[Characteristics of Eukaryotic Phytoplankton Community Structure and Its Relationship with Environmental Factors in Danjiangkou Reservoir].

Eukaryotic phytoplankton play crucial roles in ecosystem processes, and understanding their community composition and abundance is of great importance to protect the balance of aquatic ecosystems. Danjiangkou Reservoir is a canyon lake in central China that acts as the water source of the Mid-route of South-to-North Water Diversion Project. In this study, the composition of planktonic microeukaryotes from water samples with a depth ranging from 0.5 to 20 m in Danjiangkou Reservoir were investigated using high-throughput 18S rDNA gene sequencing. The environmental factors including pH, water temperature (WT), nitrate (NO3--N), ammonia (NH4+-N), total nitrogen (TN), conductivity (Cond.), water depth, and dissolved oxygen (DO) in the reservoir areas were measured, and their correlations with the abundance and diversity of eukaryotic phytoplankton were analyzed. The results of high-throughput sequencing showed that a total of 68 genera of phytoplankton belonging to 12 phyla were detected, and the phytoplankton communities were mainly composed of Dinophyceae, Bacillariophyta, and Chlorophyta. In particular, significant differences in the diversity of phytoplankton communities on a vertical distribution were found. The diversity and abundance of the phytoplankton communities in Songgang (SG), Tumen (TM), and Dangzikou (DZK) decreased with the increase in water depth, and the relationship between phytoplankton and water depth in other sampling sites was not obvious. The results of RDA showed that NO3--N, water depth, DO, pH, and WT could influence the vertical distribution of the phytoplankton community in the Danjiangkou Reservoir. Among these phytoplankton types, Dinophyceae was negatively correlated with NO3--N and water depth and positively correlated with other environmental factors. Meanwhile, Bacillariophyta was positively correlated with NO3--N and water depth and negatively correlated with other environmental factors. In addition, Chlorophyta was negatively correlated with WT, pH, and DO and not significantly correlated with water depth.

Urbanization's Impacts on Ecosystem Health Dynamics in the Beijing-Tianjin-Hebei Region, China.

Accelerated urbanization disturbs ecosystems and influences ecosystem structures and functions. Ecosystem health (ESH) assessments in regions undergoing the rapid urbanization process assist us in understanding how ESH changes and how urbanization specifically affects ESH. We assessed the ESH of Beijing-Tianjin-Hebei (BTH) region, China, including the ecosystem service value (ESV). In this study, we selected nine indicators and applied multiple pieces of software, including ArcGIS10.4, Fragstats4.2 and Geoda1.14 to detect the impacts of urbanization on regional ESH in 1995, 2000, 2005, 2010 and 2015. The results show that ESH in the BTH region increased from 2000 to 2015, especially in the northern parts. The improvements were due to the implementation of key ecological restoration projects protecting and re-establishing the forest in the north. Furthermore, the spatial correlation results indicate that urbanization had a negative impact on ESH in the BTH region, of which the dominant factor was the population density in 1995. The dominant factor was the construction land proportion from 2005 to 2015. We suggest that ecological restoration projects should be continued in northern regions with strong and relatively strong ESH levels to maintain high-level ecosystem health. In addition, more attention should be paid to the ESH level improvement in peri-urban areas.

[Characteristics of Macrobenthos Community Structure and Their Relationships with Environmental Factors in Rivers of Beijing in Spring].

Macrobenthos from 20 sites of 17 rivers in Beijing were investigated in the spring of 2019, and the relationship between community structure characteristics and environmental factors was analyzed. A total of 64 classification units (species) of macrobenthos from 3 phyla, 6 classes, and 32 families were identified. We found that there were large spatial differences between the density composition and dominant species of macrobenthos. Mountainous river area had the highest density of aquatic insects (33.95 ind.·m-2), and the main dominant species were Simuliidae sp., Hydropsyche sp., and Paraciadius alpicola. In suburban areas, Chironomidae and Oligochaeta showed the largest average density, which was 82.58 ind.·m-2 and 36.21 ind.·m-2, respectively, and Polypedilum nubeculosum and Chironomus pallidivittatus were the dominant species in this area. Furthermore, macrobenthos in urban rivers were mainly Gastropods (88.75 ind.·m-2), and the dominant species were Bellamya aeruginosa and Bellamya purificata. Fourteen more species were found in the urban and suburban river areas than in mountain areas. According to the results of the canonical correspondence analysis, there were many factors affecting the community structure of macrobenthos, including water temperature, TN, Chl-a, pH, and human activity. Nutrient concentration was the main factor affecting the community structure of macrobenthos in the suburban river area, while human activities and water temperature were the major determinants of the macrobenthos community structure in mountainous and urban rivers.

