The main constituents, types, origins and migration characteristics of DNAPLs (dense non-Aqueous phase liquids) were summarized. By introducing the characteristics of spatial distribution, phase partitioning and fate of DNAPLs at contaminated sites, the migration characteristics of DNAPLs were revealed. The advances of the latest investigation technologies of DNAPLs contaminants were reviewed. The principles for determining the presence of DNAPLs and the latest technologies for detecting the distribution of DNAPLs were introduced to offer a reference for determining the proper investigation method for DNAPLs sites, which would benefit a more precise scoping of DNAPLs distribution, as well as the development of cost-effective remedial plans.

In China, livestock management practices are under constant pressure for minimizing their impacts on the environment. This study aims at summarizing the previous researches and finding a proper way for the accounting of livestock ammonia emission in China, with the hope to provide theoretical and realistic basis for livestock regional management and delicacy management. The methods based on N or total ammoniacal nitrogen (TAN) flow and the models adopted were listed. Advantages and disadvantages of each method or model were analyzed. The results from the methods based on TAN flow are more accurate than the results from the methods based on N flow at the regional level. For Animal Feeding Operations at the farm level, the process-based models are more suitable than those methods based on N or TAN flow. For a long time, ammonia emission accounting researches in China were focused on macro accounting at the regional level, and few methods or models were adopted at the farm level. Based on the reality, a new potential bottom-up ammonia emission accounting framework was elaborated for livestock production management in China. An integrated model based on the process-based model and regional statistic model was developed for livestock production management. Different parameters, such as feed, excrement feature and disposal technology, were sorted and divided into six categories. Different factors were illustrated according to the livestock production management reality. Further researches have been proposed in the aspects of improving the accuracy of the process-based modes, investigating the status for livestock production management, gathering data at the regional level, localizing the parameters, optimizing waste disposal technology, etc.

The Chongqing Section of the Three-Gorge Reservoir Area with important eco-geographical significance was hence selected as subject of study. The method of statistics and network analysis was applied with the Landsat TM Remote Sensing Data of the region dated from 2000 to 2015 to study variation of the landscape pattern and ecosystem service value from the spatio-temporal aspect and their relationship. Results show:(1) On the whole, cultivated land and forest land still accounted for a large portion, while the other fractions of landscape, like grassland, water surface and construction land, only for small portions, separately. However, the fraction of construction land expanded the fastest; (2) Temporally speaking, during the period from 2000 to 2015 the indices of patch density and largest patch area decreased first and came backwards, and the maximum value of Landscape aggregation index and the minimum value of Shanon's diversity index appeared in 2010; and the total ecosystem service value exhibited a rising and then falling trend, and peaked in 2010; (3) Spatially speaking, the center of landscape fragmentation shifted gradually from the northeast and southeast of the region to well-built areas of the districts and counties and the main urban zone and the index of landscape integrity gradually increased in the northeast and southeast; The areas low in ecosystem service value were concentrated in the well-built areas, and the main urban zone was the lowest and the area on the west of the Yangtze River was lower than that on the east. All the findings demonstrate that a reasonable landscape pattern is of great significance to increasing ecosystem service value of a place like the Three-Gorge Reservoir Area (Chongqing Section).

In order to explore the main factors affecting agricultural carbon emission and differences between North and South China, agricultural carbon emissions in 31 provinces, autonomous regions and municipalities (Hong Kong, Macao and Taiwan not covered) were calculated based on relevant data and information available in the Agricultural Yearbooks of 1990-2014 concerning main sources of carbon input in agriculture, such as staple crops (wheat, rice and corn), pesticide, chemical fertilizer, plastic film, agricultural irrigation, farming machines and some others, for analysis of their affecting factors and regional differences in agricultural carbon emission intensity using the Kaya identical equation and Theil index, separately. Results show:(1) The agricultural carbon emission in China has been on a gradual upward trend in recent years. Some factors like the optimization of agricultural industrial structure can restrain the growth of agricultural carbon emissions. The development level of agricultural economy will promote the increase of agricultural carbon emissions. (2) In terms of spatial distribution, agricultural carbon emission is generally higher in the northern part of the country than in the southern. The intensity of agricultural carbon emission per unit of crop area is showing a rising tendency and that per unit of agricultural output a decreasing tendency. From the perspective of the regions per se, their Theil indices demonstrate that regional difference in agricultural carbon emission intensity primarily stemmed from inside of the regions. The difference in agricultural carbon emission intensity is greater in the southern part than in the northern and narrowing in the coastal areas in both parts. The differences within the northwest and southwest areas are gradually expanding. Some suggestions based on the above-listed findings are proposed.

