptiometry (DXA) derived bone phenotypes of high-level endurance runners (58 women and 45 men) to non-athletes (60 women and 52 men). Our secondary aim was to examine the influence of menstrual irregularities and sporting activity completed during childhood on these bone phenotypes. RESULTS: Female runners had higher leg (4%) but not total body or lumbar spine BMD than female non-athletes. Male runners had lower lumbar spine (9%) but similar total and leg BMD compared to male non-athletes, suggesting that high levels of site-specific mechanical loading was advantageous for BMD in females only and a potential presence of reduced energy availability in males. Menstrual status in females and the number of sports completed in childhood in males and females had no influence on bone phenotypes within the runners. CONCLUSION: Given the large variability in BMD in runners and non-athletes, other factors such as variation in genetic make-up alongside mechanical loading probably influence BMD across the adult lifespan.

Determinants of lost theatre capacity.

Secondary care Trusts nationwide are continuing to fail the 18-week referral to treatment (RTT) target despite several initiatives to improve theatre efficiency (2018 NHS England review). A limitation of wasted theatre productivity is required to alleviate pressures on waiting lists. Productivity, which is a measure of treatment time as a proportion of available/allocated time, takes into consideration variations in operator performance, early (non-funded) theatre starts, and over-run, and its analysis enables the determination of theatre downtime and lost theatre capacity. We monitored productivity over a 12-week period and performed downtime analysis as reported in the NHS Improvement national audit (NHSI). Results showed a marked but predictable variation in productivity connected to turnaround and session list scheduling. Productivity and booking efficiency correlated uniformly (Pearson's r=0.82). Theatre downtime was analysed with respect to three components defined in the NHSI national audit: late starts, early finish, and turnaround. We found that lost theatre time was predominantly due to early finishes; late starts were infrequent. Transport time correlated unfavourably with productivity (Pearson's r=-0.29, p=0.037) and over-run (r=0.44), and prolonged transport times were shorter when surgery was performed in a dedicated day surgery unit. Calculating the mean transport times for lists with high compared with low productivity helped us set a benchmark for patient transport times for future audit.

Rural health issues in rheumatology: a review.

PURPOSE OF REVIEW: Early access to rheumatology is imperative to achieve appropriate outcomes in rheumatologic diseases. But there seems to be a significant gap and disparity in the access to rheumatology care between urban and rural areas. This review was undertaken to analyze this issue. RECENT FINDINGS: A significant delay in diagnosis of rheumatic disorder has been correlated to the travel distance to rheumatologist. It is also clear that currently, a significant rheumatology workforce shortage exists and is projected to worsen significantly, thereby making this gap and disparity much bigger. SUMMARY: The scope of this gap and disparity in rheumatology care for rural patients remains incompletely defined and quantified. It is felt to be a significant issue and it is important to invest resources to obtain information about its scope. In addition, a number of solutions already exist which can be implemented using current network and infrastructure. These include relatively low-cost interventions such as patient navigator, remote rheumatology experts and if possible tele-rheumatology. These interventions can assist temporarily but a major improvement will require policy change at federal and state government level as well as involvement, buy-in, and incentivization of the providers and health networks providing rheumatology care.

AAV9-Stathmin1 gene delivery improves disease phenotype in an intermediate mouse model of spinal muscular atrophy.

Spinal muscular atrophy (SMA) is a devastating infantile genetic disorder caused by the loss of survival motor neuron (SMN) protein that leads to premature death due to loss of motor neurons and muscle atrophy. The approval of an antisense oligonucleotide therapy for SMA was an important milestone in SMA research; however, effective next-generation therapeutics will likely require combinatorial SMN-dependent therapeutics and SMN-independent disease modifiers. A recent cross-disease transcriptomic analysis identified Stathmin-1 (STMN1), a tubulin-depolymerizing protein, as a potential disease modifier across different motor neuron diseases, including SMA. Here, we investigated whether viral-based delivery of STMN1 decreased disease severity in a well-characterized SMA mouse model. Intracerebroventricular delivery of scAAV9-STMN1 in SMA mice at P2 significantly increased survival and weight gain compared to untreated SMA mice without elevating Smn levels. scAAV9-STMN1 improved important hallmarks of disease, including motor function, NMJ pathology and motor neuron cell preservation. Furthermore, scAAV9-STMN1 treatment restored microtubule networks and tubulin expression without affecting tubulin stability. Our results show that scAAV9-STMN1 treatment improves SMA pathology possibly by increasing microtubule turnover leading to restored levels of stable microtubules. Overall, these data demonstrate that STMN1 can significantly reduce the SMA phenotype independent of restoring SMN protein and highlight the importance of developing SMN-independent therapeutics for the treatment of SMA.

