The naturally occurring radionuclides in the sinking particle, surface sediments, and sediment cores near the Weizhou Island in the Beibu Gulf were simultaneously analyzed by high purity germanium γ spectrometer in this study. The sinking particle at the west station of the Weizhou Island was mainly attributed to the strong sediment resuspension that was demonstrated by the combined evidences of ⁴⁰K, ²³⁴Th_ex, ⁷Be, and ²³⁸U-²³²Th（²²⁸Ra）-⁴⁰K/10 ternary diagram. Sediment accumulation rates（SAR）of two sediment cores（WZ16and WZ20）at the west stations of the Weizhou Island were calculated to be 1.46×10^-3 and 2.25×10^-3 cm/d using the constant flux and constant sedimentation rate model of excess ²¹⁰Pb. These ²¹⁰Pb derived-sediment accumulation rates were only 0.50% and 0.89% of the sediment sinking rates（295×10^-3 and 252×10^-3 cm/d）derived from sediment trap, quantitatively indicating strong sediment resuspension before the ultimate burial in sediment. Additionally, a high recruitment of coral larvae was observed at the west station with strong sediment resuspension. It was speculated that the strong biogenic sediment resuspension would provide sufficient heterotrophic energy for coral polyps.

Using the inventory model, this study evaluated the tempo-spatial characteristics of methane emissions from rice cultivation at the county level and their emission intensity per unit of rice production over the period 1980~2060. A comparison of mitigation potentials was also conducted between the baseline（BAU）scenario, the conventional technical potential（TP）scenario, and the maximum technical potential（MTP）scenario. The results showed that China's rice cultivation methane emissions decreased and then increased from 1980 to 2020, and that they decreased by 19% in 2020 compared to 1980. Over the same period, the intensity of emissions declined by 46%. Under the TP and MTP scenarios, methane emissions are reduced by 26% and 70%, respectively, while emission intensity is reduced by 26% and 68%, respectively. Rice cultivation methane emissions and their intensity have shifted to the east during the period 1980~2020, with the emission gravity center moving to the northeast by 347km and the intensity gravity center moving to the southeast by 411km during this period. Both emissions and intensities decreased in counties in the southern regions, such as Hunan, Hubei, and Jiangxi. Rice cultivation is gradually being replaced in high-intensity regions such as Xinjiang, Shandong, and Henan, which is resulting in declining emissions. Although emissions in northeastern regions have increased, their intensity levels remain relatively low. Water management for rice has the greatest mitigation potential, contributing more than 60% of the total mitigation potential. There is a high mitigation potential in regions with high emissions, such as Hunan, Hubei, Jiangxi, Heilongjiang, and Guangdong, where the average mitigation potential is twice that of other regions.

The advanced oxidation technology of persulfate（PDS）activation by CuO have been hotly sought as one of the effective strategies for degrading organic pollutants in water. However, there are still certain issues such as the low efficiency of PDS activation, the small specific surface area of CuO, and the low conversion efficiency of Cu（II）/Cu（I）. Herein, the flake copper oxide（CCB-300）with high activity and large specific surface area（32.8m²/g）was successfully synthesized through a two-step hydrothermal-calcination method. Multiple characterization analysis, such as X-ray powder diffractometry（XRD）, N₂ adsorption-desorption analysis, Scanning electron microscopy（SEM）, Transmission electron microscopy（TEM）and X-ray photoelectron spectroscopy（XPS）, were utilized to analyze crystal structure, morphology and element composition of CCB-300. Furthermore, the performance of the CCB-300 for degradation of tetracycline（TC）via peroxydisulfate activation under visible light（Vis）was investigated. The findings revealed that the TC removal rate reached 96.9% within 60minutes under the circumstances of 0.05g/L CCB-300, 0.5mmol/L PDS, 50mg/L TC and unadjusted initial pH. Electron paramagnetic resonance spectroscopy（EPR）and radical quenching experiments indicated that both ¹O₂ produced by the non-radical pathways and and ⋅OH generated via the radical pathways were involved in the degradation reaction. Ultraviolet-visible diffuse reflectance spectroscopy and photoelectrochemical tests confirmed that CCB-300 exhibited excellent visible light absorption capacity and charge transfer performance. The photogenerated electrons excited by visible light accelerate the redox cycle of Cu（II）/Cu（I）, facilitating the conversion of PDS to and ⋅OH, and further enhancing the efficiency of TC degradation. The repeatable experiments demonstrated that CCB-300exhibited favorable reusability and stability. Finally, the possible reaction mechanism was proposed. This study provided a novel method for tetracycline degradation through synergistic persulfate activation by visible light and heterogeneous catalysts.

