Determination of Sulfamethoxazole Degradation Rate by an in Situ Experiment in a Reducing Alluvial Aquifer of the North China Plain.

Effluents from wastewater treatment facilities are reclaimed for environmental and landscaping use, resulting in infiltration to groundwater. Trace organic contaminants in these effluents have raised concerns, including the antibiotic resistance contributor sulfamethoxazole (SMX) detected frequently at concentrations exceeding 0.01 µg/L. A push-pull study to evaluate in situ degradation of SMX was undertaken in a shallow alluvial aquifer at the Tongzhou groundwater experimental site in southeast suburban Beijing. Ambient groundwater (1000 L) extracted from an experimental well at a depth of 10 m was spiked with SMX and NaBr, and then injected back into the same well. SMX and Br were "stored" over 15 days and monitored in the experimental well and 4 multilevel (depth: 10, 15, 17.5, 20, 25, and 30 m) observation wells located within 2-3 m distance. The concentration of SMX decreased faster than that of Br in the experimental and one observation well at 10 m depth; samples from all other depths contained little Br and SMX. The half-life of SMX degradation is estimated to be 3.1 ± 0.2 and 6.5 ± 0.6 days in the experimental well and observation well, respectively, under suboxic/anoxic conditions.

Urban Stormwater to Enhance Water Supply.

The capture, treatment, and recharge of urban runoff can augment water supplies for water-scarce cities. This article describes trends in urban stormwater capture for potable water supply using examples from the U.S. and Australia. In water-limited climates, water supply potential exists for large scale stormwater harvesting and recharge, such as neighborhood-scale and larger projects. The beneficial use of urban stormwater to meet nonpotable water demands has been successfully demonstrated in the U.S. and internationally. However, in terms of potable water use in the U.S., the lack of a regulatory framework and uncertainty in treatment and water quality targets are barriers to wide-scale adoption of urban stormwater for recharge, which is not so evident in Australia. More data on urban stormwater quality, particularly with respect to pathogens and polar organic contaminants, are needed to better inform treatment requirements. New technologies hold promise for improved operation and treatment, but must be demonstrated in field trials. Stormwater treatment systems may be needed for large-scale recharge in highly urbanized areas where source control is challenging. The co-benefits of water supply, urban amenities, and pollution reduction are important for financing, public acceptance and implementation-but are rarely quantified.

Nutrient Removal during Stormwater Aquifer Storage and Recovery in an Anoxic Carbonate Aquifer.

Stormwater harvesting coupled to managed aquifer recharge (MAR) provides a means to use the often wasted stormwater resource while also providing protection of the natural and built environment. Aquifers can act as a treatment barrier within a multiple-barrier approach to harvest and use urban stormwater. However, it remains challenging to assess the treatment performance of a MAR scheme due to the heterogeneity of aquifers and MAR operations, which in turn influences water treatment processes. This study uses a probabilistic method to evaluate aquifer treatment performance based on the removal of total organic C (TOC), N, and P during MAR with urban stormwater in an anoxic carbonate aquifer. Total organic C, N, and P are represented as stochastic variables and described by probability density functions (PDFs) for the "injectant" and "recovery"; these injectant and recovery PDFs are used to derive a theoretical MAR removal efficiency PDF. Four long-term MAR sites targeting one of two tertiary carbonate aquifers (T1 and T2) were used to describe the nutrient removal efficiencies. Removal of TOC and total N (TN) was dominated by redox processes, with median removal of TOC between 50 and 60% at all sites and TN from 40 to 50% at three sites with no change at the fourth. Total P removal due to filtration and sorption accounted for median removal of 29 to 53%. Thus, the statistical method was able to characterize the capacity of the anoxic carbonate aquifer treatment barrier for nutrient removal, which highlights that aquifers can be an effective long-term natural treatment option for management of water quality, as well as storage of urban stormwater.

Aligning perceptions of mistreatment among incoming medical trainees.

