[Sediment Pollution and Dredging Effect of Waiqinhuai River].

The Waiqinhuai River is an important urban landscape flood channel in Nanjing, which has been seriously polluted by industrial and domestic sewage for many years. To fully understand the characteristics of Waiqinhuai river sediment pollution and provide a decision-making basis for dredging, the sediment interface microenvironment and nutrient content of river sediment collected from method-typical sections in the upper, middle, and lower reaches were determined, and the organic index and pollution index methods were used to evaluate the sediment pollution condition. We also simulated the effect of desilting on the reduction of endogenous release in sediment according to pollutant characteristics of vertical distribution. The results showed that the average dissolved oxygen concentrations at the upper, middle, and lower sediment interfaces were 4.62, 3.25, and 3.41 mg·L-1, respectively; the concentrations were exhausted at 4.4, 3.5, and 5.5 mm, respectively, which were typical characteristics of urban river pollution. The average contents of TN, TP, and OM in the surface sediment of the investigated reach were 1734 mg·kg-1, 1337 mg·kg-1, and 4.82%, respectively. The organic pollution index of TN and OM in the sediment was 0.48 on average, which was at the clean level, whereas the individual pollution index of TP was 3.18 on average, which was at the severe pollution level. The results of simulating the dredging depth of 30 cm showed that the release rates of SRP and iron divalent were reduced by 42%-82% and 88%-96%, respectively, whereas the release rate of ammonia nitrogen was increased. The results of DGT determination and phosphorus speciation analysis showed that the phosphorus activity of surface sediment decreased significantly after desilting, and DGT-P and Mobile-P decreased by 9%-11% and 1%-35%, respectively, compared with those in the control treatment. These results indicated that the sediment of Waiqinhuai River was seriously polluted by endogenous phosphorus, and desilting could reduce the release of endogenous phosphorus to a certain extent, which may be an important method for improving the water quality of the Waiqinhuai River.

[Effects of Sediment Dredging on the Reduction in Sediment Internal Loading of Lake Taihu and the Self-recovery Ability of Benthic Organism].

Sediment dredging has a great effect on the control of lake internal loading and is one of the important methods for lake internal loading management. In this study, the dredged area of Taihu Lake was used as the main object. An estimation of the reduction in whole lake internal loading of Taihu Lake in decade years was carried out. At the same time, we evaluated the effect of sediment dredging on the control of internal loading in the northern area of Taihu Lake (Zhushan Bay and Meiliang Bay). The results indicated that a total of 42 million cubes of sediment was dredged from Taihu Lake, and the total nitrogen, total phosphorus, and organic matter in the dredged sediment was estimated to be approximately 6.26×104 tons, 1.83×104 tons, and 11.7×105 tons, respectively. This was roughly equal to the 20 years of external loading pollution accumulated in Taihu Lake. From a long-term perspective, sediment dredging could effectively increase the water quality of Meiliang Bay within five years and that where the external loading has been controlled effectively. However, the water quality of Meiliang Bay subsequently rebounded, but dredging still reduced the nitrogen and phosphorus content in surface sediment. On the contrary, dredging could not effectively control the internal loading of Zhushan Bay, which still had a large input of external loading. The amount of sediment internal loading recovered to the original level of the pre-dredging period. In a six-year-long period of continuous monitoring of the benthic organism community of Zhushan Bay, the results indicated that sediment dredging could cause negative effects on sediment dredging initially, but the density and biomass of the benthic organisms in the dredged area had later been recovered to the un-dredged level. There was no difference between the dredged and un-dredged areas with regard to the diversity indices of benthic organisms. The results of this study indicated that sediment dredging can effectively control the lake internal loading. However, the maintenance period of dredging effects was related closely to the input intensity of the external loading. In addition, sediment dredging did not have a large influence on the benthic organism community and could recover to the original level depending on self-recovery.

[Influence of Different Types of Dewatering Agents on the Solidification Effect and Physical and Chemical Properties of Sediment].

