Lactate dehydrogenase to albumin ratio as a prognostic factor in lower respiratory tract infection patients.

PURPOSE: To verify the role of lactate dehydrogenase to albumin (LDH/ALB) ratio as an independent prognostic factor for mortality due to the lower respiratory tract infection (LRTI) in the emergency department (ED). METHODS: We reviewed the electronic medical records of patients who were admitted to the ED for the management of LRTI between January 2018 and December 2020. Initial vital signs, laboratory data, and patient severity scores in the ED were collected. The LDH/ALB ratio was compared to other albumin-based ratios (blood urea nitrogen to albumin ratio, C-reactive protein to albumin ratio, and lactate to albumin ratio) and severity scales (pneumonia severity index, modified early warning score, CURB-65 scores), which are being used as prognostic factors for in-hospital mortality. Multivariable logistic regression was performed to identify independent risk factors. RESULTS: The LDH/ALB ratio was higher in the non-survivor group than in the survivor group (median [interquartile range]: 217.6 [160.3;312.0] vs. 126.4 [100.3;165.1], p < 0.001). In the comparison of the area under the receiver operating characteristic curve (AUC) for predicting in-hospital mortality, the AUC of the LDH/ALB ratio (0.808, 95% confidence interval: 0.757-0.842, p < 0.001) was wider than other albumin-based ratios and severity scales, except the blood urea nitrogen to albumin ratio. In the multivariable logistic regression analysis, the LDH/ALB ratio independently affected in-hospital mortality. CONCLUSION: The LDH/ALB ratio may serve as an independent prognostic factor for in-hospital mortality in patients with LRTI.

Detection of Testicular Torsion With Preserved Intratesticular Flow By Point of Care Ultrasound in the Emergency Department: A Case Report.

BACKGROUND: Ultrasonography is an effective diagnostic tool for testicular torsion (TT), which is typically characterized by the absence of blood flow in the affected testicle on color Doppler mode. However, there are a few reported cases of TT with symmetrical preserved flow. We report a case of TT with the preserved intratesticular flow on color Doppler ultrasound. CASE REPORT: A 14-year-old boy was admitted due to sudden-onset right scrotal pain. Point-of-care ultrasound (POCUS) revealed that the right testicle was larger than the left. The intratesticular flow in both testicles was preserved. Radiology-performed ultrasound confirmed the preserved intratesticular flow observed on POCUS, but also demonstrated a whirlpool sign of the right spermatic cord. TT was confirmed surgically. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians should investigate the presence of intratesticular blood flow and the whirlpool sign of the spermatic cord or other ultrasound features suggestive of TT, even if testicular blood flow is preserved. Suspicion of TT from POCUS findings warrants further evaluation to preserve the patient's fertility.

Utility of the blood urea nitrogen to serum albumin ratio as a prognostic factor of mortality in aspiration pneumonia patients.

PURPOSE: This study aimed to determine whether the blood urea nitrogen to serum albumin (B/A) ratio is a useful prognostic factor of mortality in patients with aspiration pneumonia. METHODS: The study included patients with aspiration pneumonia who had been admitted to our hospital via the emergency department (ED) between January 1, 2014 and December 31, 2018. The 28-day mortality after the ED visits was the primary end point of this study. The data of the survivors and non-survivors were compared. RESULTS: A final diagnosis of aspiration pneumonia was made for 443 patients during the study period. Significant differences were observed in age, respiratory rate, albumin levels, total protein levels, blood urea nitrogen levels, C-reactive protein levels, glucose, and Charlson comorbidity index scores between the survivor and non-survivor groups. Moreover, the B/A ratio was significantly higher in the non-survivor group than that in the survivor group. The area under the curve for the B/A ratio was 0.70 [95% confidence interval (CI) 0.65-0.74], 0.71 for the PSI (95% CI 0.67-0.76), 0.64 for CURB-65 (95% CI 0.60-0.69), and 0.65 for albumin (95% CI 0.60-0.70) on the receiver operating characteristic curve for predicting mortality within 28 days of the ED visit. Multivariable logistic regression analysis revealed that the B/A ratio (>7, OR 3.40, 95% CI 1.87-6.21, P < 0.001) was associated with mortality within 28 days of the ED visit. CONCLUSION: The B/A ratio is a simple and potentially useful prognostic factor of mortality in aspiration pneumonia patients.

Cerebrospinal Fluid Lactate Levels, Brain Lactate Metabolism and Neurologic Outcome in Patients with Out-of-Hospital Cardiac Arrest.

