Aquatic plants play an essential role and are effective in mitigating lake eutrophication by forming complex plant-soil system and retaining total nitrogen (TN) and phosphorus (TP) in soils to ultimately reduce their quantities in aquatic systems. Two main vegetation types (Phragmites australiscommunity andP. australis+Typha latifoliacommunity) of Qin Lake wetland were sampled in this study for the analysis of TN and TP contents and reserves in the wetland soils. The results showed that (1) the consumption effect of Qin Lake wetland on soluble N was much more significant than on soluble P. (2) The efficiency of TN enrichment in wetland soil was enhanced by vegetation covering ofP. australisandT. latifolia. (3) Wetland soil P was consumed byP. australiscommunity and this pattern was relieved with the introduction ofT. latifolia. (4) According to the grey relativity analysis, the most intensive interaction between plants and soil occurred in summer. In addition, the exchange of N in soil-vegetation system primarily occurred in the 0–15 cm soil layer. Our results indicated that vegetation covering was essential to the enrichment of TN and TP, referring to the biology-related fixation in the wetland soil.

Ulva prolifera (U. prolifera), a global eco-environmental issue, has been recurring annually in the Yellow Sea of China since 2007, leading to significant impacts on the coastal ecosystem and the economies of coastal cities. To enhance the frequency of daily monitoring for U. prolifera and to advance the multi-source remote sensing monitoring system, a combination of the Sentinel-1 SAR remote sensing satellite and the Sentinel-3 OLCI and NPP VIIRS optical remote sensing satellites was employed. This comprehensive analysis encompassed the examination of Sentinel-1 C band characteristics, the range of influence of U. prolifera, and the migration trajectory of its enrichment zones. On 6 June 2021, three satellite images depicted the northwest drift of U. prolifera, followed by a southward movement after making contact with the coast of Qingdao, China, on 12 June. The most extensive impact area caused by U. prolifera was observed on 18 June. Subsequently, the images revealed a contraction and enrichment of U. prolifera in an eas–-west direction. The amalgamation of radar and optical remote sensing satellites in a multi-frequency monitoring approach allows for a continuous all-weather surveillance mechanism for U. prolifera. This mechanism serves to provide timely alerts for the prevention and management of U. prolifera outbreaks.

Hongze Lake is the first natural sink for transferring drinking water along the east route of the South-to-North Water Diversion Project in China. Thus, the assessment of health risk associated with sediment and soil in Hongze Lake is of vital importance in terms of protecting public health. This study surveyed the distribution of sixteen polycyclic aromatic hydrocarbons in different types of bank soils and sediments at the estuary area of Hongze Lake. The total concentrations of PAHs range between 562.4 and 1585.8 ng/g, and 3- and 4-ring PAHs are the majority in all samples, accounting for 78.2% to 92.3% of the total PAHs. Source analysis was conducted, and the results showed that PAHs in the estuary area mainly come from the burning of fossil fuels, leakage of oil products, low temperature combustion, biomass fuel, and transportation. The risk assessment of the study area showed that the K values of all the points were between 0.1~3, indicating that there was a low ecological risk. This study indicates that further policies for controlling pollution sources of PAHs are needed for reducing health risks associated with fresh water in Hongze Lake.

This research conducted a series of experiments, determined that 40% is the optimal sand-soil ratio, built three rain gardens, and planted Ilex chinensis Sims and Cynodon dactylon as a key element in the rain gardens. Among them, rain garden A was planted with only Cynodon dactylon for a one-year observation period. Rain gardens B and C, designed as three-year rain gardens, were planted with Ilex chinensis Sims or Cynodon dactylon, respectively. The method of simulating rainwater runoff was used to monitor the rain gardens continuously. The results showed that the total runoff reduction rates of rain gardens A, B, and C were 43%, 53%, and 55%, respectively. The average removal rates of pollutant suspended solids in rain gardens A, B, and C were 94%, 88%, and 87%, respectively, and the suspended solids pollution load reduction rate reached 96%, 94%, and 95%, respectively. This would be significant for future work and as a reference for the selection of plants for rain gardens in China. Keyword : Ilex chinensis Sims, Cynodon dactylon, rain gardens, suspended solids removal, water cleaning technologies, biotechnologies in environmental engineering