Based on the hourly observational data from October to December 2017 in Chengdu, as well as the simultaneous data of atmospheric visibility（V）, relative humidity（RH）and nitrogen dioxide（NO₂）, aerosol hygroscopic growth factor（Gf）was retrieved by Mie scattering theory coupled with immune evolutionary algorithm, and then aerosol hygroscopic parameter κ was calculated by κ-köhler theory, the variation characteristics of aerosol hygroscopic parameter κ and its influencing factors were analyzed during the haze process. The results showed that: The aerosol hygroscopic parameters κ were 0.142±0.092、0.149±0.088、0.191±0.061and 0.200±0.041 under mild, light, moderate and heavy haze intensity conditions respectively. The set of explanatory variables of aerosol hygroscopicity parameter κ was determined, including C_BC, C_BC/C_PM2.5, C_PM1/C_PM2.5 and C_PM2.5/C_PM10（C_BC, C_PM1, C_PM2.5 and C_PM10 represented mass concentrations of BC, PM₁, PM_2.5 and PM₁₀ respectively）. There were significant differences in the explanatory power for aerosol hygroscopic parameter κ of each variable as the haze intensities changed. The multifactor GAM model could be well characterized aerosol hygroscopic parameter κ variation（passed the significance test of α=0.001）. As to the above four haze conditions, the corresponding adjusted coefficients of determination（R²）were 0.303, 0.488, 0.504 and 0.631, the coefficients of determination（R²）for the regression of the pressure axis were 0.327, 0.517, 0.558 and 0.739, and the residual sum of squares（RSS）were 1.448, 0.721, 0.209, and 0.025, respectively. The above study revealed the complexity of the multifactorial influence on aerosol hygroscopic parameter κ, and further clarified the intrinsic connection between aerosol hygroscopicity and haze evolution.

In this paper, we reviewed the measured data of heavy metals in farmland soils in Guangdong Province since 2010. We applied a meta-analysis approach to combine the data based on “average concentration” “number of sampling points” and “standard deviation”. The results showed that the concentration of lead（Pb, 48.83mg/kg）and mercury（Hg, 0.18mg/kg）in Guangdong Province are among the highest in China, likely influenced by industrial and mining activities. In addition, subgroup analyses explored the effects of spatial distribution and cropping systems across different cities. The results revealed that heavy metal concentrations were higher in the economically developed Pearl River Delta and mineral-rich regions. Notably, some of the most polluted cities include Foshan city（As:18.32mg/kg, Cr:73.5mg/kg, Ni: 35.4mg/kg）, Shaoguan city（Pb: 86.61mg/kg）, Shenzhen city（Cd: 0.51mg/kg）, Meizhou city（Cu: 61.1mg/kg）, etc. Among them, farmland soil Cd concentration was significantly correlated with regional industrial output value（r=0.77, P<0.01）, with additional impacts from factors such as the local population and energy consumption. The analyses of different farming systems showed that Cd, Pb, Zn, Cr, and Hg concentrations in soils were higher in land and paddy fields; while Cu, Zn, As, and Ni were enriched in orchards and facility-based agriculture, which may be related to the soil physicochemical properties, fertiliser and the geological backgrounds in different farming systems. This study provides province-wide information on the spatial distribution of heavy metals in agricultural soils and cropping systems, which is of great significance to the management and control strategies of heavy metal pollution in agricultural soils in Guangdong Province.

The coupling and coordinated relationship between ecosystem services and water use efficiency is calculated and analyzed according to the land use and water consumption data from 2005 to 2020 in Xinjiang. The results indicated that food production increased significantly from 2005 to 2020, while other ecosystem services had no significant change. The agricultural water efficiency was greater than 0.649 and increased with rate of 0.023/a from 2005 to 2020. The ecological water use efficiency decreased with rate of 0.013/a, and had significant regional difference. The water efficiency in domestic industry was higher and changed little. The coupling coordination degree of food production and agriculture water efficiency increased with rates of 0.057/a, and achieved highly coordination（0.995）in 2020. The coupling coordination degree of habitat quality and ecological water use efficiency decreased with rate of 0.052/a, and achieved slightly dysregulation（0.251）in 2020. The results indicated that the allocation and utilization efficiency of water resources in agricultural production reached highly coordination in Xinjiang, but the attention of ecological environment water use needs to be improved.

In order to further supplement the mechanism of the enhanced coagulation efficiency of the fine bubble co-coagulation process and the potential of the process for engineering applications, this paper investigated the effect of calcium ion concentration response on the enhanced removal of humic acid（HA）by the fine bubble co-coagulation process. The results showed that the fine bubbles could enhance the removal of HA with different calcium ion concentration responses, but the enhancement effect was different with different circulation times. When the cycle time of fine bubbles was kept constant at 1min, the participation of fine bubbles in the coagulation process could enhance the removal efficiency of HA by forcing the hydrolysis of polyaluminum chloride（PACl）, elevating the potential of the solution to the isoelectric potential, and promoting the complexation between HA and Ca²⁺, and the removal efficiency of HA increased with the increase of Ca²⁺ concentration, and the removal efficiency of HA increased about 42% with the increase of Ca²⁺ concentration, and increased about 42% with the increase of Ca²⁺ concentration, and increased about 42% with the increase of Ca²⁺ concentration. The HA removal efficiency increased with increasing Ca²⁺ concentration, up to about 42% compared to the conventional coagulation process without the presence of fine bubbles. In addition, with the extension of the fine bubbles circulation time, the Zeta potential of the solution gradually increased, which affected the enhanced removal efficiency of HA. The above findings provide data and theoretical support for the application of the fine bubble co-coagulation process in engineering practice.