BACKGROUND: Learner mistreatment has been a long-standing example of unprofessional behavior in medical training. Alignment of perceptions of professional behavior is a critical component of developing a defined organizational culture. Clinical vignettes addressing learner mistreatment can help to achieve this goal. Our aim was to determine whether using clinical vignettes to address learner mistreatment during onboarding can reduce variability in the perceptions of mistreatment. MATERIALS AND METHODS: External experts in the field of labor and employment relations embedded in the clinical learning environment identified six thematic areas of potential mistreatment. Corresponding clinical case vignettes were developed and presented to incoming trainees during the onboarding process, followed by facilitated discussion. Perceptions of mistreatment before and after discussion were assessed on a Likert scale, with results compared using F-test and t-test. RESULTS: There were 145 participants. Most participants reported previously witnessing or experiencing episodes of mistreatment before matriculation (84%), with the majority reporting multiple events. The most common offenders were faculty (57%), residents/fellows (49%), and nurses (33%). Only 10% of incoming trainees reported a previous incident of mistreatment. Postintervention scores demonstrated decreased variability (P < 0.05) in perceptions of mistreatment in all but one vignette (withholding learning opportunities). Two vignettes demonstrated higher perception of mistreatment after intervention (noneducational tasks and gender or racial discrimination, P < 0.05). CONCLUSIONS: Mistreatment remains a prevalent phenomenon in medical training involving a wide cross-section of healthcare providers. Trainees arrive with discordant definitions of mistreatment. Alignment of individuals' definitions can be achieved through the use of carefully crafted clinical vignettes and facilitated discussion.

Perceptions of mistreatment among trainees vary at different stages of clinical training.

BACKGROUND: Mistreatment of trainees remains a frequently reported phenomenon in medical education. One barrier to creating an educational culture of respect and professionalism may be a lack of alignment in the perceptions of mistreatment among different learners. Through the use of clinical vignettes, our aim was to assess the perceptions of trainees toward themes of potential mistreatment at different stages of training. METHODS: Based on observations from external experts embedded in the clinical learning environment, six thematic areas of potential mistreatment were identified: verbal abuse, specialty-choice discrimination, non-educational tasks, withholding/denying learning opportunities, neglect and gender/racial insensitivity. Corresponding clinical vignettes were created and distributed to 1) medical students, 2) incoming interns, 3) residents/fellows. Perceptions of the appropriateness of the interactions depicted in the vignettes were measured on a 5-point Likert scale. Scores were categorized into neutral or appropriate (≤3) or inappropriate (i.e. mistreatment) (>3) and compared using chi-squared tests. RESULTS: Four hundred twenty seven trainees participated (182 students, 120 interns, 125 residents/fellows). Proportions of students perceiving mistreatment differed significantly from those of interns and residents/fellows in domains of verbal abuse, specialty discrimination and gender/racial insensitivity (p < 0.05). In scenarios comparing interns to residents/fellows, no significant differences were noted in perceptions of mistreatment in the domains of non-educational tasks, withholding learning and neglect. CONCLUSIONS: Perceptions of mistreatment differ at different developmental stages of medical training. After exposure to the clinical learning environment, perceptions of incoming interns did not differ from those of residents/fellows, implicating clinical rotations as a key period in indoctrinating students into the prevailing culture. More longitudinal studies are needed to confirm or better examine this phenomenon.

Reframing Surgical Care: Understanding Complexity and Promoting Teaming.

Reframing healthcare delivery in terms of the principles of complex adaptive systems has practical implications for addressing the challenges in improving surgical care. In an Integrated Practice Unit (IPU) - such as a surgical service line, a surgical in-patient floor, or an acute care unit - a diverse group of caregivers must interact in a highly interdependent fashion in an environment characterized by ambiguity, uncertainty, and time constraints. Understanding of the concept of teaming and the tenets of relational coordination are crucial to the promotion of a successful patient-centric approach to surgical care.

Determinants of 30-d readmission after colectomy.

