Combined sewer overflows (CSOs) are one of the main sources of pollution in urban water systems and significantly impede the restoration of water body functionalities within urban rivers and lakes. To understand the research and frontier trends of CSOs comprehensively and systematically, a visual statistical analysis of the literature related to CSOs in the Web of Science core database from 1990 to 2022 was conducted using the bibliometric method using HistCite Pro and VOSviewer. The results reveal a total of 1,209 pertinent publications related to CSOs from 1990 to 2022, and the quantity of CSOs-related publications indicated an increasing trend. Investigations of the distribution and fate of typical pollutants in CSOs and their ecological effects on receiving waters and studies on pollution control technologies (source reduction, process control, and end-of-pipe treatment) are the current focus of CSOs research. CSOs pollution control technologies based on source reduction and the monitoring and control of emerging contaminants are at the forefront of scientific investigations on CSOs. This study systematically and comprehensively summarized current research topics and future research directions of CSOs, thus providing a reference for CSOs control and water environment management research.

The chemical flame retardants represented by organophosphate esters (OPEs) are widely used and have a serious impact on the environment. In this study, we collected data on the exposure levels of ten OPEs in Chinese soils in recent years and performed an ecological risk assessment. The results showed that the levels of OPEs varied considerably throughout different regions of China, with high exposure levels in highly urbanized or industrialized areas such as Guangdong Province and Northeast China, where the mean value was >200 ng/g. The content of OPEs in the soil in industrial and commercial areas was significantly higher than in other regions, indicating that the concentration of OPEs in the soil is closely related to local economic development and the degree of industrialization. Meanwhile, the number of studies reporting on OPEs and their exposure concentrations have increased significantly since 2018. Through the ecological risk assessment, it was found that TCP, EHDPP and TEHP pose high ecological risks. Although some OPEs, such as TCIPP, have low ecological risk levels overall, their high exposure concentrations are still worthy of attention. This study details the general status of OPE contamination in Chinese soils, which can serve as a reference for ecological environmental supervision.

The reuse of reclaimed water (RW) for irrigation and recharge is a promising approach to mitigate water scarcity and promote efficient water resource management. Nevertheless, there is increasing concern regarding the ecological and environmental impacts of soil and groundwater contamination resulting from the irrigation and recharge of RW. To understand the current state of research on the ecological risk of soil and groundwater during RW reuse, a bibliometric analysis of 1109 publications throughout 2002-2021 in the Web of Science Core Collection (WoSCC) database about the research topic was conducted. Through the use of HistCite Pro and Citespace, this study analyzed and visualized the number of publications, authors, citation frequency, keywords, institutions, journals, and countries where these publications have appeared. The results of this research showed an ongoing rise in the total number of publications during the 20 years prior. China was identified as the most prominent country in terms of production in this field, while the Chinese Academy of Sciences showed the highest level of productivity among institutions. Water has been identified as the most productive journal, while Li YK was identified as the most productive author. This current research focuses on the migration and transformation of RW contaminants in the soil-groundwater system and their ecological effects on soil and plants, whereas future research will concentrate on the risk assessment and health effects of emerging contaminants (ECs). The analysis presented in this study provides insights into research orientations, historical trends, and current research hotspots in the field of study. The aforementioned findings will offer valuable insights for formulating development strategies pertaining to RW reuse. Additionally, they will serve as guidance for decision-making processes within governmental management organizations

Introduction: Cultivated land resources are essential for maintaining food security and promoting agricultural economic growth. However, the reduction in cultivated land area and environmental contamination have hindered the sustainable and healthy development of agriculture. Understanding the impact of cultivated land use transformation (CLUT) on agricultural green total factor productivity (AGTFP) is therefore a crucial step toward advancing sustainable agriculture. Methods: This study utilizes panel data from 62 cities in the Yellow River Basin between 2000 and 2020. We employ the entropy weight method to assess cultivated land use transformation, and the super-efficient non-radial SBM model with the GML index to measure AGTFP. A two-way fixed effects model is established to examine the influence of CLUT on AGTFP. Results: The findings indicate that: (1) From 2000 to 2020, the CLUT index showed a fluctuating upward trend, peaking in the southeastern regions and being lowest in the central areas, indicating a movement toward regional equalization. (2) AGTFP also exhibited an overall fluctuating rise, with substantial growth concentrated in the middle and lower reaches and the central part of the upstream section. Productivity growth in the upstream and midstream sectors was mainly driven by efficiency change (EC), whereas the downstream sector was advanced by technical change (TC). (3) Cultivated land use transformation significantly contributes to AGTFP, with a stronger effect observed in major grain-producing areas and eastern regions. Both functional and modal transitions of cultivated land use significantly promote AGTFP, with modal transitions being more effective. In major grain-producing areas and production-marketing balance areas, both types of transformations promoted AGTFP, though functional transformation had a greater effect in major grain-producing areas. Discussion: This paper provides mechanistic and empirical evidence on how cultivated land use transformation affects AGTFP from a spatio-temporal perspective. The results offer a scientific reference for formulating policies to ensure food security and promote high-quality development in the agricultural economy.