Table of Content

Volume 37 Issue 2
25 February 2021
Knowledge Map of Rural Ecological Civilization Research Based on CiteSpace V Visualization Analysis
FENG Liang, WANG Shu-bin, TANG Hai-ying, YU Xia, LI Shu-juan, YUAN Jia-xin, HUANG Guo-qin
2021, 37(2):  137-144.  doi:10.19741/j.issn.1673-4831.2020.0442
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The construction of rural ecological civilization is one of the important contents of rural revitalization. CiteSpace V visualization and quantitative methods were used to analyze the development of rural ecological civilization in China in the past 20 years, and the hot research direction and existing problems in this research field are expounded. Corresponding suggestions are given which will have important reference to the future development of rural ecological civilization in China. The results show that the research on rural ecological civilization can be divided into three stages: initial development, slow growth and rapid growth; By investigation it is found that the highest number (412) of papers are related to ecological civilization construction, accounting for 26.10 % of the total. Beijing Forestry University ranked the first in the number of papers issued; Through the analysis of the key words emergence map, it is concluded that the key word emergence intensity of "Rural Revitalization" (28.28) ranked the first and is consistent with the number of papers published in the construction of rural ecological civilization followed by "Rural Revitalization Strategy" with the emergence intensity of 9, indicating that the research on rural revitalization has attracted the attention of Chinese scholars since 2018. The following problems were found by the investigation and suggestions are proposed:Imbalance of rural ecological civilization focused researches. It is suggested that the later researches should be balanced, with comprehensive and coordinated researches.In the organization co-occurrence map, the institutions were lacking of cooperation and exchange, so that, the cooperation and exchange of all related institutions should be strengthened, and jointly improved.The involvement of universities was not enough, so that, universities should take their advantage on talent think tanks to play more important role for providing better conrtributions to the construction of rural ecological civilization in China.The relevant representative literatures of each cluster are mostly out of date with low reference value for the current rural ecological civilization construction and rural revitalization strategy. The later researches should bring forth new ideas and methods on the basis of the previous research. In short, the development of rural economy should not be at the expense of ecological environment, but should vigorously develop rural characteristic industries, pay attention to rural personnel training, and make overall planning, which is conducive to the development of rural ecological civilization.
Transition Metal Activated Persulfate for Environmental Remediation: A Review
WANG Xiao-lei, WU Gen-hua, FANG Guo-dong, ZHOU Dong-mei
2021, 37(2):  145-154.  doi:10.19741/j.issn.1673-4831.2020.0347
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Sulfate radical (SO4·-)-based advanced oxidation technologies (AOTs) has received increasing attention for environmental remediation in recent years. Persulfate is a general precursor of sulfate radical, and the activation of persulfate to produce sulfate radicals, which can degrade a wide range of pollutants. Transition metal is one of the most popular activators for persulfate activation, and has been studied extensively for pollutant remediation. Meanwhile, the new mechanisms of persulfate activation by transition metal and free radical generation have been explored. For example, it has been reported that the activation of persulfate by transition metal can produce free radicals, singlet oxygen and high valence of ferrous. In addition, soil properties such as organic matter, minerals and pH would influence the remediation efficiency when persulfate activation by transition metal was used in filed applications. Therefore, the present study reviewed some new progresses on persulfate activation by transition metal for environmental remediation and several mechanisms for activation of persulfate by transition metal were discussed. The potential influence of soil properties such as soil organic matter, mineral and soil pH on the application of persulfate remediation was also elucidated.
