[Simulation of Inorganic Nitrogen Fluxes at the Sediment-water Interface in a Typical Intertidal Zone, Eastern China].

Taking 12 typical intertidal zones along the eastern coast of China as the research object, indoor tide simulation experiments were conducted to measure exchange fluxes of nitrate nitrogen (NO3--N) and ammonia nitrogen (NH4+-N) between overlying water and sediments, to investigate their spatial distribution, and to clarify controlling factors such as salinity, temperature, and organic matter. Results showed that the total NO3--N flux was -2.91-3.34 mmol·(m2·h)-1, while the total flux of NH4+-N was -4.36-2.34 mmol·(m2·h)-1. The average flux, at 12℃ and 35℃, was -0.04 mmol·(m2·h)-1, indicating that typical intertidal zone sediment is an effective sink for ammonia nitrogen and nitrate nitrogen. There was a significant difference in the spatial distribution of nitrate and ammonia nitrogen fluxes. At 12℃, the higher the latitude, the greater the ammonia nitrogen flux; results for the 25°-35°N intertidal nitrate flux were as follows:<15°-25°N < 35°-45°N at 25℃ and 35℃, while the flux of ammonia nitrogen was 25°N-35°N > 15°-25°N > 35°-45°N. The fluxes of the three intertidal zones decreased with increase in temperature, which controls the coupled nitrification-denitrification taking place in the upper layer of sediment and at the bottom of overlying water. NO3--N fluxes first increased and then decreased with temperature at 15°-25°N and 35°-45°N, while NO3--N fluxes at 25°-35°N always decreased with temperature. At each latitude, the higher the temperature, the lower the NH4+-N flux. There was no single significant effect of environmental factors on fluxes. Salinity, sediment organic carbon (OC), sediment total nitrogen (TN), concentrations of ammonia nitrogen and nitrate nitrogen in pore water, and bulk density synergistically affected the spatial differentiation of exchanged NO3--N and NH4+-N fluxes.

[Distribution Characteristics and Health Risk for Heavy Metals in Vegetables Near the Industrial Areas in Shanghai].

The concentrations of Cd, Zn, Pb, Cu, Hg, and As in vegetables collected from the industrial areas in suburban Shanghai were analyzed before and after washing. Results showed that the average concentrations (fresh weight) of Cd, Zn, Pb, Cu, Hg, and As in washed vegetables were 0.023, 4.444, 0.112, 0.826, 0.004, and 0.094 mg·kg-1, respectively. Amaranth accumulated the highest Cd, Zn, Pb, and Cu, while pakchoi accumulated the highest Hg and As. There was no significant difference of heavy metals between different sites. Washing vegetables prior to cooking reduced the health risk for heavy metals related to the consumption of vegetables. A health risk evaluation indicated that more than 55% of the Total Target Hazard Quotient (TTHQ) came from As, while the other elements contributed less than 1, indicating that the health risk from vegetable consumption was mainly caused by As. Children have higher health risks than adults when eating the same vegetables.

[Concentrations and Health Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Soils and Vegetables influenced by Facility Cultivation].

The concentrations, sources, and health risks of 16 United States Environmental Protcction Agency(USEPA) priority polycyclic aromatic hydrocarbons (PAHs) in vegetables (leafy lettuce, amaranth, water spinach, and Shanghai green), in soils inside and outside the vegetable greenhouse, and in wet deposition were investigated by conducting an experiment on facility cultivation. The results showed that the average concentrations of total PAHs in vegetables and soils were 99.27 ng·g-1and 128.01 ng·g-1 in the greenhouse, and 109.11 ng·g-1 and 173.07 ng·g-1 out of the greenhouse. The concentrations of PAHs in the greenhouse were lower than those outside and the high ring-PAHs were lower than the low ring-PAHs both inside and outside. The PAH concentrations in suspended particular matter in dissolved phases of wet deposition were 2986.49 ng·g-1 and 61.9 ng·L-1, respectively. The low rings were easily enriched by the vegetables based on the shoot concentration factors. PAHs in soils and vegetables mainly originated from oil emissions and grass, wood, and coal combustion, while those in suspended particular matter in wet deposition were from petrogenic sources and the combustion of grass, wood, and coal. Petroleum combustion emissions were the main sources of PAHs in dissolved phases. We used the model of incremental lifetime cancer risks to evaluate the health risk of eating these vegetables. There was a potential risk of cancer for both children and adults for all vegetables except amaranth. The carcinogenic risk of vegetables outside the greenhouse was higher than the risk inside. Amaranth had a low carcinogenic risk with the value of incremental lifetime cancer risk lower than 10-6, while the risk of Shanghai green ranged between 10-4 and 10-6.

