Water Environment Pollution and Control, Volume III

This study analyzed the distribution characteristics and sources of pollutants in the coastal estuaries of Zhanjiang Bay (ZJB) to provide theoretical and data support for the scientific prevention and control of bay pollution. Monitoring data from eight rivers and flood drains flowing into ZJB in March 2021 were used to analyze the composition and spatial distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) and phthalate esters (PAEs) in the water bodies of the bay. The dominant components in the eight rivers and flood drains were 3–4-ring PAHs, with Bis (2-ethylhexyl) phthalate (DEHP), Diisobutyl phthalate (DIBP), and Dibutyl-O-phthalate (DBP) being the main PAE compounds. Higher pollutant levels were observed in residential areas, aquaculture zones, and industrial areas. Eigen-ratio analysis and principal component analysis were used to identify pollution sources, including atmospheric inputs (coal, petroleum products, biomass combustion products), offshore petroleum pollution, and plastic pollution sources. The assessment showed that atmospheric inputs contributed to 89.75% of the total PAHs in the bay, with coal and biomass combustion accounting for 62.12% and petroleum fuel combustion accounting for 27.63%. The content of ΣPAEs ranged from 588.43 to 1427.26 ng·L⁻¹, with a mean value of 906.59 ng·L⁻¹, which is at a low to medium level compared to other regions of China and abroad, indicating a medium-low level of pollution risk. The results of this study have important implications for guiding urban development, adjusting energy consumption structures, and planning pollution prevention and control measures in ZJB. Full article

The improvement of water usage efficiency and productivity, as well as the development of effective water management plans, necessitates a comprehensive understanding of how water utilization patterns in different soil layers within arid and semi-arid climates impact the capacity of plant roots to absorb water. However, there is currently no knowledge regarding the water use strategies employed by artificial yellow willow. So, we conducted a study on the hydrogen and oxygen isotopic composition of rainfall in yellow willow (Salix gordejevii) from the semi-arid region located at the southern edge of the Hunshandak Sandland in China. This study utilized measured data on xylem water, groundwater, soil moisture, and rainfall. By employing a combination of the direct comparison method and the MixSIAR model, we investigated the water uptake strategies employed by yellow willow throughout its growing season. The findings revealed that the mean δ D was highest in precipitation and lowest in groundwater, whereas the mean δ¹⁸O was highest in stem water and lowest in groundwater. The δ D and δ¹⁸O fluctuated significantly in precipitation but were steady in groundwater. Because precipitation was significantly less than evaporation, the slope and intercept were lower for the local than global atmospheric precipitation line. Water availability steadily declined with increasing depth. Lower δ¹⁸O values were caused by precipitation diluting the soil water. The MixSIAR results indicated that the primary source in May, September, and October was utilized at 19%, 18%, and 18%, respectively. In contrast, the utilization rate of each source varied considerably in June, July, and August (the primary source was utilized at 19%, 18%, and 18%, respectively). Comparatively high rates of water absorption and utilization were observed in June (19% of the total water source), July (18%), and August (23%). Therefore, the vertical distribution of the root system and variations in the soil water content regulate water usage for the yellow willow. To prevent excessive water usage and promote ecosystem restoration with artificial yellow willow plantations in water-limited desert settings, policy makers should consider the patterns of plant water use and soil water availability. By selecting drought-adapted plant species and optimizing irrigation management, it is possible to reduce water wastage and ensure that water is used efficiently for revegetation and ecosystem restoration, avoiding overuse of water and maintaining the sustainability of revegetation in water-stressed desert areas. Full article

It is imperative to elucidate the process of evaporation in lakes, particularly those that are freshwater and are situated in middle and high latitudes. Based on one-year evaporation and high-frequency meteorological–water quality data of Lake Wuliangsuhai, this study analyzed the applicability and driving mechanism of the evaporation model. These dynamics are elucidated by the vorticity covariance method combined with the multivariate constrained evaporation Modelling method. The findings of this study revealed that (1) Lake evaporation (ET) is affected by multiple meteorological–water quality constraints, and the water quality indicators significantly related to ET are also affected by lake stratification. The coupled meteorological–water quality evaporation model can explain 93% of the evaporation change, which is 20% higher than the traditional meteorological Modelling evaporation model. (2) The nighttime ET is mainly affected by the thermal inertia lag, and the nighttime ET loss in Lake Wuliangsuhai accounts for 37.34% of the total evaporation, which cannot be ignored. (3) The actual water surface evaporation of the lake is much smaller than that measured by the pan conversion method and the regional empirical C formula method. The cumulative evaporation of Lake Wuliangsuhai from the non-freezing period to the early glacial period converted from meteorological station data is 1333.5 mm. The total evaporation in the non-freezing period is 2.77~3.68 × 10⁸ m^3, calculated by the lake area of 325 km², while the evaporation calculated by the eddy station is 1.91 × 10⁸ m³. In addition, the ET value measured by the cumulative C formula method was 424.2% higher than that of the model method and exceeded the storage capacity. Low-frequency and limited environmental index observations may lead to an overestimation of the real lake evaporation. Therefore, in situ, high-frequency meteorological–water quality monitoring and the eddy method deserve more consideration in future research on lake evaporation. Full article