BACKGROUND/OBJECTIVE: Cerebrospinal fluid (CSF) and serum lactate levels were assessed to predict poor neurologic outcome 3 months after return of spontaneous circulation (ROSC). We compared arterio-CSF differences in the lactate (ACDL) levels between two neurologic outcome groups. METHODS: This retrospective observational study involved out-of-hospital cardiac arrest (OHCA) survivors who had undergone target temperature management. CSF and serum samples were obtained immediately (lactate0), and at 24 (lactate24), 48 (lactate48), and 72 (lactate72) h after ROSC, and ACDL was calculated at each time point. The primary outcome was poor 3-month neurologic outcome (cerebral performance categories 3-5). RESULTS: Of 45 patients, 27 (60.0%) showed poor neurologic outcome. At each time point, CSF lactate levels were significantly higher in the poor neurologic outcome group than in the good neurologic outcome group (6.97 vs. 3.37, 4.20 vs. 2.10, 3.50 vs. 2.00, and 2.79 vs. 2.06, respectively; all P < 0.05). CSF lactate's prognostic performance was higher than serum lactate at each time point, and lactate24 showed the highest AUC values (0.89, 95% confidence interval, 0.75-0.97). Over time, ACDL decreased from - 1.30 (- 2.70-0.77) to - 1.70 (- 3.2 to - 0.57) in the poor neurologic outcome group and increased from - 1.22 (- 2.42-0.32) to - 0.64 (- 2.31-0.15) in the good neurologic outcome group. CONCLUSIONS: At each time point, CSF lactate showed better prognostic performance than serum lactate. CSF lactate24 showed the highest prognostic performance for 3-month poor neurologic outcome. Over time, ACDL decreased in the poor neurologic outcome group and increased in the good neurologic outcome group.

The Association Between Neurological Prognosis and the Degree of Blood-Brain Barrier Disruption in Cardiac Arrest Survivors Who Underwent Target Temperature Management.

BACKGROUND: This study aimed to compare day-specific associations of blood-brain barrier (BBB) disruption with neurological outcome in survivors of out-of-hospital cardiac arrest (OHCA) treated with target temperature management (TTM) and lumbar drainage. METHODS: This retrospective single-center study included 68 survivors of OHCA who underwent TTM between April 2018 and December 2019. The albumin quotient (QA) was calculated as QA = albumincerebrospinal fluid/albuminserum immediately (day 1) and 24 (day 2), 48 (day 3), and 72 h (day 4) after the return of spontaneous circulation. The degree of BBB disruption was weighted using the following scoring system: QA value of 0.007 or less (normal), QA value greater than 0.007-0.01 (mild), QA value greater than 0.01-0.02 (moderate), and QA value greater than 0.02 (severe). Points were assigned as follows: 0 (normal), 1 (mild), 4 (moderate), and 9 (severe). Neurological outcome was determined at 6 months after the return of spontaneous circulation, as well as cerebral performance category (CPC), dichotomized as good (CPC score 1-2) and poor (CPC score 3-5) outcome. RESULTS: We enrolled 68 patients (48 men, 71%); 37 (54%) patients had a poor neurological outcome. The distributions of poor versus good outcomes at 6 months in patients with moderate and severe BBB disruption were 19 of 22 (80%) vs. 18 of 46 (50%) on day 1, 31 of 37 (79%) vs. 6 of 31 (32%) on day 2, 32 of 37 (81%) vs. 5 of 31 (30%) on day 3, and 32 of 39 (85%) vs. 5 of 29 (30%) on day 4 (P < 0.001), respectively. Using receiver operating characteristic analyses, optimal cutoff values (sensitivity, specificity) of QA levels for the prediction of neurological outcome were as follows: day 1, greater than 0.009 (56.8%, 87.1%); day 2, greater than 0.012 (81.1%, 87.1%); day 3, greater than 0.013 (83.8%, 87.1%); day 4, greater than 0.013 (86.5%, 87.1%); the sum of all time points, greater than 0.039 (89.5%, 79.4%); and scoring system, greater than 9 (91.9%, 87.1%). CONCLUSIONS: In this proof of concept study, QA was associated with poor neurological outcome in survivors of OHCA treated with TTM with no contraindication to lumbar drainage. A large multicenter prospective study is needed to validate the utility of BBB disruption as a prognosticator of neurological outcome.

A novel predictive tool for prognosis in elderly patients with urinary tract infection: Modified PRACTICE.