The traditional environmental enforcement framework is fraught with conflicts stemming from the dichotomy between fragmented enforcement and integrated governance, the tension between local protectionism and stringent environmental regulation, and the disparity between imbalanced information structures and the need for precise governance. These conflicts have led to weakened environmental regulation and a concomitant decline in environmental quality. In response, the Chinese central government has initiated a centralized environmental enforcement system reform（EESR）. The theoretical underpinnings of this reform are rooted in the integration of functions to mitigate the fragmentation, the reconfiguration of power to prevent local interference, and the leveraging of technology to facilitate comprehensive and transparent oversight. Based on this, we have constructed annual panel data for 192 prefecture-level cities spanning the period from 2013 to 2022. Utilizing a Difference-in-Differences（DID）approach, we found that EESR has significantly led to stricter environmental enforcement, with a post-EESR increase of 49.8% in environmental administrative penalties levied by cities. However, economic factors would modulate the efficacy of the EESR. Cities closer to the western regions exhibit a less pronounced positive impact of the reform on environmental enforcement. Further analysis indicated that the EESR has had a significant positive effect on air quality, with substantial reductions in concentrations of PM_2.5, PM₁₀, and SO₂ following its implementation. This study offers guidance for the further development and improvement of the EESR in later stages, as well as insights into understanding the positive effects of a centralized environmental control system.

This paper investigated the application of an improved perfusion method for microbial-induced calcium carbonate precipitation（MICP）technology in the solidification of heavy metals. Bacillus pasteurii was employed as the urease-engineered bacterium, and a 0.5cm diameter channel filled with pebbles and wire mesh was constructed to facilitate the injection treatment of industrial solid waste tailings. The migration behavior of heavy metals in the tailings was examined, the mechanisms of MICP solidification were analyzed, and a risk assessment was conducted. The results indicated that, following MICP treatment, the migration factors（MF）of Cu, Pb, and Cd in the tailings were significantly reduced by 78.94%, 61.88%, and 64.06%, respectively. Calcium carbonate precipitation was formed, filling the tailings model box and significantly increasing the residual fractions of Cu, Pb, and Cd（76.43%~92.48%）. Consequently, the environmental risks of Cu, Pb, and Cd were reduced from very high to moderate levels, significantly lowering the pollution risk of the tailings. The improved perfusion method was shown to enhance the diffusion channels of the bacterial solution, increased its contact efficiency with the tailings, promoted rapid calcium carbonate precipitation and solidification, and ensured uniform penetration while avoiding uneven solidification. This study provides a valuable reference for the engineering application of MICP technology in heavy metal pollution remediation.

Using surface meteorological and air quality observational data and the 5^th Generation of ECMWF Reanalysis data（ERA5）, the characteristics of ozone（O₃）pollution impact by the sea-land breezes（SLBs）over the Pearl River Estuary（PRE）in 2022 were studied. The results showed that the SLBs days in the seven cities of PRE were at the range of 40~64, and most of SLBs days occurred in spring and autumn. The averaged median of maximum daily 8-hour average of O₃（O₃-8h）and over-standard rate of regional SLBs days were 141µg/m³ and 38%, respectively, while only 74µg/m³ and 11% were found in non-SLBs days. The averaged O₃-8h were 26%, 41% and 29%, respectively, higher in SLBs days than those of non-SLBs days in Zhuhai, Zhongshan and Jiangmen（ZZJ）, the three cities located in the western part of PRE, indicating that the impact of SLBs was the most significant in those areas. The averaged time of peak concentration in SLBs days was 0.5h later than that of non-SLBs days, with 29% increase in averaged peak concentration. When the sea breezes firstly occurred at 17:00 and 18:00, 72% and 41% of the hourly growth rates of ozone concentrations were positive, and the averaged growth rates were 5% and 7% higher, respectively, than those of non-SLBs days. But the growth rates declined obviously 1h after the occurrence of sea breezes. The averaged recirculation factor（RF）of SLBs days was 39% lower than those of north wind days and south wind days. RF of transition periods was 14% and 15% lower than those of land and sea breezes periods, respectively. Besides, compared to non-SLBs over-standard days, RF in SLBs over-standard days was 28%lower. The atmospheric diffusion capability was weakened by the SLBs, and that exacerbated the ozone pollution.