Rice–duck and rice–crayfish co-culture patterns can increase soil productivity and sustainability and reduce the use of chemical pesticides and fertilizers, thereby reducing the resulting negative environmental impacts. However, most studies have focused on the rice–duck and rice–crayfish binary patterns and have ignored integrated systems (three or more), which may have unexpected synergistic effects. To test these effects, a paddy field experiment was carried out in the Chaohu Lake Basin, Hefei city, Southeast China. Four groups, including a rice–duck–crayfish ecological co-culture system (RDC), idle field (CK), single-season rice planting system (SSR), and double-season rice planting system (DSR), were established in this study. The results showed that the RDC improved the soil physical properties, fertility, humus content, and enzyme activity. In the RDC system, the soil total nitrogen content ranged from 8.54% to 28.37% higher than other systems in the 0-10 cm soil layer. Similar increases were found for soil total phosphorus (8.22–30.53%), available nitrogen (6.93–22.72%), organic matter (18.24–41.54%), urease activity (16.67–71.51%), and acid phosphatase activity (23.41–66.20%). Relative to the SSR treatment, the RDC treatment reduced the total losses of nitrogen and phosphorus runoff by 24.30% and 10.29%, respectively. The RDC also did not cause any harm to the soil in terms of heavy metal pollution. Furthermore, the RDC improved the yield and quality of rice, farmer incomes, and eco-environmental profits. In general, the RDC can serve as a valuable method for the management of agricultural nonpoint-source pollution in the Chaohu Lake area and the revitalization of the countryside.

An in-depth study of the degradation of bisphenol S (BPS) by both single-walled carbon nanotubes and heat activated persulfate (PS) was conducted in detail. The effects of various factors, namely, material dosage, initial substrate concentration, initial pH and the water matrix, on the removal of BPS were evaluated, and 10 μM BPS was completely removed in 90 min under the optimal conditions of [BPS]₀ : [PS]₀ = 1 : 100, T = 25 °C, pH₀ = 7.0, and [N-SWCNTs] = 20 mg L⁻¹. Fast removal of BPS was also obtained when the reaction temperature reached 65 °C without catalyst. There were 15 intermediates identified in total, and hydroxylation, sulfate addition, carboxylation, S–C bond cleavage and polymerization were considered to be the main transformation pathways of BPS in both the systems based on LC-MS analysis. The discrepancy in the proportion of hydroxyl and sulfate radicals involved in the two systems led to different distribution and abundance of the observed products. According to quantum chemical calculations, hydroxylation, hydrogen atom abstraction and sulfate addition occurred as the initial reactions between radicals and BPS. Furthermore, the intrinsic reaction coordinate (IRC) paths of the generated primary products were obtained using the program Gaussian 09. Low reaction barriers (22.20, 25.06 and 13.85 kJ mol⁻¹, respectively) revealed that the H atom linked to the phenoxy group and the ortho-C of BPS were the most likely sites to react. The present work reveals the overall transformation behavior of BPS in a radical-triggered PS system by combining experimental and theoretical study.