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Based on the ground-based observations from seven atmospheric background stations during 2009 to 2018 in monsoon Asia (including BKT station in Indonesia, LLN and WLG stations in China, RYO and YON stations in Japan, TAP station in Republic of Korea, and UUM station in Mongolia), we analyzed the temporal and spatial variation of atmospheric CH 4 concentration and its driving factors using harmonic model and maximal information-based nonparametric exploration. The results showed that the CH 4 concentration in monsoon Asia varied from 1853.04 to 1935.61 nmol·mol -1 , higher than that in Mauna Loa (MLO) station (1838.33 nmol·mol -1 ) in Hawaii, USA. The CH 4 concentration decreased from north to south, with the highest value in TAP station (1935.61 nmol·mol -1 ) in Republic of Korea and RYO station (1907.19 nmol·mol -1 ) in Japan. The average seasonal amplitude at YON station in Japan was the largest (108.20 nmol·mol -1 ); while that at WLG station in China was the smallest (29.48 nmol·mol -1 ). The seasonal amplitude of TAP station in Republic of Korea changed faster at the rate of 4.49 nmol·mol -1 ·a -1 . Except for WLG and TAP stations, CH 4 concentrations were low in summer and high in winter. From the long-term perspective, the CH 4 concentration at LLN (7.68 nmol·mol -1 ·a -1 ) and WLG (7.56 nmol·mol -1 ·a -1 ) stations in China exhibited the most obvious growth trend. Compared with wind speed, temperature and precipitation had greater impact on CH 4 concentration, which were negatively associated with CH 4 concentration. Local CH 4 emission at some stations had a significant positive effect on CH 4 concentration.

Sewage irrigation has been widely used in areas of water shortage in northern China, and it may introduce organic contaminants into groundwater. To characterize the organic contaminants in groundwater in sewage irrigation area, the Xiaodian sewage irrigation area in Shanxi Province was chosen as the case study area. A total of 16 groundwater samples (13 from shallow aquifer, 3 from deep aquifer) were collected. Polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatography-mass spectrometry (GC-MS) and organochlorine pesticides (OCPs) were ainalyzed by gas chromatography-electron capture detection (GC-ECD). The results showed that the concentrations of PAHs ranged from 13.98 to 505.89 ng x L(-1) with an average concentration of 115.67 ng x (L)(-1). The 2 and 3 ring-PAHs were the main components, while naphthalene and phenanthrene were most frequently detected. The concentrations of OCPs were in the range of 13.91-103.23 ng x L(-1) with an average concentration of 40.99 ng x L(-1), while alpha-HCH, delta-HCH, o,p'-DDD, Aldrin, Endosulfan-sulfate and HCB were most frequently detected. Overall, shallow aquifers appeared more contaminated with these pollutants than deep aquifers. In the area, the order of the organic contaminants concentration in groundwater was: East Main Channel < Beizhang Drainage < Taiyu Drainage, which indicated the quality of groundwater was influenced by the sewage irrigation.

Runoff samples were collected from traffic roads, campus, residential road and roof in a typical rain event. Polycyclic aromatic hydrocarbons (PAHs) in both dissolved and particle phases were investigated at impervious surfaces. The PAHs wash-off process at different monitoring sites was analyzed. The scatters of first flush were conducted in a method of fitting power function to quantitatively assess the magnitude of first flush effect (FFE). The sources of PAHs were identified using factor analysis. The results showed that PAHs concentrations in runoff samples varied from 317.21 ng x L(-1) to 10364.3 ng x L(-1) with the maximal and minimal contents of PAHs found on Longwu Road and campus, respectively. The values of event mean concentration ( EMC) varied considerably at different sampling sites. The concentration of washed-off pollutant generally decreased with runoff duration, which showed an obvious attenuation trend. The runoff process indicated the occurrence of FFE at different levels. PAHs mainly came from the incomplete combustion of fossil fuels, oil leakage and coking, and the contribution of each source was different in accordance with various surfaces.

This review focused on the distribution, pollution status, sources and influencing factors of PCBs in the coastal areas (seawater, surface sediments and biota) in China. A few main points are listed as follows: (1) For coastal seawater, concentrations of PCBs were increasing from the north to the south and the highest concentrations of PCBs were observed in the developed east coastal areas. The concentrations of PCBs in most coastal areas were higher than the seawater standard of U. S. EPA (30 ng x L(-1)), indicating that there was a high potential risk. (2) Only a small part of surface sediments had PCBs concentrations higher than the ISQG (interim sediment quality guideline) and ERL (effects range-low) values, suggesting little probability of causing biological adverse effects and potential risk in surface sediments. (3) High-molecular-weight PCBs (4, 5 and 6 chlorinated biphenyl) were bio-accumulated in marine biota. The concentrations of PCBs in organisms were generally lower than 2000 ng x g(-1), which may have negligible effects on human health. (4) The main sources of PCBs were wastewater discharged from factories and the leakage of dismantling PCBs from electronic wastes. Factors influencing the concentrations and distribution of PCBs in the coastal areas included distance from land, flow exchange situation, water-carrying capacity, season, sediment particle size and total organic carbon content.

