Acidification of Northeastern USA Lakes From Rising Anthropogenic-Sourced Atmospheric Carbon Dioxide and Its Effects on Aluminum Speciation

The impact of rising atmospheric CO2 (pCO2atm) from anthropogenic activities on pH, dissolved inorganic carbon, carbonate mineral saturation, and aluminum (Al) speciation is evaluated for 18 northeastern USA lakes using polythermal, sliding activity reaction path models. pCO2atm was forced using two scenarios from the IPCC\u27s Sixth Assessment Report in which pCO2atm attains either 600 or 1,100 ppm in 2,100. Results suggest pH will decrease 0.15 and 0.32 pH units, aCO2-3 will decrease 24% and 49%, and Ωaragonite will decrease 21% and 45%, respectively. These changes are of the same magnitude as those expected for the oceans. The effects of rising pCO2atm on sub‐lethal 20% effect concentrations (i.e., EC20) of Al for brook trout (Salvelinus fontinalis) are evaluated with the biotic ligand model, which indicates Al toxicity effects will increase as pH decreases. These changes could reverse gains in water quality and fisheries health achieved since implementation of the Clean Air Act

Characteristics and Predictors of Intensive Care Unit Admission in Pediatric Blunt Abdominal Trauma

BACKGROUND: Pediatric trauma patients sustaining blunt abdominal trauma (BAT) with intra-abdominal injury (IAI) are frequently admitted to the intensive care unit (ICU). This study was performed to identify predictors for ICU admission following BAT. METHODS: Prospective study of children (\u3c 16 years) who presented to 14 Level-One Pediatric Trauma Centers following BAT over a 1-year period. Patients were categorized as ICU or non-ICU patients. Data collected included vitals, physical exam findings, laboratory results, imaging, and traumatic injuries. A multivariable hierarchical logistic regression model was used to identify predictors of ICU admission. Predictive ability of the model was assessed via tenfold cross-validated area under the receiver operating characteristic curves (cvAUC). RESULTS: Included were 2,182 children with 21% (n = 463) admitted to the ICU. On univariate analysis, ICU patients were associated with abnormal age-adjusted shock index, increased injury severity scores (ISS), lower Glasgow coma scores (GCS), traumatic brain injury (TBI), and severe solid organ injury (SOI). With multivariable logistic regression, factors associated with ICU admission were severe trauma (ISS \u3e 15), anemia (hematocrit \u3c 30), severe TBI (GCS \u3c 8), cervical spine injury, skull fracture, and severe solid organ injury. The cvAUC for the multivariable model was 0.91 (95% CI 0.88-0.92). CONCLUSION: Severe solid organ injury and traumatic brain injury, in association with multisystem trauma, appear to drive ICU admission in pediatric patients with BAT. These results may inform the design of a trauma bay prediction rule to assist in optimizing ICU resource utilization after BAT. STUDY DESIGN: Prognosis study

Association of Gangrenous, Suppurative, and Exudative Findings With Outcomes and Resource Utilization in Children With Nonperforated Appendicitis.

IMPORTANCE: The clinical significance of gangrenous, suppurative, or exudative (GSE) findings is poorly characterized in children with nonperforated appendicitis. OBJECTIVE: To evaluate whether GSE findings in children with nonperforated appendicitis are associated with increased risk of surgical site infections and resource utilization. DESIGN, SETTING, AND PARTICIPANTS: This multicenter cohort study used data from the Appendectomy Targeted Database of the American College of Surgeons Pediatric National Surgical Quality Improvement Program, which were augmented with operative report data obtained by supplemental medical record review. Data were obtained from 15 hospitals participating in the Eastern Pediatric Surgery Network (EPSN) research consortium. The study cohort comprised children (aged ≤18 years) with nonperforated appendicitis who underwent appendectomy from July 1, 2015, to June 30, 2020. EXPOSURES: The presence of GSE findings was established through standardized, keyword-based audits of operative reports by EPSN surgeons. Interrater agreement for the presence or absence of GSE findings was evaluated in a random sample of 900 operative reports. MAIN OUTCOMES AND MEASURES: The primary outcome was 30-day postoperative surgical site infections (incisional and organ space infections). Secondary outcomes included rates of hospital revisits, postoperative abdominal imaging, and postoperative length of stay. Multivariable mixed-effects regression was used to adjust measures of association for patient characteristics and clustering within hospitals. RESULTS: Among 6133 children with nonperforated appendicitis, 867 (14.1%) had GSE findings identified from operative report review (hospital range, 4.2%-30.2%; P \u3c .001). Reviewers agreed on presence or absence of GSE findings in 93.3% of cases (weighted κ, 0.89; 95% CI, 0.86-0.92). In multivariable analysis, GSE findings were associated with increased odds of any surgical site infection (4.3% vs 2.2%; odds ratio [OR], 1.91; 95% CI, 1.35-2.71; P \u3c .001), organ space infection (2.8% vs 1.1%; OR, 2.18; 95% CI, 1.30-3.67; P = .003), postoperative imaging (5.8% vs 3.7%; OR, 1.70; 95% CI, 1.23-2.36; P = .002), and prolonged mean postoperative length of stay (1.6 vs 0.9 days; rate ratio, 1.43; 95% CI, 1.32-1.54; P \u3c .001). CONCLUSIONS AND RELEVANCE: In children with nonperforated appendicitis, findings of gangrene, suppuration, or exudate are associated with increased surgical site infections and resource utilization. Further investigation is needed to establish the role and duration of postoperative antibiotics and inpatient management to optimize outcomes in this cohort of children

