Effect of freeze-thaw frequency plus rainfall on As and Sb metal(loid)s leaching from the solidified/stabilized soil remediated with Fe-based composite agent.

The composite agent of ferrous sulfate, fly ash, and calcium lignosulfonate (FFC) can remediate the soil contaminated by As and Sb under cyclic freeze-thaw (F-T) via stabilization/solidification (S/S). However, the impact of high-frequency F-T cycles on the leaching behavior and migration of As and Sb in FFC-treated soils remains unclear. Here the leaching concentrations, heavy metal speciation (Wenzel's method), and Hydrus-1d simulations were investigated. The results showed that FFC effectively maintained the long-term S/S efficiency of arsenic remediation subject to an extended rainfall and freeze-thaw cycles, and stabilized the easily mobile form of As. The short-term S/S effect on Sb in the remediated soils suffering from F-T cycles was demonstrated in the presence of FFC. In a 20-year span, the mobility of Sb was affected by the number of F-T cycles (FT60 > FT20 > FT40 > FT0) in soil with a depth of 100 cm. As leaching progressed, FFC slowed the upward proportion of adsorbed As fractions but converted parts of the residual Sb to the form of crystalline Fe/Al (hydro) oxide. Moreover, the adsorption rate and capacity of As also preceded that of Sb. Long-term curative effects of FFC could be observed for As, but further development of agents capable of remedying Sb under cyclic F-T and long-term rainfall was needed. The predictive results on the migration and leaching behavior of heavy metals in S/S remediated soils may provide new insight into the long-term assessment of S/S under natural conditions.

Hemoglobin-to-Red Cell Distribution Width Ratio is Associated with All-Cause Mortality in Critically Ill Patients with Traumatic Brain Injury.

BACKGROUND: Hemoglobin-to-red cell distribution width ratio (HRR) has shown good prognostic value in various cancers. However, the relationship between HRR and outcomes in critically ill patients with traumatic brain injury (TBI) remains unclear. This study aimed to investigate the association between HRR and mortality among critically ill patients with TBI. METHODS: The Medical Information Mart for Intensive Care-IV (MIMIC-IV) database was utilized to conduct this retrospective cohort study. TBI patients were divided into four quartiles according to their HRR values. The primary outcome was 30-day mortality, whereas the secondary outcomes were 60-day and 120-day mortality. Univariable and multivariable Cox proportional risk models were performed to evaluate the hazard ratio (HR) and 95% confidence interval (CI) for the relationship between HRR and mortality. Receiver operating characteristic (ROC) curves were conducted to assess the prognostic value of HRR. RESULTS: For 30-day mortality, after adjustment for all potential covariates, the relationship remained significant with HRR treated as a continuous variable (HR, 95% CI: 0.87 [0.81, 0.92]; p < 0.001). In the fully adjusted model, the HR with 95% CI for the second, third, and fourth quartile groups were 0.67 (0.5, 0.9), 0.65 (0.46, 0.94), and 0.5 (0.32, 0.79), respectively, compared to the first quartile group. A similar relationship was also observed for 60-day mortality and 120-day mortality. HRR had a better predictive value than hemoglobin and red cell distribution width (RDW). CONCLUSIONS: A lower level of HRR is significantly associated with higher all-cause mortality among critically ill patients with TBI.