Analysis on the Land Evolution of Rural Settlement and Its Main Control Factors in Guangdong Province
JIAN Yu-qing, GONG Jian-zhou, LUO Ya-hong, LI Bai-he
2021, 37(2):  155-163.  doi:10.19741/j.issn.1673-4831.2020.0353
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The purpose of this study is to analyze rural settlement evolution characteristics and the identification of main factors in Guangdong Province, which can promote the theoretical research and action implementation of rural transformation and spatial reconstruction. Methods of the landscape index analysis and the geographical detector were employed to reveal the expansion mode and mechanism of rural settlement from 1980 to 2015. The results show that rural settlement land in Guangdong presents a spatial expansion pattern with the pearl river delta as the main and the east and west as the auxiliary. From 1980 to 2015, rural settlement was dominated by marginal expansion, while the filling type changed and enclave type changed alternately. The evolution of rural land under urbanization shows significant stage characteristics and there are obvious differences between the master factors of different expansion mode. The identification results of main factors show that socio-economic factors such as per capita GDP, per capita grain output and per capita agricultural output value are the main controlling factors of rural settlements evolution in different periods. In 1990-2000 Guangdong was in a period of rural industrialization and urbanization, forming a trend of complexity of rural landscape elements, differentiation of spatial structure and diversification of regional functions. The area of rural settlements increased significantly. In 2000-2015, during the period of centralization and integration of rural planning, the change range of rural settlement land was relatively small. On the whole, Guangdong Province has gradually entered a high and steady stage of rural development and restructuring under the multifaceted synergy of "production-life-ecology". In conclusion, multi-perspective analysis of the evolution characteristics and mechanism of rural settlements are the theoretical supports for the optimization and reorganization of rural space, as well as the premise and foundation for the implementation of the strategy of rural revitalization and new type of urbanization.
Spatial Pattern of Rural Settlements in Fuzhou Mountainous Area and Its Coupling With Water and Soil Resources
HU Hang-xiao, DAI Wen-yuan, XU Yi-wen, LIN Tao
2021, 37(2):  164-171.  doi:10.19741/j.issn.1673-4831.2020.0296
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The analysis of rural settlements and the water and soil coupling situation in mountain area is helpful to highlight the advantages and characteristics of rural mountain area and promote rural vitalization. With a case study of mountain area in Fuzhou, the spatial distribution characteristics of rural settlements in mountain area and water and soil coupling situation were analyzed based on GIS and spatial coupling correlation model. The results show that: (1) To the year of 2015, there were a total of 5232 rural settlement patches in Fuzhou mountain area, featured in large numbers with small scale, and mainly distributed in the area below 650m of altitude. (2) The rural settlements in each town area showed spatial pattern characteristics of "gather in center as well as diffuse toward north-south " with agglomeration distribution and differentiation. (3) There was a good coupling situation between settlements and cultivated land but less satisfactory coupling with water system, showing obvious "farmland directivity" and small-scale "water system directivity", without obvious correlation with the road. The influence of cultivated land and water resources on villages and towns showed strong spatial heterogeneity, and soil and water resources have become an important factor restricting the development and transformation of rural settlements in Fuzhou mountain area.
Distribution of Carbon, Nitrogen and Phosphorus in Sediments of Lhalu Wetland in Dry and Wet Seasons and It's Pollution Risk Assessment
REN Jing-wen, WANG Jia-jun, ZHOU Lei, XU De-fu, ZHANG Jian-wei
2021, 37(2):  172-181.  doi:10.19741/j.issn.1673-4831.2020.0338
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Lhalu wetland is the world's highest and largest natural wetland in city. In order to study the changes of its sediment pollution, the sediments from 59 and 48 points of Lhalu wetland were collected in December 2018 (dry season) and May 2019 (wet season), respectively, which were analyzed for the spatial distribution characteristics and stoichiometric ratio of total nitrogen (TN), total phosphorus (TP) and total organic matter (OM). In addition, pollution risk assessment was carried out by the comprehensive pollution index method and organic pollution index. Results show that the content of TN, TP and OM in sediments were higher in wet season than in dry season. The content of TN, TP and OM in sediment in dry season was 0.18-6.35 g·kg-1, 0.33-2.88 g·kg-1 and 27.18-268.98 g·kg-1, respectively. The highest content of TN and OM was found in middle-west and east of Lhalu wetland. However, the highest content of TP was found in west and middle-west of Lhalu wetland. The ratio of C/N in dry season was 15.04-85.31, which was significantly higher in the north part than in other parts of the Lhalu wetland (P<0.05). The ratio of C/N in wet season was 3.09-97.46, which was significantly lower in the west part than in the other parts of the Lhalu wetland (P<0.05). The ratio of C/N of the wetland was higher than 10, which suggests that the organic matters in dry and wet seasons were from outside. The OM in the sediments was mineralized during the wet season. The Lhalu wetland is relatively clean in the north, while some degrees of pollution were found in other parts of the wetland.