Comparative Performance of Multiple Linear Regression and Biotic Ligand Models for Estimating the Bioavailability of Copper in Freshwater

An increasing number of metal bioavailability models are available for use in setting regulations and conducting risk assessments in aquatic systems. Selection of the most appropriate model is dependent on the user's needs but will always benefit from an objective, comparative assessment of the performance of available models. In 2017, an expert workshop developed procedures for assessing metal bioavailability models. The present study applies these procedures to evaluate the performance of biotic ligand models (BLMs) and multiple linear regression (MLR) models for copper. We find that the procedures recommended by the expert workshop generally provide a robust series of metrics for evaluating model performance. However, we recommend some modifications to the analysis of model residuals because the current method is insensitive to relatively large differences in residual patterns when comparing models. We also provide clarification on details of the evaluation procedure which, if not applied correctly, could mischaracterize model performance. We found that acute Cu MLR and BLM performances are quite comparable, though there are differences in performance on a species-specific basis and in the resulting water quality criteria as a function of water chemistry. In contrast, the chronic Cu MLR performed distinctly better than the BLM. Observed differences in performance are due to the smaller effects of hardness and pH on chronic Cu toxicity compared to acute Cu toxicity. These differences are captured in the chronic MLR model but not the chronic BLM, which only adjusts for differences in organism sensitivity. In general, we continue to recommend concurrent development of both modeling approaches because they provide useful comparative insights into the strengths, limitations, and predictive capabilities of each model. Environ Toxicol Chem 2021;40:1649-1661. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC

Validation study of the acute biotic ligand model for silver

An important final step in development of an acute biotic ligand model for silver is to validate predictive capabilities of the biotic ligand model developed for fish and invertebrates. To accomplish this, eight natural waters, collected from across North America, were characterized with respect to ionic composition, pH, dissolved organic carbon, and sulfide. Tests were conducted with the cladoceran Ceriodaphnia dubia (48-h static) and the fish Pimephales promelas (96-h static renewal) to determine the concentrations causing lethality to 50% of the organisms (LC50s) for silver in each of these waters. Overall, the biotic ligand model adequately predicted silver toxicity to C. dubia; however, in some cases, predicted LC50 values exceeded measured values. The accuracy of the biotic ligand model predictions was less convincing for silver toxicity to P. promelas with pronounced problems in low-ionic strength waters. Another issue was the use of acclimated organisms in toxicity studies because the biotic ligand model has been developed with the use of a mix of studies with acclimated and nonacclimated test organisms of varying ages and sizes. To evaluate whether effects of acclimation to test waters influence biotic ligand model predictions, a subset of the natural waters were also tested with P. promelas that had been acclimated to the natural water for 7 d before testing. These experiments revealed no differences in toxicity between acclimated and nonacclimated P. promelas. To determine the influence of organism size, which has been previously correlated to Na(+) turnover and acute silver toxicity across multiple species, Na(+) and Cl(-) influx rates were measured in P. promelas of different sizes. Our results show that Na(+) and Cl(-) influx rates were inversely related to fish mass and positively correlated with silver sensitivity