BACKGROUND: Readmission after colectomy has become an important metric for measuring quality of care. Our aim was to investigate the impact of patient and hospital characteristics on 30-d readmission rates among patients undergoing colectomies in Pennsylvania. METHODS: Data were obtained from the Pennsylvania Health Care Cost Containment Council, which included all patients undergoing colectomy during 2011 (n = 10,155). Characteristics of non-readmitted and readmitted patients were compared with univariate tests. The primary outcome was 30-d readmission, which was modeled using multivariable logistic regression. RESULTS: Of the 10,155 patients who underwent colectomy, 1492 (14.7%) were readmitted within 30 d of discharge. Readmission was influenced by the underlying diagnosis (P < 0.001). Additionally, readmission was more likely with a Charlson comorbidity index ≥ 2 (odds ratio [OR] = 1.57, P < 0.001), emergent admission (OR = 1.26, P = 0.001), an in-hospital complication (OR = 1.46, P < 0.001), lowest quartile for surgeon volume (OR = 1.24, P = 0.01), and construction of an ileostomy (OR = 2.31, P < 0.001). Factors associated with decreased likelihood of readmission included laparoscopic surgery (OR = 0.73, P < 0.001). No association with hospital volume was found. CONCLUSIONS: A 30-d readmission after colectomy is influenced by numerous patient- and surgeon-related factors. Reducing in-hospital complications, and improving patient education after ileostomy construction, provide substantial targets for intervention. Our data also suggest that there may be a critical range of colectomies performed annually by surgeons, greater than which no additional benefit is conferred in reducing readmissions, but below which there is an increased risk of readmission. Further research is needed to determine the influence of laparoscopic surgery in reducing readmission in equally matched patient populations.

Length of Stay and Readmissions in Mastectomy Patients.

Interest is growing in preventing readmissions as payers start to link reimbursement to readmission rates. The purpose of this study was to assess factors that contribute to 30-day readmission rates for women undergoing mastectomy for breast cancer. Data from the Pennsylvania Health Care Cost Containment Council were queried for women undergoing mastectomy for breast cancer during 2011 (n = 2,919). The outcomes measured were length of stay (LOS) and 30-day readmission. Univariate comparisons between characteristics of readmitted (n = 172) and nonreadmitted patients were performed using t-tests and chi-square tests. Readmission was modeled using logistic regression; LOS was modeled using linear regression and controlled for potential confounders. In multivariate analyses, patients with peripheral vascular disease were more likely to be readmitted (OR 4.36, p = 0.002). Increased LOS was also associated with increased odds of readmission (OR 1.26, p = <0.0001). Since LOS was an important predictor of readmission we also estimated determinants of LOS using linear regression. The occurrence of reconstructive surgery (p = <0.0001) and renal disease (p < 0.0001) were highly predictive of longer LOS. This study showed peripheral vascular disease and longer lengths of stay were associated with higher odds of readmission in women undergoing mastectomy. Clinicians should be cognizant that optimizing a patient's vascular status before mastectomy may lead to lower rates of readmission. Additional research is needed to determine whether the relationship between readmissions and length of hospital stay is a causative versus associative phenomenon since LOS is a modifiable factor that may lead to lower readmissions.

Forecasting cyanobacteria dominance in Canadian temperate lakes.

Predictive models based on broad scale, spatial surveys typically identify nutrients and climate as the most important predictors of cyanobacteria abundance; however these models generally have low predictive power because at smaller geographic scales numerous other factors may be equally or more important. At the lake level, for example, the ability to forecast cyanobacteria dominance is of tremendous value to lake managers as they can use such models to communicate exposure risks associated with recreational and drinking water use, and possible exposure to algal toxins, in advance of bloom occurrence. We used detailed algal, limnological and meteorological data from two temperate lakes in south-central Ontario, Canada to determine the factors that are closely linked to cyanobacteria dominance, and to develop easy to use models to forecast cyanobacteria biovolume. For Brandy Lake (BL), the strongest and most parsimonious model for forecasting % cyanobacteria biovolume (% CB) included water column stability, hypolimnetic TP, and % cyanobacteria biovolume two weeks prior. For Three Mile Lake (TML), the best model for forecasting % CB included water column stability, hypolimnetic TP concentration, and 7-d mean wind speed. The models for forecasting % CB in BL and TML are fundamentally different in their lag periods (BL = lag 1 model and TML = lag 2 model) and in some predictor variables despite the close proximity of the study lakes. We speculate that three main factors (nutrient concentrations, water transparency and lake morphometry) may have contributed to differences in the models developed, and may account for variation observed in models derived from large spatial surveys. Our results illustrate that while forecast models can be developed to determine when cyanobacteria will dominate within two temperate lakes, the models require detailed, lake-specific calibration to be effective as risk-management tools.