Eighty-one surface water samples were collected from 3 tributaries of the Yangtze River in different periods. Contents of 28 PCB congeners in surface water samples were measured using Varian CP3800/300 GC-MS/MS technique. PCB8, 18, and 28 are the most predominant PCB congeners in the samples from tributaries. The measured level of PCBs in the samples from the Tuo river, downstream of Ouchi River and Songlihongdao tributary were 1.96-2.59 ng x L(-1), 1.84-2.54 ng x L(-1) and 1.52-2.38 ng x L(-1). The average concentrations of PCBs in the samples were lower than USEPA criterion continuous concentration (14 ng x L(-1)), which were also in the same order of magnitude of those reported with lower levels in European and American countries. The estimated cumulative cancer risk for the local residents who drink water from tributaries were 0.15 x 10(-7)-0.26 x 10(-7), which shows that cancer risk are negligible due to PCBs contamination in these samples.

In order to study temporal variation characteristics and influencing mechanism of platinum group elements (PGEs) in road dust, 24 seasonal samples and 18 inter annual samples of road dust were collected from roads in Shanghai, and were analysed by ICP-MS following aqua regia digestion. The results are as following: average concentrations of PGEs in spring, summer, autumn, winter were 10.40 (6.06-17.28) ng/g, 11.60 (5.52-20.11) ng/g, 32.91(18.53-61.05) ng/g, 32.33 (16.29-47.89) ng/g with Rh, 52.99 (27.48-100.2) ng/g, 53.77 (20.42-72.31) ng/g, 125.50 (75.41-247.8) ng/g, 132.59 (78.45-199.9) ng/g with Pd, 13.58 (7.96-30.97) ng/g, 13.24 (6.40-17.96) ng/g, 48.20 (25.07-122.9) ng/g, 53.63 (22.11-107.7) ng/g with Pt. PGEs concentrations had obvious seasonal change that were lower in spring and summer, higher in autumn and winter, and rainfall were main effect factors. The comparison of levels of PGEs between 2003 and 2007 showed that PGEs concentrations in road dust had increased over the period of 4 years with 11% - 19% of average annual growth rate because of the rapid increase in the number of vehicles in Shanghai. Meanwhile, the average PGEs ratios of road dust samples from Shanghai were inconsistent with Ely's result. These differences were contributed by the change of VECs type.

Filtration and cross-flow ultrafiltration (CFUF) was applied for the effective separation of NPs in the Yangtze Estuary. The physiochemical properties of NP were characterized, and their relationships with environmental factors were further studied in the present study. The results show that NP size in Yangtze Estuary ranged from 69.5 to 263.5 nm with the average value of 157.3 nm and Zeta-potential values ranged from -40.1 mV to 196.0 mV. NOC concentrations ranged from 0.3 mg/L to 1.5 mg/L and the average value was 0.7 mg/L. NOC account for 5.1% to 30.5% of DOC, with an average of 16.7%. The binding capacity of metals with NP in the Yangtze River Estuary was in the order of Zn > Cu > total Cr > Co > Ni > Mn > Fe > Li > Al > B > K > Ba > Sr > Mg > Ca > Na, which reveals that terrigenous input may be the main source of NOC in the Yangtze River. The binding capacity of NP with trace metal is generally higher than the conventional metallic element. There was no significant correlation between NP size and salinity, DOC, NOC, SPM and Zeta-potential, respectively. Compared to NOC and UOC, better correlation was investigated between DOC, salinity and NP bound trace metals.

Objective: To analyze the impact of the measures for securing quality air for the 2008 Beijing Olympic and Paralympics Games on air pollution index (API) in Beijing and forecast the aftereffects., Methods: The time-distribution of API in Beijing from 2004 to 2008 was described. The time sequence analysis was used and the autoregressive integrated moving average model (ARIMA) was chosen to establish an API forecasting model to predict the API in December, 2008., Results: From 2004 to 2008, the average API in March (120 +/- 66) was the highest followed by November (116 +/- 72) and the average API in July (83 +/- 28) was the lowest followed by August (77 +/- 27). The proportion of "excellent" and "good" days from 2004 to 2008 were 9.56% (35/366), 54.37% (199/366), 8.49% (31/365), 54.52% (199/365), 7.12% (26/365 ), 58.90% (215/365 ), 8.77% (32/365), 58.63% (214/365), 16.67% (61/366), 58.20% (213/366) respectively, with an increasing trend year by year (chi2(trend) = 11.397, P = 0.001). The model of ARIMA (1, 0, 0) fitted well; according to the prediction of the ARIMA (1, 0, 0) model, the decrease of API that attributed to interim measures during the Olympic Games was 37. 1% and the average API of December was 82., Conclusion: The interim measures during the Olympic Games were effective on promoting air quality. After the Olympic Games, air quality would still remain good.

