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This study was conducted in response to the current situation in our country in which neonicotinoid pesticides (NNIs) are used in large quantities and their concentration in surface water is gradually increasing. Based on the species sensitivity distribution (SSD), the hazard quotient (HQ) and probabilistic risk assessment (PRA) were used to compare single and mixture risks of NNIs in the surface water in China. The target and recommended values of NNIs in China's surface water quality supervision were also presented. The results showed that:① in the single acute hazard assessment, imidacloprid (IMI) was the most harmful insecticide, and in the single chronic hazard assessment, imidacloprid (IMI) and acetamiprid (ACE) were more harmful. Furthermore, insects were the most sensitive creatures. ② Hainan province was the region with the highest single acute and chronic hazard in the study area. ③ Based on the joint probability curves of five neonicotinoids, the probability in which 5% of species would be affected by long-term exposure was approximately 91.12%. Thus, the combined ecological risk of these five neonicotinoids cannot be ignored. ④ Based on the toxicity reference value from SSD and the combined results of HQ and PRA, the regulatory values of surface water quality in China were as follows:acetamiprid (ACE) 0.04 μg·L

Typical halogenated persistent organic pollutants (Hal-POPs), including polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), polychlorinated biphenyls (PCBs), and dichlorodiphenyltrichloroethane (DDT), are a group of ubiquitous organic pollutants with an endocrine disrupting effect. This study evaluated the accumulation and congener profiles of Hal-POPs in the bodies of men who live/work in areas of South China where electronic wastes are collected and managed, especially in their semen samples. The results show that the detection frequency and serum concentrations of Hal-POP congeners within the high-exposure group (HEG) were higher than those of the low-exposure group (LEG). Furthermore, an identical trend was observed for the seminal plasma concentrations of Hal-POPs. The distribution characteristics, such as their mean, median, and discrete values, of PBDE congeners in serum and semen samples from the same subjects were consistent with each other. However, the distribution characteristics of PCB congeners in serum samples were different from those in semen samples. BDE153 was one of the most abundant congeners found in the serum and semen samples; hence, it can be identified as an indicator PBDE congener. Further research is needed to explore the mechanism of Hal-POPs distribution in human semen and serum samples. Keywords: Halogenated persistent organic pollutants (Hal-POPs), Polybrominated diphenyl ethers (PBDEs), Polychlorinated biphenyls (PCBs), Semen, Congener profiles

Our previous study reported that the Ca-dependent aggregation of polyacrylate-coated TiO

To understand the influence of a Microcystis aeruginosa bloom on the bacterioplankton community composition in Lake Xuanwu, water samples were collected during the outbreak and decline of the bloom. Traditional microbial methods and denaturing gradient gel electrophoresis were used to characterize the bacterioplankton community. During the outbreak of bloom, the proportions of firmicutes, bacteroidetes, and α-, β-, and γ-proteobacteria were respectively 31.3%, 25.0%, 18. 8%, 12.5%, and 12.5% of the total bacteria. At the decline of the bloom, the total abundance of bacterioplankton increased, and the proportion of γ- proteobacteria increased to 50%. Pseudomonas and Bacillus were always the principal genera but with changing species. Sixteen genera of bacteria were predominant in the community during the outbreak of bloom, but some species of Hydrogenophaga, Vogesella, Sphingomonas, and Exiguobacterium disappeared at the decline of the bloom, and only six predominant genera remained.