Surgical specialty and outcomes for carotid endarterectomy: evidence from the National Surgical Quality Improvement Program.

BACKGROUND: Carotid endarterectomy (CEA) has been performed since the 1950s and remains one of the most common surgical procedures in the United States. The procedure is performed by cardiothoracic, general, neurologic, and vascular surgeons. This study uses data from the National Surgical Quality Improvement Program (NSQIP) to examine the outcomes after CEA when performed by general or vascular surgeons. MATERIALS AND METHODS: Data included 34,493 CEAs from years 2005 to 2010 recorded in the NSQIP database. Primary outcomes measured were length of stay, 30-d mortality, surgical site infection, cerebrovascular accident, myocardial infarction, and blood transfusion requirement. Secondary outcomes measured were the remaining intraoperative outcomes from the NSQIP database. RESULTS: After controlling for patient and surgical characteristics, patients treated by general surgeons did not have a significantly different LOS or 30-d mortality than those treated by vascular surgeons. Patients of general surgeons had nearly twice the risk of acquiring a surgical site infection (odds ratio [OR] = 1.94; P = 0.012), >1.5 times the risk of cerebrovascular accident (OR = 1.56; P = 0.008), and >1.8 times the risk of blood transfusion (OR = 1.85; P = 0.017) than those of vascular surgeons. Patients of general surgeons had less than half the risk of having a myocardial infarction (OR = 0.34; P = 0.031) than those of vascular surgeons. CONCLUSIONS: Surgical specialty is associated with a wide range of postoperative outcomes after CEA. Additional research is needed to explore practice and cultural differences across surgical specialty that may lead to outcome differences.

Interaction of extrinsic chemical factors affecting photodegradation of dissolved organic matter in aquatic ecosystems.

Photochemical degradation of dissolved organic matter (DOM) plays an important role in the carbon cycle. Irradiation experiments were conducted to evaluate the influence of chemical factors, specifically those expected to be altered in natural waters by atmospheric acid deposition, on photodegradation of DOM. These included pH, nitrate, iron and calcium. The experiments were carried out using stream and lake water samples with a wide range of dissolved organic carbon (DOC) concentration. Decreasing DOC concentration along with decreasing absorbance was observed during three-week exposures to natural solar radiation as well as during laboratory experiments with artificial solar radiation. The pH of the samples significantly affected degradation rates of DOM especially with elevated iron, while no influence of nitrate or calcium concentration was observed. Addition of Fe(III) did not significantly affect photodegradation and photobleaching rate constants in samples at circumneutral pH. Acid pH increased photodegradation rates. The results suggest that photodegradation rates of DOM will decrease during recovery from acidification. Hence, lower photodegradation rates may be responsible for increases in DOM observed in some regions of North America and Europe.

How do risk factors for mortality and overall complication rates following laparoscopic and open colectomy differ between inpatient and post-discharge phases of care? A retrospective cohort study from NSQIP.