Factors responsible for forest and water bird distributions in rivers and lakes along an urban gradient in Beijing.

Urban rivers and lakes, in combination with nearby green spaces, provide important habitat for urban birds, but few urban studies have focused on forest and water birds simultaneously along an urban intensity gradient. In this study, we randomly chose 39 rivers and lakes along an urban gradient of Beijing to examine bird community parameters in relation to aquatic and terrestrial habitat conditions, aquatic life data, and water quality data. We selected models with the AICc (corrected Akaike information criterion) method, bivariate linear or generalized linear regressions, and structural equation modeling to determine distribution patterns of avian communities along an urban gradient and bird-environment relationships. We found that both forest and water bird species and individuals peaked at intermediate urbanization intensities, especially for abundance of both forest and water bird and water bird species richness and abundance. We suggest that the differences in the strength of response to urbanization and the similarities in the gradient distribution pattern between forest and water birds should receive more attention in future urbanization gradient studies. Significant correlation ship between species richness of resident water birds, fish foragers, and insectivore-frugivores, abundance of insectivores, insectivore-frugivores (negative), and granivores (positive) and impervious surface proportion within 1-km radius buffer of sampled sites became more evident after coverage of artificial surfaces exceeded a 50% threshold. Regressions showed that distance from the urban center, number of islands in waterbody, and proportion of gross or unarmored shoreline length were significantly and positively related to species richness and abundance of both forest and water birds. The availability of unarmored shoreline is a critical pathway through which urbanization detrimentally impacts avian diversity. Our results demonstrate how the urban intensity gradient affects the relative availability of food resources and habitat, which could provide practical applications for urban landscape planning and avian biodiversity conservation in urban areas.

Analysis of Runoff Trends and Drivers in the Haihe River Basin, China.

During the past decades, runoff has been highly influenced by climate change and human activities in Haihe River basin, and it is important to analyze the runoff trends and the drivers of its change to guide water resources management. The Mann-Kendall method and Pettitt test were conducted to analyze the hydrological and climate trends. Data from six sub-basins were used, including runoff at six representative hydrological stations and precipitation and air temperature at 49 meteorological stations. We used multiple-regression analysis and policy review to explore the influence of climate change and human activities on the runoff change at six sub-basins. According to the results, annual runoff showed a significant downward trend at six hydrological stations (p < 0.05), and the most probable change points at all stations showed up during the period from the late 1970s to the early 1980s. Moreover, the middle and late 1990s could be another probable abrupt change point at Luan River and Chaobai River. The declining trend of the annual mean precipitation at the six sub-basins was insignificant (p > 0.05), and there were no significant abrupt change points except the Zhang River area (p < 0.05). Compared with the precipitation trend, the annual mean air temperature exhibited a significant increasing trend at all stations, and the period from the late 1980s to the early 1990s might be the most probable abrupt change points at all four sub-basins. The trend analysis and the abrupt change point analysis suggest that mean air temperature is the main climate factor that will lead to the decline in the runoff time-series, while the insignificant downward trend of the precipitation might accelerate the downward trend of the runoff data. Through elevant policy measures, including land-use reform and the construction of the Three-North (north, northeast, and northwest China) Shelter Forest, China started to implement a family-contract responsibility system and initiated the first stage of construction of the Three-North Shelter Forest Program in 1978. The land-use reform policies greatly stimulated the peasants' initiative for land management and significantly changed the land use pattern and water use quantity in the Haihe River basin in a short time. Besides, the precipitation decreased and the air temperature rose, so an abrupt change in runoff occurred from the late 1970s to the early 1980s. The abrupt change in the runoff in the middle and late 1990s highly tallied with the construction time of the Three-North Shelter Forest Program. After near 20 years of construction of the Three-North Shelter Forest Program, the forest area increased, the forest quality had been improved, and the vegetation coverage on the underlying surface had been changed significantly, so the construction of the Three-North Shelter Forest Program was an important cause of runoff change in the middle and late 1990s. Also, change in precipitation and air temperature enlarged the effect of change in the runoff.