Lake Taihu and Lake Hulun in southern and northern China were selected for the investigation of differences in the characteristics and influencing factors of phosphorus (P) adsorption on the sediments of these two lakes by laboratory simulation experiment. The results showed that: (1) The P adsorption capacity of sediment in Lake Taihu was much higher than that in Lake Hulun, and the maximum adsorption capability for the sediments in these two lakes was 1428.57 mg x kg(-1) and 56.81 mg x kg(-1), respectively; (2) Compared with the sediments in Lake Hulun, the particle diameters from sediments in Lake Taihu were much smaller, and their specific surface areas were much larger, so their P adsorption capacity were much higher; (3) The equilibrium adsorbed amounts in these two lakes were correlated with the total amounts of Al, Fe, Mn (P0.05) and significantly correlated to the contents of active Al, Fe, Si, Mn (P0.01). However, there was significant negative correlation between the equilibrium adsorbed amounts and total Si contents for the sediments in these two lakes (P0.01); (4) The P adsorption capacity decreased as pH values in the overlying water increased, and the increase of pH values affected the adsorption behavior of phosphorus on the sediments in Lake Taihu much more obviously. Therefore, the characteristics of sediments and the variations of pH values in the overlying water affected the adsorption behavior of P on sediments in lake water body.

To probe the effect of nitrogen and phosphorus (P) in sediment on aqueous nutrient concentrations, forms of phosphorus, sediment water interface diffusion fluxes and phosphorus release and adsorption of 10 lakes in the west Jiangsu province were studied. Sediments were sequentially extracted by the modified Ruttenberg's method, and the result showed that inorganic phosphorus in sediments of the lakes was the major fraction of total phosphorus, but the proportion of bioavailable phosphorus was relatively low. Compared with the lakes in northern Jiangsu, the Fe-P was relatively high in sediments of lakes in southern Jiangsu. The diffusion fluxes of lakes were mainly based on NH4(+) -N diffusion in the west Jiangsu, and ions of most of lakes diffused from overlying water to sediment, NO3(-) -N diffused from sediment to overlying water in lakes except for Lake Hongze, Lake Shijiu and Lake Xuanwu. The condition leaning to acidic (pH4) or alkaline (pH10) was beneficial to phosphorus release, and except for Lake Xuanwu, the least amount of phosphorus released form sediment was higher in acidic condition than that in alkaline condition. The amount of phosphorus adsorption was increasing with temperature increase. Considering the phosphorus adsorption on native phosphorus polluted (NAP-polluted) sediments. All data of P adsorption on sediment samples collected from 7 lakes were fitted to the modified Langmuir model. And the values of the maximum adsorption capacity (Q(m)), phosphorus binding constant (k), native adsorbed exchangeable phosphorus (Q(NAP)), were subsequently obtained. The results showed that the adsorption amount of P in Lake Hongze and Lake Xuanwu was relatively low, which were liable to release P from sediments.

The various forms of nitrogen in 25 rivers surrounding Lake Taihu as well as in some typical lake zones such as Meiliang Bay and East Lake Taihu were analyzed during the hydrological year of 2009-2010. Furthermore, the nitrogenous self-purification capacity of Lake Taihu was studied in combined with the investigation of water flow, cyanobacteria salvages and aquatic product outputs. In the whole hydrological year, the inflow and outflow fluxes of total nitrogen (TN) were 7.00 x 10(4) t and 4.01 x 10(4) t, respectively. About 3.02 x 10(4) t and 0.20 x 10(4) t nitrogen in water body were removed by denitrification and sediment adsorption during this hydrological year, respectively, suggesting a strong nitrogen self-purification capacity of Lake Taihu. The potential denitrification is stronger in western Lake Taihu (e.g., Meiliang Bay) than that in eastern Lake Taihu (e.g., East Lake Taihu), and is stronger in summer than that in other seasons. Thus, the nitrogenous self-purification capacity plays an important role in nitrogenous transference and transformation in Lake Taihu.