[Spatial Distribution Characteristics and Risk Assessment of Polychlorinated Biphenyls (PCBs) in Sediments and Soils from the Dishui Lake and Its River System].

In order to investigate the pollution levels of PCBs in urban artificial lake, fourteen PCB congeners in sediments and soils of Dishui Lake and its river system were quantified by GC/MS, and then the distributions, sources and ecological risk of PCBs were discussed. The results showed that the concentrations of ∑14 PCBs in sediments and soils ranged from 0.65-16.41 ng·g-1 (dry weight, dw) and 0.47-1.27 ng·g-1, respectively, which were at a low level in general. Higher concentrations of PCBs were found in surface sediments from the river system of Dishui Lake than those in surface and core sediments from Dishui Lake, which indicated that the sediments in Dishui Lake would be polluted by the river system in the process of diversion. The concentrations of PCBs in core sediments decreased with depth, which showed that the sediments of Dishui Lake had been polluted by PCBs since its completion. In all samples, Tetra-CBs and Penta-CBs accounted for 20.65% and 67.12% of ∑14 PCBs, respectively, and PCB105, PCB118 and PCB77 were the dominant compounds. The results of source apportionment by principal component analysis (PCA) indicated that PCBs in sediments and soils from Dishui Lake and its river system were influenced by the historical cumulative emissions of 2#, 1# PCBs used in China and municipal solid waste incineration and combustion sources. The toxic equivalents (TEQs) of 12 (DL-PCBs) ranged from 0.01-79.40 pg·g-1, and the TEQs in 7 samples of surface sediments from Dishui Lake and its river system were beyond the interim sediments quality guidelines (ISQGs) suggested by USEPA, which would result in potential eco-toxicological risks for aquatic organisms.

[Distribution and ecological risk assessment of polycyclic aromatic hydrocarbons in surface sediments and soils from Ddishui Lake and its water exchange areas].

Twenty-three surface sediment samples were collected from Dishui Lake and its surroundings, and 16 polycyclic aromatic hydrocarbons (PAHs) were analyzed using GC-MS. The distribution characteristics, possible sources and ecological risk were investigated. The results show that the concentrations of total PAHs range between 11.49 ng x g(-1) and 157.09 ng x g(-1) with a mean value of 66.60 ng x g(-1) in sediments from Dishui Lake, which is lower than the mean value in the catchment area but higher than that in the drainage area. Median and high molecular weight PAHs (4 rings, 5-6 rings) are the dominant compounds compared to the low molecular weight PAHs (2-3 rings) in surface sediments and soils from the lake's surroundings, while in Dishui Lake low and high molecular weight PAHs are the dominator. Based on the PAHs molecule ratios, using principal component analysis and multiple line regression, a combustion source is diagnosed in the lake's surroundings, while the mix sources of leakage of petroleum and combustion are found in Dishui Lake. Ecological risk assessment result indicates that PAHs in the sediments and soils in Dishui Lake and its water exchange areas pose little biological adverse impact.

[Phosphorus adsorption characteristics of soils and sediments surrounding Dishui Lake in Shanghai].

Soils and sediments of different origins were collected, which included the cropland soils surrounding Dishui Lake, the sediments from rivers, the sediments of wetland and the sediments in Dishui Lake. These samples were used for the experiment of phosphorus isothermal adsorption. The results of this experiment were analyzed and fitted. It shows that, the adsorption-desorption equilibrium mass concentration (EPC(0) value) of the sediments in Dishui Lake (0.11-0.63 mg x L(-1)) is higher than that of the soils and sediments from other sources, which indicates that it is easier to release phosphorus to overlying water. Both the Langmuir model and Freundlich model have a high fitting degree to the isothermal adsorption of phosphorus. The maximum adsorption capacity (Q(m)) calculated by Langmuir model demonstrate that the adsorption capacity of soils and sediments from different sources follows the order: sediments from rivers (1 003.05-2977.65 mg x kg(-1)) > sediments in Dishui Lake (669.77-1 717.94 mg x kg(-1)) > sediments of wetland (368.60-1 145.51 mg x kg(-1)) > cropland soils(441.36-702.30 mg x kg(-). It shows that the adsorption capacity of cropland soils is the weakest. Cropland soils can be a source of phosphorus in Dishui Lake when extra fertilizer is used.

