[Spatio-Temporal Distribution and Risk Assessment of Heavy Metals in Middle and Lower Reaches of Le'an River].

The Le'an River is a main tributary of the Poyang Lake, which is the largest freshwater lake in China. The aim of this study is to research the distribution and potential ecological risks of heavy metals in the middle and lower reaches of the Le'an River, which is contaminated by nearby copper mines. Sediment and water samples were collected from 12 stations during the dry, wet, and normal season in 2016, respectively. The geo-accumulation index and potential ecological risk index were used to determine general pollution characteristics of trace metals in sediments. Results suggested that sediments in the Le'an River were considerably polluted by Cd, Pb, Cu, and Zn. Sediment concentrations of heavy metals showed significant spatial variations. The concentrations of heavy metals such as Cu, Zn, and Cd in water are higher in the dry season than in the normal and wet seasons. The distribution of heavy metals along the river is influenced by hydraulic conditions. The flow velocities in wet and normal seasons are positively correlated with the concentrations of heavy metals such as Cd, Pb, Cu, and Cr. There are seasonal differences in the distribution characteristics of heavy metals in surface sediments. In the dry season, the concentration of heavy metals in sediments is the highest in the middle reaches of rivers near mining areas, while during the wet and normal season, it reaches the highest value in the lower reach near the estuary. Except for Cd, whose major form of heavy metal in the sediment is in an exchanging state, the other heavy metals occur mainly in stable states. The assessment of the geo-accumulation index showed significant Cu, Cd, and Cr pollution. Among the heavy metals investigated, Cd was likely to result in more harmful effects.

[Seasonal and Spatial Variations of Microcystins and Their Relationships with Physiochemical and Biological Factors in Poyang Lake].

Poyang Lake is the largest freshwater lake in China and an important drinking water source for Jiangxi Province. Since the year 2000, toxic cyanobacteria have been observed frequently in Poyang Lake. In this study, water samples were collected in the lake quarterly (April 2012, August 2012, October 2012, and January 2013) to examine the spatial and seasonal variations in the concentrations of microcystins (MCs; MC-RR, -YR, and -LR) and their relationships with physiochemical and biological factors. MCs were determined by ultra-high-performance liquid chromatography-electrospray ionization tandem triple quadrupole/mass spectrometry (UPLC-MS/MS). MC-RR (accounting for 75.01% and 71.34% of intracellular MC (IMC) and extracellular MC (EMC) concentrations, respectively) was the most dominant variant in Poyang Lake, followed by MC-LR (accounting for 21.95% and 24.97% of IMC and EMC concentrations, respectively), while MC-YR was detected in low concentrations (accounting for 3.01% and 3.69% of IMC and EMC concentrations, respectively). Total MC concentrations (IMC + EMC, TMC) ranged from 0.49 to 3517.85 ng·L-1, with an average of 337.43 ng·L-1 and only 2.53% (2 out of 79 water samples) of the water samples contained MCs concentrations exceeding the drinking water guideline level of 1 ng·L-1 for MC-LR proposed by World Health Organization (WHO). IMC concentrations showed significant relationships with Microcystis biomass (r=0.47, P<0.01), Oscillatoria biomass (r=0.68, P<0.01), Cyanobacteria biomass (r=0.56, P<0.01), and Chl-a (r=0.28, P<0.01), but no significant correlation was found between intracellular MC concentration and Anabena biomass (P>0.05), suggesting that Microcystis and Oscillatoria might be the main MCs-producing cyanobacteria in Poyang Lake. In addition, IMC concentrations were positively correlated with water temperature (r=0.51, P<0.01), transparence (r=0.69, P<0.01), Fe (r=0.43, P<0.01), and Zn contents (r=0.43, P<0.01), and negatively correlated with TN (r=-0.44, P<0.01), TP (r=-0.29, P<0.01), NH4+-N (r=-0.33, P<0.05), NO2--N (r=-0.28, P<0.05), Ca (r=-0.34, P<0.01), and Mg(r=-0.35, P<0.05), while no significant correlations were observed between IMC concentrations and pH, PO43--P, NO3--N, electrical conductivity, permanganate index, and Cu content (P>0.05). These results indicated that light intensity (represented by transparence), nitrogen, phosphorus, and water temperature might be the regulating factors of MCs production in Poyang Lake and trace elements (Fe, Zn, Ca, and Mg) can influence the MC production to a certain extent. IMCs and EMCs exhibited similar seasonal variations in Poyang Lake. The highest values of IMCs (531.87 ng·L-1) and EMCs (232.44 ng·L-1) were observed in summer. The concentrations of IMCs and EMCs in autumn were 31.97 ng·L-1 and 6.49 ng·L-1, respectively. Low concentrations were observed in spring (0.55 ng·L-1 and 0.88 ng·L-1 of IMCs and EMCs, respectively) and winter (0.69 ng·L-1 and 4.14 ng·L-1 of IMCs and EMCs, respectively). The highest IMCs and EMCs values of Poyang Lake in summer were 2298.08 ng·L-1 and 1219.77 ng·L-1, respectively, and the lowest values were 92.53 ng·L-1 and 38.80 ng·L-1, respectively. Overall, the concentrations of IMCs in eastern bays, the vicinity of Songmen Mountain, Banghu Lake, and its outlet were higher than those in other regions. However, the spatial distributions of EMCs in Poyang Lake were different from those of IMCs. EMCs concentrations in the vicinity of Songmen Mountain, Banghu Lake, and its outlet were higher than those in other regions.

[Synthesis, spectroscopic characterization and antitumoral activities of cyclopentadienylvanadium derivatives of polyoxotungstates].

Cyclopentadienylvanadium derivatives of polyoxotungstates [Bu4 N]4 [(CpV)PW11O39] (1), [Bu4 N]4 H[(CpV) SiW11 O39] (2) and [Bu4 N]4 [A-beta-(eta5-CpV)SiW9 V3 O40] (3) were synthesized, and characterized by elemental analysis, IR, 51V and 183 W NMR spectroscopy. Experiment results indicate that (1) and (2) are polyoxometalate-incorporated organometallic complexes, and (3) is a polyoxometalate supported organometallic complex. Antitumoral activities were examined by MTT method. Experiment results indicate that the title complexes did exhibit to a certainty antitumor activity for HL-60 and B16.