Psychological intervention (ConquerFear) for treating fear of cancer recurrence: mediators and moderators of treatment efficacy.

PURPOSE: ConquerFear is an efficacious intervention for fear of cancer recurrence (FCR) that demonstrated greater improvements than an attention control (relaxation training) in a randomized controlled trial. This study aimed to determine mediators and moderators of the relative treatment efficacy of ConquerFear versus relaxation. METHODS: One hundred and fifty-two cancer survivors completed 5 therapy sessions and outcome measures before and after intervention and at 6 months' follow-up. We examined theoretically relevant variables as potential mediators and moderators of treatment outcome. We hypothesized that metacognitions and intrusions would moderate and mediate the relationship between treatment group and FCR level at follow-up. RESULTS: Only total FCR score at baseline moderated treatment outcome. Participants with higher levels of FCR benefited more from ConquerFear relative to relaxation on the primary outcome. Changes in metacognitions and intrusive thoughts about cancer during treatment partially mediated the relationship between treatment group and FCR. CONCLUSIONS: These results show that ConquerFear is relatively more effective than relaxation for those with overall higher levels of FCR. The mediation analyses confirmed that the most likely mechanism of treatment efficacy was the reduction in unhelpful metacognitions and intrusive thoughts during treatment, consistent with the theoretical framework underpinning ConquerFear. IMPLICATIONS FOR CANCER SURVIVORS: ConquerFear is a brief, effective treatment for FCR in cancer survivors with early-stage disease. The treatment works by reducing intrusive thoughts about cancer and changing beliefs about worry and is particularly helpful for people with moderate to severe FCR.

Systemic Vasculitis Associated With Immune Check Point Inhibition: Analysis and Review.

PURPOSE OF REVIEW: Immunotherapy with immune checkpoint inhibitors (ICIs) has become a well-established modality to treat a number of different malignancies, especially in cases with advanced stages and/or recurrent diseases. These agents have been associated with development of a variety of autoimmune disorders as immune-related adverse events (IRAEs or irAEs). This review focuses on development of vasculitis with use of ICI. RECENT FINDINGS: Available information on vasculitis associated with immune checkpoint inhibition is limited primarily to case reports at this time. Most immune-related adverse events will not present as vasculitis, and it is an uncommon manifestation and/or is under-reported. There are no current well-established guidelines for treating vasculitis associated with ICIs; initial management would usually start with consideration of discontinuing the ICI and administering corticosteroids. Collaboration between treating oncologists and rheumatologists is necessary for a combined approach to management. While arthralgias, myalgias, and inflammatory arthritis frequently occur as irAEs, vasculitis is an uncommon presentation. Vasculitis has been reported with all of the available ICI agents, and there seems to be no clear difference in the risk based on small numbers. Large vessel vasculitis and vasculitis of the nervous system were the most commonly reported types of vasculitis but cases of vasculitis involving medium and small vessels have also been reported. It is challenging to know if the underlying disease or ICIs are the main culprit in development of vasculitis and requires a collaborative relationship between the treating oncologist and rheumatologist. Except in very mild cases, development of vasculitis during ICI therapy requires temporary or permanent discontinuation of ICI.

Novel outreach settings to enhance sexually transmitted infection/HIV awareness, diagnosis and treatment in hard-to-reach populations.