PURPOSE: We evaluated whether combining the serum albumin level and the Prediction Rule for Admission policy in Complicated urinary Tract InfeCtion LEiden (PRACTICE) class could be a prognostic predictor in elderly patients with urinary tract infection (UTI). METHODS: We retrospectively included adult patients (age ≥ 65 years) with UTI who were hospitalized in the emergency department (ED) between January 1, 2014 and December 31, 2018. We graded the serum albumin level and classified the PRACTICE score; the modified PRACTICE was defined as the sum of the albumin level grade and the PRACTICE class. We comparatively assessed the predictive value for in-hospital mortality and admission to the intensive care unit (ICU) in survivor and non-survivor groups. RESULTS: In total, the study analysis included 1159 patients, and in-hospital mortality was 3.4% (n = 39). The modified PRACTICE score (4.0 [1.4] vs 6.1 [1.2], p < 0.001) was significantly increased in the non-survivor group. The area under the curve value of factors associated with in-hospital mortality were the Modified Early Warning Score (MEWS) 0.57 (95% CI 0.54-0.60), albumin 0.83 (95% CI 0.81-0.85), PRACTICE 0.71 (95% CI 0.69-0.74), and the modified PRACTICE 0.86 (95% CI 0.84-0.88). Factors associated with ICU admission were MEWS 0.65 (95% CI 0.62-0.68), albumin 0.66 (95% CI 0.64-0.69), PRACTICE 0.66 (95% CI 0.63-0.68), and the modified PRACTICE 0.72 (95% CI 0.69-0.74). CONCLUSION: The modified PRACTICE score can be a useful prognostic predictor in elderly patients with UTI.

Comparison of cosmetic appearances after facial lacerations repaired by junior residents and experts.

PURPOSE: The technical factors which improve cosmetic outcomes and which need to be emphasized in education of junior residents have yet to be described. We compared cases in which suturing was performed by either junior emergency medicine residents or experts, in order to determine the focus of future education and training. METHODS: Wound registry data was reviewed and retrospectively analyzed from September 2015 to February 2016. Only patients who visited the emergency room with facial lacerations were enrolled, and their wound registry data sheets were reviewed. Practitioners were divided into junior resident and expert groups. We assessed the progress using the Stony Brook Scar Evaluation Scale (SBSES) 5-10 days following suturing. RESULTS: Sixty-six patients were enrolled; 43 (65.2%) were men. The median (interquartile range) cosmetic scores (SBSES scale) for suturing performed by junior residents or experts were 3 (2-4) and 5 (4-5), respectively (p = 0.001). The percentage of maximum scores for each SBSES category was significantly lower in the junior resident group than in the expert group for width (68% vs. 86%), hatch marks (68% vs. 93%), and overall appearance (41% vs. 80%) (all p < 0.001). CONCLUSIONS: There were significant differences in scar widths and hatch marks, which were attributable to the skill level of the practitioner who performed the suturing of facial lacerations. Junior residents should be educated about maintenance of proper tension, atraumatic technique, and performing appropriate trimming or debridement.

Usefulness of new method of central venous catheter securement using a continuous suture.

INTRODUCTION: To reduce the time required for suture closure for central venous catheterization, a new procedure was developed using a continuous suture technique. The present study was conducted to investigate the usefulness of this method. METHOD: The study was conducted with 90 volunteers among the doctors in the university hospital. Preliminary training (using video) on the two fixation methods was given to the participants prior to the experiment. After applying the central vein of the pig skin, a suture up to the butterfly seal was prepared, and the participant was allowed to fix the suture using the classic method and the new method. The time required for suturing was measured in seconds, and the tension was determined using a tension measuring device after suturing. RESULT: When using the new "one-time method," the time required was shortened by about 20.50s on average compared with the conventional method (P<0.001). The median and quartile of the tension of the thread for the one-time method was 1.10kg (1.00-1.20kg) and of the conventional method was 1.10kg (1.00-1.20kg), which showed no statistically significant difference between the two groups (P=0.476). CONCLUSION: We found that the new one-time method provided faster and more convenient central catheterization and catheter securement than the conventional methods.

Electro-absorption modulator with an asymmetric coupled triple quantum well for low-voltage operation.