[Pollution load and the first flush effect of BOD5 and COD in urban runoff of Wenzhou City].

Four typical rainfalls were monitored in two different research areas of Wenzhou Municipality. Concentrations of BOD5 and COD in six different urban runoffs were measured. In addition the event mean concentration (EMC), M (V) curve and BOD5/COD of pollutant were calculated. The results showed that concentrations of BOD5 and COD in different urban runoffs of Wenzhou ranged from ND to 69.21 mg x L(-1) and ND to 636 mg x L(-1). Concentrations of BOD5 and COD in different urban runoffs were decreasing over time, so it is greatly significant to manage the initial runoff for reducing organic pollution. Judged by EMC of BOD5 and COD in these five rainfalls, concentrations of pollutant in some urban runoffs were out of the integrated wastewater discharge standard. If these runoffs flowed into river, it would cause environmental pressure to the next level receiving water bodies. According to the M (V) curve, the first flush effect of COD in most urban runoffs was common; while the first flush effect of BOD5 was same as that of COD. The result also showed that organic pollution was serious at the beginning of runoff. The underlying surface type could affect the concentration of BOD5 and COD in urban runoff. While the results of BOD5/COD also suggested that biodegradation was considered as one of the effective ways to decrease the pollution load of organics in urban runoff, and the best management plans (BMPs) should be selected for various urban runoff types for the treatment of organic pollution.

Phosphorus loads from different urban storm runoff sources in southern China: a case study in Wenzhou City.

Storm runoff from six types of underlying surface area during five rainfall events in two urban study areas of Wenzhou City, China was investigated to measure phosphorus (P) concentrations and discharge rates. The average event mean concentrations (EMCs) of total phosphorus (TP), total dissolved phosphorus (TDP), and particulate phosphorus (PP) ranged from 0.02 to 2.5 mg · L(-1), 0.01 to 0.48 mg · L(-1), and 0.02 to 2.43 mg · L(-1), respectively. PP was generally the dominant component of TP in storm runoff, while the major form of P varied over time, especially in roof runoff, where TDP made up the largest portion in the latter stages of runoff events. Both TP and PP concentrations were positively correlated with pH, total suspended solids (TSS), and biochemical oxygen demand (BOD)/chemical oxygen demand (COD) concentrations (p<0.01), while TDP was positively correlated with BOD/COD only (p<0.01). In addition, the EMCs of TP and PP were negatively correlated with maximum rainfall intensity (p<0.05), while the EMCs of TDP positively correlated with the antecedent dry weather period (p<0.05). The annual TP emission fluxes from the two study areas were 367.33 and 237.85 kg, respectively. Underlying surface type determined the TP and PP loadings in storm runoff, but regional environmental conditions affected the export of TDP more significantly. Our results indicate that the removal of particles from storm runoff could be an effective measure to attenuate P loadings to receiving water bodies.

[Pollution load and the first flush effect of phosphorus in urban runoff of Wenzhou City].

Five typical rainfalls were monitored in two different research areas of Wenzhou municipality. The pH and concentrations of total phosphorus (TP), dissolved phosphorus (DP), particulate phosphorus (PP), total inorganic carbon (TIC), total organic carbon (TOC), total suspended substances (TSS), BOD5 and COD in six different kinds of urban runoff were measured. The results showed that, the concentrations of TP, DP and PP in different kinds of urban runoff of Wenzhou ranged from 0.01 to 4.32 mg x L(-1), ND to 0.88 mg x L(-1) and ND to 4.31 mg x L(-1), respectively. In the early stages of runoff process PP was dominated, while in the later, the proportion of DP in most of the runoff samples would show a rising trend, especially in roof and outlet runoff. Judged by the event mean concentration (EMC) of TP and DP in these five rainfalls, some kinds of urban runoff could cause environmental pressure to the next level receiving water bodies. Meanwhile, the differences among the TP and DP content (maximum, minimum and mean content) in various urban runoffs were significant, and so were the differences among various rainfall events. According to the M (V) curve, the first flush effect of TP in most kinds of urban runoff was common; while the first flush effect of DP was more difficult to occur comparing with TP. Not only the underlying surface types but also many physico-chemical properties of runoff could affect the concentration of TP in urban runoff. All the results also suggested that different best management plans (BMPs) should be selected for various urban runoff types for the treatment of phosphorus pollution, and reducing the concentration of TSS is considered as one of the effective ways to decrease the pollution load of phosphorus in urban runoff.