Spatio-Temporal Distribution Characteristics of Nitrogen and Phosphorus in the Typical Inflow River of Taihu Lake
LI Cong-yang, SHI Chen-fei, FANG Jia-qi, ZHANG Shi-wei, WANG Xuan, XIN Yue, LIU Hua-ji, LIU Jin-e, WANG Guo-xiang
2021, 37(2):  182-187.  doi:10.19741/j.issn.1673-4831.2020.0370
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Liangxi River, one tributary of Taihu Lake, was selected as study region in order to explore the water environmental situation of the typical inflow water. The temporal and spatial distribution characteristics of nitrogen and phosphorus of the water was investigated based on the data of water quality from December 2017 to December 2018. The results show that the pollution status of the tributaries of the Liangxi River was more serious than that of the main stream and their water quality was mostly worse than Grade V. In details, the concentrations of TN, NH4+-N, NO3--N and TP in the main stream ranged from 0.57-2.86, 0.10-0.75, 0.02-0.53 and 0.05-0.39 mg·L-1, respectively. The concentrations of TN, NH4+-N, NO3--N and TP in tributaries ranged from 2.42-5.63, 1.12-3.35, 0.32-2.33 and 0.07-0.52 mg·L-1, respectively. Correlation analysis indicate that the form of inputs and pathways of nitrogen and phosphorus in Liangxi River were consistent. Peak values of TN were observed in spring and summer, while concentrations of TP were lower in winter and higher than those in summer. Concentrations of nitrogen and phosphorus in summer presented an upward trend toward the downstream along the main stream. The pollution of nitrogen and phosphorus was more serious in some tributaries, thus imposing an impact on main stream. In future river restoration and improvement, a comprehensive restoration strategy of joint regulation of the main stream and tributaries should be followed.
Spatiotemporal Characteristics and Risk Assessment of Ampicillin in Water Source of Nanjing Section of the Yangtze River
GONG Run-qiang, WANG Bo, JI Mu-lan, ZHAO Xin, SU Liang-hu, BU Yuan-qing, CHEN Yu, ZHANG Sheng-hu, QIU Hui
2021, 37(2):  188-193.  doi:10.19741/j.issn.1673-4831.2020.0475
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In order to evaluate the temporal-spatial characteristics and risk assessment of Ampicillin (AMP) in the water source of Nanjing Section of the Yangtze River, 14 sampling sites of Nanjing section of Yangtze River were sampled in November, December 2019 and January, 2020, respectively, and AMP in water was analyzed by SPE-UPLC-MS/MS. The results show that the total mass concentration of AMP ranged from ND to 42.44 ng·L-1, the average mass concentration was 19.67 ng·L-1, and the detection rate was 57.5% after testing the samples collected from 14 sampling sites for three consecutive months. The detection rate of AMP in three months was 7.14%, 100% and 66.67%, respectively. The detection concentration and detection rate of AMP in December and January were generally higher than that in November. Risk quotient method was used to assess the risk of AMP in water bodies. The results show that the ecological risk entropy QR of AMP in Nanjing Section of the Yangtze River ranged from 0.40 to 0.57, which was a moderate risk. AMP's health risk entropy QRH ranged from 3.2×10-5 to 5.1×10-5, which had no risk to human health.
Investigation and Fauna Analysis of Butterflies in Jinyun Mounta in National Nature Reserve in Chongqing
YAN Zhen-tian, LU Ming-juan, LI Ting-jing, FU Qiao, FU Wen-bo, CHEN Bin
2021, 37(2):  194-200.  doi:10.19741/j.issn.1673-4831.2020.0555
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Butterflies are important ecological and ornamental insects; however, the butterflies in Jinyun Mountain National Nature Reserve in Chongqing have not been systematically investigated and analyzed. The present study morphologically identified the butterflies collected from 2012 to 2019 in the Jinyun Mountain National Nature Reserve, and butterflies housed in Insect Collection of Chongqing Normal University. A total of 569 butterflies were identified in the Jinyun Mountain National Nature Reserve, and they belong to 5 families, 79 genera and 128 species, including 2 newly recorded genera and 8 newly recorded species for Chongqing and 5 newly recorded genera and 32 newly recorded species for the Jinyun Mountain National Nature Reserve. Among the 5 families, the family Nymphalidae has the richest biodiversity with 31 genera and 49 species, followed by Lycaenidae (20 genera, 27 species), Hesperiidae (17 genera, 26 species), Papilionidae (5 genera. 16 species) and Pieridae (6 genera, 10 species). The family Hesperiidae has the highest species richness index, reaching 3.920, followed by Nymphalidae (3.130), Lycaenidae (2.486), Papilionidae (1.985) and Pieridae (1.015). Resulted from the fauna analysis for these species' distribution in the world zoogeographic regions, the species in the reserve belong to both the Oriental region and the Palearctic region have the highest proportion, 63.98%, followed by Oriental region (34.12%), and only 1.9% of species are cosmopolitan distributed. Resulted from the analysis of Chinese zoogeographic regions, these butterfly species in the reserve have 31 distribution patterns, and 27.01% of species are commonly distributed across Southwest-South-Central China zoogeographic subregions, and 14.7% of species are across Southwest-Central-South-North China zoogeographic subregions. The study is of importance for understanding, conservation and utilization of butterfly biodiversity in Chongqing as well as in the reserve.
