Phosphorus fractions and its release in the sediments of Haihe River,China

The amounts and forms of phosphorus （P） in surface sediments of Haihe River, Tianjin, North China, were examined using a sequential chemical extraction procedure. Five fractions of sedimentary P, including loosely sorbed P （NH4Cl-P）, redox-sensitive P （BD-P）, metal oxide bound P （NaOH-P）, calcium bound P （HCI-P）, and residual P （Res-P） （organic and refractory P）, were separately quantified. The results indicated that the contents of different P fractions in the sediments varied greatly. The total P （TP） contents ranged from 968 to 2017 mg/kg. Phosphorus contents in NH4Cl-P, BD-P, NaOH-P, and HCl-P ranged from 6.7 to 26.6 mg/kg, 54.5 to 90.2 mg/kg, 185.2 to 382.5 mg/kg, and 252.3 to 425.5 mg/kg, respectively, which represented 1.2%-3.2%, 7.7%-13%, 33.3%-48.9%, and 36.2%-54.2% of the sedimentary inorganic P, respectively. For all the sediment samples, the rank order of P-fractions was Res-P 〉 HCl-P 〉 NaOH-P 〉 BD-P 〉 NH4Cl-P. The highly positive relationship between the amounts of P released from the sediments and those in the NH4Cl-P and BD-P fractions, indicated that NH4Cl-P and BD-P were the main fractions that can release P easily.

Characterization and distribution of polycyclic aromatic hydrocarbon in sediments of Haihe River, Tianjin, China

In this study sediment samples were collected from 13 sites of Haihe River in Tianjin City, China, sixteen of priority polycyclic aromatic hydrocarbons （PAHs） listed in USEPA were analyzed by means of GC-MS. The total concentrations of PAH ranged from 774.81 to 255371.91 ng/g dw, and two to four rings of PAHs were dominant in sediment samples. Molecular ratios, such as phenanthrene/anthracene, fluoranthene/pyrene and low-molecular-weight PAH/high-molecular-weight PAH, were used to study the possible sources of pollution. It indicated a mixed pattern of parolytic and petrogenic inputs of PAHs in sediments in Haihe River. The petrogenic PAHs may be mainly derived from the leakage of refined products, e.g., gasoline, diesel fuel and fuel oil vehicle traffics or gas stations from urban area. The pyrolytic PAHs might be from the discharge of industrial wastewater and the emission of atmospheric particles from petrochemical factories. In addition, the levels of PAHs in the urban and industrial areas are far beyond the values reported from other rivers and marine systems reported. This situation may be due to polluted discharging from some petrochemical industrial manufactories and worse traffic conditions in Tianjin.

Quantitative Evaluation of Sustainable Development and Eco-Environmental Carrying Capacity in Water-Deficient Regions:A Case Study in the Haihe River Basin,China

Quantitative assessment of development sustainability could be a challenge to regional management and planning, especially for areas facing great risks of water shortage. Surface-water decline and groundwater over-pumping have caused serious environmental problems and limited economic development in many regions all around the world. In this paper, a framework for quantitatively evaluating development sustainability was established with water-related eco-environmental carrying capacity （EECC） as the core measure. As a case study, the developed approach was applied to data of the Haihe River Basin, China, during 1998 through 2007. The overall sustainable development degree （SDD） is determined to be 0.39, suggesting that this rate of development is not sustainable. Results of scenario analysis revealed that overshoot, or resource over- exploitation, of the Basin＇s EECC is about 20% for both population and economy. Based on conditions in the study area in 2007, in order to achieve sustainable development, i.e., SDD〉0.70 in this study, the EECC could support a population of 108 million and gross domestic product （GDP） of 2.72 trillion CNY. The newly developed approach in quantifying ecoenvironmental carrying capacity is anticipated to facilitate sustainable development oriented resource management in waterdeficient areas.