BACKGROUND: Risk factors for complications differ between laparoscopic (LC) and open colectomy (OC) patients, given the selection bias between these groups. How risk factors for these outcomes differ between inpatient and post-discharge phases of care requires further study. METHODS: A retrospective cohort study (2005-2010) using NSQIP data was performed comparing OC and LC patients. Multivariable logistic regression was used to compare covariates associated with mortality and overall complication rates both before and after hospital discharge. RESULTS: Patients in the LC cohort were younger (64.2 vs. 62.5 years; P < 0.0001) with a lower incidence of comorbidities. OC was associated with a higher incidence of mortality compared to LC among inpatients (3.3 vs. 0.61%, P < 0.0001) and following discharge (0.88 vs. 0.29%, P < 0.0001). OC also demonstrated a higher incidence of overall complication rates for both inpatients (22.32 vs. 9.36%, P < 0.0001) and following discharge (8.83 vs. 7.24%, P < 0.0001). Risk factors (P < 0.05) for mortality following LC included age and emergency procedures for inpatients; pre-operative SIRS was associated with mortality occurring after discharge. For the OC cohort, risk for mortality was increased with smoking and contaminated/dirty wounds for inpatients; pre-operative weight loss was associated with death following discharge. Factors associated with increased risk of morbidity following LC included smoking history for inpatients and pre-operative steroid therapy following discharge. Following OC, morbidity was strongly associated with ASA scores for inpatients; pre-operative steroid therapy was a risk factor following discharge. Obesity was strongly associated with non-mortal complications in both cohorts following discharge. CONCLUSIONS: (1) LC is associated with a lower incidence of post-operative mortality and complications. (2) Risk factors associated with adverse post-operative outcomes change during the post-operative period; surveillance for these outcomes should be tailored by operative technique and phase of post-operative care (3) Obesity is an underappreciated risk for complications following discharge for both LC and OC.

Temporal and spatial variation in Hg accumulation in zebra mussels (Dreissena polymorpha): possible influences of DOC and diet.

Zebra mussels (Dreissena polymorpha) are filter feeders located near the base of the foodweb and these animals are able to utilize a variety of carbon sources that may also vary seasonally. We conducted both a spatial and a temporal study in order to test the hypotheses: (1) dissolved organic carbon (DOC) concentrations influence Hg accumulation in zebra mussels sampled from a series of lakes and (2) seasonal variations in diet influence Hg accumulation. In the spatial study, we found a significant negative relationship between Hg concentrations and DOC concentrations, suggesting an influence of DOC on Hg bioaccumulation. In the temporal study, we used stable isotope ratios of nitrogen (δ(15)N) and carbon (δ(13)C) as ecological tools to provide a temporally integrated description of the feeding ecology of zebra mussels. Both δ(15)N and δ(13)C varied seasonally in a similar manner: more depleted values occurred in the summer and more enriched values occurred in the fall. Mercury concentrations also varied significantly over the year, with highest concentrations occurring in the summer, followed by a progressive decrease in concentrations into the fall. The C/N ratio of zebra mussels also varied significantly over the year with the lowest values occurring mid-summer and then values increased in the fall and winter, suggesting that there was significant variation in lipid stores. These results indicate that in addition to any effect of seasonal dietary changes, seasonal variation in energy stores also appeared to be related to Hg levels in the zebra mussels. Collectively results from this study suggest that DOC concentrations, seasonal variation in diet and seasonal depletion of energy stores are all important variables to consider when understanding Hg accumulation in zebra mussels.

Successful application of the innovation process to a case of Floyd Type I tracheal agenesis.

