Hydrochemistry and source apportionment of boron, sulfate, and nitrate in the Fen River, a typical loess covered area in the eastern Chinese Loess Plateau.

Fen River Basin (FRB) is water-deficient and strongly influenced by human activities in the eastern Chinese Loess Plateau. The spatio-temporal variation and controlling factors of hyrochemistry and quality, sources of high boron, sulfate, and nitrate of surface waters in FRB were unclear. Major ions, δ11B, δ15N, and δ18O in surface waters in dry season and wet season of FRB were analyzed and correlation analysis (CA), principal component analysis (PCA), self-organizing map (SOM), forward model, and Bayesian isotope mixing model (MixSIAR) were used to solve above problems. Results showed that average riverine δ11B, δ15N, and δ18O of FRB was 7.8‰, 11.2‰, and 1.3‰ (1SD), respectively. Dissolved solutes ranked midstream > downstream > upstream with water type of Na +-Cl-, Ca2+-Mg2+-Cl-, and Ca2+-HCO3-, respectively. Low dissolved solutes were in forest areas while high values were in cropland and city areas. SOM analysis indicated that hydrochemistry was both influenced by natural (upstream) and pollutional input (midstream and downstream) and variation between dry season and wet season was minor. The abnormally high boron concentrations were mainly from silicate weathering (43%) and evaporites dissolution of loess (32%), urban and industrial input contributed 15% of riverine boron. High SO42- (207 ± 267 mg/L, 1SD) was mainly from sulfates. δ15N and δ18O analysis indicated that nitrification was the primary N cycling process. Further, MixSIAR showed that NO3- was mainly from municipal sewage (∼67%) and the total contribution of chemical fertilizer and soil nitrogen was ∼30% with slightly higher values in upstream and wet season. Influenced by land-use types, evaporite dissolution, and anthropogenic input, water quality below midstream was worse and strict sewage reduction policies must be developed. This study highlights the significant influence of evaporite dissolution of loess and anthropogenic input (urban and industrial input for B and sewage for NO3-) on hydrochemistry and water quality.

Cardiac Injury and Clinical Course of Patients With Coronavirus Disease 2019.

Background: Cardiac injury is recognized as one of the most common critical complications during exacerbation of coronavirus disease 2019 (COVID-19). This study aimed to investigate the effect of cardiac injury on the clinical course of COVID-19 and to examine its potential mechanism and treatments. Methods and Results: A total of 222 hospitalized patients with COVID-19 from Wuhan were selected for the study during February 10 to March 28, 2020. Demographic, laboratory, and clinical data on admission and during hospitalization were compared between patients with COVID-19 with or without cardiac injury. On admission, cardiac injury (n = 29) was associated with advanced age, more underlying coronary artery disease, and a lower Pao2. Troponin levels were correlated with inflammatory markers (C-reactive protein: r = 0.348, P < 0.001; interleukin 6: r = 0.558, P < 0.001) and d-dimer levels (r = 0.598, P < 0.001). During hospitalization, another six patients suffered from cardiac injury and cardiac injury (n = 35), resulting in higher rates of ventilation (invasive: 51.4 vs. 1.6%, P < 0.001; non-invasive: 31.4 vs. 1.1%, P < 0.001) and mortality (54.3 vs. 1.1%, P < 0.001). Cardiac injury on admission was a predictive factor for mortality (adjusted hazard ratio = 4.73, 95% confidence interval = 1.35-16.63, P = 0.015). Receiver operating characteristic curve analysis showed that, on admission, a troponin level of 36.35 pg/mL was predictive for mortality with a sensitivity of 73.7% and a specificity of 92.1%. Conclusions: Cardiac injury complicates the disease course and increases the mortality rate of COVID-19. Troponin levels should be checked at admission and during hospitalization for triage, better monitoring, and managing those with COVID-19, especially in the most severe patients. Condensed Abstract: Cardiac injury is not uncommon in COVID-19. In a cohort of 222 patients with COVID-19, cardiac injury was found in 29 patients on admission and in another 6 patients during hospitalization. The admission level of troponin was well-correlated with inflammatory factors and d-dimer levels and strongly predicted mortality. Cardiac injury is a manifestation secondary to hypoxia and systemic infection, but which nevertheless further complicates the disease course and increases the mortality rate. Troponin levels should be checked at admission and during hospitalization for triage, better monitoring, and managing those with COVID-19, especially in the most severe patients.