Two novel aromatic hydrocarbons: facile synthesis, photophysical properties and applications in deep-blue electroluminescence.

Two efficient novel fluorescent naphthalene and fluorene-based aromatic hydrocarbon isomers (1 and 2) are prepared and investigated for organic electroluminescence. These compounds show bright violet to deep-blue emission, narrow full width at half maximum (52 nm), and high photoluminescence efficiency (e.g. 0.61 in CH2Cl2, 0.67 in film). Alternation of substituent position on the naphthalene moiety can give rise to remarkable emission variation. The relatively large torsion angle between naphthalene and fluorene suppresses the π-π interactions by weakening the intermolecular interactions in the solid state, which can result in highly efficient fluorescence. Moreover, the 1931 Commission Internationale de L'Eclairage coordinates and maximum emission peak for deep-blue electroluminescence based on 1 are (0.16, 0.08) and 410 nm, respectively.

[Analysis of River Zooplankton Community Characteristics in Autumn in Beijing].

To clarify the spatial distribution characteristics of zooplankton communities and the relationship between zooplankton and water environmental factors, 81 samples from 28 rivers and lakes in Beijing were collected in September 2017. A total of 68 species of zooplankton were identified, including 17 species of protozoa (25%), 36 species of rotifers (53%), 13 species of cladocera (19%), and copepods (3%, which were mainly copepodids and nauplii). Among 15 dominant species, 12 were copepods and rotifers. Zooplankton communities varied between the different rivers:The zooplankton in rivers in mountainous areas were mainly protozoa and copepods; in suburban areas, communities were dominated by copepods; and in urban areas, rotifers were dominant. A comprehensive water quality index, the Shannon-Wiener index, the Pielou evenness index, and the Margalef richness index were also calculated. Results showed that the water quality of the rivers in mountainous areas was generally better than in urban areas, which was better than in suburban areas. TN was found to be the main form of pollution using the single factor water quality index. Principal component analysis (PCA) and canonical correspondence analysis (CCA) identified that NH4+-N, BOD5, and COD had a significant effect on zooplankton community characteristics.

[Water Quality Analysis of Beijing Segment of South-to-North Water Diversion Middle Route Project].

Water quality is the key problem that water management departments concern. Water quality of Beijing segment of South-to-North Water Diversion Middle Route Project is closely related to water security and social stability in Beijing. Since the connection of Beijing part in Middle Route of South-to-North Diversion Project, water quality data of Daning regulation and storage reservoir and Daning surge tank was collected, and water quality indexes including water temperature, total nitrogen, nitrate nitrogen, chloride ion, sulfate, dissolved oxygen, permanganate index, pH, ammonia nitrogen, fluorine ion and total phosphorus, were monitored monthly. With variance analysis, water quality difference among different water sources of the South-to-North Water Diversion of Middle Route was analyzed. With factor analysis method, the water quality risk factors of Daning regulation and storage reservoir and Daning surge tank were identified. The results were as following, water from Hebei province had higher contents of nitrate nitrogen, total nitrogen, fluorine ion, chloride ion and sulfate than those of water from Danjiangkou reservoir, but the water quality was not as good as that from Danjiangkou reservoir. LSD difference test results showed that the dissolved oxygen, nitrate nitrogen and total nitrogen of the water from Hebei province had significant differences (P<0.05) between flood season and non-flood season, there was significant difference (P<0.05) in pH of water from Danjiangkou reservoir between flood season and non-flood season, and the water quality of Danjiangkou reservoir was more stable than water from Heibei province. No matter in flood season or non-flood season, there were no significant differences (P<0.05) in pH, dissolved oxygen, permanganate index, total phosphorus and ammonia nitrogen between the water from Danjiangkou reservoir and Heibei province, but there were significant differences (P<0.05) in nitrate nitrogen, total nitrogen, fluorine ion and sulfate ion and chloride ion. Contents of Nitrate nitrogen, total nitrogen, sulfate and chloride ion in 2015 (the mixture of water from Hebei province and Danjiangkou reservoir) in Daning regulation and storage reservoir were lower than those in 2012-2014 (water from Hebei province), and the water from Danjiangkou reservoir played a key role in dilution and adjustment of the water from Hebei province in Daning regulation and storage reservoir. The water quality differences test results between 2012-2014 and 2015 showed that there were significant differences (P<0.05) in the nitrate nitrogen, total nitrogen, fluorine ion, sulfate and chloride ion both in flood season and non-flood season, and the water quality of 2015 was better than that of 2012~2014 in non-flood season, but the differences of pH, dissolved oxygen, permanganate index, total phosphorus, ammonia nitrogen were not obvious (P<0.05). The difference test results between Daning regulation and storage reservoir and Daning surge tank showed that Permanganate index, total nitrogen, fluorine ion, sulfate and chloride ion had significant differences (P<0.05) both in flood season and non-flood season, and the contents of permanganate index, fluorine ion, sulfate and chloride ions in Daning regulation and storage reservoir were higher than those in Daning surge tank. The factor analysis results indicated that water quality potential risk factors both in Daning regulation and storage reservoir and Daning surge tank were mainly nitrogen, including ammonia nitrogen, nitrate nitrogen and total nitrogen, and potential risk factors also included total phosphorus in Daning regulation and storage reservoir.

