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Table of Content

Volume 33 Issue 5
25 May 2017
Review of Researches on Bioavailability of Ionizable Organic Compounds in Environment
XU Shi-ji, HE Ying, LI Si-qi, LIU Kai-lin, LIU Xiang-ying, ZHOU Xiao-mao, BAI Lian-yang
2017, 33(5):  385-395.  doi:10.11934/j.issn.1673-4831.2017.05.001
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With the development of the chemical industry, an increasing proportion of synthetic organic compounds detected today in the environment are ionizable. As ionizable organic compounds (IOCs) may exist in the form of molecules and/or ions in the environment, their bioavailabilities in the environment are site-specific. Factors affecting IOCs bioavailabilities in the environment mainly from the angle of their physicochemical adsorption and biological absorption are elaborated. IOCs adsorption to environmental media is mainly influenced by pH. Generally, neutral molecules are more easily absorbed by the medium than ionized ones. Bioavailability of IOCs depends on ionization degree of these compounds and bioaccumulation factor. According to the theory of ion trap, neutral molecules can penetrate plasma membranes more easily than ionized ones. Once neutral molecules enter into cell, the bioavailability of IOCs depends on pH of the cytoplasm, and the effect inside the cells has nothing to do with pH in the outside environment. Compared with the techniques of biological monitoring and model monitoring, the technique of hollow fiber liquid microextraction is more efficient in evaluating bioavailability of IOCs. Besides, in future studies on bioavailability of IOCs, more emphasis should be laid on influences of pH of the environmental media and pH inside the cells.

Willingness of the Local Farmers to Accept Ecological Compensation in Qilihai Wetland
YAO Xiang-shu, JIN Ru-wei, HOU Guang-hui
2017, 33(5):  396-402.  doi:10.11934/j.issn.1673-4831.2017.05.002
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The topics of economic assessment of damages to wetland ecological systems and willingness of the farmers to accept ecological compensation have long been hot spots for researchers at home and abroad. In this study the double-bounded contingent valuation method was used to evaluate willingness of the farmers to accept ecological compensation and quantitatively estimate ecological losses of the Qilihai wetlands incurred by "reclamation of farmland, artificial division and over-exploitation", and the logistic model was to identify major factors affecting willingness of the local farmers to accept compensation. Results show that the annual mean compensation the local farmers are willing to accept is 23 896.65 yuan·hm-2·a-1, and the annual total ecological loss 129.221 1 million yuan·a-1; Household income, non-farming income, pension and knowledge about status of the wetlands are the main factors affecting willingness of the farmers, land attachment is the major cause of the local farmers resisting loss of land.

Environmental Health Risk Assessment of Drinking Water Resource of a Village in Guiyang
CHEN Sheng-ke, WAN Yu, YANG Ming-jiao, GAN Xiu-hai
2017, 33(5):  403-408.  doi:10.11934/j.issn.1673-4831.2017.05.003
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Based on the water quality monitoring data of of a village in Guiyang, covering 13 hazardous pollutants, including Cr6+, As and Cd, tentative environmental health risk assessment was carried out of the water body at the water head site of the region, using the USEPA health risk assessment model. Results show that the health risk of the villagers exposed to the carcinogenic substance in the water body through drinking water was rated in the range from 10-7 to 10-4. Cr6+ was the major contributor to the risk, varying in the range of 7.2×10-5~3.7×10-4 a-1, all significantly higher than the maximum acceptable levels specified by ICRP and USEPA as 5.0×10-5 a-1 and 1.0×10-6 a-1, respectively. The non-carcinogenic risks of the water body through drinking water ranged from 10-11 to 10-8, much lower than the maximum levels specified by ICRP and USEPA. The risk caused by the carcinogens in the drinking water was about 1 000 times as high as that of the non-carcinogens, contributing 99.9% of the total risk. So that, the issue of Cr6+ in the drinking water should arouse the attention of relevant departments, and deserves the first priority for management.