We present an electro-absorption modulator based on the enhanced electro-optic effect of an asymmetric coupled triple quantum well (ACTQW) to achieve a large transmittance difference at a low driving voltage for high-definition (HD) three-dimensional (3D) imaging applications. Our numerical calculations show that an ACTQW structure can provide a significantly lower-voltage operation without degrading the absorption coefficient change at the operating wavelength of 850 nm. The fabricated electro-absorption modulator (EAM) based on an ACTQW shows that the operating voltage can be reduced by nearly 50% compared with an EAM based on a conventional rectangular quantum well while also achieving a large transmittance difference in excess of 50%, which is in good agreement with the numerical calculation results. These results suggest that using an EAM with an ACTQW is a promising approach for the realization of a high-resolution 3D imaging system.

Usefulness of the compression-adjusted ventilation for adequate ventilation rate during cardiopulmonary resuscitation.

BACKGROUND: To perform high-quality cardiopulmonary resuscitation (CPR), high-quality chest compression and ventilation support should be performed. However, many providers still have not maintained an adequate ventilation rate but hyperventilated during CPR. Thus, this study was conducted to verify that the compression-adjusted ventilation (CAV) would be a more accurate ventilation method compared with the conventional ventilation (CV). METHODS: Volunteer medical students and emergency medical services personnel were recruited. They were randomly divided into either the CV group or the CAV group. In the CV group, participants performed ventilation with estimation of the rate of 8 to 10 per minute (1 ventilation/6-8 seconds). In the CAV group, the ventilation rate was adjusted in line with the compression rate (compression:ventilation, 12:1). In each group, 2-rescuer adult CPR was performed on a manikin, which was intubated with an endotracheal tube, during a period of 8 minutes. The compression rate and the ventilation rate were recorded during CPR. RESULTS: Data on 56 medical students and 41 emergency medical services personnel were analyzed. No significant difference was observed in compression rate (P =.817); however, median (interquartile range) ventilation rate differed significantly between the CV and CAV groups (8.79 [2.19] per minute vs 9.25 [1.07] per minute, P = .016). In addition, compared with the CV group, adequacy of ventilation rate was better in the CAV group (47.9% vs 85.7%, P < .001). CONCLUSION: In comparison with the CV, the CAV is a more accurate method for maintenance of an adequate ventilation rate.

Comparison of modified quick sequential organ failure assessment models as triage tools for febrile patients.

Object: Effective triage of febrile patients in the emergency department is crucial during times of overcrowding to prioritize care and allocate resources, especially during pandemics. However, available triage tools often require laboratory data and lack accuracy. We aimed to develop a simple and accurate triage tool for febrile patients by modifying the qSOFA score. Methods: We retrospectively analyzed data from 7,303 febrile patients and created modified versions of qSOFA using factors identified through multivariable analysis. The performance of these modified qSOFAs in predicting in hospital mortality and intensive care unit (ICU) admission was compared using the area under the receiver operating characteristic curve (AUROC). Results: Through multivariable analysis, the identified factors were age (A), male sex (M), SpO2 (S), and lactate levels (L). The AUROCs of ASqSOFA (for in-hospital mortality: 0.812; 95% CI: 0.789-0.835, for ICU admission: 0.794; 95% CI: 0.771-0.817), which included age and SpO2 with qSOFA, were simple and not inferior to other more complex models (e.g., ASMqSOFA, ASLqSOFA, and ASMLqSOFA). ASqSOFA also displayed significantly higher AUROC than other triage scales, such as the modified early warning score and Korean triage and acuity scale. The optimal cut-off score of ASqSOFA for the outcome was 2 and the score for redistribution to a lower-level emergency department was 0. Conclusion: We demonstrated that ASqSOFA can be employed as a simple and efficient triage tool for emergency febrile patients to aid in resource distribution during overcrowding. It may also be applicable in pre-hospital settings for febrile patient triage.

Coupled tandem cavities based electro-absorption modulator with asymmetric tandem quantum well for high modulation performance at low driving voltage.

We propose and demonstrate a new electro-absorption modulator (EAM) based on coupled tandem cavities (CTC) having asymmetric tandem quantum well (ATQW) structure with separated electrode configuration to achieve large transmittance change over a broad spectral range at low driving voltage for high definition (HD) 3D imaging applications. Our theoretical calculations show that CTC with ATQW structure can provide large transmittance change over a wide spectral range at low driving voltage. By introducing separated electrode configuration, the fabricated EAM having CTC with ATQW structure shows a large transmittance change over 50%, almost three times larger spectral bandwidth compared to that of EAM having single cavity with a single thickness quantum well without significantly increasing the applied voltage. In addition, the CTC with ATQW structure also shows high speed modulation up to 28 MHz for the device having a large area of 2 mm x 0.5 mm. This high transmittance change, large spectral bandwidth and low voltage operation over a large device area for the EAM having CTC with ATQW demonstrates their huge potential as an optical image modulator for HD 3D imaging applications.