Spatial and temporal variability of daily precipitation in Haihe River basin, 1958-2007

The seasonal variability and spatial distribution of precipitation are the main cause of flood and drought events. The study of spatial distribution and temporal trend of precipitation in river basins has been paid more and more attention. However, in China, the precipitation data are measured by weather stations （WS） of China Meteorological Administration and hydrological rain gauges （RG） of national and local hydrology bureau. The WS data usually have long record with fewer stations, while the RG data usually have short record with more stations. The consistency and correlation of these two data sets have not been well understood. In this paper, the precipitation data from 30 weather stations for 1958-2007 and 248 rain gauges for 1995-2004 in the Haihe River basin are examined and compared using linear regression, 5-year moving average, Mann-Kendall trend analysis, Kolmogorov-Smirnov test, Z test and F test methods. The results show that the annual precipitation from both WS and RG records are normally distributed with minor difference in the mean value and variance. It is statistically feasible to extend the precipitation of RG by WS data sets. Using the extended precipitation data, the detailed spatial distribution of the annual and seasonal precipitation amounts as well as their temporal trends are calculated and mapped. The various distribution maps produced in the study show that for the whole basin the precipitation of 1958-2007 has been decreasing except for spring season. The decline trend is significant in summer, and this trend is stronger after the 1980s. The annual and seasonal precipitation amounts and changing trends are different in different regions and seasons. The precipitation is decreasing from south to north, from coastal zone to inland area.

Persistent organochlorine residues in sediments of Haihe River and Dagu Drainage River in Tianjin, China

Persistent organochlorine compounds were analyzed by means of GC-ECD in surface sediment samples from two selected rivers in Tianjin, Haihe River and Dagu Drainage River. A total of 16 surface sediment sites were selected along the both rivers. The frequency of detection of T-HCH and T-DDT in sediment samples both was up to 100%, which illustrated that the contamination of HCH and DDT was widespread in Haihe and Dagu Drainage Rivers. Results indicated that the concentrations of various pesticides in sediments from Haihe River were in the range of 3.30-75.96 ng/g dw for T-HCH and 1.57-211.57 ng/g dw for T-DDT. Compared with Haihe River, Dagu Drainage River was contaminated by HCHs and DDTs along the all locations and the values of T-HCH and T-DDT residues in sediments ranged from 2.30 to 124.61 ng/g dw and from 11.28 to 237.30 ng/g dw, respectively, The possible pollution sources were analyzed through monitoring results of organochlorine pesticides（OCPs） residues in sediments from the two rivers. The investigation also indicated that HCH was still used as pesticide in Tianjin partial area.

Risk assessment of water security in Haihe River Basin during drought periods based on D-S evidence theory

The weights of the drought risk index （DRI）, which linearly combines the reliability, resiliency, and vulnerability, are difficult to obtain due to complexities in water security during drought periods. Therefore, drought entropy was used to determine the weights of the three critical indices. Conventional simulation results regarding the risk load of water security during drought periods were often regarded as precise. However, neither the simulation process nor the DRI gives any consideration to uncertainties in drought events. Therefore, the Dempster-Shafer （D-S） evidence theory and the evidential reasoning algorithm were introduced, and the DRI values were calculated with consideration of uncertainties of the three indices. The drought entropy and evidential reasoning algorithm were used in a case study of the Haihe River Basin to assess water security risks during drought periods. The results of the new DRI values in two scenarios were compared and analyzed. It is shown that the values of the DRI in the D-S evidence algorithm increase slightly from the original results of Zhang et al. （2005）, and the results of risk assessment of water security during drought periods are reasonable according to the situation in the study area. This study can serve as a reference for further practical application and planning in the Haihe River Basin, and other relevant or similar studies.

Change of the solar radiation and its causes in the Haihe River Basin and surrounding areas

Solar radiation is an important driving force for the formation and evolution of climate system. Analysis of change in solar radiation is helpful in understanding mechanism of climate change. In this study, the temporal and spatial variations of solar radiation and the cause of the change in solar radiation have been analyzed based on meteorological data from 46 national meteorological stations and aerosol index data from TOMS over the Haihe River Basin and surrounding areas. The results have shown that solar radiation and direct radiation significantly decreased, while scattered radiation increased during the period 1957-2008. Spatially, the decreasing trend of solar radiation was more and more significant from low population density areas to high population density areas. The spatial distribution of increase in aerosol index is consistent with that of decrease in solar radiation. The increase in aerosols resulting from human activities was an important reason for the decrease in solar radiation.