[Pollution characteristics and sources of polycyclic aromatic hydrocarbons in riparian soils along urban rivers of Wenzhou city].

Twenty one riparian soil samples along Jiushanwai River and Shanxia River of Wenzhou city were collected in August 2010 to investigate the pollution characteristics of polycyclic aromatic hydrocarbons (PAHs). The samples were extracted by an accelerated solvent extractor (ASE), purified by a purification column and determined by GC-MS. Results showed that the total concentrations of PAHs in the riparian soils ranged from 60.7 ng x g(-1) to 3 871.3 ng x g(-1), and the concentrations of sigma PAHs in soils along the Shanxia River were significantly lower than the levels along Jiushanwai River. The dominant compounds were 2 to 3 rings in the riparian soils along both rivers, which in average accounted for 62.47% - 72.51% in sigma PAHs. Compared with the PAHs concentrations in soils of other areas in the world, the riparian soils of the studied rivers were moderately polluted by PAHs, but the concentrations of BaP in three soil samples were much higher than the soil standard value of the former Soviet Union, which should be paid more attention. Based on the ratios of Ant/(Ant + Phe) and Fla/(Fla + Pyr) and principal component analysis results, PAHs in riparian soils of the studied rivers were mainly derived from both the petroleum and combustion.

[Pollution characteristics and sources of polycyclic aromatic hydrocarbons in urban rivers of Wenzhou city].

Concentrations of 18 polycyclic aromatic hydrocarbons (PAHs) in water and surface sediments collected from the urban rivers of Wenzhou city in spring and summer were measured by GC-MS. The results showed that the total PAHs concentrations in water and sediments of the studied rivers varied in ranges of 146.74-3 047.89 ng x L(-1) and 21.01-11 990.48 ng x g(-1), respectively. Higher concentrations occurred in spring. The low and middle rings of 2-4-ring were dominant in both water and sediments, but the concentrations of 5-ring and 6-ring PAHs in sediments were relatively higher than those in water. The EBaP values of PAHs in water of the studied rivers in spring and summer were 1.69-51.95 ng x L(-1) and 0-3.03 ng x L(-1), respectively. Eighty percent of water samples in spring surpassed the limits of BaP in surface water of China. The concentrations of sigma PAHs in the sediments both in spring and summer were lower than the ERM value, but part of the components of PAHs had values higher than the ERM, suggesting possible toxic effect on living organisms. Based on the PAHs molecule ratios and principal component analysis, a mixed PAHs source of petroleum and combustion in water and sediments was diagnosed, while sediments showed a greater proportion of combustion sources.

[Distribution and ecological risk assessment of polycyclic aromatic hydrocarbons in agricultural soil of the Chongming Island in Shanghai].

The concentration and ecological risk of Polycyclic aromatic hydrocarbons (PAHs) were investigated in thirty-three surface soil samples collected from cultivated land in Chongming Island in July 2008. Those samples were extracted using an accelerated solvent extractor (ASE) and determined by GC-MS. Results showed that the concentrations of PAHs ranged between 24.92-1014.61 ng x g(-1) (dry weight), with a mean value of 192.83 ng x g(-1). The sixteen priority PAHs with exception of Indeno(1, 2, 3-cd) pyrene (IcdP) and Dibenzo(a, h)anthracene (DahA) were all detected in all the samples. The dominant compounds were 2-3 ring and 4 ring PAHs, which accounted for 42.6% and 42.2%, respectively, while the 5-6 ring PAHs accounted for 15.7%. PAHs in soil were mainly derived from the fossil oil and the combustion of wood and coal, as determined by the concentration ratio method. The non-industrial combustion and automobile exhaust emissions in Chongming Island may be two of the important sources of PAHs in farmland soil. The analysis of ecological risk showed that the agricultural soil of Chongming Island had low ecological risk.

[Characteristics of organochlorine pesticide residues in agricultural soil of Chongming Island in Shanghai].

