经济发达地区农村居民点潜力释放空间选择

农村居民点潜力释放是城乡统筹发展的重要课题,潜力释放的空间优选则是城乡空间格局统筹的基础。基于农村居民点适宜性评价,构建经济发展潜力、居住便利性和生态环境耦合而成的指标体系,评估研究区域以行政村为单元的居住适宜性空间序列,形成适宜性分区,并根据农村居民点潜力的空间分布,统筹考虑城镇发展和耕地保护的要求,建立农村居民点潜力释放优先序的选择矩阵,形成分时序、分空间的潜力释放方案。研究结果表明：陆渡镇、浏河镇农村居民点潜力释放最优的区域主要位于沿江的东海等4个行政村,次优先潜力释放的区域包括陆渡等3个行政村,第三优先潜力释放的区域包括斑竹等10个行政村,第四优先潜力释放区域包括天浜等6个行政村,最后释放潜力的区域主要是陆渡镇和浏河镇建成区内的农村居民点。最后,提出了不同区域潜力释放模式的建议。
     

Biodegradation of nicotine by a novel Strain Shinella sp. HZN1 isolated from activated sludge

The nicotine-degrading bacterium HZN1 was isolated from activated sludge and identified as Shinella sp. based on its physiological characteristics and analysis of 16S rDNA gene. Strain HZN1 is capable of using nicotine as the sole carbon source in the mineral salts medium. The optimum temperature and pH for strain HZN1 growth and nicotine degradation were 30°C and 7.0, respectively. It could degrade approximately 100 % of 0.5 g L(-1) of nicotine within 9 h. Three intermediate metabolites were produced by the strain HZN1 and identified as cotinine, myosmine and nicotyrine using gas chromatography-mass spectrometry. This is the first report of nicotine-degrading strain from the genus of Shinella. The results showed that strain HZN1 could be potentially employed in bioremediation of nicotine. Our findings would provide a new insight into the biodegradation of nicotine.     

在线喷水加湿控制道路扬尘排放的研究

利用实验室模拟装置,模拟道路扬尘在自由下落过程中的飞扬溢出情况,并采用气水两相流雾化喷头,通过在线喷水加湿的方法以控制道路扬尘的排放量,探讨了喷头的空气压力和加水流量对道路扬尘排放的影响,并考察了最佳加湿条件(最佳的空气压力和加水流量)下道路扬尘中可吸入颗粒物的排放控制效果.结果表明,当气水两相流雾化喷头的空气压力为0...     

Characterization of ACC deaminase-producing endophytic bacteria isolated from copper-tolerant plants and their potential in promoting the growth and copper accumulation of Brassica napus

One hundred Cu-resistant-endophytic bacteria were isolated from Cu-tolerant plants grown on Cu mine wasteland, of which, eight Cu-resistant and 1-aminocyclopropane-1-carboxylate (ACC) deaminase-producing endophytic bacteria were obtained based on the ACC deaminase activity of the bacteria and characterized with respect to metal resistance, production of ACC deaminase, indole-3-acetic acid (IAA) as well as siderophores and mineral phosphate solubilization. Ralstonia sp. J1-22-2, Pantoea agglomerans Jp3-3, and Pseudomonas thivervalensis Y1-3-9 with higher ACC deaminase activity (ranging from 213 to 370 μM α-ketobutyrate mg(-1)h(-1)) were evaluated for promoting plant growth and Cu uptake of rape grown in quartz sand containing 0, 2.5, and 5 mg kg(-1) of Cu in pot experiments. The eight bacteria were found to exhibit different multiple heavy metal resistance characteristics, to show different levels of ACC deaminase activity and to produce indole acetic acid. Seven bacteria produced siderophores and solubilized inorganic phosphate. Pot experiments showed that inoculation with the strains (J1-22-2, Jp3-3, and Y1-3-9) was found to increase the biomass of rape. Increases in above-ground tissue Cu contents of rape cultivated in 2.5 and 5 mg kg(-1) of Cu-contaminated substrates varied from 9% to 31% and from 3 to 4-fold respectively in inoculated-rape plants compared to the uninoculated control. The maximum Cu uptake of rape was observed after inoculation with P. agglomerans Jp3-3. The results show that metal-resistant and plant growth promoting endophytic bacteria play an important role in plant growth and Cu uptake which may provide a new endophytic bacterial-assisted phytoremediation of Cu-contaminated environment.     

长江水体溶解有机质与金属离子作用污染分析

将万州区牌楼段的长江水与金属离子混合,通过测定荧光光谱得出,在金属离子质量浓度较低(1.0×10-7 mg/mL)时,长江水中的腐殖质与金属离子发生螯合作用而使荧光强度降低,而在更高浓度时,则由于吸附/解吸作用而使荧光强度增强.三维荧光谱图的测定结果表明,金属离子浓度的大小决定了其与腐殖质的基团反应类型.实验结果表明,...     