Characteristics and Sources of Ion Deposition With Precipitation in the Upper Reaches of Heihe River, Xi'an
ZHU Yi-wen, ZHANG Fu-ping, WANG Hu-wei, LIU Xiao
2017, 33(5):  409-416.  doi:10.11934/j.issn.1673-4831.2017.05.004
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Samples of atmospheric precipitation were collected during the period from September 2014 to August 2015 at the Yunlonggou Station in the water source region of the upper reaches of the Heihe River in Xi'an for analysis of ions the samples contained. Then characteristics and sources of the ions were explored through correlation analysis and with the enrichment factor method. The main cations contained in the samples were Ca2+ and NH4+ and the main anions SO42- and NO3-, which was similar to the characteristics of the precipitations in most urban areas of China. All the ions, except for NH4+ and F-, varied in concentration with the season, in an order of winter > spring > summer > autumn, which indicates that concentrations of the ions were related to their origins and amount of the precipitation as well. Correlation analysis of the ions and their origins indicates the correlation between SO42- and NO3- was very high and both were affected by human factors; the correlation between Na+ and Cl- was very high, too, because they are from the same source, i. e. sea; and so were the correlations between Ca2+, Mg2+ and K+ for they are all earth crust elements. Source analysis of the ions shows that human activities contribute 52.90%, more than half, of the ions in the precipitation, the earth crust does 38.43% and the oceans do 8.67%.

Spatial Pattern and Driving Factors of Vegetation Degradation in Beijing-Tianjin-Hebei
LÜ Guo-xu, CHEN Yan-mei, ZOU Chang-xin, FENG Chao-yang, HAO Fang-fang
2017, 33(5):  417-425.  doi:10.11934/j.issn.1673-4831.2017.05.005
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Net primary productivity (NPP) of vegetation is one of the important indicators of a regional ecosystem showing whether it is healthy and degrading. The 2000-2010 data of NPP and land use were cited for analysis of, spatial pattern of vegetation degradation in the Beijing-Tianjin-Hebei region and its human factors, by means of trend analysis, superposition analysis and significance test. Results show that:(1) NPP of the study area varied in the range of 400-700 g·m-2·a-1 in the past years, with high values distributed mainly in the Yanshan Mountains, the Taihang Mountains and the east piedmont plain of the Taihang Mountains, and low value in the grassland region northwest of, the eastern coastal zone of the study area and saline-alkali land of the Jidong Plain. (2) During the 11 years, 59.214% of the Beijing-Tianjin-Hebei area has witnessed declining of the vegetation NPP, and the decline was particularly significant or ultra-significant in 10.050% of the area. In part of the study area, vegetation degradation tended to apparent. The area with vegetation degraded reached 21 545.07 km2, of which 5 775.66 km2 fell into the category of severe degradation, 8 168.18 km2 into the category of moderate degradation and 7 601.23 km2 into slight degradation. Vegetation degradation in the study area exhibits a feature of clustering in spatial distribution, of which there are two examples; One is a band of contiguous patches along the east piedmont of the Taihang Mountains and the other is the circle around the Beijing-Tianjin-Tangshan metropolitan area. (3) There are three main human factors driving variation of the vegetation degradation pattern in the Beijing-Tianjin-Hebei region. 1) Sprawling of cities (towns). The correlation coefficient of the area of newly built cities with the area of severe, moderate and mild vegetation degradation is 0.897 9, 0.783 5 and 0.686 9 (P<0.05), respectively; 2) Density of regional road network. It affects the pattern and degree of vegetation degradation in the region. Vegetation degradation declines in degree from the important traffic line as the core to its flanks. And 3) Regional economic development strategies and industrial layout, which directly affects spatial pattern of the vegetation in the region.