Acute contralateral reexpansion pulmonary edema within a few hours of pleural drainage.

We report a case of an 83-year-old male patient with massive tuberculous pleural effusion. Percutaneous drainage was performed following a diagnosis of tuberculous pleurisy. Fifteen minutes into the procedure, the patient's condition deteriorated suddenly, necessitating mechanical ventilatory support. A chest radiograph performed after intubation showed partial collapse of the affected lung with pneumothorax. Despite sufficient air drainage and lung expansion, the patient's oxygen demand remained high. A repeat chest radiograph performed 30 minutes after chest tube insertion revealed partial expansion of the affected lung and severe infiltrative patterns in the unaffected lung, suggesting contralateral reexpansion pulmonary edema.

Preliminary Prognostication for Good Neurological Outcomes in the Early Stage of Post-Cardiac Arrest Care.

We investigated prognostic strategies for predicting good outcomes in the early stage of post-cardiac-arrest care using multiple prognostic tests that are available until 24 h after the return of spontaneous circulation (ROSC). A retrospective analysis was conducted on 138 out-of-hospital cardiac-arrest patients who underwent prognostic tests, including the gray-white-matter ratio (GWR-BG), the Glasgow Coma Scale motor (GCS-M) score before sedative administration, and the neuron-specific enolase (NSE) level measured at 24 h after the ROSC. We investigated the prognostic performances of the tests as single predictors and in various combination strategies. Classification and regression-tree analysis were used to provide a reliable model for the risk stratification. Out of all the patients, 55 (44.0%) had good outcomes. The NSE level showed the highest prognostic performance as a single prognostic test and provided improved specificities (>70%) and sensitivities (>98%) when used in combination strategies. Low NSE levels (≤32.1 ng/mL) and high GCS-M (≥4) scores identified good outcomes without misclassification. The overall accuracy for good outcomes was 81.8%. In comatose patients with low NSE levels or high GCS-M scores, the premature withdrawal of life-sustaining therapy should be avoided, thereby complying with the formal prognostication-strategy algorithm after at least 72 h from the ROSC.

Tailored versus conventional surgical debridement in complex facial lacerations in emergency department: A retrospective study.

Surgical debridement is an essential step in treating complex facial lacerations (CFL). As the CFL severity increases, conventional surgical debridement (CSD) of wound edges becomes difficult and may be insufficient. Because the severity and shape of each CFL vary, it is necessary to tailor the customized pre-excisional design, that is, tailored surgical debridement (TSD), for each case before performing surgical debridement. The use of TSD can enable effective debridement of CFL with higher severity. This study aimed to compare the cosmetic outcomes and complication incidence of CSD versus TSD according to CFL severity. In this retrospective observational study, eligible patients with CFL who visited the emergency department between August 2020 and December 2021 were examined. CFL severity was graded as Grades I and II. The outcomes of CSD and TSD were compared using the scar cosmesis assessment and rating (SCAR) scale, wherein a good cosmetic outcome was defined as a SCAR score of ≤ 2. The percentage of good cosmetic outcomes between the 2 groups was compared. The SCAR score and percentage of good cosmetic outcomes between the 2 groups were compared overall and by severity. For analyzing complication incidence, asymmetry, infection, and dehiscence incidence were compared. In total, 252 patients were enrolled [121 (48.0%) CSD and 131 (52.0%) TSD]. The median SCAR scores were 3 (1-5) and 1 (0-2) in all enrolled patients (P < .001), 2 (0-4), and 1 (0-1) in Grade I patients (P < .01), and 5 (4-6) and 1 (1-2) in Grade II patients (P < .001) in the CSD and TSD groups, respectively. The percentage of good cosmetic outcomes was 46.3% and 84.0% overall (P < .001), 59.6% and 85.0% in Grade I patients (P < .01), and 9.4% and 83.5% in Grade II patients (P < .001) in the CSD and TSD groups, respectively. The incidence of complications was significantly higher in the CSD group than in the TSD group, but this was limited to asymmetry. No significant difference was noted in infection or dehiscence. Compared with CSD, TSD can lead to an objectively good cosmetic prognosis at higher CFL severity and can reduce facial asymmetry occurrence.

Large aperture asymmetric Fabry Perot modulator based on asymmetric tandem quantum well for low voltage operation.