Analyses on Spatial-temporal Distribution Patterns of the Amphibian Diversity in Xunwu Sample Zones, Jiangxi Province
WANG Qin, HE Yu-xiao, KE Can, LI Zhen, CHEN Zhuo, WANG Qiu-ya, XU Hai-gen, LIU Wen-ming, CHEN Xiao-hong
2021, 37(2):  201-207.  doi:10.19741/j.issn.1673-4831.2020.0488
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Xunwu County is located in southeastern Ganzhou City, Jiangxi Province, and at the junction of Fujian, Jiangxi, and Guangdong Provinces. Due to the unique geographical location, warm and humid subtropical monsoon climate, and developed river networks, Xunwu County has been listed as the observation region by the National Amphibian Diversity Observation Network. According to the topography, landform and habitat, 12 survey lines were set up for rivers, ponds and artificial canals, and observations were conducted in Late April, Mid-June and Late July, 2018. A total of 755 amphibian individuals were found and they belong to one order, 5 families, 10 genera and 10 species. The dominance index (Pi) of Duttaphrynus melanostictus, Boulengerana guentheri, Fejervarya multistriata was greater than 0.1, and they were the dominant species during the surveys. Fifteen individuals of Hoplobatrachus chinensis, listed as endangered species (EN) by IUCN, were found and its dominance index (Pi>0.01) was higher than that of Rana longicrus, Rhacophorus dennysi and Microhyla fissipes (Pi<0.01). The fauna composition of amphibians in Xunwu belong to Southern China fauna, and only Pelophylax nigromaculatus is widely distributed. Most species were terrestrial aquatic and still water types, whereas only one flow type and one arboreal type species were found. The richness and relative abundance reached the highest in April, and the temporal pattern of the species diversity was affected by the breeding season and the length of the breeding period. Most of the observed species reproduced in spring, whereas Nidirana adenopleura and Odorrana huangangensis reproduced mainly in summer which were only observed in July. The spatial patterns show that the river habitat has more sample lines, higher environmental heterogeneity, and the highest species richness. The pond habitat was relatively stable and the relative abundance reached to 51.4% of the total in this survey, although the number of survey lines accounts for only 25% of the total numbers of this survey. The richness and relative abundance of artificial canals were the lowest. Due to only one year data of 2018 was obtained, there is a lack of long-term observations, and the cover of the season and habitats in this survey is incomplete, and the species diversity revealed is lower than that recorded in Jiangxi province. Long-term data accumulation and comprehensive observations should be conducted to address the issues of diversity, population size and threatened factors of amphibians and to provide scientific basis for the ecological protection and restoration of mountains, lakes, forests and grasses.
Metazooplankton Community Structure and Ecological Evaluation of Water Quality of Eriocheir sinesis Ecological Culture Ponds
DAI Dan-chao, MA Xu-zhou, ZHANG Wen-bo, ZHANG Yong, ZHOU Zhen
2021, 37(2):  208-216.  doi:10.19741/j.issn.1673-4831.2020.0244
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This study aims to explore the metazooplankton community structure and water status of Eriocheirsinesis ecological breeding ponds. Samples were taken from three ponds and water inlet, and species identification and quantitative analysis of the metazooplankton were then conducted. The biodiversity index was used to evaluate the water quality. A total of 49 metazooplankton species were found, including 22 species of Rotifera, 15 species of Cladocera, and 12 species of Copepoda. Brachionus urceus, Brachionus calyciflorus, and Polyarthra trigla of Rotifera, Ceriodaphnia setosa, Ceriodaphnia pulchella and Moina rectirostris of Cladocera, Nauplii, Microcyclops varicans and Ectocyclops phaleratus of Copepoda were the dominant species. Rotifera had the largest density, but the biomass was the smallest, while the density of Cladocera was the smallest, but they had the largest biomass, followed by the density and biomass of Copepoda. RDA ordination analysis shows that T, TN, PO43--P and CODMn were the main influencing factors of the metazooplankton community structure in ponds. The evaluation results of biodiversity index on water quality show that both ponds and water inlet were in the state of medium pollution, and the water quality of ponds was not significantly better than that of water inlet, which was related to the high breeding density in this area, and finding a reasonable breeding density should be taken as the research direction in the future.