Thirty surface soil samples were collected to investigate the residue concentrations of organochlorine pesticides (OCPs) in agricultural soil of Chongming Island in July 2008. Those samples were extracted using accelerated solvent extraction (ASE) and determined by gas chromatography with an electron capture detector (GC-microECD). Results showed that the concentrations of OCPs (dry weight) ranged between 3.11-117.47 ng x g(-1), with mean value of 26.25 ng x g(-1). Two major contaminants of OCPs were DDTs and HCHs, the concentration of which varied from 0.14 ng x g(-1) to 77.89 ng x g(-1) and from 1.14 ng x g(-1) to 22.43 ng x g(-1), respectively. At the same times, hexachlorobenzene (0.23-11.63 ng x g(-1)), aldrin (0.03-0.75 ng x g(-1)), heptachlor epoxide (0.05-1.44 ng x g(-1)), dieldrin (0.05-5.33 ng x g(-1)), endrin (ND-14.66 ng x g(-1)) and mirex (0.03-10.58 ng x g(-1)) could also be detected. Most of DDTs had been degraded to DDD and DDE, with the major compounds of DDE (about 64.7%), and the recent existed DDT was the residue of early input. All of the four isomers of HCHs were detected, and the contents of alpha-HCH (about 48.1%) and beta-HCH (about 33.4%) were the maximum. The highest OCPs residues appeared in the soil of farm cultivation compared to greenhouse cultivation and ordinary open-air cultivation.

[Laboratory simulation study on the influence of resuspension on the release of mercury from Yangtze estuarine tidal flat].

Using a Particle Environment Simulator, laboratory simulation experiment on the influence of resuspension on the release of mercury from sediments collected from medium tidal flat and low tidal flat in Chongming Dongtan was conducted. Results indicated that the conditions of overlying water changed significantly during resuspension. The concentrations of HgD and HgP were mainly in the rang of 0.152-2.657 microg x L(-1), 0.080-2.722 microg x L(-1) separately. In the resuspension processes, mercury was released from the medium intertidal sediments under the salinity condition of 4.1 per thousand, 8.0 per thousand, 10.0 per thousand, 13.0 per thousand, and from the low intertidal sediments under the salinity condition of 13.0 per thousand. However, the release of mercury from the medium intertidal sediments is not significant under the salinity condition of 4.1 per thousand, 8.0 per thousand, 10.0 per thousand. The salinity of overlying water had an important effect on resuspension. In different salinity condition, the release of mercury was different. And the release of mercury from medium tidal flat and low tidal flat was different during the resuspension periods, the release of mercury from the medium intertidal sediment was significantly higher than the release from the low intertidal sediment. When the rotate speed was (210 +/- 5) r x min(-1), the desorption of mercury significantly increased, thereby the rotate speed had an effect on the release of mercury.

[Transport and release of Cd, Pb and Cr from the Yangtze Estuarine sediments during sediment resuspension event].

The effects of resuspension energy and duration on release and transport of sediment bound Cd, Pb and Cr in the southern coastal areas of Yangtze Estuary were analyzed experimentally using a particle entrainment simulator (PES). In the sediment resuspension experiment, concentrations of dissolved Cd, Pb and Cr in the overlying water were 0.015-0.157, 0.013-0.890 and 0.066-1.468 microg x L(-1) respectively, and concentrations of particulate Cd, Pb and Cr varied between 0.37-5.40, 8.3-137.1 and 31.6-557.7 microg x g(-1) respectively. Before the biofilm in column surface was not damaged by disturbance, a large number of Cd adsorption to biofilm was released to the overlying water during the resuspension, but after part of the biofilm was damaged with the enhanced disturbance energy, Pb and Cr were released from the sediments to overlying water in short-term. Intensity of physical disturbance was the main factor that influenced the variation of particulate heavy metal concentrations. Results of resuspension fluxes showed that Cd, Pb and Cr released to the water by resuspension were then re-adsorption to suspended particles, and gradually deposited in the bottom sediments when the hydrodynamic conditions weakened, which had less harm to the aquatic ecosystems of Yangtze Estuary. The resuspension process of Cd, Pb and Cr mainly includes the following migration and transformation process: adsorptions of heavy metals in biofilm, direct release and diffusion of dissolved heavy metals from pore water, oxidative release of sulfide associated metals in sediments, re-adsorption of heavy metals to suspended particles in overlying water and deposition of particulate heavy metals.