Background: Innovation is broadly defined as the act of introducing a new product, idea, or process. The field of surgery is built upon innovation, revolutionizing technology, science, and tools to improve patient care. While most innovative solutions are aimed at problems with a significant patient population, the process can also be used on orphan pathologies without obvious solutions. We present a case of tracheal agenesis, a rare congenital anomaly with an overwhelming mortality and few good treatment options, that benefited from the innovation process and achieved survival with no ventilator dependence at three years of age. Methods: Utilizing the framework of the innovation process akin to the Stanford Biodesign Program, 1) the parameters of the clinical problem were identified, 2) previous solutions and existing technologies were analyzed, newly invented solutions were brainstormed, and value analysis of the possible solutions were carried out using crowd wisdom, and 3) the selected solution was prototyped and tested using 3D modeling, iterative testing on 3D prints of actual-sized patient parts, and eventual implementation in the patient after regulatory clearance. Results: A 3D-printed external bioresorbable splint was chosen as the solution. Our patient underwent airway reconstruction with "trachealization of the esophagus": esophageotracheal fistula resection, esophagotracheoplasty, and placement of a 3D-printed polycaprolactone (PCL) stent for external esophageal airway support at five months of age. Conclusions: The innovation process provided our team with the guidance and imperative steps necessary to develop an innovative device for the successful management of an infant survivor with Floyd Type I tracheal agenesis. Article summary: We present a case of tracheal agenesis, a rare congenital anomaly with an overwhelming mortality and few good treatment options, that benefited from the innovation process and achieved survival with no ventilator dependence at three years of age.The importance of this report is to reveal how the innovation process, which is typically used for problems with significant patient population, can also be used on orphan pathologies without obvious solutions.

The impacts of ontogenetic dietary shifts in yellow perch (Perca flavescens) on Zn and Hg accumulation.

Yellow perch (Perca flavescens) undergo several ontogenetic dietary shifts, and consequently these fish feed at different trophic levels and rely on different carbon sources over their lifetime. Stable isotope ratios of nitrogen (δ(15)N) and carbon (δ(13)C) are powerful ecological tools that are used to provide a temporally integrated description of the feeding ecology of aquatic animals such as fish. The main objective of this study was to use stable isotopes of nitrogen and carbon to determine if dietary changes affected mercury (Hg) and zinc (Zn) accumulation in yellow perch ranging in size from approximately 5 cm to 27 cm. Results showed that Hg bioaccumulation generally increased with increasing trophic level in fish feeding at higher trophic levels, however, the relationship between Hg levels and δ(15)N was non-linear showing no relationship in small fish (less than 15 cm). In contrast, there was a negative, linear relationship between δ(15)N and Zn, suggesting that as perch fed at progressively higher trophic levels, less of Zn bioaccumulated. No relationship was observed between δ(13)C and metal levels in perch. Collectively, these results demonstrate a contrast in the behavior of Zn and Hg bioaccumulation in yellow perch as a function of trophic status.

Evaluating long-term trends in littoral benthic macroinvertebrate communities of lakes recovering from acid deposition.

The Mann-Kendall test has been proposed as a nonparametric method to evaluate trends in long-term water quality datasets with missing values, serial correlation, and non-normality. However, this test has rarely been used to evaluate long-term trends in biological data. In this study, we used the Mann-Kendall test to evaluate trends in 15 years of data on benthic macroinvertebrate communities from 17 Precambrian Shield lakes. We also used the van Belle and Hughes test of trend homogeneity to assess whether common among-lake temporal trends existed. We assumed that evidence of a common regional trend among lakes would support the hypothesis of long-term biological recovery from past acidification. We found decreasing proportions of Chironomidae and increasing proportions of Ephemeroptera, Plecoptera, and Trichoptera (EPT) in both single-lake and multi-lake trend analysis. Moreover, six of the nine lakes with significant trends in more than one benthos metric displayed a significant decrease in Chironomidae and increase in EPT concurrently, indicating a shift towards more acid-sensitive taxa. Weak trends in several of the biological metrics indicated that recovery in these lakes has been impeded. Results of this study indicate that the Mann-Kendall and van Belle and Hughes trend tests are useful statistical tools to evaluate long-term patterns in biological data.

Cost-effectiveness of the National Surgical Quality Improvement Program.