Enhanced Decolorization Capacity About Alginate Encapsulation System of Shewanella oneidensis MR-1 Mingled With Nano-Fe3O4
HUANG Hong-yang, HUANG Jin-jin, WANG Guo-xiang, WU Xiang-yang, SHEN Nan, SUN Li
2021, 37(2):  217-223.  doi:10.19741/j.issn.1673-4831.2020.0297
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Shewanella oneidensis MR-1 has been proved to be a potential bacterium to decolorize methyl orange (MO). Nevertheless, longer reaction time was needed to achieve higher decolorization efficiency. Thus, it's necessary to further improve the decolorization efficiency of azo dyes using S. oneidensis MR-1. The embedding of S. oneidensis MR-1 and nano-Fe3O4 with sodium alginate (SA) is an ideal mode for efficient decolorization of MO. Morphology, rheology and mechanical strength were studied to better understand the decolorization capacity and recycle of the beads. The MO decolorization efficiency with SA, SA/Fe3O4, SA/S. oneidensis MR-1 and SA/S. oneidensis MR-1/Fe3O4 beads was studied. Compared with the beads of SA/S. oneidensis MR-1, the decolorization efficiency with SA/S. oneidensis MR-1/Fe3O4 was improved. After three cycles, 77.83% of decolorization capability could be recovered with beads of SA/S. oneidensis MR-1/Fe3O4 while only 53.19% recovered with SA/S. oneidensis MR-1 at 1.75 h in cycle 4 under transverse condition, respectively. The addition of Fe3O4 not only improved the decolorization capacity of beads of SA/S. oneidensis MR-1/Fe3O4 but also increased the mechanical strength. This research would provide the feasibility for recycling of immobilized microbial with higher efficiency and longer lifetime during wastewater treatment.
Nitrate Removal from Water by Activated Carbon Derived from Wheat Straw with FeCl3 Activation
LI Ji-hui, WEI Ping, LI Bao-qiang, GUO Jin-yi, LI Jing, YANG Bao-shan, SONG Ji-qing
2021, 37(2):  224-233.  doi:10.19741/j.issn.1673-4831.2020.0348
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Wheat straw activated carbon (AC) coated with iron oxide (FeCl3 solution) as activator was prepared to obtain strong nitrate adsorption capacity, and response surface methodology (RSM) was applied to determine the optimal preparation condition for AC to have maximized adsorption capacity. According to RSM, the optimal condition is 527 ℃ of carbonization temperature and 92.5% of chemical weight ratio (FeCl3/wheat straw). The adsorption capacity of FAC, prepared at the optimal condition was higher than that of wheat straw bio-char (WBC) prepared at the same condition without chemical activation. Plenty of pores with varying sizes were developed at the surface of FAC because of FeCl3 activation. The surface of FAC had more iron content, the specific surface area and pore volume increased, and a large amount of iron oxide was introduced into the FAC pores, and the saturation magnetization value was 4.12 emu·g-1 with good magnetic responds. The N2 adsorption-desorption isotherm would become combination of types Ⅱ and IV with an adsorption hysteresis loop and contains a large number of pores that like the narrow slot. The pore structures of WBC and FAC were mainly micropore and mesopore and the pore volume of FAC was larger than that of WBC. With the increase of the nitrogen concentration, the amount of nitrogen adsorbed onto FAC was rising rapidly, the Langmuir maximum nitrogen adsorption capacity of FAC was 14.68 mg·g-1 (65.01 mg·g-1 for NO3- ions). Nitrate adsorption capacity decreased with an increase in pH. With the increase of FAC content, the removal rate of nitrate increased to about 90%. The nitrate uptake was rapid in the beginning and followed by a slower removal that gradually reached a plateau, and this equilibrium was established after 120 min. The Kinetic studies showed that a pseudo second-order rate equation fit the experimental data well. Therefore, FAC could be used for nitrate removal from water and be separated from water readily by using magnetic separation, providing a method to improve the ecological environment (crop straw using and water pollutant removing efficiently).
