Conflict between urbanization and water environmental protection: Lessons from the Xiangjiang River Basin in China.

China, the largest developing country, has experienced rapid urbanization since its reform and opening-up. However, the increasing pollution load from urban areas has deteriorated urban river water quality, contradicting the concept of sustainable and green development promoted by the Chinese government. This situation elucidates governmental shortcomings in systematic environmental protection. Our study revealed that the current wastewater treatment plant (WWTP) discharge standards in urban areas are insufficient for attaining the desired urban river water quality and thus intensify the conflict between urbanization and water environmental protection. As urbanization continues, the urban population will grow, further exacerbating pollution and conflict. Our focus was the Xiangjiang River basin in Zunyi, a typical urbanized city in China. Using a validated one-dimensional mathematical model, we compared the water quality in the Xiangjiang River between current and upgraded WWTP discharge standards. The results showed that the water quality in the Xiangjiang River falls short of the standards, with more than 60 % of the river exceeding limits. However, upgrading WWTP discharge standards significantly reduces the proportion of river sections exceeding limits, with only 0.4 % exceeding standards during specific periods. This enhancement greatly improved the Xiangjiang River's water quality, aided in restoring the entire water environment in the basin, and supported water environmental protection goals. Our research findings offer crucial support for local governments in shaping comprehensive water environmental protection policies and insights for addressing similar environmental challenges caused by rapid urbanization in other developing regions.

Restoration of a fish-attracting flow field downstream of a dam based on the swimming ability of endemic fishes: A case study in the upper Yangtze River basin.

The construction of fish passage facilities can mitigate the negative effects of dams and other water engineering construction on river connectivity and have a significant positive effect on the conservation of local fish diversity. To attract target fishes into fish passage facilities effectively, the optimal flow velocity range to attract fish must be determined. Three local endemic species of the Mishi Reservoir were considered as the protection targets. However, their swimming abilities remain unclear. Therefore, the induced swimming speed (Uind), critical swimming speed (Ucrit) and burst swimming speed (Uburst) of three fish species were tested. Based on these results, we identified the optimal flow velocity to attract fish, which falls within the range of 0.15-0.51 m/s. A validated three-dimensional hydrodynamic model was used to simulate different schemes. By comparing the flow field simulation results of different schemes, we obtained the optimal measure to restore the flow field, namely, a multiple engineering measure combining increased the fish attraction flow in the fish collection pond and the construction of a spur dike. This study offers a solution for the specific case and enhances the database of swimming characteristics of endemic fish in the upstream reaches of the Yangtze River. It also provides a valuable reference for designing fish-attracting flows and potential measures for restoring flow fields in similar future projects.

Serial Cardiac MRI for Quantification of the Dynamics of Anthracycline-Induced Subclinical Myocardial Injury.

BACKGROUND: Anthracyclines are known to be associated with chemotherapy-induced cardiotoxicity. Limited data focus on dynamic myocardial injury during the course of chemotherapy in patients with breast cancer. PURPOSE: To investigate the variation of tissue characterization and myocardial deformation derived by cardiac MRI during anthracycline chemotherapy. STUDY TYPE: Prospective. POPULATION: Fifty-eight female breast cancer patients (mean age: 52.82 ± 2.61 years) were enrolled. FIELD STRENGTH/SEQUENCE: A 3.0-T, cardiac MRI including cine balanced steady-state free precession, a modified Looker-Locker inversion recovery (MOLLI), and a fast spin echo (FSE) T2-weighted sequences were performed. ASSESSMENT: Cardiac MRI was performed baseline and after two, four, and six cycles of chemotherapy. Assessment of global longitudinal strain (GLS), global circumstance strain (GCS), global radial strain (GRS), and strain rate (GLS-s, GCS-s, GRS-s) and T1, T2 and T2* were accomplished by CVI42. The anthracycline dose and risk factors were also collected before each cardiac MRI. STATISTICAL TESTS: Analysis of variance (ANOVA) for repeated measures was used to compare the changes in LVEF cardiac function, strain and T1/T2/T2* parameters over time. Pearson correlation analyses were performed to estimate the potential associations between differences in myocardial characteristics (∆) and the chemotherapy cycle. A P value <0.05 was considered statistically significant. RESULTS: LVEF was not significantly different from pretreatment MRI regarding each cycle of chemotherapy (P = 0.54). Compared with baseline, patients had significantly lower GLS (-15.85% ± 0.83%, -14.50% ± 0.88%, -12.34% ± 1.01% vs. -18.82% ± 0.92%) and GLS-s (-0.71% ± 0.07%, -0.65% ± 0.05%, -0.64% ± 0.04% vs. -0.95 ± 0.06%) and increased T2 values (57.21 ± 4.27 msec, 58.60 ± 3.93 msec, 58.10 ± 3.17 msec vs. 43.88 ± 3.28 msec) at two, four and six cycles of chemotherapy treatment. ∆GLS and ∆GLS-s were significantly associated with the chemotherapy cycle (correlation coefficients for GLS = 0.75, GLS-s = 0.75). DATA CONCLUSION: Cardiac MRI can precisely detect the dynamic changes of anthracycline-induced subclinical myocardial injury that is represented as a gradually decrease in GLS and GLS-s. These parameters may provide new insight for monitoring risk and therapy in patients with breast cancer. EVIDENCE LEVEL: 2. TECHNICAL EFFICACY: Stage 1.