In order to study the comprehensive effects of different types of dehydrating agents on the dewatering and solidification of dredged sediments, this study took the dredged sediments of Taihu Lake as the research object and selected microorganisms, polymeric iron aluminum salts, organic polymers, organic-inorganic composites, and aluminum salt microorganisms. These five types of composite dehydrating agents were used to conduct a three-month solidification test on the dredged sediment by means of geotechnical pipe bag solidification. The results of the study showed that the dehydration efficiency of organic polymers and organic-inorganic composite chemicals was better. After one month, the water content of sediment dropped to 61.78% and 63.26%, respectively, which then dropped to 40.56% and 32.16% after three months. Compared with that of the unsolidified sludge, the total nitrogen of the bottom sludge after solidification by the organic-inorganic composite agent was reduced by 74.82%, reaching 591 mg·kg-1, primarily due to the reduction in ammonia nitrogen. The solid sludge contained mainly aluminum-bound phosphorus, calcium-bound phosphorus, and iron-bound phosphorus. Among them, four groups (organic-inorganic composite) had the largest reduction in active phosphorus, with the lowest being 64.3 mg·kg-1. In addition, organic polymer agents had the best curing effect on heavy metals, the comprehensive ecological risk index of heavy metals was reduced by 51.3%, and the leaching toxicity concentration was far below the standard threshold. This study showed that organic polymers and organic-inorganic composite medicaments have a better effect on the dehydration and solidification of bottom sludge and thus have good application prospects.

[Sediment Pollution Characteristics and Dredging in the Nanfei River Estuary, Chaohu Lake].

To clarify the endogenous pollution characteristics of sediments in the Nanfei River estuary, Chaohu Lake, and provide a theoretical basis for the dredging works, the organic index, pollution index, and potential ecological risk were determined. The results show that the average total nitrogen (TN), total phosphorus (TP), and organic matter (OM) content of the sediment was 1461 mg·kg-1, 438 mg·kg-1, and 1.77%, respectively, showing enrichment in the surface layer (0-10 cm). The nutrient pollution status and TP pollution index show that the organic pollution level was moderate and the TP pollution was severe. Furthermore, the pollution risk gradually reduced with sediment depth, representing a low risk at depths below 30 cm. Static release results showed that the average release fluxes of NH4+-N and TP in the sediment were 8.04 mg·(m2·d)-1 and 0.19 mg·(m2·d)-1, respectively, and showed highest release potentials consistent with areas of sediment nutrient pollution. Except for Cr and Ni, the concentrations of six heavy metals were higher than the soil background values for Anhui Province, and the concentrations of Hg and Cd far exceeded the standards. According to the assessment of potential ecological risk from heavy metals, the 0-20 cm sediments present a high level of risk and sediments below 30 cm have a low level of risk. Heavy metal leaching toxicity indicated that the risk of heavy metal release after dredging is low and non-hazardous. These results were used to determine the key dredging area (3.93 km2) and depth (30 cm) for the Nanfei River estuary, providing an important basis for future dredging activities.

[Endogenous Pollution and Release Characteristics of Bottom Sediments of Hengshan Reservoir in Yixing City].

To clarify the endogenous pollution and release characteristics of the bottom sediment of Hengshan Reservoir in Yixing City, a typical section of the reservoir was sampled and analyzed. The research results show that the average concentrations of total nitrogen, total phosphorus, and organic matter in the surface sediments of Hengshan Reservoir are 2778 mg·kg-1, 899 mg·kg-1, and 3.1%, respectively. The endogenous pollution is serious, and the downstream sediments are highly polluted upstream of the reservoir. Phosphorus spectroscopic analysis results show that iron-bound phosphorus (Fe-P) and aluminum-bound phosphorus (Al-P) are the main bound phosphorus forms in the sediment, accounting for 28% and 39% of the total phosphorus, respectively. The average concentration of activated phosphorus in the sediment (combination of weakly adsorbed phosphorus, organic phosphorus, and iron phosphorus) is 255 mg·kg-1, accounting for 38% of the total phosphorus. The average release rates of nitrogen and phosphorus in sediments were 18.0 mg·(m2·d)-1 and 0.60 mg·(m2·d)-1. The correlation analysis results show that the organic matter content of the sediment is significantly correlated with the diffusion flux of phosphate, ammonia nitrogen, and ferrous iron (P<0.05), indicating that the mineralization of organic matter in the sediment may be the main release source of nitrogen and phosphorus in the sediment influencing factors.