A New Adsorbent for Phosphorus Removal From Bark of Hibiscus syriacus Modified by Lanthanum
NI Lin-jie, QIU Huan, LIU Xiao-ling, LEI Yan, ZHANG Ke, LUO Hong-bing, CHENG Lin, FAN Liang-qian, CHEN Wei
2021, 37(2):  234-241.  doi:10.19741/j.issn.1673-4831.2020.0305
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Based on the bark of Hibiscus syriacus, a new phosphorus adsorbent was modified by lanthanum chloride to remove phosphorus from wastewater. The mono-factor method was used to determine the optimal modification conditions of the adsorbent. The effects of pH, adsorbent amount, adsorption time and adsorption temperature were investigated. Results show that: (1) The optimal modification conditions of the bark of Hibiscus syriacus were the lanthanum chloride solution concentration of 7%, the calcination temperature of 300 ℃ and the roasting time of 2.5 hours. (2) When the initial concentration of phosphorus was 5 mg·L-1, the solution acidity was pH 7 and the optimum dosage was 0.35 g, the best adsorption phosphorus removal rate reached to 94.99%. (3) When the adsorption time was 130 min, the adsorption reaction was in equilibrium. The adsorption modes of bark of Hibiscus syriacus modified by lanthanum chloride were all determined to the pseudo-second-order kinetic equation at different temperatures. (4) The Langmuir equation was suitable to describe the adsorption reaction which belonged to single molecule layer adsorption. At temperatures of 288, 298 and 308 K, the maximum adsorption capacity of modified bark of Hibiscus syriacus was 1.54, 1.55 and 1.63 mg·g-1, respectively. (5) Adsorption thermodynamic analysis results show that the ΔGθ, ΔHθ and ΔSθ was <0, >0 and <0, respectively, which means that the adsorption reaction was promoted when the temperature rose. These results also indicate that adsorption reaction using bark of Hibiscus syriacus modified by lanthanum chloride was a spontaneous, entropy increasing and endothermic process and belonged to the chemical adsorption. This study provides a theoretical reference for treating phosphorous wastewater by using bark of Hibiscus syriacus modified by lanthanum chloride.
The Effect of Soil Samples Preserved with Methanol for VOCs on the Determination of Site Pollution Risk
LI Qun, LONG Tao, ZHOU Yan, FAN Ting-ting, ZUO Fei-ran, WU Yun-jin
2021, 37(2):  242-248.  doi:10.19741/j.issn.1673-4831.2020.0524
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The limit of detection (LOD) was increased by preserving with methanol when collecting soil volatile organic compounds (VOCs), which may result in undetecting of higher levels of VOCs. Thus, it exerts the influence on the determination of site pollution risk. Firstly, the improvement range of LOD after soil VOCs sampling preserved with methanol was calculated. Secondly, it is assumed that the contents of 62 VOCs commonly in soil were equal to the screening value (or risk control value) of soil contamination of construction land. Thirdly, the comparisons between the improved LODs and screening values (or risk control values) of these VOCs were made to analyze the risk levels of contaminated site. According to the analysis, the corresponding sampling suggestions were put forward. The results show that 1,2,3-trichloropropane, 1,2-Dibromoethane and chloroethylene were the most affected pollutants in the first type of construction land use, followed by vinyl chloride, bromodichloromethane, trichloromethane, 1,1-dichloropropene, 1,2-dibromo-3-chloropropane, 1,2-dichloroethane, methyl bromide, 1, 1,2-trichloroethane, benzene, trichloroethylene, carbon tetrachloride, 1,2-dichloropropane, while other pollutants had little effect. Nevertheless, trichloromethane, 1,2,3-trichloropropane, 1,2-dibromoethane and vinyl chloride were the moderately affected pollutants in the second type of construction land use, while other pollutants had been little affected.
