In this study, two open-pit coal mine dumps in Ordos City, Inner Mongolia, namely, Shigetai and Heidaigou, were selected as research subjects. Soil physicochemical properties, structure, heavy metal pollution (assessed using a single-factor evaluation index), and their interrelationships were analyzed at each dumping site along eight directions: east, west, south, north, northeast, northwest, southeast, and southwest. The aim of this study was to elucidate the factors influencing heavy metal contamination in open-pit coal mine dumps. The results of this study can guide the selection of ecological remediation measures for mining areas based on local conditions. The results showed that: (1) There were considerable differences in soil physicochemical properties, structure, and heavy metal contamination between the Shigetai and Heidaigou mining areas. (2) Soil total phosphorus varied considerably among the different orientations in Shigetai, whereas there was a considerable difference in soil total potassium among the different orientations in Heidaigou. (3) Heavy Cd pollution was observed, and there was slight Mn pollution in Shigetai. In Heidaigou, there was heavy Cd pollution and slight Cu and Ni pollution. (4) While there was a considerable difference in the level of Cd pollution along the different directions in Shigetai, the level of Mn pollution showed no correlation with direction. There was a considerable difference in Ni pollution levels among the different orientations in Heidaigou, whereas Cd and Cu pollution levels were not related to orientation. (5) The trends in the Cd pollution levels in Shigetai and Ni in Heidaigou along the different directions were generally consistent with the changes in their topography. In other words, areas with lower topography experienced more severe heavy metal pollution. (6) Correlation analysis revealed that the level of heavy metal contamination was strongly associated with soil pH, total K content, and the proportion of large-sized soil particles. In conclusion, varying levels of heavy metal pollution were observed in the different mining dumps. Significant correlations were observed between three soil environmental factors, namely, the topography of the dump, soil fertility, soil structure, and the level of soil heavy metal pollution.
Currently, industrial enterprises primarily utilize two initial rainwater collection methods based on time (first 15 ~ 30 min) and depth (first 20 ~ 30 mm) according to the relevant specifications and standards. However, online monitoring and control of rainwater discharge water quality in chemical industrial parks is relatively weak and there is limited research on the pollution control effects of different initial rainwater collection methods. This study utilized monitoring data from rainwater outlets in a Shanghai chemical industrial park to investigate the pollution risks associated with different initial rainwater collection methods and align them with the requirements for pollution emission load control and water quality compliance. The cumulative distribution curve of the runoff pollution load was used to examine the response of key water quality indicators to rainfall. This study discusses variations in different initial rainwater collection and management methods in chemical industrial parks from the perspective of pollution reduction. Chemical companies generally adopt time-based initial rainwater collection for operational convenience during continuous heavy rainfall, with its rainwater pollution control effect being relatively limited. Therefore, it is recommended that chemical industrial parks adopt depth-based collection methods tailored to rainfall characteristics to effectively reduce rainwater pollution loads and mitigate pollution risks.
This study developed an evaluation system for urban wastewater treatment plants (WWTPs) based on Environment, Social, Governance, and Economy (ESG + E), encompassing four dimensions: environmental impact, social responsibility, corporate governance, and economic benefits. Seven detailed criteria and twenty evaluation indicators were developed accordingly. The analytic hierarchy process method and fuzzy comprehensive evaluation method were used to create the evaluation model, which was then used to evaluate the overall performance of three urban WWTPs in Shanghai. The results showed that WWTP1 and WWTP3 performed exceptionally well, while WWTP2 performed admirably. Recommendations for WWTP2 include improving resource utilization, diversifying employee training, and strengthening disclosure systems. The evaluation results were consistent with the WWTPs’ actual operational status, demonstrating the accuracy and scientificity of the evaluation system. This study provides a useful reference for the performance evaluation of urban WWTPs.
Owing to the tidal dynamic inundation, the vegetation information of low cover saltmarsh located at the front of tidal flat and edge of tidal ditch in the estuarine and coastal area is difficult to accurately extract using common terrestrial vegetation indices. This study considered the tidal flat wetland in the Yangtze River Estuary as research area. Based on the comparison and evaluation of commonly used terrestrial vegetation indices, combined with the humidity index, a vegetation index ETFVI (Estuarine Tidal Flat Vegetation Index) suitable for the intended region was developed. The accuracy of the extracted vegetation distribution information and the inverted fractional vegetation cover results was verified. The results suggested that, compared with the commonly used eight vegetation indices, ETFVI improved the extraction accuracy and F1 score of vegetation distribution information by 10.38% and 6.9%, respectively, compared to the second place considering the impact of humidity changes of underlying surface on vegetation indices. The fractional vegetation cover inversion results based on ETFVI are consistent with the actual situation, with the lowest mean relative error among various vegetation indices. The study results can provide new ideas and methods for monitoring spatiotemporal changes of vegetation cover in estuarine tidal wetlands.
The measurement errors of particulate carbon and nitrogen in water using three pretreatments were evaluated quantitatively, and impact factors were discussed. Next, an optimized sample collection, pretreatment, and measurement method was suggested. The results showed that the measurement errors of samples analyzed on whole filters were the lowest, and those of samples pretreated by scraping were the highest. The measurement errors of carbon were lower than those of nitrogen and were negatively related to the carbon content on the filter (r = –0.545, p = 0.000). When the carbon content on the filter was > 0.5 mg, the measurement error of the carbon was < 10%. When the carbon content on the filter reached 1 mg, the measurement error could be < 5%. In conclusion, the predominant factors influencing the measurement error were the carbon content, uniformity of the particulate, and sample residue on the filter. The results suggested that more complicated factors influenced the measurement of nitrogen content. An optimized method for the sample collection, pretreatment, and measurement was recommended, namely, a smaller glass microfiber filter (GF/F: diameter 25 mm) should be used to collect the samples, the whole filter should be analyzed without cutting and scraping pretreatment, and the carbon content of the particulate matter on the filter should be > 0.5 mg.
中国综合性科技类核心期刊(北大核心)