Spatio-Temporal Distribution of Grassland Degradation in Qinghai-Lake Valley
ZHANG Ming, CUI Jun, CAO Xue-zhang
2017, 33(5):  426-432.  doi:10.11934/j.issn.1673-4831.2017.05.006
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Grassland degradation is an effective indicator of eco-environment in the Qinghai-Lake Valley, an ecologically vulnerable area of the Qinghai-Tibetan Plateau. Eight sample plots representing different types of grasslands different in degradation degree in different regions in the valley were set up within the key grassland degradation region and based on grading of grassland degradations in the Qinghai-Lake Valley, spatial distribution and temporal dynamics of the degraded grasslands in the valley were obtained by means of remote sensing. Results show that during the period between 1977 and 2000, grassland degradation was very serious in the valley, with the total area of grassland cut by 206.68 km2, most of which turned into farmlands and sand lands. Grassland degradation occurred mainly in three regions, i. e. the south shore of the Qinghai Lake, Heimahe Township of the Gonghe County, and the Bird Island in the estuary of the Buha River. In the years after 2000, grassland degradation altered in trend with grassland beginning to increase in area, which was attributed to the changes in climate. Increased temperature and precipitation was favorable to growth of grasses and development of grassland. Besides, the government promulgated and enforced a series of grassland protection policies. The year of 2004 was a turning point for the valley, where air temperature and precipitation increased significantly, and consequently, the declining tendency of the water table of the lake was somewhat retarded and grassland degradation lost its momentum. Overall, grassland is the important indicator vegetation of the Qinghai-Lake Valley, and normalized difference vegetation index (NDVI) can be used to accurately monitor vegetation dynamics in the valley.

The Ecological Characteristics of Oenanthe javanica Floating Mats and Its Feedback to Pond Water Quality
ZHAO Wan-wan, GUO Li-yun, ZHOU Guo-qin, WU Wei
2017, 33(5):  433-439.  doi:10.11934/j.issn.1673-4831.2017.05.007
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Oenanthe javanica was used to construct an artificial floating bed in aquaculture system of situ circulating ecological engineering. The focus of the research was to study the growth and the ecological characteristics of Oenanthe javanica, and to receive the response to pond water quality and environment. The research revealed that the average height, the dry weight and the root surface area of Oenanthe javanica increased constantly over the running 80 days. The plant grew rapidly and the overall heights were ranging from 23.05 to 38.37 cm in the period of 50 to 80 days. Moreover, the plant root system, which was assessed by measuring taproot number, root tip number, taproot diameter and lateral root diameter, was enhanced significantly in the 30th to 50th days. The nitrogen content of each plant was increased consistently with the increase of plant weight, and was high-positive correlated with its dry weight (r=0.952). While the phosphorus contents fluctuated between 3.45 and 4.14 mg, which were relatively stable. The average N/P ratios were from 2.51 to 6.80, and varied significantly in different parts of the plant. In addition, the N/P ratios of root variated from 4.27 to 4.67, which were more stable than those of the stems and leaves. The roots of Oenanthe javanica had the ability to reveal radial oxygen loss, and the rate of radial oxygen loss was ranging from 2.74 to 3.27 μmol·h-1·g-1. The rate of radial oxygen loss had a positive correlation with the surface area of root per gram (r=0.795). The O2 secretion of roots led to the oxidation of ferrous and reductive manganese the formation of oxide film around with ionic iron and manganese, and it reduced the contents of iron and manganese in the water, which affected the phosphorus absorption for the plants. Oenanthe javanica floating mats kept daily growth by using nutrients in the pond and gave relevant feedback on water ecological factors through their respective ecological characteristics simultaneously. Results show planted float system had the capacity to adjust the temperature, pH and dissolved oxygen in the water. What is more, it reduced total nitrogen and total phosphorus in the pond, and it had the limit of phosphorus removal. The study suggests the regeneration of plant roots and their corresponding properties play a vital role in the purification of water ecological environment.

Environmental Risk Caused by Successive and Heavy Application of Mineral Fertilizer and Compost With the Same Amount of Nitrogen Applied
TIAN Wei, LI Gang, CHEN Qiu-hui, WANG Chao, ZHANG Chi, LIU Ming-qing, WANG Lei, XI Yun-guan
2017, 33(5):  440-445.  doi:10.11934/j.issn.1673-4831.2017.05.008
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The environmental risk caused by successive and heavy application of mineral fertilizer has attracted wide attention, but scarce for that of compost.After fully investigation of the local fertilization rate of mineral fertilizer in winter wheat-rice cropping system, the dose of compost applied was determined according to the amount of total nitrogen contained in mineral fertilizers, and a 3-year (a total of six seasons) field experiment was carried out to study the environmental risk derived from compost heavy application. Soil samples were analyzed after the third year of rice harvested of the plough layer soil(0-25 cm). It was found that mineral fertilizer and compost may both result in environmental risk after the 3-year successive and heavy application. In contrast to the untreated control (CK), heavy application of mineral fertilizer (CF) easily lead to soil acidification and nitrate accumulation, while soil phosphorus and heavy metals (Zn, Cu, CD and Ni) content increased significantly when manure-based compost carried the same amount of total nitrogen with mineral fertilizer was applied (CP); In addition, heavy application of mineral fertilizer and compost both caused significant decrease of SMBN/TN ratio, SMBC/SOC ratio and bacterial diversity. The results of this study may be conducive to the rational application of compost in the future.