Estimation and Characteristic Analysis of Biomass within the Haihe River Basin Based on CASA Model

Using CASA model, biomass within the Haihe River basin during 2002 -2007 was estimated based on remote sensing images, corresponding data of temperature, precipitation and solar radiation, and 1：400 000 0 maps of vegetation coverage in China. Variations in the biomass with vegetation type and vegetation coverage in 2007 were analyzed. Meanwhile, its temporal and spatial changes were discussed. The results validate the applicability of CASA model in the estimation of biomass within the Haihe River basin. During the past 6 years, annual average biomass within the basin was 405.5 Tg in total; annual average biomass in the basin was high in the southeast but low in the northwest, namely plains 〉 mountains 〉 plateaus.

Spatial and vertical variations of perfluoroalkyl substances in sediments of the Haihe River,China

The levels of six perfluoroalkyl substances（PFASs） in surface sediment and their vertical variations in dated sediment cores from the Haihe River were investigated; studied substances included perfluorooctanoic acid（PFOA）,perfluorononanoic acid（PFNA）,perfluorooctane sulfonate（PFOS）,perfluorodecanoic acid（PFDA）,perfluoroundecanoic acid（PFUnA）,and perfluorododecanoic acid（PFDoA）. Results showed that the total PFAS concentration in surface sediment ranged between 0.52 and 16.33 ng/g dry weight（dw） with an average of3.47 ng/g dw,with PFOS and PFOA as the dominant PFASs. In general,the PFAS concentrations in the mainstream increased from the upper to the lower reaches,except that a drop occurred downstream of the Erdao dam. Although the PFASs in the sediment cores did not show a clear decreasing or increasing trend with depth,the three cores had a similar vertical variation.The PFAS levels were relatively low in the surface sediment,and reached the first high point at8–20 cm as a result of the wide use of PFASs from 1990 to 2000. After that the PFAS levels decreased,and then increased to a second high point at about 40–48 cm,which might be caused by the leaching of PFASs in sediment. Because PFASs have hydrophilic groups and relatively high solubility,the PFASs will transfer from the upper to lower layers of sediment when water infiltration occurs,leading to the fluctuation of PFAS levels in sediment cores. This study suggests that both the temporal variation of sources and transfer processes of PFASs in sediments are important factors influencing the vertical variation of PFASs in sediment cores.

Climate Simulation and Future Projection of Precipitation and the Water Vapor Budget in the Haihe River Basin

The climatological characteristics of precipitation （HRB） are analyzed using daily observations at 740 and the water vapor budget in the Haihe River basin stations in China in 1951 2007 and the 4-time daily ERA40 reanalysis data in 1958 2001. The results show that precipitation and surface air temperature present significant interannual and interdecadal variability, with cold and wet conditions before the 1970s but warm and dry conditions after the 1980s. Precipitation has reduced substantially since the 1990s, with a continued increase of surface air temperature. The total column water vapor has also reduced remarkably since the late 1970s. The multi-model ensemble from the Fourth Assessment Report （AR4） of the Intergovernmental Panel on Climate Change （IPCC） has capably simulated the 20th century climate features and successfully reproduced the spatial patterns of precipitation and temperature. Unfortunately, the models do not reproduce the interdecadal changes. Based on these results, future projections of the climate in the HRB are discussed under the IPCC Special Report on Emissions Scenarios （SRES） B1, A1B, and A2. The results show that precipitation is expected to increase in the 21st century, with substantial interannual fluctuations relative to the models＇ baseline climatology. A weak increasing trend in precipitation is projected before the 2040s, followed by an abrupt increase after the 2040s, especially in winter. Precipitation is projected to increase by 10% 18% by the end of the 21st century. Due to the persistent warming of surface air temperature, water vapor content in the lower troposphere is projected to increase. Relative humidity will decrease in the mid-lower troposphere but increase in the upper troposphere. On the other hand, precipitation minus evaporation remains positive results, the HRB region is expected to get wetter throughout the 21st century. Based on these projection in the 21st century due to global warming.