[Sorption behavior of phenanthrene to natural carbonaceous sediments].

Natural sediments impacted by previous coal mining activities were collected and separated according to grain size and density. Sorption experiments were performed with original sediments and different sub-fractions. Abundant coal and other coal-derived particles were identified using organic spectrographic analysis. Both Freundlich and partitioning and pore-filling model were applied to fit the experimental data. All sorption isotherms showed non-linear sorption properties, with n in the range of 0.72-0.76. The light fraction had the highest sorption capacity (lgK(Fr) = 4.03), which is comparable to that of raw coal. In addition, partitioning and pore-filling model yields the better fitting than Freundlich model, indicating that at low c(w), "pore-filling" dominants the whole sorption; while with the increase of c(w), partition takes place of adsorption and dominants the sorption. In addition, in spite of the very low mass weight, the light fraction dominated by carbonaceous materials contributed more than 60% of the sorption for the whole sediments.

[Transfer and release of Hg from the Yangtze Estuarine sediment during sediment resuspension event].

The effect of resuspension energy and duration on release and subsequent redistribution of sediment bound Hg in Yangtze Estuary was measured experimentally using a particle entrainment simulator. Concentrations of Hg(D) (Dissolved Hg) and Hg(P) (Particulate Hg) in the overlying water were 34-268 ng x L(-1) and 25-195 microg x kg(-1) respectively, and sensitive to disturbance energy and time during sediment resuspension. There is no significant correlation between Hg(D) and Hg(P) concentration. After the first disturbance intensity experiment for 3 h, Hg was released to the overlying water in general, with Hg(D) and Hg(P) concentrations increasing from 179 ng x L(-1) to 268 ng x L(-1) and from 116 microg x kg(-1) to 139 microg x kg(-1) respectively. And then concentrations of Hg(D) and Hg(P) decreased after the overlying water was disturbed for 3 h at the second intensity, while after the third disturbance intensity experiment for 3 h, a slight increase was observed in Hg(D), and Hg(P) concentration increased from 89 microg x kg(-1) to 162 microg x kg(-1) in overlying water. The distribution coefficient (lg K(d)) of Hg in overlying water had no significant correlations with the water column pH, Eh, DO and TSS, but influenced by the combined physical and chemical conditions of the water column. In each disturbance energy treatment, both the content of suspended particles and lg K(d) for Hg increased rapidly in the overlying water in the early stage, especially the first 5 min, indicating a strong absorption of Hg on the suspended particles. After that, a decrease of the lg K(d) for Hg occurred with the time and content of suspended particles increased. It can be explained that the released Hg by oxidation of sulfide was bounded by the newly generated colloidal material such as the hydrate iron-manganese oxide. In relatively strong disturbance energy treatment, part of the coarse particles settled with time. The concentrations of Hg(P) increased in some resuspension stage in the overlying water due to the "fine particle concentration effect".

[Kinetics of adsorption of Pb2+ onto small river sediment].

The batch experiments of adsorption of Pb2+ onto small river sediments were conducted. The kinetics of the sorption process was analyzed. The results showed that the equilibrium time of adsorption increased with the increasing of sediment mass in solution, while both adsorbed Pb2+ on per unit of sediment and Pb2+ concentration in the solution after equilibrium decreased. More than 95% of Pb2+ in solution was removed when sediment contents larger than 0.6 g x L(-1). Both pseudo-first-order and pseudo-second-order kinetics were tested and it was found that the latter gave a better explanation of the adsorption process. The equilibrium adsorption capacities calculated from the pseudo-second-order model could represent the true value. There was no significant correlation between initial adsorption rate of Pb2+ and the amount of sediment in solution. However, the pseudo-second-order rate constant increased in the solution with more adsorbent, namely chemical adsorption controlled the process. Elovich equation could explain the mechanism of sorption in the solution with higher contents of sediment; nevertheless, the process of low concentration of adsorbent adsorbing Pb2+ disagreed well with Elovich equation. In terms of adsorption rate in the sorption, intra-particle diffusion dominated in the more sediment solution. On the other hand, multi-linearity was presented for the adsorption rate in less adsorbent solution. The first, sharper portion represented adsorption on the external surface. The second portion indicated Pb2+ diffused gradually into the interior of particles and intra-particle diffusion controlled.