Despite recent rises in the number of cases of sexually transmitted infections (STIs) such as syphilis and gonorrhoea in England and increasing rates of HIV diagnosis among several men who have sex with men populations, many individuals are still not engaging with sexual health services. The John Hunter Clinic for Sexual Health, Chelsea and Westminster Hospital, London set up outreach clinics at the two world's largest adult lifestyle exhibitions in 2013 and 2015. This was the first time that a sexual health screening and promotion service was available at these large-scale (over 10,000 attendees at each) adult lifestyle events. A total of 381 individuals underwent STI screening across the two events. Nineteen (5.0%) patients were diagnosed with an infection. Twelve (3.1%) patients with Chlamydia trachomatis, three (0.8%) patients with syphilis, one (0.3%) patient with Neisseria gonorrhoeae, one (0.3%) patient with HIV, one (0.3%) patient with hepatitis B and one (0.3%) patient with hepatitis C. All 19 patients were promptly contacted with their results and had arrangements made for treatment or were referred for specialist follow up. Where possible, contact tracing was also performed. Implementing such outreach-based projects is challenged by lack of on-site laboratory support, high staffing demands and potentially high costs. However, we achieved a total HIV screening uptake rate of 94.5% amongst our outreach clinic attendees (versus 67% nationally in conventional sexual health clinic attendees) with an HIV positivity rate of 0.3% (versus 0.2% nationally in high HIV prevalence band populations). Additionally, 30.7% had never been tested for HIV previously (versus 20.7% nationally). Our work demonstrates that these strategies can help to address issues related to lack of STI/HIV screening in hard-to-reach populations and promote risk reduction behaviour.

TTN genotype is associated with fascicle length and marathon running performance.

Titin provides a molecular blueprint for muscle sarcomere assembly, and sarcomere length can vary according to titin isoform expression. If variations in sarcomere length influence muscle fascicle length, this may provide an advantage for running performance. Thus, the aim of this study was to investigate whether the titin (TTN) rs10497520 polymorphism was associated with muscle fascicle length in recreationally active men (RA; n=137) and marathon personal best time in male marathon runners (MR; n=141). Fascicle length of the vastus lateralis was assessed in vivo using B-mode ultrasonography at 50% of muscle length in RA. All participants provided either a whole blood, saliva or buccal cell sample, from which DNA was isolated and genotyped using real-time polymerase chain reaction. Vastus lateralis fascicle length was 10.4% longer in CC homozygotes, those carrying two copies of the C-allele, than CT heterozygotes (P=.003) in RA. In the absence of any TT homozygotes, reflective of the low T-allele frequency within Caucasian populations, it is unclear whether fascicle length for this group would have been smaller still. No differences in genotype frequency between the RA and MR groups were observed (P=.500), although within the MR group, the T-allele carriers demonstrated marathon personal best times 2 minutes 25 seconds faster than CC homozygotes (P=.020). These results suggest that the T-allele at rs10497520 in the TTN gene is associated with shorter skeletal muscle fascicle length and conveys an advantage for marathon running performance in habitually trained men.

Processing two-dimensional X-ray diffraction and small-angle scattering data in DAWN 2.

A software package for the calibration and processing of powder X-ray diffraction and small-angle X-ray scattering data is presented. It provides a multitude of data processing and visualization tools as well as a command-line scripting interface for on-the-fly processing and the incorporation of complex data treatment tasks. Customizable processing chains permit the execution of many data processing steps to convert a single image or a batch of raw two-dimensional data into meaningful data and one-dimensional diffractograms. The processed data files contain the full data provenance of each process applied to the data. The calibration routines can run automatically even for high energies and also for large detector tilt angles. Some of the functionalities are highlighted by specific use cases.

Polymorphisms in PTK2 are associated with skeletal muscle specific force: an independent replication study.