Although biomass of algae (Chl-a) were in variant levels between different lake regions in China under the same nutrients conditions, it demonstrated that efficiencies of TN/TP used by algae had regional differences. In order to clarify the differences, curve estimation in SPSS was used to analyze the linear relationship between Ig Chl-a and Ig TN/lg TP. The slopes of these linear equations were identified as the efficiencies of TN/TP used by algae. The slopes of linear equations from Mengxin Plateau, Yungui Plateau, Northeast Mountain-Plain, lower reach of Yangtze River Plain and North Plain were 1.002, 0.817, 0.761, 0.545, 0.250, orderly. The efficiencies of TN used by algae ranged from the highest to the lowest were lower reach of Yangtze River Plain, Yungui Plateau, North Plain, Northeast Mountain-Plain, Mengxin Plateau, and the slopes of linear equations were 1.401, 1.058, 0.447, 0.239, 0. 099, respectively. Consequently, in Northeast Mountain-Plain, Mengxin Plateau the efficiencies of TP used by algae were higher than those of TN, and in Yangtze River Plain, Yungui Plateau, North Plain, the efficiencies of TN used by algae were higher than those of TP. On the other hand, in order to describe the effects of algae on transparency in different lakes, the relationships between Chl-a and SD were analyzed. The results showed that in Yungui Plateau the effect of algae on transparency was the most obvious as the variation of SD explained by Chl-a was the highest, and Northeast Mountain-Plain, Mengxin Plateau and North Plain followed. However, in lower reach of Yangtze River Plain, the relationship between Chl-a and SD was not significant.

In order to construct high accumulating-phosphate microorganism, the ppk gene from E. coli was inserted to the broad-host-range plasmid pBBR1MCS-2 to form plasmid pBBR1MCS-2-ppk. The complete ppk gene with promoter and terminator sequences from pBBR1MCS-2-ppk was then cloned and inserted to suicide plasmid pUTmini-Tn5 to form plasmid pUTmini-Tn5-ppk, which was transformed into Pseudomonas putida KT2440 by triparental conjugation. Finally, ppk gene was integrated into the chromosomal DNA of KT2440. The results of RT-PCR showed that the selected genetically engineered bacterium KT2440-PPK expressed ppk efficiently, while KT2440 as control expressed weakly. The results of artificial wastewater treatment showed after 1h inoculation, the concentration of poly-phosphate in KT2440-PPK came to the maximum approximately 3.05 mg/g, which was 15 times higher than that in KT2440 at the same experimental condition. And KT2440-PPK can remove more than 90% phosphate in artificial wastewater.

The physicochemical characteristics, nutritions and the microbial community diversity of sediment core samples of three different space locations in the Lake Taihu were studied by fumigation-digestion and PCR-DGGE analysis respectively. The results indicated that below the surface of sediments Eh declined rapidly with increase of sediment depth and it was under anaerobic condition except the top layer of sediment. pH value changed silightly in the profile of sediments, which ranged from 7.2 to 7.8. TN and TP concentrations in sediments of Lake Taihu were high,and the maximum concentrations reached 2.436 mg/g and 0.731 mg/g, respectively. Their vertical profiles showed that TN and TP concentrations in surface sediments were much higher than in deeper layers and decreased with the increase of the depth of sediment layers. OM concentrations declined rapidly at the top 15 cm of sediment layers. There were prominent difference spatially in microbial diversity and the comparability and dynamics of community structure between different sediment samples of different space locations and different depth. The little significant correlation at alphaor = 0.05 level was observed between the Eh, pH, percentage organic matter, TN concentration and TP concentration and microbial community structure diversity index except of TN concentration and percentage organic matter.