[Algal-flocculation removal by modified sediment of Taihu Lake in wind action].

Removal effects of cyanobcateria algal cells in chitosan-mediated in-situ-sediment in the sediment resuspension was studied in the laboratory. The research simulated the sediment suspension through quantitative simulated the middle-grade wave of lake Taihu, which usually experienced, by using the Y-type sediment resuspended generator. The results showed that the blue-green algal's removal effect is 93.55% and 99.19% as the dosage adding of chitosan and sediment were (0.100 + 0.200) g x L(-1) and (0.150 + 0.200) g x L(-1), respectively. The removal rate of turbidity of the water body reached 78.60% after still 30 min, in which the chitosan adding dosage was 0.150 g x L(-1); the removal rate of turbidity achieved 93.88% after 8 h of water body still. Furthermore, adding the chitosan could decrease the PO4(3-) -P concentration of water body in a short term. Preliminary results showed that the chitosan which adding dosage was 0.15 g x L(-1) could effectively remove the cyanobacteria cells in middle-grade wave situation; and also indicates using the chitosan-mediated sediment to flocculate the algal bloom of the Taihu Lake has a better application prospect. Contrast study shows that the quantitative simulation method of hydrodynamic intensity and the height of water has the obvious advantage to determine the dosage of chitosan in algal-flocculation removal.

The stimulatory effect of insulin-like growth factor-1 on the proliferation, differentiation, and mineralisation of osteoblastic cells from Holstein cattle.

This study investigated the effect of exogenous insulin-like growth factor (IGF)-1 on the proliferation and differentiation of osteoblastic cells from Chinese Holstein cattle and the resultant bone nodule formation and mineralisation in vitro. The osteoblastic cells were isolated and cultured, then identified using Giemsa and alkaline phosphatase (ALP) staining methods. The effect of different concentrations of IGF-1 on cell growth was assessed by MTT assay. The ALP activity and osteocalcin (OC) concentration in the osteoblastic cells were measured by a colorimetric assay and a radioimmmunoassay, respectively. Calcium nodules were observed using alizarin red S stain, while the content of matrix calcium was determined by atomic absorption spectrophotometry. Cell proliferation in the cultures was stimulated by IGF-1 at concentrations ranging from 1 to 200ng/mL, with the maximum effect observed at 100ng/mL. This effect was observed from day 1 and peaked at day 5, but decreased at day 7. At concentrations of 10ng/mL and 100ng/mL, IGF-1 significantly induced ALP activity, OC level, matrix calcium content, and nodule formation of the osteoblastic cells by 20-180% (P<0.05 or P<0.01), compared to controls. The results suggested that IGF-1 is an anabolic agent for the proliferation, differentiation, mineralisation and calcium content of dairy cow osteoblasts, and could therefore act as a potential treatment for the metabolic bone diseases in these animals.

[Distribution characteristic and correlation relationship of reactive sulfur and heavy metals in sediments of Meiliang Bay and Wuli Lake of Taihu Lake].

The distribution characteristic of acid volatile sulfide (AVS), simultaneously extracted metals (SEM), and total metals were studied in the surface and core sediments of Meiliang Bay and Wuli Lake in Taihu Lake. It was found that there were similar distribution characteristics for AVS and SEM in surface sediments, and the concentration of AVS and SEM decreased from the steady deposition area of estuary to the centre of the bay (lake). The ratio of AVS/SEM was < 1 in the surface sediments, indicating that heavy metals in surface sediment might have potential bioavailability. The concentration of AVS increased with sediment depth, followed by decrease with large variation, while the concentration of SEM remained constant. Though comparing the concentration of SEM with total metals, it was shown that the extracted Cu and Ni decreased with sediment depth, indicating that increasing association of Cu and Ni with sulphides in deeper sediment layer, while the lower extracted ratios for Pb and Zn compared with sulfidic sediment illustrated that the AVS should not have a strong controlling on sediment Pb and Zn. From the molar ratio of AVS and reactive iron, it is known that the heavy metals were rather dynamic and active in sediments of studied sites.

[Effects of sediment resuspension on aqueous nutrient loading in grass type zone of Lake Taihu].