Variation in nitrate isotopic signatures in sewage for source apportionment with urbanization: a case study in Beijing, China.

Nitrate (NO3-) pollution is a severe problem in urban aquatic systems especially within megacity undergoing rapid urbanization, and mostly, sewage is supposed as the prevailing NO3- source. A dual isotope approach (δ 15N-NO3- and δ 18O-NO3-) was applied to explore the variation in NO3- isotopic signatures in sewage processed by wastewater treatment plants (WWTPs) in Beijing from 2014 to 2015. We found that the raw and treated sewage owned the different NO3- isotopic signatures, including δ 15N from 1.1 to 24.7 ‰ and δ 18O from 1.6 to 22.8 ‰ in raw sewage, as well as δ 15N from 6.1 to 22.8 ‰ and δ 18O from 1.6 to 13.2 ‰ in treated effluents. The WWTP processing would result in the enrichment of NO3- isotopic compositions in discharged effluents with NO3- concentrations increasing. Besides, advanced sewage treatment technology with more pollutant N reduction may raise the heavier NO3- isotopic compositions further. The NO3- isotope value ranges of urban sewage and manure should be separated, and the seasonal and tighter NO3- isotope value ranges are supposed to improve the accuracy of source apportionment. The NO3- isotope value ranges conducted in this study might provide useful information for tracing NO3- sources towards the implementation of efficient water pollution control in Beijing.

[δ¹5N-NO3⁻ and δ¹8O-NO3⁻ Tracing of Nitrate Sources in Beijing Urban Rivers].

In order to quantitatively identify sources of nitrate pollution in Beijing urban area and provide effective guidance for relevant departments to control the pollution of Beijing rivers, δ¹5N-NO3⁻ and δ¹8O-NO3⁻ isotope tracing method was used to analyze the composition of nitrogen and oxygen stable isotopes from nitrate in Beijing urban river. Besides, stable isotope mixing model was adopted to track nitrogen sources of nitrate in Beijing urban rivers and the contribution rates of respective pollution sources were evaluated. The results showed that: (1) NO3⁻-N pollution was the main inorganic nitrogen pollution in Beijing rivers and pollution of downstream was more serious than that of upstream. (2) δ¹5N-NO3⁻ in Beijing urban surface rivers was in range of 6.26 per thousand-24.94 per thousand, while δ¹8O-NO3⁻ ranged -0.41 per thousand-11.74 per thousand; δ¹5N-NO3⁻ increased from upstream to downstream along the flow of the surface water. (3) The nitrate pollution composition of Beijing rivers could be gained from the stable isotope mixing model. The average contribution rates of manure and sewage, soil nitrate and atmospheric deposition were 61.2%, 31.5% and 7.3%, respectively.

[Seasonal Dynamics of Airborne Pollens and Its Relationship with Meteorological Factors in Beijing Urban Area].