PURPOSE: The aim of the study was to investigate two single nucleotide polymorphisms (SNP) in PTK2 for associations with human muscle strength phenotypes in healthy men. METHODS: Measurement of maximal isometric voluntary knee extension (MVCKE) torque, net MVCKE torque and vastus lateralis (VL) specific force, using established techniques, was completed on 120 Caucasian men (age = 20.6 ± 2.3 year; height = 1.79 ± 0.06 m; mass = 75.0 ± 10.0 kg; mean ± SD). All participants provided either a blood (n = 96) or buccal cell sample, from which DNA was isolated and genotyped for the PTK2 rs7843014 A/C and rs7460 A/T SNPs using real-time polymerase chain reaction. RESULTS: Genotype frequencies for both SNPs were in Hardy-Weinberg equilibrium (X 2 ≤ 1.661, P ≥ 0.436). VL specific force was 8.3% higher in rs7843014 AA homozygotes than C-allele carriers (P = 0.017) and 5.4% higher in rs7460 AA homozygotes than T-allele carriers (P = 0.029). No associations between either SNP and net MVCKE torque (P ≥ 0.094) or peak MVCKE torque (P ≥ 0.107) were observed. CONCLUSIONS: These findings identify a genetic contribution to the inter-individual variability within muscle specific force and provides the first independent replication, in a larger Caucasian cohort, of an association between these PTK2 SNPs and muscle specific force, thus extending our understanding of the influence of genetic variation on the intrinsic strength of muscle.

Retrospective review of the management of epididymo-orchitis in a London-based level 3 sexual health clinic: an audit of clinical practice.

The aetiology of epididymo-orchitis is largely related to a patient's age with sexually transmitted pathogens being the common aetiological agents in those below 35 years of age. In individuals aged over 35, uropathogens represent the commonest cause. National guidelines exist for the appropriate management of this condition and its varying aetiology. We aimed to assess the management of epididymo-orchitis in our clinic with reference to the British Association for Sexual Health and HIV national guidelines. We describe the demographics, investigations, treatment and outcomes of patients presenting with epididymo-orchitis to the John Hunter Clinic for Sexual Health, Chelsea and Westminster Hospital.

Geochemical and mineralogical characterization of sulfur and iron in coal waste rock, Elk Valley, British Columbia, Canada.

Exposure of coal waste rock to atmospheric oxygen can result in the oxidation of sulfide minerals and the release of sulfate (SO42-) and associated trace elements (e.g., Se, As, Cd, and Zn) to groundwaters and surface waters. Similarly, reduced iron minerals such as siderite, ankerite, and the sulfide, pyrite, present in the waste rock can also undergo oxidation, resulting in the formation of iron oxyhydroxides that can adsorb trace elements released from the oxidation of the sulfide minerals. Characterization and quantification of the distribution of sulfide and iron minerals, their oxidation products, as well as leaching rates are critical to assessing present-day and future impacts of SO42- and associated trace elements on receiving waters. Synchrotron-based X-ray absorption near edge spectroscopic analysis of coal waste rock samples from the Elk Valley, British Columbia showed Fe present as pyrite (mean 6.0%), siderite (mean 44.3%), goethite (mean 35.4%), and lepidocrocite (mean 14.3%) with S present as sulfide (mean 26.9%), organic S (mean 58.7%), and SO42- (mean 14.4%). Squeezed porewater samples from dump solids yielded mean concentrations of 0.28mg/L Fe and 1246mg/L SO42-. Geochemical modeling showed the porewaters in the dumps to be supersaturated with respect to Fe oxyhydroxides and undersaturated with respect to gypsum, consistent with solids analyses. Coupling Fe and S mineralogical data with long-term water quality and quantity measurements from the base of one dump suggest about 10% of the sulfides (which represent 2% of total S) in the dump were oxidized over the past 30years. The S from these oxidized sulfides was released to the receiving surface water as SO42- and the majority of the Fe precipitated as secondary Fe oxyhydroxides (only 3.0×10-5% of the Fe was released to the receiving waters over the past 30years). Although the data suggest that the leaching of SO42- from the waste rock dump could continue for about 300years, assuming no change in the rate of oxidation of sulfides, SO42- is currently not a concern in receiving surface waters as the concentration levels are below regulatory limits.