Water samples were collected in the outbreak and decline of Microcystis spp. bloom in three different lake areas of Lake Xuanwu for studying the bacterial community composition during the bloom to provide clew for understanding the dynamics of water bloom. Traditional microbiological methods were used for culturable bacterial analysis, while the amplified products of variable V3 region of bacterial 16S rDNA were used for bacterial community DNA finger print by using denaturing gradient gel electrophoresis (DGGE), and the 16S rDNA sequences of predominant bacteria in the community were used for phylogenetic analysis. Results showed three groups of bacteria were detected during Microcystis spp. bloom, including Proteobacteria, Firmicutes and Bacteroides. In the outbreak of the boom, the propotion of Firmicutes, Bacteroides and alpha-, beta-, gamma-Proteobacteria in total bacteria account for 31.25%, 25%, 18.75%, 12.5% and 12.5% respectively, and sixteen genera of bacteria are predominant in the bacterial community. While in the decline of the bloom, the proportion of gamma-Proteobacteria increases up to 50%, followed by Firmicutes and alpha-Proteobacteria, with the proportion of 33.3% and 16.7% respectively. Some species including Hydrogenophaga, Vogesella, Sphingomonas, and Exiguobacterium disappear when the bloom declining, but the abundance of total bacterial goes up. Pseudomonas and Bacillus are always the leading genera but with changing in species. During the same stage of the bloom, bacterial diversity in the lake area with more Microcystis spp. aggregates is lower. The variation in bacterial community composition may be correlated with changes of organic matters and other environmental factors that affected directly by wax and wane of Microcystis spp. aggregates, and the density of the aggregates may have effect on bacterial diversity.

The abundance of phosphate solubilizing bacteria, together with the alkaline phosphatase (ALPase) activity in the sediment samples of Lake Taihu in different seasons, sites and depths, was analyzed. And the relationship between the distribution of phosphate solubilizing bacteria and the ALPase activity was discussed. Results show that phosphate solubilizing bacteria is universally detected in surface sediments. With the increasing depth, the amount of phosphate solubilizing bacteria decreases. The number of phosphate solubilizing bacteria strains reaches the maximum in autumn while the minimum in winter. ALPase activity ranges from 0.001 mmol (g x min)(-1) to 0.006 mmol (g x min)(-1) and it varies with different sites and seasons and declines with the increasing depth. ALPase activity varies widely above 12cm, and stabilizes about 0.001 mmol x (g x min)(-1) under 12 cm in each site. There is a correlation between ALPase activity and the number of phosphate solubilizing bacteria and the correlation coefficients range from 0.50 to 0.85.

The effects of different forms of phosphorus sources on the phosphorus metabolism of Microcystis aeruginosa and attached Pseudomonas sp. were investigated after four substance of different phosphrus forms: NaH2PO4, Natrium-beta-glycerophosphate (NaGly), Ca3(PO4)2 and lecithin were added in the non-phosphorus MA culture. The growth of Microcystis aeruginosa, total phosphorus, alkaline phosphatase activity in water and total phosphorus in Microcystis aeruginosa were measured every day or every two days. Results show that attached Pseudomonas sp. could accelerate the growth of Microcystis aeruginosa, and transform some phosphrus forms which could not be assimilated very easily by Microcystis aeruginosa to some forms as phosphate to utilize for Microcystis aeruginosa. Alkaline phosphatase plays an important role in the utilization of large molecular organic phosphorus by Microcystis aeruginosa and attached Pseudomonas sp.

Growth and uptake of exogenous phosphate by Microcystis aeruginosa in batch culture under different temperature, photoperiod, and turbulence were studied by the method of phosphate isotope tracer. Relatively high temperature, long photoperiod and strong turbulence increased the cell density of M. aeruginosa in these batch cultures. The initial rapid uptake of phosphate by M. aeruginosa was independent of the temperature, photoperiod, and turbulence. Similarly, maximum exogenous phosphate uptake was not related to these environmental factors. However, elevated temperature and turbulence shortened the time, required to obtain maximum P accumulation. The growth of M. aeruginosa could alleviate the phosphorous leakage. Total amounts of exogenous phosphate uptake to M. aeruginosa and the phosphorus leakage of M. aeruginosa were significantly influenced by the growth state of M. aeruginosa closely correlated with the environmental factors. The maximum volume of exogenous phosphate uptake to M. aeruginosa was 46% of added exogenous phosphate in water with 16 hours of photoperiod. Thus, total amounts of exogenous phosphate uptake to M. aeruginosa were more strongly affected by the photoperiod length than temperature and turbulence.