The seasonal dynamics of airborne pollens and their relationship with meteorological conditions, which are considered to be important factors for appropriate construction of urban green system and reliable prevention of tropic pollinosis, were investigated in Beijing urban area. The airborne pollens were monitored from December 31st 2011 to December 31st 2012 by Burkard volumetric trap, and the data were analyzed. The results revealed that: (1) In 2012 the pollen dispersion period lasted 238 days from March 17 to November 18th, accounting for 65% of the year. There were two peaks of pollen amount in air, which occurred from March to May and from August to October, respectively. In the spring peak, tree pollens such as Oleaceae, Populus and Salix pollens were the dominant, accounting for 53% of the total annual pollens, while in the autumn period, weed pollens such as Compositae, Chenopodiaceae and Amaranthaceae pollens made up about 40% of the annual total value; (2) The highly allergenic weeds pollens dominated in autumn, which caused a high incidence of tropic pollinosis; (3) The airborne pollen amount of Beijing urban area was significantly affected by meteorological condition like the wind speed, temperature, humidity, precipitation and so on; (4) When temperature ranged from OC to 15 degrees C, the pollen amount showed positive relation with temperature; while in the temperature range of 18 degrees C to 30 degrees C, it showed negative relation; (5) The average temperature of spring and autumn season in 2012 was 17 degrees C, and 79% of airborne pollens were detected in these two seasons. This temperature condition was conducive to the pollen dispersion. (6) The pollen amount showed negative relation with relative moisture between 20% and 50% and larger than 70%, while in the moisture range of 50% to 60%, it showed positive relation; (7) The wind speed smaller than 3 m x s(-1) was good to pollen distribution, when it was larger than 4 m x s(-1) or the wind lasted for a long time, the pollen amount in the air would decrease; (8) The pollen release was decreased by the rain. The above results can be helpful to forecast the pollen amount in the air. monitoring; pollen amount

[Study on the Temperature Dependent Phase Transformation of Raman Spectra for Cyclobutanol].

Cyclobutanol (C4H8O) is one of the four-membered ring type molecules, which usually adopts a non-planar equilibrium conformation, and the substituent group OH can adopt two positions relative to the puckered ring, the axial or the equatorial, giving rise to an additional degree of freedom and various molecular conformations. Additionally, temperature is one important thermodynamic parameter that greatly influents the structure and induces the possibility of conformational change or crystal change. As a consequence, there may be a number of phase transitions and molecular conformations for cyclobutanol under different temperature. In this paper, Raman and infrared spectroscopic technique were applied to investigate the vibration modes of cyclobutanol. The results indicate that the main component of the liquid cyclobutanol is equatorial-trans (Eq-t) conformer with a few Eq-g conformers at ambient condition. Then differential scanning calorimetry (DSC) and low temperature Raman spectroscopic were applied to study the phase transition of cyclobutanol during the cooling and heating process. It is observed that the Raman spectra and the intensities of these bands are not significantly changed during the cooling process. The results indicate that there is sill no presence of solidification especially cooling to 140K, which indicates that the cyclobutanol still remains the liquid state and supercooled state is observed during the cooling process. And this supercooled liquid is one metastable state, not in thermodynamic equilibrium. Further cooling to 138 K, the super-cooling liquid cyclobutanol will transform into the glassy state, accompanied with a small change of entropy. During the heating process, as the temperature is raised to 180 K, the Raman peaks became sharper and some new characteristic peaks appeared abruptly and a discontinuous change was observed in bandwidths versus temperature. And these new signatures can be maintained upon to 220 K, and then will disappear as the temperature increasing continuously. This result indicates the one crystal phase transition and a melting transition present at around 180 and 220 K. In addition, it can be observed that the component of Eq-g conformer increases, accompanied with the crystallization during heating at around 180 K. These results were helpful to understand the kinetics of the crystallization process of other small organic molecules.

[Characteristics of Total Nitrogen and Total Phosphorus Pollution and Eutrophication Assessment of Secondary River in Urban Chongqing].

To understand the secondary river quality in Chongqing urban area, six typical secondary rivers were chosen to investigate the pollution characteristics of total nitrogen and total phosphorus and to evaluate the water eutrophication level according to the monitoring data of water physicochemical characteristics and chlorophyll content from April 2013 to March 2014. The study results showed that: the six rivers mentioned above have been seriously polluted by TN and TP, with the monthly mean values of TN and TP far exceeding the universally accepted threshold values of water eutrophication. Water eutrophicaton appraisal result indicated that all rivers in each season were in a state of eutrophication, and the eutrophication level could be arranged in the order of Panxi River > Qingshui River > Tiaodeng River > Huaxi River > Funiu River > Chaoyang River. The seasonal changes in TN and TP of secondary rivers were significant, with high concentrations of TN and TP in spring and winter, and lower concentrations in summer and autumn. TN and TP of the rivers showed a trend of increasing from the upstream to the downstream in each season. Pollutant concentration accumulated gradually along rivers and the maximum accumulation rate reached 1. 25 mg . (L . km) -1. Therefore, further study on urban secondary river pollution characteristics is of great significance to urban water pollution control.