Long-Term Remediate Effect of Three Amendments on Polluted Soil Near Guixi Smelter and Health Risk Assessment
SU Bin-bin, CUI Hong-biao, FAN Heng-liang, MA Kai-qiang, ZHOU Jing, HU You-biao
2017, 33(5):  446-452.  doi:10.11934/j.issn.1673-4831.2017.05.009
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The leachability (toxicity characteristic leaching procedure),availability (CaCl2) and bioaccessibility (simplified bioaccessibility extraction test) of Cu and Cd were evaluated after application of apatite, lime and charcoal for the first year(2010) and fourth year(2013) by chemical extractable methods. Results show that addition of apatite, lime and charcoal increased soil pH and decreased the concentrations of exchangeable acid and aluminum. Moreover, applications of lime and apatite were more effective in reducing the contents of leachable and available Cu and Cd than the charcoal treated soil, but the immobilization effect was reduced over time. Applications of apatite and lime significantly decreased bioaccessibility of Cu by 28.6% and 23.1%, respectively, and bioaccessibility of Cd by 21.7% and 22.8%, respectively, in 2010, but bioaccessibility of Cu and Cd were increased in the 2013 than those in 2010. The health risk coefficient (QH) of Cu and Cd for people were all lower than 1. Nevertheless, it should be noted that QH values for the children were higher than those for adults. Compared to lime and charcoal, apatite was the most effective in decreasing leachability, availability and bioaccessability of Cu and Cd.

Effects of Application of Straw-Derived Biochar on Forms of Heavy Metals in Mining Contaminated Soil
WU Ping-ping, LI Lu-jiu, WANG Jia-jia, LI Min
2017, 33(5):  453-459.  doi:10.11934/j.issn.1673-4831.2017.05.010
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An in-lab incubation experiment was conducted on applying biochar derived from wheat straw as a soil remediation amendment to study effect of the application, relative to rate, on forms of heavy metals in mining contaminated soil. Results show that after 150 days of incubation, biochar in the soil significantly increased soil pH and organic carbon content by 0.96%-2.62% and 9.1%-38.6%, respectively. With increasing biochar application rate, the content of acid-extractable Cu, Zn and Cd in the contaminated soil decreased by 7.0%-16.9%, 6.7%-11.8% and 5.3%-9.6%, respectively, while acid-extractable Pb remained almost unchanged. Biochar reduced the contents of reducible Cd and oxidizable Cu, Zn and Pb. The content of residual Cu, Zn, Cd and Pb increased obviously by 10.6%-46.8%, 5.9%-15.7%, 40.9%-191.9% and 1.5%-2.6%, respectively, in biochar amended treatments. Correlation analysis shows that soil pH values and organic carbon contents were significantly correlated with the contents of acid-extractable and residual heavy metals. In short, biochar can promote transformation of Cu, Zn, Cd and Pb in the contaminated soil from acid-extractable, reducible and oxidizable forms to residual form.