[Analysis of algal blooms in Da-Ning River of Three Gorges Reservoir].

According to the survey conducted from Apr. to Jun. 2007 and from Apr. to May. 2008, the changes of water quality, forms and distributions of nutrient salts and characters of algal blooms in Da-ning River of Three Gorges Reservoir (TGR) were studied. The results indicated that the concentrations of nitrogen and phosphorus nutrient were abundant during sensitive period of algal blooms in Da-ning River. Total nitrogen (TN) and total phosphorus (TP) values are 0.84-3.21 mg/L and 0.011-0.531 mg/L respectively, and the nutrients concentrations become high gradually from upstream to downstream. Total dissolved nitrogen (TDN) is the major form of TN accounting for 84%, and total dissolved phosphorus (TDP) is dominant (TDP/TP = 60%). Algal blooms bring phosphorus nutrient bio-concentration. The rates of TN and TP are all in excess of 16, which show eutrophication is limited by phosphorus. Potassium permanganate index and dissolved oxygen (DO) are at low levels and change stably. But chlorophyll a (Chl-a) becomes frequently, the value is 1.41-219.04 mg x m(-3). Significant positive correlations are all observed by correlation analysis between Chl-a and the main parameters (r(Chla-TP) = 0.453, r(Chla-potassium permanganate index) = 0.641, r(Chla-DO) = 0.584, r(Chla-pH) = 0.409, p < 0.01), but significant negative correlations are observed between Chl-a and Secchi depth (SD) (r(Chla-SD) = - 0.392, p < 0.01). The pH is fluctuated by multiparameter esp. in algal blooms. Widespread algae are observed by microscope during sensitive period of algal blooms in Da-ning River accounting for 8 phylum 82 genus 124 species, which Bacillariophyta and Chlorophyta are dominant, and then Cyanophyta and Pyrrophyta. Three whole watershed algal blooms break out in Da-ning River during the period, and the highest values of algal density are 14-1 427 times as many as the normal values. The dominant species of algal blooms are mostly involved with O. borgei, C. microporum, Chlorococcum humicola, P. morum and C. vulgaris of Chlorophyta; P. pleuronectes and T. oblonga of Euglenophyta; Cyclotella, Stephanodiscus astraea and Navicula of Bacillariophyta; P. elpatiewskyi of Pyrrophyta. Multi-algal species blooms are observed in the same time and place, and there are few algae in the estuary of Da-ning River to Changjiang River.

[Systematic investigation into winter and spring algal blooms in Daning River of Three Gorges Reservoir].

According to the survey conducted from winter and spring algal blooms, the changes of water quality and characteristics of Daning River of Three Gorges Reservoir (TGR) were studied. The results suggested that during the period of winter algal blooms centered on Tangjia bay in Daning river, chlorophyll a (Chl-a) had a wide range (the rates of (Chl-a)max and (Chl-a)min is 260). The contents of total nitrogen (TN), total phosphorus (TP) and potassium permanganate index were at very high levels because of bioaccumulation from algal blooms, but the values of dissolved oxygen (DO) and pH were very low. During winter algal blooms fastigium poor algae were observed accounting for 2 phylum 4 species, dominant species are Microcystis aeruginosa and Microcystis flos-aquae, the maximum value of algal density was 3.15 x 10(7) cells/L, and the correlation weighted nutrition state index was 80, which indicated water body was at high eutrophication level. However the spring algal blooms belonged to whole watershed outbreak, the values of Chl-a, TN, TP and potassium permanganate index became all markedly high with outbreak of algal blooms. There were 5 phylum 44 species algae being observed during spring algal blooms fastigium, different sections observed different dominant species and algal density values. The correlation weighted nutrition state index showed water of Dongping bar and Baishui River sections was at slight eutrophication level. During winter algal blooms there were significantly positive correlations between Chl-a and TN, TP, potassium permanganate index, water temperature, between pH and SD. Significantly negative correlations were observed between Chl-a and DO, SD, between pH and TN, TP, potassium permanganate index. In spring algal blooms significantly positive correlations were observed between Chi-a and TP, potassium permanganate index, DO, pH, between pH and Chla, TP, potassium permanganate index, DO, air temperature. Significantly negative correlations were observed between Chl-a and SD, between pH and SD.