Nitrogen and phosphorus associating with different size suspended solids in roof and road runoff in Beijing, China.

Roofs and roads, accounting for a large portion of the urban impervious land surface, have contributed significantly to urban nonpoint pollution. In this study, in Beijing, China, roof and road runoff are sampled to measure the suspended solids (SS), nitrogen (N), and phosphorus (P) contained in particles with different sizes. The SS content in the road runoff (151.59 mg/L) was sevenfold that in the roof runoff (21.13 mg/L, p < 0.05). The SS contained more coarse particulates in the roof runoff than in road runoff. The small particulates in the range of 0.45-50 µm consisted of 59 % SS in the roof runoff and 94 % SS in the road runoff. P was mainly attached to particle sizes of 10-50 µm in the roof (73 %) and road (48 %) runoffs, while N was mainly in a dissolved phase state in both runoffs. So, the different associations of N and P raise a challenge in preventing stormwater pollution in urban environments.

[Characterization of Pollutant Wash-off in the Urban Stormwater].

To understand the pollution character of urban road runoff, the concentrations of TSS, EC, N and P in the ring road runoff of Beijing from June to September 2013 were evaluated, the correlations among pollutants were examined, and the load of TSS, N and P were estimated. Result showed that the small particulates in the range of 1-10 µm consisted of 60% TSS in the road runoff. Totally 89 percent of the nitrogen (N) was dissolved phase state in the road runoff, 80 percent of the phosphorus (P) was particular phase state in the road runoff. Based on the characteristics of correlations between EC, TSS and TN, TP, EC and TSS were the surrogate indexes of pollution degree assessment for the dissolved N and particulate P in the urban road runoff, respectively. Based on our results, the SS, N and P year load per unit area in Beijing ring road runoff were 16 725.69, 1777.91 and 24.23 mg x (m2 x a)(-1), respectively. Our findings described the polutant wash off character in urban road runoff, which provide a scientific basis for management of nonpoint pollution in a city and an alternative method for controlling pollution.

[Characteristics of atmospheric nitrogen wet deposition in Beijing urban area].

With the ion-exchange resin method, the atmospheric nitrogen wet deposition in Beijing urban area within the Fifth Ring Road was investigated from June to October, 2012. The relationship between atmospheric nitrogen wet deposition and rainfall precipitation was investigated, the differences of nitrogen wet deposition in different months, different ring roads (the Fifth Ring Road, the Fourth Ring Road, the Third Ring Road and the Second Ring Road) and different functional areas (institutes and colleges district, ring-road, residential areas, railway station and public garden) were also investigated. The results showed that the average value and standard deviation of ammonia-nitrogen, nitrate-nitrogen and nitrite-nitrogen were significantly different during different months in 2012. The atmospheric nitrite nitrogen deposition first decreased and then increased, the maximum value appeared in September. The positive relationships between ammonia nitrogen (nitrate nitrogen) and mean monthly precipitation and negative relationships between nitrite nitrogen and mean monthly precipitation were both significant (P < 0.05). The three nitrogen depositions of ring-road and railway station were higher than other functional areas, but only the nitrite nitrogen deposition had obvious regional difference. The differences of the three nitrogen depositions among different ring roads were all not significant and it meant that the nitrogen wet deposition was equally distributed in Beijing urban area.

Quality and seasonal variation of rainwater harvested from concrete, asphalt, ceramic tile and green roofs in Chongqing, China.

There is an urgent requirement to examine the quality of harvested rainwater for potable and non-potable purposes, based on the type of roofing material. In this study, we examined the effect on the quality of harvested rainwater of conventional roofing materials (concrete, asphalt and ceramic tile roofs) compared with alternative roofing materials (green roof). The results showed that the ceramic tile roof was the most suitable for rainwater-harvesting applications because of the lower concentrations of leachable pollutants. However, in this study, the green roof was not suitable for rainwater harvesting applications. In addition, seasonal trends in water quality parameters showed that pollutants in roof runoff in summer and autumn were lower than those in winter and spring. This study revealed that the quality of harvested rainwater was significantly affected by the roofing material; therefore, local government and urban planners should develop stricter testing programs and produce more weathering resistant roofing materials to allow the harvesting of rainwater for domestic and public uses.