Distribution and potential ecological risk of heavy metals in the typical eco-units of Haihe River Basin

The distribution and characteristics of seven heavy metals in sediments located in the typical ecological units （eco-units） （e.g., rivers, lakes, and estuaries） of Haihe River Basin were analyzed. The Hakanson potential ecological risk index was used for ecological risk assessment. The results indicated that the concentration scales of As, Hg, Cr, Cd, Pb, Cu, and Zn in the eco-units were 2.08 to 24.80 mg·g-1, 0.01 to 1135.50 mg·g-1, 28.70 to 152.73mg·g-1, 0.03 to 195765.83mg·g-1, 8.65 to 157.82mg·g-1, 6.47 to 178.61mg·g-1, and 21.09 to 1076.25 mg·g-1, respectively. The maximum concentra- tions of Hg, Cd, and Zn showed higher levels than other water bodies around the world. Hg and Cd have high concentrations in Zhangweinanhe River （1135.50 and 195765.83mg·g-1, respectively） and Haihe Estuary （790.50 and 548.47 mg·g-1, respectively）. According to the ecological factor, Cd and Hg showed very strong ecological risks. The seven heavy metals, namely, Cd, Hg, As, Cr, Pb, Cu, and Zn, exhibited ecological risk levels in descending order. Based on the potential ecological risk index, Luanhe River and Baiyangdian Lake had moderate ecological risks, whereas every site in Zhangweinanhe River and Haihe Estuary had substantial risk levels. The risk order of the typical eco-units are as follows： Zhangweinan River （2278345.68） 〉 Estuary （161914.74） 〉 Luanhe River （191.54）〉Baiyangdian Lake （120.95）. These results provided a scientific basis for water environment improve- ment and risk management of the Haihe River Basin.

Determination of hexabromocyclododecanes in sediments from the Haihe River in China by an optimized HPLC–MS–MS method

Hexabromocyclododecanes（HBCDs）,a new type of persistent organic pollutants widely used as brominated flame retardants,have attracted wide attention due to their increasing level and toxicity. A method based on high-performance liquid chromatography mass spectrometry（HPLC–MS–MS）in electrospray ionization mode has been developed by optimization of various parameters,which effectively improved the separation degree and responsive intensity of α-,β-and γ-HBCD isomers. The concentrations and distribution profiles of three HBCD isomers were investigated in sediments from the Haihe River in China.It was observed that the concentrations of HBCDs varied in the range of 0.4–58.82 ng/g,showing a decreasing trend along the flow direction,possibly due to attenuation and biodegradation along the flow direction of the Haihe River. The distribution profile of α-,β-,γ-HBCD was 7.91%–88.6%,0–91.47%,and 0.62%–42.83%,respectively. Interestingly,α-HBCD dominated in most sample sites. This was different from the distribution profile in commercial industrial products,which might be attributed to the inter-transformation and different degradation rates of the three HBCD isomers. The potential ecological risk of HBCDs in sediment was characterized under the two-tiered procedure of the European Medicines Evaluation Agency for environmental risk assessment. Although the HBCDs in the selected section of the Haihe River presented ＂no risk＂ in the sediment compartment,its risk in sediment cannot be neglected since sediment is one of the important sinks and reservoirs of pollutants.

The Influence of Large-Scale Circulation on the Summer Hydrological Cycle in the Haihe River Basin of China

In this study, we focus on changes in three important components of the hydrological-cycle in the Haihe River basin （HRB） during 1957-2005： precipitation （Prep）, actual evaportranspiration （ETa）, and pan evaporation （PE）-a measure of potential evaporation. The changes in these components have been evaluated in relation to changes in the East Asian summer monsoon. Summer Prep for the whole basin has decreased significantly during 1957-2005. Recent weakening of the convergence of the integrated water vapor flux, in combination with a change from cyclonic-like large-scale circulation conditions to anti-cyclonic-like conditions, led to the decrease in the summer Prep in the HRB. ETa is positively correlated with Prep on the interannual timescale. On longer timescales, however, ETa is less dependent on Prep or the large-scale circulation. We found negative trends in ETa when the ERA40 reanalysis data were used, but positive trends in ETa when the NCEP/NCAR reanalysis data were used. PE declined during the period 1957-2001. The declining of PE could be explained by a combination of declining solar radiation and declining surface wind. However, the declining solar radiation may itself be related to the weakening winds, due to weaker dispersion of pollution. If so, the downward trend of PE may be mainly caused by weakening winds.