Effects of size of gaps in a Cryptomeria fortunei plantation in the Zhougong Mountain, Southwest China on soil physicochemical propertis and species diversity were investigated. Soil samples and floral and faunal species were gathered from five gaps different in size, i. e. 50-100, >100-150, 200-250, 400-450 and 600-650 m², for analysis of soil properties, like pH, organic matter content, and some others and species diversity. Results show:(1) With the gap increasing in size, the number of species in various layers of the community exhibits a parabolic curve, that is, rising first and then falling, while Shannon-Wiener index (H), Simpson index (H') and Pielou index (J_sw) of the shrub layer and herb layer are higher in the gaps than under closed canopy; (2) The content of soil available potassium in the 0-20 cm soil layer is on the same trend; (3) In the gaps, variation of species diversity is related to a various extent to soil physico-chemical properties for instance species richness index (D), H and H' of the herb layer are closely related to soil pH, and D and H to soil available potassium (P<0.05), indicating that plant species diversity is closely related to soil pH and available potassium in the forest.

For assessing the effects of transgenic glyphosate tolerance and glufosinate-ammonium tolerance maize C0010.1.1 on biodiversity of arthropod community, which supplied basic data for the studies of transgenic crop biosafety, in the isolated field the number of species and individuals in the arthropod communities were counted and the functional groups, biodiversity index, dominance index, evenness index and the community similarity were analyzed and compared in 2015. Compared to the non-transgenic maize counterpart 178 and conventional line Xianyu 335, the parameters, such as the number of species, biodiversity index, dominance index and evenness index, were similar in the trend over time with no significant difference. These results suggest that the arthropod community structures in the fields of the transgenic maize C0010.1.1, the counterpart 178 and the conventional line Xianyu 335 were equivalent, and no significant effects of genetically modified maize on field arthropod community were found.

A long-term stationary field experiment was carried out to study effect of zero-tillage (ZT) and/or cultivation of green manure crops (CGMC) on composition and diversity of soil microbial community. Results show that ZT affected soil microbes less significantly than CGMC did; ZT plus CGMC was significantly higher than ZT and CT (conventional tillage) and the former had a ratio of copy numbers of bacteria and fungi being 2.51×10³. Bacteria in the soils varied somewhat in relative population and composition relative to treatment, but remained to be dominated by with Proteobacteria, Chloroflexi and Acidobacteria and almost the same in diversity of soil microbial community (Shannon index and Simpson index) abundance (ACE and Chao 1) in all the treatments. Correlation analysis shows that to a certain extent, soil structure, contents of soil nutrients and soil pH determine soil microbial composition.

Rice is broadly planted in China. Ammonia volatilization, nitrogen (N) and phosphorus (P) runoff and leakage have caused agricultural non-point source pollution and other issues due to excessive fertilization. The concentration of N and P in surface water during the flooding period is the key control factor. The dynamic characteristics of N and P in surface water of paddy field and their potential environmental impact were studied by field experiment with different P and N application. The results show that the concentration of total P (TP), total dissolved P (TDP) and particulate P (PP) all increased rapidly within 9 days after P application and then decreased. The concentrations of TP, TDP, and PP reached 0.76, 0.71 and 0.03 mg·L^-1 with 214 and 90 kg·hm^-2 N and P application, respectively. Besides, the concentration of TP and TDP showed an obvious rise after the soil-drying period. The concentration of ammonium nitrogen and nitrate in all treatments reached to maximum in 2 and 5 days, respectively, after the application of basal fertilizer. The concentration of ammonium nitrogen with 214,182 and 162 kg·hm^-2 of N application were 15.83, 9.16 and 7.86 times of that in control treatment. N concentration decreased rapidly after 5 days and the differences between treatments became much smaller. In addition, increasing N and P application amount did not significantly increase the rice yield, but inversely, rice yield decreased with 214 and 90 kg·hm^-2 of N and P application, respectively. Therefore, 9 days after P application and the stage after rewetting were the key periods for controlling P losses through runoff in surface water from paddy field, while 5 days following N application is the vital period for controlling N losses. By considering both rice yield and fertilizer agronomic efficiency, it is feasible to reduce 25% of N and P application. However, this should be further investigated for high yield consistency through field experiment.

To remove the low concentration nitrate in water and eliminate eutrophication, the biochar was prepared from three kinds of macrophytes, including Thalia dealbata, Typha orientalis and Phragmites australis, and then were modified by ferric chloride. FTIR and SEM-EDS results of the biochar and equilibrium adsorption tests show that the Fe-O was formed on the surface of the modified biochar which greatly enhanced biochar's adsorption performance to the nitrate-nitrogen. The nitrate was absorbed rapidly in 4 hours and then reached equilibrium slowly in 24 hours. The equilibrium adsorption capacity of the modified Typha orientalis biochar was the highest, which reached up to 1.747 mg·g^-1. The adsorption performance of low concentration nitrate onto three kinds of modified macrophytes biochar fitted well to pseudo-second-order equation and Freundlich equation, indicating that inhomogeneous polymolecular layer chemisorption occurred on the surface of modified biochar. The initial pH of the solution in the range of 3.0-9.0 has little effect on the adsorption performance of nitrate, and the most appropriate pH is neutral. At the initial nitrate-nitrogen concentration of 2 mg·L^-1, the most appropriate dosages of the three kinds of modified macrophytes biochar are 1.50, 1.14, and 1.22 g·L^-1 for iron modified biochar of Thalia dealbata, Typha orientalis and Phragmites australis, respectively. Therefore, the iron modified macrophytes biochar can not only effectively remove the nitrate-nitrogen in water, but also realize resource utilization of the macrophytes, which has a promising application prospect.