Large aperture image modulators used as demodulator in receiver path are an important component for the use in three dimensional (3D) image sensing. For practical applications, low voltage operation and high modulation performance are the key requirements for modulators. Here, we propose an asymmetric Fabry-Perot modulator (AFPM) with asymmetric tandem quantum wells (ATQWs) for 3D image sensing. By using ATQWs for the AFPM design, the device operated at -4.25V, and the operating voltage was significantly lower by about 23% compared to -5.5V of a conventional AFPM with 8nm thick multiple QW with a single QW thickness (SQWs), while achieving high reflectivity modulation in excess of 50%. The performance of the fabricated devices is in good agreement with theoretical calculations. The pixelated device shows a high modulation speed of 21.8 MHz over a large aperture and good uniformity. These results show that AFPM with ATQWs is a good candidate as an optical image modulator for 3D image sensing applications.

Wide spectral bandwidth electro-absorption modulator using coupled micro-cavity with asymmetric tandem quantum well.

For reliable three dimensional (3D) imaging system, it is necessary for the optical shutter to have a wide spectral bandwidth operation and enhanced modulation depth. We propose an electro-absorption modulator (EAM) based on coupled Fabry-Perot cavities with micro-cavity (CCMC) which uses asymmetric tandem quantum wells (ATQWs) to obtain improved spectral bandwidth and enhanced modulation depth. Several modulator designs are investigated to obtain improved modulation performance such as wider spectral bandwidth and enhanced modulation depth. It was found that among all the studied modulator geometries, CCMC structure with ATQWs provides the widest spectral bandwidth of 9.6nm and high modulation depth in excess of 50% at -24V, which is good agreement with theoretical calculations. These results suggest that EAM has excellent potential as optical shutter for 3D imaging application.

Precise minute ventilation delivery using a bag-valve mask and audible feedback.

OBJECTIVES: The efficacy of a modified bag-valve mask (BVM) with a ventilation rate alarm system was compared with conventional BVM to maximize adequate minute ventilation volume delivery in a manikin model. METHODS: After a 30-minute instructional session on how to use the 2 types of BVM, volunteers were randomly assigned to ventilate a manikin in a 2-minute arrest simulation using 2 different types of BVM. The manikin cardiopulmonary resuscitation was performed with a mechanical chest compression device, to which we added a rate alarm, which makes a ticking sound to indicate each second and buzzes every sixth second, to ensure a regular ventilation rate (10 breaths per minute). Fifty-two volunteers attempted to squeeze the classic BVM at a rate of 8 to 10 times per minute during 2-minute trial (volume marked BVM [VBVM]). After a 1-hour break, artificial ventilation was performed at a rate of 9 times per minute with the guidance of the rate alarm (rate and volume adjusted BVM [RVBVM]). RESULTS: There were no correlations between the data and the participants' physical characteristics or levels of training. In this study, the accuracy of minute ventilation between the 2 groups showed a significant difference (P < .001). The minute ventilation rate was constant in the RVBVM group, whereas in the VBVM group, the minute ventilation rate was irregular. CONCLUSION: In a manikin arrest model, the use of RVBVM results in a more constant and regular minute tidal ventilation rate than the use of VBVM and is, therefore, expected to produce more favorable outcomes in practical resuscitative situations.

Characteristics, Possible Origins, and Health Risk Assessment of Trace Elements in Surface Waters of the Han River Watershed, South Korea.

To safeguard aquatic environments in and around the Han River watershed in South Korea, a multivariate statistical evaluation of trace elements, a trace element concentration analysis and source determination, and a human health risk assessment were conducted on 10 trace elements at 25 sites. The results demonstrated that the Han River watershed was mainly affected by anthropogenic activities (traffic/industrial activity). The range of concentrations was arranged in descending order: Fe (217.13 ± 301.03 µg/L) > Mn (102.36 ± 153.04 µg/L) > Zn (23.33 ± 79.63 µg/L) > Ba (29.05 ± 12.37 µg/L) > Ni (5.14 ± 11.57 µg/L) > Cu (3.80 ± 3.56 µg/L) > Pb (0.46 ± 0.52 µg/L) > Se (0.06 ± 0.04 µg/L) > Cd (0.01 ± 0.01 µg/L) > Ag (0.004 ± 0.013 µg/L). The hazard index values of trace elements in surface water for combined pathways (ingestion and dermal contact) were < 1.0 for both adults and children, indicating no possible human health hazards. The estimated total cancer risk did not exceed the acceptable limit (1 × 10-4) for adults and children. The findings of this study provide data-driven guidelines for water environment policy decisions in the study area.