OBJECTIVE: The purpose of this study was to compare the cost-effectiveness of the National Surgical Quality Improvement Program (NSQIP) at an academic medical center between the first 6 months and through the first and second years of implementation. BACKGROUND: The NSQIP has been extended to private-sector hospitals since 1999, but little is known about its cost-effectiveness. METHODS: Data included 2229 general or vascular surgeries, 699 of which were conducted after NSQIP was in place for 6 months. We estimated an incremental cost-effectiveness ratio (ICER) comparing costs and benefits before and after the adoption of NSQIP. Costs were estimated from the perspective of the hospital and included hospital costs for each admission plus the total annual cost of program adoption and maintenance, including administrator salary, training, and information technology costs. Effectiveness was defined as events avoided. Confidence intervals and a cost-effectiveness acceptability curve were computed by using a set of 10,000 bootstrap replicates. The time periods we compared were (1) July 2007 to December 2007 to July 2008 to December 2008 and (2) July 2007 to June 2008 to July 2008 to June 2009. RESULTS: The incremental costs of the NSQIP program were $832 and $266 for time periods 1 and 2, respectively, yielding ICERs of $25,471 and $7319 per event avoided. The cost-effectiveness acceptability curves suggested a high probability that NSQIP was cost-effective at reasonable levels of willingness to pay. CONCLUSIONS: In these data, not only did NSQIP appear cost-effective, but also its cost-effectiveness improved with greater duration of participation in the program, resulting in a decline to 28.7% of the initial cost.

Isotopic character of nitrous oxide emitted from streams.

Global models have indicated agriculturally impacted rivers and streams may be important sources of the greenhouse gas nitrous oxide (N(2)O). However, there is significant uncertainty in N(2)O budgets. Isotopic characterization can be used to help constrain N(2)O budgets. We present the first published measurements of the isotopic character of N(2)O emitted from low (2-4) order streams. Isotopic character of N(2)O varied seasonally, among streams, and over diel periods. On an annual basis, δ(18)O of emitted N(2)O (+47.4 to +51.4‰; relative to VSMOW) was higher than previously reported for larger rivers, but δ(15)N of emitted N(2)O (-16.2 to +2.4‰ among streams; relative to atmospheric N(2)) was similar to that of past studies. On an annual basis, all streams emitted N(2)O with lower δ(15)N than tropospheric N(2)O. Given these streams have elevated nitrate concentrations which are associated with enhanced N(2)O fluxes, this supports the hypothesis that streams are contributing to the accumulation of (15)N-depleted N(2)O in the troposphere.

Water quality requirements for sustaining aquifer storage and recovery operations in a low permeability fractured rock aquifer.

A changing climate and increasing urbanisation has driven interest in the use of aquifer storage and recovery (ASR) schemes as an environmental management tool to supplement conventional water resources. This study focuses on ASR with stormwater in a low permeability fractured rock aquifer and the selection of water treatment methods to prevent well clogging. In this study two different injection and recovery phases were trialed. In the first phase ~1380 m(3) of potable water was injected and recovered over four cycles. In the second phase ~3300 m(3) of treated stormwater was injected and ~2410 m(3) were subsequently recovered over three cycles. Due to the success of the potable water injection cycles, its water quality was used to set pre-treatment targets for harvested urban stormwater of ≤ 0.6 NTU turbidity, ≤ 1.7 mg/L dissolved organic carbon and ≤ 0.2 mg/L biodegradable dissolved organic carbon. A range of potential ASR pre-treatment options were subsequently evaluated resulting in the adoption of an ultrafiltration/granular activated carbon system to remove suspended solids and nutrients which cause physical and biological clogging. ASR cycle testing with potable water and treated stormwater demonstrated that urban stormwater containing variable turbidity (mean 5.5 NTU) and organic carbon (mean 8.3 mg/L) concentrations before treatment could be injected into a low transmissivity fractured rock aquifer and recovered for irrigation supplies. A small decline in permeability of the formation in the vicinity of the injection well was apparent even with high quality water that met turbidity and DOC but could not consistently achieve the BDOC criteria.

The APSA Board of Governors enthusiastically endorses the position paper ``Diversity, Equity, and Inclusion: A Strategic Priority for the American Pediatric Surgical Association''.

This Commentary by the APSA Board of Governors enthusiastically endorses the position paper "Diversity, Equity, and Inclusion: A Strategic Priority for the American Pediatric Surgical Association".