Internal nutrient loading caused by sediment resuspension is becoming a key issue in studying water eutrophication of shallow lakes. A Y-shape apparatus was used to simulate sediment resuspension and sedimentation process under hydrodynamic conditions in situ in grass type zone of Lake Taihu, and effects on aqueous nutrient loading were investigated. The results indicated that, in the light and moderate wind processes, content of ammonia nitrogen and phosphate had remarkably reduced with the increase of the amount of suspended sediments in water column, with the maximal change of -0.140 g x m(-2) and -1.59 mg x m(-2) at the sediment-water interface for the two nutrients respectively, and in the strong wind process, concentration of aqueous phosphate had a significant increase, with the maximal flux of 0.81 mg x m(-2) at the sediment-water interface, while concentration of aqueous ammonia nitrogen showed a small decrease. And in the later sedimentation process after wind, content of aqueous ammonia nitrogen was lower than that before the light and moderate wind processes, but approximated to that before the strong wind process. Content of aqueous phosphate was close to that before the light and moderate wind processes, but had a marked increase compared to that before the strong wind condition, with the maximal increment of 1.36 mg x m(-2). Consequently, sediment resuspension and sedimentation processes impact nutrients loading of overlaying water evidently. Comparison of the results with those from non-grass type zone in Lake Taihu illustrates that the presence of aquatic macrophytes played some roles in reducing the release of nutrients during the sediment resuspension process.

[Estimation of releasing fluxes of sediment nitrogen and phosphorus in Fubao Bay in Dianchi Lake].

NH4(+)-N and PO4(3-)-P release from the sediment of Fubao Bay in Dianchi Lake were simulated using static incubations of intact sediment cores. The results showed that the releasing rates of sediment NH4(+)-N and PO4(3-)-P were 22.941-163.117 mg x (m2 x d)(-1) and 0.90-2.06 mg x (m2 x d)(-1), respectively, with large variation in different sampling areas. The lower releasing rates were associated with declined concentration gradients between sediment pore water and overlying water,which might be related to the high input of sewages in the bay. Using peeper (in situ dialysis membrane samplers) method, concentration gradients of NH4(+)-N and PO4(3-)-P were obtained at the interstitial water-overlying water profiles. Based on calculations using the Fick's First Law,the releasing rates of sediment NH4(+)-N and PO4(3-)-P were estimated at 2.85-81.96 mg x (m2 x d)(-1) and 0.118-0.265 mg x (m2 x d)(-1), respectively. Comparison of the two methods using to estimate the fluxes of sediment NH4(+)-N and PO4(3-)-P, the NH4(+)-N and PO4(3-)-P flux from the calculation using Fick's First Law was lower than that using static incubations. For the whole bay,the area-weighted releasing fluxes of NH4(+)-N and PO4(3-)-P from static incubations were estimated to be (49.9 +/- 8.8) t x a(-1) and (0.79 +/- 0.53) t x a(-1), respectively.

[Construction and characteristics analysis of somatic cell lines from common carp Cyprinus carpio].

Epithelia of rostral side and fins from common carp were taken to culture in vitro. As a result, cells of tail fins were successfully passed from generation to generation, and constructed cell lines. During the culture procedure, the passage cells were observed and their biological characteristics were analyzed, which consist of morphologic analysis, drawing of growth curve, detection of producing rate for clones, insight of adaptation to temperatures, calculation of chromosomes and investigation for thaw of frozen cells. According to the observation results, we found that (1) there is an increase trend of fibroblast. epithelia of rostral side and tail fin from common carp are the best materials for culturing cells; (2) the optimum culturing temperature is 27 degrees C; (3) there isn't any change in cell chromosomes, which still are normal diploid. However, with, the generations increasing, the mode of chromosome has an inclination of decrease in normal ranges. We inferred the donor cells from 4-10 generations are the best choice for nuclear transplanted experiments in order to guarantee their genetic stabilities and survival rates after transplanting the nuclei. And, the cells will grow extremely well when cultured for 48-72h at 27 degrees C. We suggest the temperature should be descended little by little involving in preserving cells with DMSO. So far, the cells were passed 30th generations and part of them was preserved into liquid nitrogen.