Remote sensing monitoring on regional crop water productivity in the Haihe River Basin

Crop water productivity （CWP） agricultural development in water scarcity is one of the important indicators for sustainable area. There is serious conflict between water sup- ply and requirement in the Haihe River Basin. CWP of winter wheat and summer maize from 2003 to 2007 in the Haihe River Basin is estimated based on large-scale evapotranspiration （ET） and crop yield obtained by remote sensing technology. Spatial and temporal distribution of CWP of winter wheat and summer maize is investigated in this study. Results show that CWP of winter wheat in most parts of the study area varies from 1.02 kg/m3 to 1.53 kg/m3, and CWP of summer maize varies from 1.31 kg/m3 to 2.03 kg/m3. Multi-year averaged CWP of winter wheat and summer maize in the study area is about 1.19 kg/m3 and 1.59 kg/m3. CWP results show certain promotion potential to alleviate the water shortage in the Haihe River Basin. Correlation analysis of CWP, crop yield and ET shows that there is great potential for crop yield promotion without the growth in irrigation water. Large-scale CWP estimated by remote sensing technology in this study shows spatial distribution features, which could be used to real-time agricultural water resource management combined with crop yield and ET.

Limitation of spatial distribution of ammonia-oxidizing microorganisms in the Haihe River, China, by heavy metals

The Haihe River is characterized by high ammonia pollution. Therefore, it is necessary to determine how environmental factors, such as heavy metals in the fiver limit the spatial distribution of ammonia-oxidizing microorganisms. In this study, the relationships between five heavy metals and ammonia-oxidizing microorganisms were studied. The results showed that under high ammonia, low oxygen and high concentrations of suspended particles, ammonia-oxidizing bacteria （AOB） ranged from 1013 to 104.8 gene copies/mL and ammonia-oxidizing archaea （AOA） ranged from 102.7 to 104.9 gene copies/mL. The average metal concentrations in water were 23.57 （Cr）, 21.58 （Ni）, 65.09 （Cu）, 622.03 （Zn） and 10.16 （As） Ixg/L, with those of Zn, Cu and Cr being higher than the US EPA criteria. Scatter plots of microbial abundance and metals indicated that both AOA and AOB were limited by heavy metals, but in different ways. As had an inhibitory effect on AOB, while Ni and Zn promoted AOA, and the other metals investigated showed no significant correlation with microbial abundance. Overall, our results indicated that the effects of heavy metals on ammonia-oxidizing microorganisms in water are complex, and that the final effect is determined by the physiological role of each element in the microorganisms, as well as environmental conditions such as complexation of organic matter, not simply the total metal concentration.

Effects of climate and land use changes on runoff,sediment,nitrogen and phosphorus losses in the Haihe River Basin

Investigating the impacts of climate and land use changes on the hydrological cycle and water environment at the basin scale is important for providing scientific evidence to manage the trade-offs and synergies among water resources,agricultural production and environmental protection.We used the Soil and Water Assessment Tool(SWAT)with various spatiotemporal data to quantify the contributions of climate and land use changes to runoff,sediment,nitrogen(N)and phosphorus(P)losses in the Haihe River Basin since the 1980s.The results showed that 1)climate and land use changes significantly increased evapotranspiration(ET),transport loss,sediment input and output,and organic N and P production,with ET,sediment input and organic N affected the most;2)runoff,sediment and ammonia N were most affected by climate and land use changes in the Daqing River Basin(217.3 mm),Nanyun River Basin(3917.3 tons)and Chaobai River Basin(87.6 kg/ha),respectively;3)the impacts of climate and land use changes showed explicit spatiotemporal patterns.In the Daqing,Yongding and Nanyun River Basins,the contribution of climate change to runoff and sediment kept increasing,reaching 88.6%-98.2%and 63%-77.2%,respectively.In the Ziya and Chaobai River Basins,the contribution of land use was larger,reaching 88.6%-92.8%and 59.8%-92.7%,respectively.In the Yongding,Chaobai,Ziya and Daqing River Basins,the contribution of land use to N and P losses showed an increasing trend over the past 40 years(maximum 89.7%).By contrast,in Nanyun and Luanhe River Basins,the contribution of climate change to N and P losses increased more(maximum 92.1%).Our evaluation of the impacts of climate and land use changes on runoff,sediment,and N and P losses will help to support the optimization of land and water resources in the Haihe River Basin.

