Evidence from experiments, modeling, and field observations for effects of increased salinization on re-distribution of sediment base cations in Taihu Lake, China.

Taihu Lake, the third largest freshwater lake in China, has experienced rapid salinization in the past decades; however, little is known about the impact of sodium (Na) on ion exchange in the lake environment. To explore the potential effect of increased Na on the migration of base cations (Ca and Mg) and resulting redistribution between the water and sediment, we used the adsorption-exchange experiment, MINTEQ modeling to explore the cation exchange induced by high Na input, and its impact on the redistribution of Ca and Mg in Taihu different media. The results indicated that exchanged quantity of Ca and Mg increased with time, and the exchange process reached 90% during 0-4 h and reached equilibrium after 24 h under 100 mg/L Na (the maximum Na concentration in Taihu sediment pore water). Our MINTEQ modeled result indicated that the exchanged quantity of Ca and Mg increased with the increasing Na concentration, with Ca being preferably exchanged over Mg at the same Na concentration. The MINTEQ model further predicted that, in the Taihu lake environment, the exchange adsorption would reach the equilibrium at the concentration of 6000 mg/L Na, with exchanged Ca2+ and Mg2+ accounting for 47% and 55% of the total exchangeable Ca and Mg in the sediment, respectively. Although current Na-induced exchange in the Taihu lake has been far from the equilibrium, the MINTEQ result confirmed the existence of this reaction and predicted the potential redistribution of base cations or Ca/Mg ratio in the lake sediment and water phase with further Na increase. Furthermore, our field observations not only confirmed the existence of Na-induced cation exchange in this lake environment but also were generally in agreement with our experimental and modeled results. The increased salinization-induced ion exchange would alter the re-distribution of base cations and the resulting potential ecosystem consequences should be given close attention in this large freshwater lake.

A modified Blumgart procedure in laparoscopic pancreaticoduodenectomy / 中华普通外科杂志

Objective:To evaluate A modified Blumgart pancreaticojejunostomy in laparoscopic pancreaticoduodenectomy.Methods:The clinical data of 81 patients undergoing laparoscopic pancreaticoduodenectomy in Zhengzhou University Affiliated Cancer Hospital from Jan 2019 to Jan 2022 were retrospectively analyzed. Among them, 26 patients underwent modified Blumgart anastomosis and 55 underwent conventional Blumgart anastomosis.The data of demographics, liver function, pancreatic texture, operational result and complications were compared between the two groups.Results:The preoperative data (body mass index, preoperative albumin, prealbumin, transaminase, total bilirubin) between two groups were comparable ( P>0.05). There was no significant difference in pancreatic texture, pancreatic duct diameter and intraoperative blood loss between the two groups ( P>0.05). The modified group had shorter total operation time ( P<0.05), shorter pancreaticojejunostomy time ( P<0.05), shorter postoperative hospital stay ( P<0.05). The incidence of total pancreatic fistula and biochemical fistula in the modified group were lower than those in the conventional group ( P<0.05). There was no significant difference in the incidence of B/C grade pancreatic fistula and bile leakage, postoperative bleeding, infection and delayed gastric emptying between the two groups ( P>0.05). Conlusions:The modified Blumgart pancreaticojejunostomy during laparoscopic pancreaticoduodenectomy is safe, easy to do and time saving. While the incidence of postoperative pancreatic fistula with clinical significance　and other major complications were similar to traditional Blumgart procedure.

Accelerated carbonate dissolution caused by anthropogenic acidification - contrast of watershed soils to lake sediments in Taihu Region, China.

Although Taihu watershed is an "acid-insensitive" region, anthropogenic acidification has greatly changed the water chemistry in Taihu Lake. However, how soil carbonates responded to the long-term human-induced acidification received less attention. In this work, we investigated soil carbonate concentrations from different land uses in the upstream of the lake and sediment carbonate profiles in the lake, to explore the linkage of carbonates dissolution in the land and sedimentation in the lake. The result showed that the wheat-rice surface soil, the most acidification-impacted by fertilization and acid deposition, had significantly lower pH than vegetable and wetland soils (p < 0.05). Meanwhile, the carbonate concentration in wetland soils, only impacted by acid deposition, was significantly higher than that in wheat-rice and vegetable soils (p < 0.05). The pH profile of fertilized soils, with an increasing trend from the surface to bottom, further indicated the acidifying effect of fertilization. Although the average soil pH across all land uses was 6.6 in the upstream of the lake, remaining carbonate buffering system, the significant carbonate decrease especially in surface soils evidenced the definite carbonate dissolution by acidification, which is cumulative and irreversible. Contrary to the topsoils, the sediment carbonate concentration presented an increasing trend from the depth of 15 cm (denoting around the early 1980s) to the surface, indicating that lake sediment is a major sink of carbonate Ca and Mg from the watershed, particular under an alkaline lake environment caused by frequent algae blooms in the past decades. In addition, Ca/Mg ratio in the sediment, having higher values in a higher pH environment, was quite different from the watershed soil pattern, suggesting different biogeochemical processes Ca and Mg underwent during their transportation and sedimentation. The effects of acidification-altered re-distribution of carbonate Ca and Mg and Ca/Mg ratio in the terrestrial and aquatic environments deserve wider considerations of ecosystem consequence.