Effect of Deicing Salts on Microbial Activity and Nitrogen Transformation in Roadside Soil
ZHANG Ying, LI Fa-yun, SUN Ting-ting, ZHANG Guo-hui, CHENG Zhi-hui, LI Xia
2021, 37(2):  249-256.  doi:10.19741/j.issn.1673-4831.2020.0333
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Large quantities of deicing salts are used as a dominant way to keep road safety during the winter seasons. In many studies the effects of deicing salts on roadside soil environment, especially the potential disruption effects of deicing salts on the biochemical properties and nitrogen cycle of soil have been largely ignored. This research aimed to find correlations between the effects of 0.1%-0.6% deicing salts contaminants on microbial activity and nitrogen transformations of roadside brown soils in Shenyang. The results show a significant negative exponential relationship between the concentrations of deicing salts and soil microbial biomass C, microbial biomass N, soil basal respiration, urease and catalase activity, soil mineralization and nitrification, especially under the stress of 0.5% deicing salts per dry weight of soil. Soil microbial biomass C, soil basal respiration, urease enzyme activiy, the content of mineralizable N and nitrate N growth were inhibited significantly by the stress of 0.5% deicing salts compared with control. The C/N ratio of soil microbial biomass tended to be lower in soils with higher salinity, reflecting the bacterial dominance in microbial biomass of saline soils. Increased value of metabolic quotients (qCO2) show that microbial community was apparently under stress. The positive relationship between microbial biomass and the content of urease enzyme, mineralizable N and nitrate N indicate that the remarkable influence of deicing salts on the activity and community structure of soil microorganisms, which could induce the decrease of nitrogen mineralization and nitrification in the soils.
Life Cycle Assessment of Two Manure Treatment Modes in Intensive Dairy Farms
LI Dan-yang, HU Jie, DONG Yi-wei, JIN Hong-mei
2021, 37(2):  257-264.  doi:10.19741/j.issn.1673-4831.2020.0336
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Quantifying the energy and material consumption and environmental emissions of different treatment modes of dairy manure is of guiding significance for accurately assessing the environmental impact of manure management in intensive dairy farms and scientifically formulating emission reduction measures. In this study, life cycle assessment (LCA) method was used to compare the environmental emission of pollutants from mode Ⅰ (i.e., complete utilization of dairy manure) and mode Ⅱ (i.e., standard processing of dairy slurry) in two intensive dairy farms. The results show that the emission of CO2, SO2, NOx, CO, CH4, VOC and soot in mode Ⅰ were 17.28, 0.14, 0.09, 0.04, 0.02, 0.002 and 0.007 kg, respectively lower than those of mode Ⅱ. The total environmental impact potential was 0.007 6 kg eq per person per year in mode Ⅰ, which was 23.2% lower than that in mode Ⅱ. Meanwhile, it had obvious economic benefits in mode Ⅰ. In the dairy manure treatment process, the environmental impact potential of slurry treatment is the highest. Thus, the optimization of dairy slurry treatment is a focus and also a difficult issue in the dairy manure treatment process. It is suggested that enough farmland should be arranged for recieving the dairy manure. In addition, more precision application techniques and evaluation methods should be developed to enhance the utilization efficiency of nutrient in dairy manure and to reduce the environmental emission of pollutants from dairy manure treatment.
Discussion and Suggestion on the Value of Baseline Oxygen Content for Pollutant Emissions of Household Biomass Heating Stove
SHAN Ming, XING Yong-jie, DENG Meng-si, LIU Yan-qing, LI Ding-kai, YANG Xu-dong
2021, 37(2):  265-271.  doi:10.19741/j.issn.1673-4831.2020.0154
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Promoting the efficient and clean utilization of densified biomass fuel is an important measure to the implementation of the rural revitalization strategy and the promotion of clean heating in rural areas of Northern China. Designing applicable standards for household biomass heating stoves is the key factor to ensure the benign development of this technology. This paper analyzed the actual situation of domestic biomass stove emission standards by taking five common fuels (three types of pellets and two types of coals) as examples. Based on the industrial analysis results, both quantity of air required for complete combustion and the theoretical flue gas emissions were calculated. The results show that the air required for complete combustion and the theoretical flue gas emissions from biomass pellets were significantly less than coal due to biomass itself containing more oxygen element. Therefore it is unreasonable to directly adopt the benchmark oxygen content of coal-fired stove for biomass stove emission standard. Based on the current technical level of domestic biomass stoves and relevant emission standards abroad, it is suggested that the reasonable pollutant emission concentration of domestic household biomass stoves should be converted into oxygen content from 9% to 13%-15%.