Biologic risk and source diagnose of 16 PAHs from Haihe River Basin, China

Surface sediments of rivers can exhibit spatial and temporal variations in contaminant concentrations that may significantly affect risk evaluations. As to pollution control and remediation of watershed, large-scale and further background data on PAHs in China were required urgently. Spatial distribution and compositional character- istics of 16 polycyclic aromatic hydrocarbons （PAHs） in surface sediments from Haihe River Basin were investi- gated. A method based on effects range （ER） was used to assess ecosystem risk of ZPAHs （the total of 16 PAH） sensitively and accurately. The results indicated that ∑PAHs content levels ranged from 257 to 16901 μg·kg-1 dry weight. The lower tings predominated in the samples, and 2-, 3-, 4-, 5- and 6-ring PAHs accounted for 12%, 21%, 30%, 30%, and 7% respectively in total PAHs. The ratio of F1 / （F1 ＋ Py） uniformly distributed in the interval 0.20- 0.80, indicating that it may be affected by petroleum origin, oil combustion, biomass and coal combustion jointly. ∑PAHs in Cetian （S6）, Dongwushi （S19）, Handan （S20）, Aixinzhuang （S21） and Tianjin （S37） exceeded effects range low （ERL）, in which biologic effects were in a medium level with an adverse effect on biologic organisms. Thus, it is necessary to strengthen the PAHs monitoring and research of the Haihe River Basin.

Characteristics of phosphorus chemistry and its geographical distribution in

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Spatiotemporal optical properties of dissolved organic matter in a sluice-controlled coastal plain river with both salinity and trophic gradients

Due to the combined effect of sluices and sea tide,the sluice-controlled coastal plain river would be characterized by both trophic state and salinity gradients,affecting the spatiotemporal optical properties of dissolved organicmatter(DOM).In this study,we investigated the spatiotemporal variation of water quality parameters and optical properties of DOM in the Haihe River,a representative sluice-controlled coastal plain river in Tianjin,China.A significant salinity gradient and four trophic states were observed in the water body of the Haihe River.Two humic-and one protein-like substances were identified from the DOM by the three-dimensional fluorescence spectra combined with the parallel factor(PARAFAC)analysis.Pearson’s correlation analysis and redundancy analysis(RDA)showed that the salinity significantly affected the abundance of chromophoric DOM(CDOM)but did not cause significant changes in the fluorescence optical characteristics.In addition,the effect of Trophic state index(TSI)on the CDOM abundance was greater than that on the fluorescence intensity of fluorescent dissolved organic matter(FDOM).In the water body with both salinity and trophic state gradients,TSI posed a greater influence than salinity on the CDOM abundance.Our results fill the research gap in spatiotemporal DOM characteristics and water quality variation in water bodies with both salinity and trophic state gradients.These results are beneficial for clarifying the joint influence of saline intrusion and sluices on the DOM characteristics and water quality in sluice-controlled coastal plain rivers.

CHINA'S FOUR MAJOR METEOROLOGICAL SCIENTIFIC EXPERIMENTS

China lies in East-Asian monsoon region,which is one of the well-known active monsoon zones around the world.Monsoon anomaly results in frequent natural disasters,such as drought, torrential rain and flood.In 1998,joint intensified observations for 4 major meteorological scientific experiments have been carried out over Chinese major monsoon affected areas.A number of valuable data have been obtained and some observational facts have come out after initial analysis.The present paper is to give an introduction to the 4 major meteorological scientific experiments conducted in 1998 in China.including its origin and scientific goals,implementation and planning,equipment and progress,and initial findings from the important observational facts. It aims to provide a comprehensive report on the progress of the above experiments for those who are interested in.