Based on polycyclic aromatic hydrocarbons (PAHs) field data of particle phase and dissolved phase, partition coefficients Kp in particle-water interface from the Yangtze Estuarine and nearby coastal areas were obtained. The results show partition coefficients of PAHs in dry season were higher than those in flood season, and all of them ranged from 507 L/kg to 10,179 L/kg, increasing with the rise of PAH compounds. The linear free-energy relationship coefficients between Koc value and octanol-water partition coefficients Ko, in dry season and flood season were 0.82 and 0.68, respectively. These relationships inferred that suspended particle matters in the Yangtze Estuarine and coastal areas had weakly lipophilic characteristics and adsorption ability. lgKoc values of PAH compounds in the different sampling sites were higher than the upper limit value predicted by the classic equilibrium partition model. The partition processes of PAHs were not controlled by concentrations of suspended particle matters, particle grain sizes, overlying water salinity and dissolved organic carbon ( R2 < 0.1), but influenced by particle organic carbon and heterogeneous mixtures of particle soot carbon. The expanded partition model which included soot partitioning could well predict in situ partition processes of PAH compounds whose octanol-water partition coefficients lgKow was lower than 6.

Contents of heavy metals (Cu, Zn, Pb, Cd, Cr, Hg and As) in agricultural surface soils from Shanghai were analyzed. Different evaluation methods and assessment standards of heavy metals were also used for comparison. In addition, inverse distance interpolation (IDW) method was also applied to study the spatial variability of heavy metals pollution, based on GIS. The results show that mean concentrations of heavy metals in soils all exceeded their corresponding natural-background values, except for As. Compared mean concentrations of heavy metals with the National Standard, the soils were not contaminated. All the determined heavy metals excluding Pb in some regions, however, exceeded the critical values of national soil quality standard. Additionally, it is indicated that most of cropland soils were good, and the ratio of good soil, certified soil and disqualified soil were 71.4%, 94.9% and 5.1%, respectively. Most of the disqualified soils, which distributed in Jiading and Pudong, however, have been urbanized and covered with buildings and factories. Moreover, the soil quality was influenced by different heavy metals at different levels, thus the regional differentiation of soil pollution was obvious. Zn, Cd and Hg were the dominant elements causing soil heavy metal pollution in the study area. Furthermore, it was found there was a close relationship between the urban distribution and heavy metal pollution of the soils. Therefore, it is concluded that with the expanding of urbanization, a new polluted area may appear.

Distributions of biogenic silica (BSi) in surface sediments from the shoals in the Yangtze Estuary were investigated using an 8-hour sequential extraction method, and the relationships of BSi with the sediment physio-chemical characteristics were also discussed. The findings indicated that the BSi contents in the shoal sediments varied from 0.47% to 1.02%, and the average content was 0.75%. The BSi contents range of the high, middle and low intertidal flats was 0.47%-0.91%, 0.48%-1.02% and 0.47%-0.96%, respectively. The significant positive relationships were found between BSi and the clay and silt contents in sediments, which indicated that the accumulation of BSi in sediments closely depended on sediment compositions. There also existed the remarkable positive relationships between BSi and organic carbon (OC) and nitrogen (ON). This implied that BSi was apt to accumulate in sediments enriched in organic matter. Compared with Redfield ratios, the ratios of OC/BSi and ON/BSi in shoal sediments were relatively lower and in the range of 0.28-2.59 and 0.05-0.21, respectively. Therefore, it was shown that the dissolution rate of BSi in shoal sediments was lower than the rate of organic matter decomposition. In addition, it was also found that there was the weak positive correlation between BSi and chlorophyll in the sediments, reflecting that primary productivity such as diatoms, to some certain, made contribution to the storage of BSi.

Urban surface dust is a major concern of urban non-point source pollution, which has been noticed by the scientists abroad since the 1970s, and many research achievements have been made. However, no sufficient recognition was given in China. This paper put forward a new idea about the concept of urban surface dust, summarized the development stages and present status of urban surface dust research both at home and abroad, and brought forward the key points and directions of further research. Urban surface dust is a complex environmental carrier, acting as the "sink" and "source" of pollutants. It is a valuable archive of environmental information, and can act as a useful indicator of local environmental pollution status. The study on urban surface dust should become a new focus of urban environment research in China, which is of significance in urban ecology and in the management of non-point source pollution.