Four types of biochars were prepared out of chicken droppings or wheat straw through pyrolysis at 350 or 650℃ separately and analyzed for physic-chemical properties. Batch sorption tests were conducted to explore Cd²⁺ adsorption characteristics of the biochars relative to duration of the adsorption, pH of the solution, and Cd²⁺ concentration in the solution. Results show that the higher the temperature of pyrolysis, the higher the pH, ash content, aromaticity and hydrophobicity and the lower the polarity of the biochar. Under the same temperature in pyrolysis, the chicken manure derived biochar was higher in pH and ash contents than the plant-derived one, and more complete in aromatic structure. The Cd²⁺ sorption kinetics of the biochars well fitted the pseudo second order kinetic model (R²>0.99), and the adsorption reached equilibrium in 12 h. And the sorption processes were controlled jointly by external liquid film diffusion, surface adsorption and intraparticle diffusion, and the latter was found to be the main rate-controlling step. With pH in the solution rising from 2.0 to 6.0, Cd²⁺ adsorption rate of the biochars gradually increased, and peaked at pH 6.0. The Langmuir model can be used to describe Cd²⁺ adsorption isotherm of the plant-derived biochars (R², 0.970 3~0.981 5), whereas the Freundlich model was better at describing the chicken-manue-derived biochars (R², 0.971 7~0.976 9). The chicken manure-derived biochars are superior to the plant-derived biochars in Cd²⁺ adsorption. Cation-π action and precipitation were the two main mechanisms for biochars pyrolyzed at 650℃ adsorbing Cd²⁺.

In order to study protective effect of roadside tree lines on heavy metals pollution (Pb, Zn, Cd, Cu, Cr and Mn) to roadside tea gardens in Wuyishan, samples of soils and tea leaves were collected from two neighboring sections of a roadside tea plantation, of which one has a roadside tree line (Section B) and the other does not (Section A). With an ICP-MS, concentrations of these heavy metals in the samples were measured. Correlation analysis and principal component analysis of heavy metals in the soil and tea leaves differed in result between Section A and Section B, which may be attributed to the effect of the roadside tree lines intercepting pollutants from the road. The principal component analysis reveals that concentrations of the six heavy metals in the samples, that Pb, Cu and Zn was mainly affected by traffic, while that of Mn and Cr by both traffic and geological background, and that of Cd by both traffic and fertilization. Moreover, it was also found that a single row of fir trees along the roadside in Section B could reduce not only the mean concentrations of heavy metals in the tea trees 1-150 m away from the roadbed, but also the range of maximal concentrations of Zn and Pb alongside the road from 50-80 m down to 1-10 m, which was possibly attributed directly to the effect of the roadside tree line intercepting pollutants from the traffic and indirect to its interception of carbonate dispersal affecting soil pH. Obviously, decreasing the concentrations of traffic related heavy metals in tea and improving quality of the tea in roadside tea gardens can be achieved through planting roadside trees alongside the road in the tea gardens.

The use of ultrasound to pretreat waste activated sludge (WAS) is one of the cleanest means, but its practical application is restrained by its high energy consumption. Double frequency as a new parameter is expected to improve dehydration property of WAS and consequently reduce energy consumption. To explore effect of the use of double frequency ultrasound in pretreatment of WAS on its dehydration property, a sequencing batch experiment on use of ultrasound was designed to have three treatments in terms of frequency, i. e. 17, 33 kHz and 17+33 kHz, and carried out under the specific energy of 0-12 000 kJ·kg^-1 per unit of total solids (TS). Changes in filterability and centrifugal dehydration property of WAS were monitored by measuring specific resistance of filtration (SRF) and moisture content of dehydrated WAS cake. Results show that double-frequency ultrasound was far too superior to single-frequency one in improving dehydration property of the WAS, when the ultrasounds were low in energy. When treated with ultrasound of 17, 33 kHz, and 17+33 kHz, separately, SRF of WAS was reduced by 44.67%, 57.30%, and 80.41%, respectively. The maximum effect of reducing moisture content in WAS cake by 20.62% was observed in the treatment of double frequency, 17+33 kHz and specific energy of 1 000 kJ·kg^-1. With increasing specific energy, mean particle size of WAS declined steadily, but degradation degree of WAS increased steadily, which indicates that extracelluar polymers and organic matter in cells of WAS were changing steadily from solid phase to liquid phase. The higher energy utilization efficiency of double frequency enables it to achieve better dehydration effect with lower energy supply than single frequency, which may serve as a scientific support to extrapolate the pretreatment technique of double frequency ultrasound in practical application.