Degradation and Adsorption of 2 Kinds of Strobilurin Fungicides in Soils and Their Effects on Groundwater
GUO Min, WU Wen-zhu, ZHANG Sheng-hu, SONG Ning-hui, SHI Li-li
2017, 33(5):  460-465.  doi:10.11934/j.issn.1673-4831.2017.05.011
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Adsorption and degradation of two kinds of strobilurin fungicides in red soil from Jiangxi, black soil from Northeast China and paddy soil from the Taihu region were systematically studied through an in-lab simulation experiment, and their impacts on groundwater analyzed with GUS index. Results show that the two fungicides vary quite sharply in degradation rates, because they have different functional groups. Under room temperature and aerobic conditions, Picoxystrobin is fairly hard to degrade in the red soil and black soil, and hard to degrade pesticides in the paddy soil, while trifloxystrobin degrades easily in all the 3 types of soils. But under room temperature and anaerobic waterlogging conditions, picoxystrobin is moderate in degradability, while trifloxystrobin is high in all the three types of soils. Obviously, anaerobic waterlogging conditions facilitate degradation of the pesticides and anaerobia is an important factor affecting the degradation of strobilurin fungicides. Picoxystrobin is well adsorbed in the 3 types of soils, which fits the Freundlich equation well, with Koc being 811, 613 and 926 in the red soil, black soil and paddy soil, respectively, indicating that the soils are quite low in adsorption capability. Content of organic matter in the soil is the major factor affecting the soil's capacity of adsorbing picoxystrobin. HPLC reveals that trifloxystrobin is higher than 20 000 in Koc indicating that trifloxystrobin belongs to the category of chemicals easily adsorbed. In all the three types of soils picoxystrobin varies between 1.8 and 2.8 in GUS index, indicating that the pesticide is leachable and poses a potential risk of polluting the groundwater, while trifloxystrobin is lower than 1.8 in GUS index, indicating that the chemical poses little pollution risk to the groundwater.

Isolation, Identification and Degradation Characters of a Crude Oil-Degrading Strain ODB01
LAN Hui, WANG Chong, YANG Hui, PAN Hu, LU Xiang-yang, TIAN Yun
2017, 33(5):  466-473.  doi:10.11934/j.issn.1673-4831.2017.05.012
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A crude oil-degrading bacteria ODB01 was isolated from crude oil-contaminated soil of Changqing Oilfield, capable of utilizing crude-oil as the sole source of carbon for growth, and identified as Enterobacter sp., based on physiological characteristics and the analysis of 16S rDNA gene sequence. The optimization of crude oil degradation condition was carried out by response surface methodology (Box-Behnken), the results are as follows:pH, 8.91; NaCl concentration, 1.19%; oil-bacteria liquid proportion, 1:4.12; temperature, 36.78℃, and degradation rate reaches to 34.6% under the optimum condition; In addition, adding to 0.05% Tween 80 or 0.05% Triton X-100, the degradation rates of crude oil reached to 42.5% and 46.1%, respectively. These results indicated that the bacterium ODB01 had the capability of biodegrading crude oil and it maybe developed as a remediation agent.

Estimation of Parameters in Daily Total Solar Radiation Model for Lake Songhua Region
QIU Min, CHEN Ming-yuan, LUO Lian-cong, LI Hui-yun, DAI Shu-jun
2017, 33(5):  474-480.  doi:10.11934/j.issn.1673-4831.2017.05.013
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Lack of daily total solar radiation (DTSR) data for the Lake Songhua Region leaves a blank in the research on DTSR models for the region. Consequently, an attempt to estimate parameters in the DTSR model for the region based on hours of sunshine was taken. On the basis of generalization of methods and equations used currently for calculate of DTSR based on hours of sunshine, the 1961-2000 data of DTSR and daily number of sunshine hours recorded at Changchun and Yanji Stations were cited for calculation of parameters, using the generalized pattern search algorithm. The calculated parameters were then validated with the 2001-2012 data of DTSR and number of sunshine hours from the same cities. Verification demonstrates that the DTSR model performed well with fitting values being quite approximate to the observed values. The fitting was 0.93 and 0.94 in Nash-Sutcliffe Efficiency (NSE) coefficient and 22.39 and 19.53 W·m-2 in Root Mean Square Error (RMSE), respectively, at Changchun and Yanji. On such a basis, two empirical parameters, as and bs for DTSR were figured out to be 0.164 34 and 0.591 02, respectively by regression. In view of the geographical location of the Lake Songhua Region, the mean of as and bs could be used as the empirical parameter of calculation of DTSR of the region. Analysis of the DTSR and hours of sunshine in the Lake Songhua Region reveals that DTSR is positively related to hours of sunshine at both multi-year and annual scales, DTSR in the Lake Songhua Region has been on a declining trend in the past 50 years and the change was lower in 1982-2010 than in other years. The index of hours of sunshine followed a similar trend.