大宝山矿区水体和沉积物中重金属的污染评价

分别于丰水期和枯水期对广东省大宝山矿区铁龙拦泥坝至凉桥河段水体中溶解态的重金属进行了调查,应用EPA推荐的健康风险评价模型发现,水体中非致癌物通过饮水途径所导致平均个人年风险排列顺序是Cu〉Pb〉Zn,最大值的平均个人年风险在丰水期和枯水期的平均值分别是2.14×10-7 a-1和4.13×10-7 a-1,小于国际防辐射委员会（ICRP）推荐的最大可接受平均个人年风险5.0×10-5a-1。致癌物Cd的平均个人年风险在丰水期和枯水期的平均值分别是3.52×10-4 a-1和4.53×10-4 a-1,大于ICRP推荐的最大可接受值,同时也大于非致癌物3～4个数量级。另外,通过对枯水期沉积物的重金属总量分析,发现凉桥槽对坑支流受水体pH的影响,导致其沉积物重金属的浓度最高。根据Long和Macdonald利用生物效应数据库法建立的沉积物质量基准,发现除冷水泾外,其他采样点的平均效应中值指数（mERMQ）值都大于1.5,可见沉积物中的重金属会对当地底栖生物产生毒害作用。     

Correction methods for organic carbon artifacts when using quartz-fiber filters in large particulate matter monitoring networks: the regression method and other options

Sampling and handling artifacts can bias filter-based measurements of particulate organic carbon (OC). Several measurement-based methods for OC artifact reduction and/or estimation are currently used in research-grade field studies. OC frequently is not artifact-corrected in large routine sampling networks (e.g., U.S. Environmental Protection Agency (EPA)'s Chemical Speciation Network). In some cases, the OC artifact has been corrected using a regression method (RM) for artifact estimation. In this method, the gamma-intercept of the regression of the OC concentration on the fine particle (PM2.5) mass concentration is taken to be an estimate of the average OC sampling artifact (net of positive and negative artifacts). This paper discusses options for artifact correction in large routine sampling networks. Specifically, the goals are to (1) articulate the assumptions and limitations inherent to the RM, (2) describe other artifact correction approaches, and (3) suggest a cost-effective method for artifact correction in large monitoring networks. The RM assumes a linear relationship between measured OC and PM mass: a constant slope (OC mass fraction) and a constant intercept (RM artifact estimate). These assumptions are not always valid. Additionally, outliers and other individual data points can have a large influence on the RM artifact estimates. The RM yields results within the range of measurement-based methods for some datasets and not for others. Given that the adsorption of organic gases increases with atmospheric concentrations of organics, subtraction of an average artifact from all samples (e.g., across multiple sites) will underestimate OC for lower-concentration samples (e.g., clean sites) and overestimate OC for higher-concentration samples (e.g., polluted sites). For relatively accurate, simple, and cost-effective artifact OC estimation in large networks, the authors suggest backup filter sampling on at least 10% of sampling days at all sites with artifact correction on a sample-by-sample basis as described herein.     

Evaluation of photolysis and hydrolysis of pyraclostrobin in aqueous solutions and its degradation products in paddy water

This study evaluated the hydrolysis and photolysis kinetics of pyraclostrobin in an aqueous solution using ultra-high-performance liquid chromatography–photodiode array detection and identified the resulting metabolites of pyraclostrobin by hydrolysis and photolysis in paddy water using high-resolution mass spectrometry coupled with liquid chromatography. The effect of solution pH, metal ions and surfactants on the hydrolysis of pyraclostrobin was explored. The hydrolysis half-lives of pyraclostrobin were 23.1–115.5?days and were stable in buffer solution at pH 5.0. The degradation rate of pyraclostrobin in an aqueous solution under sunlight was slower than that under UV photolysis reaction. The half-lives of pyraclostrobin in a buffer solution at pH 5.0, 7.0, 9.0 and in paddy water were less than 12?h under the two light irradiation types. The metabolites of the two processes were identified and compared to further understand the mechanisms underlying hydrolysis and photolysis of pyraclostrobin in natural water. The extracted ions obtained from paddy water were automatically annotated by Compound Discoverer software with manual confirmation of their fragments. Two metabolites were detected and identified in the pyraclostrobin hydrolysis, whereas three metabolites were detected and identified in the photolysis in paddy water.     

Distribution,source, and environmental risk assessment of phthalate esters (PAEs) in water,suspended particulate matter,and sediment of a typical Yangtze River Delta City,China

Phthalates (PAEs) in drinking water sources such as the Yangtze River in developing countries had aroused widespread concern. Here, the water, suspended particulate matter (SPM), and sediment samples were collected from 15 sites in wet and dry seasons in Zhenjiang, for the determination of six PAEs (DMP, DEP, DIBP, DBP, DEHP, and DOP) using the solid-phase extraction (SPE) or ultrasonic extraction coupled with gas chromatography-mass spectrometry (GC-MS). The total concentrations of six PAEs (Σ₆PAEs) spanned a range of 2.65–39.31 μg L^?1 in water, 1.97–34.10 μg g^?1 in SPM, and 0.93–34.70 μg g^?1 in sediment. The partition coefficients (K_d1) of PAEs in water and SPM phase ranged from 0.004 to 3.36 L g^?1 in the wet season and from 0.12 to 2.84 L g^?1 in the dry season. K_d2 of PAEs in water and sediment phase was 0.001–9.75 L g^?1 in the wet season and 0.006–8.05 L g^?1 in the dry season. The dominant PAEs were DIBP, DBP, and DEHP in water and SPM, DIBP, DEHP, and DOP in sediment. The concentration of DBP in water exceeded the China Surface Water Standard. The discharge of domestic sewage and industrial wastewater might be the main potential sources of PAEs. The risk quotient (RQ) method used for the risk assessment revealed that DBP (0.01 < RQ < 1) posed a medium risk, while DIBP and DEHP (RQ > 1) posed a high environmental risk in water, DIBP (RQ > 1) also showed a high risk in sediment.

     

Study of the adsorption of endocrine disruptor compounds on typical filter materials using a quartz crystal microbalance

Environmental Science and Pollution Research - Drinking water containing environmental endocrine disruptor compounds (EDCs) endangers human health, and researching the purification process of...