[Characteristic comparative study of particulate matters in Beijing before and during the Olympics].

Two city ecosystem research stations were selected for continuous monitoring of atmospheric fine particulate matter (PM2.5) concentration from June to September 2008, when the Beijing Olympic Games was held. The relationship between meteorological factors, artificial control management measures and PM2.5 dynamic characteristics were analyzed. The results showed that the daily average concentration of PM2.5 at RCEES Station, which is near the 5th North Ring, was 0.067 mg x m(-3) during the study period, and the particle concentration during the Olympic Games was 0.060 mg x m(-3), which was decreased by about 26% compared with the content before the Olympic Games (0.081 mg x m(-3)). As for JX Station located in the 2th South Ring, its daily average concentration of PM2.5 was 0.078 mg x m(-3). Similar to RCEES Station, PM2.5 average content during the Olympic Games (0.069 mg x m(-3)) was 27% lower compared with the content before the Olympic Games (0.095 mg x m(-3)). Two peaks could be found when daily distribution of PM2.5 was displayed, one appeared between 08:00 and 10:00 (the average content for RCEES and JX were 0.068 and 0.089 mg x m(-3), respectively), and the other appeared at 20:00-22:00, which could be attributed to traffic emission and road dust pollution, especially the emission from the growing number of cars in rush hours. Meteorological condition during the whole period was typical in summer in Beijing with both high temperature and humidity. Correlation analysis revealed that the concentrations of PM2.5 had a positive correlation with the air temperature (P < 0.01), while it had no significant relationship with wind speed, relative humidity or precipitation (P > 0.05). Our monitoring results suggested that the artificial air pollution control strategies were effective measures for air pollution control during 2008 Beijing Olympic Game.

The temporal changes in road stormwater runoff quality and the implications to first flush control in Chongqing, China.

This study investigates the quality of stormwater runoff from a driveway in the southwest mountainous urban area of Chongqing, China, from 2010 to 2011. The results showed that the mean concentrations of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) were 4.1, 2.4, and 2.2 times the grade V levels of the national surface water standard of China. The pollutant concentration peak preceded or synchronized with the rainfall intensity peak and occurred 10 min after the runoff started. The significant high pollutant concentration in the initial stage of the rainfall suggested that first flush control is necessary, especially for the most polluted constitutes, such as total suspended solids, COD, and TN. Three potential pollution sources were identified: the atmospheric dry and wet deposition (TN, NO3(-)-N, NH4(+)-N, and DCu), the road sediment and materials (total suspended solids, COD, and TP), and the vehicle emissions (DPb and DZn). Therefore, this study indicates that reductions in road sediments and material pollution and dry and wet deposition should be the priority factors for pollution control of road stormwater runoff in mountainous urban areas.

[Analysis of first flush effect of typical underlying surface runoff in Beijing urban city].

Rapid increase of the urban impervious underlying surfaces causes a great increase of urban runoff and the accumulation of pollutants on the roof and road surfaces brings many pollutants into the drainage system with the runoff, and it thus becomes a great threat to the urban water environment. To know the runoff pollution process and to build scientific basis for pollutant control, runoff processes from the roof and road surfaces were monitored and analyzed from 2004 to 2006, and the runoff EMC (Event Mean Concentration) was calculated. It was found that two types of runoff were seriously polluted by COD and TN. The COD and TN of roof runoff exceeded the fifth level of the surface water environmental quality standard (GB 3838-2002) by 3.64 and 4.80 times, respectively, and the COD and TN of road runoff exceeded by 3.73 and 1.07 times, respectively. M (V) curve was used to determine the relation between runoff volume and runoff pollution load. Various degrees of the first flush phenomenon were found for TSS, COD, TN and TP in roof runoff. But this phenomenon occurred only for TSS and TP of the road runoff, and on the whole it was not obvious. Properties of the underlying surfaces, rainfall intensity, and pollutant accumulation are all important factors affecting the roof and road runoff pollutant emission characteristics.