In situ studies on the distribution patterns and dynamics of microcystins in a biomanipulation fish--bighead carp (Aristichthys nobilis)

The distribution and dynamics of microcystins in various organs of the phytoplanktivorous bighead carp were studied monthly in Lake Taihu, which is dominated by toxic cyanobacteria. There was a good agreement between LC-MS and HPLC-UV determinations. Average recoveries of spiked fish samples were 63% for MC-RR and 71% for MC-LR. The highest MC contents in intestine, liver, kidney and spleen were 85.67, 2.83, 1.70 and 1.57 microg g-1 DW, respectively. MCs were much higher in mid-gut walls (1.22 microg g-1 DW) than in hind- and fore-gut walls (0.31 and 0.18 microg g-1 DW, respectively), suggesting the importance of mid-gut wall as major site for MC absorption. A cysteine conjugate of MC-LR was detected frequently in kidney. Among the muscle samples analyzed, 25% were above the provisional tolerable daily intake level by WHO. Bighead is strongly resistant to microcystins and can be used as biomanipulation fish to counteract cyanotoxin contamination in eutrophic waters.     

直线、圆曲线上斜交涵洞长度精确计算通用程序设计

将直线上斜交涵长计算归化为圆曲线上斜交涵长计算的一种特例,本文对其作了理论上的推导证明.并编写了计算程序.通过算例验证:计算程序的可靠有效的.     

乡村生活空间网络结构特征与优化——以江汉平原典型乡建片区为例

乡村生活空间网络是一定地域乡村居民依托社区节点，通过日常生活实践彼此联系而形成的社会空间系统，探究其空间结构与优化策略对认识乡村生活空间内涵、重塑乡村日常生活秩序具有重要意义。以江汉平原典型乡建片区培育的9个节点社区为研究对象，基于乡村生活空间网络三元系统，构建社区生活质量指标体系，运用改进引力模型与社会网络分析法描述网络结构总体与节点特征，提出乡村生活空间网络优化策略。研究表明：区域乡村生活空间网络结构处于发育阶段，网络兼具整体松散与局部集聚特征，社区间联系正在加强；乡村生活空间网络节点质量有待提升，网络呈现层次清晰的3级节点体系，核心节点虽具有无法替代的网络地位但本身质量不高，次级节点的结构具有相似性需要择优培育，边缘节点需要丰富网络内外联系；基于此，必须构建“1心、8点、1轴、3区”的乡村生活空间网络结构。为评估并识别区域网络节点特征，预测并构建区域网络化发展体系提供了新思路，为平原农区的乡建片区提供了网络化发展的新模式。     

Evaluation of an electrolysis apparatus for inactivating antineoplastics in clinical wastewater

We recently reported a system for inactivating antineoplastics in which sodium hypochlorite is supplied by the electrolysis of sodium chloride solution. In this study, we designed an electrolysis apparatus for inactivating the cytotoxicity of antineoplastics in clinical wastewater using the system. The apparatus consists of an electrolysis cell with platinum-iridium electrodes, a pool tank, a circulating system for wastewater, a safety system for explosive gas and overflow, and an exhaust duct. The free chlorine concentration increased linearly up to 6500 mg l(-1), and pH also increased to 9.0-10.0 within 2h, when 0.9% sodium chloride solution was electrolyzed. We examined its efficacy with model and clinical wastewaters. The reciprocal of dilution factor for disappearance of cytotoxicity using Molt-4 cells was compared before and after electrolysis. In the model wastewater, that was 9.10 x 10(4) before electrolysis, and 3.56 x 10(2) after 2h of electrolysis. In the clinical wastewater (n=26), that was 6.90 x 10(3)-1.02 x 10(6) before electrolysis, and 1.08 x 10(2)-1.45 x 10(4) after 2h of electrolysis. Poisonous and explosive gases released by the electrolysis were measured; however, they were found to be negligible in terms of safety. The environmental load was evaluated by carbon dioxide generation as an index and it was found that the carbon dioxide generated by the electrolysis method was 1/70 lower than that by the dilution method with tap water. Moreover, the cost of the electrolysis method was 1/170 lower than that of the dilution method. This method was found to be both effective and economically valuable.     

周庄古镇旅游解说系统实证研究

旅游解说作为一种关键而有效的管理手段，是旅游景区的使用功能、教育功能、服务功能得以发挥的必要基础。以周庄古镇旅游解说系统为研究对象，采用问卷调查和直接访谈相结合的方法，分析出目前影响周庄古镇旅游解说功能发挥的主要因素是动态解说系统不完善、空间解说线路不科学，并提出优化措施。     

紫外辐射下的生物降解及微生物群落的变化

分别采用一体式循环床紫外光/生物膜反应器（PCBBR）和气升式内循环的紫外光/生物膜反应器（ILPBR）,用于苯酚、2,4,6-三氯酚（TCP）和抗生素药物磺胺甲恶唑（SMX）的降解.结果表明,苯酚、TCP和SMX在紫外光解与生物降解的共同作用下,其去除速率分别达到0.65、0.11和0.17 mg.（L.min）–1...     

应用后续确定性问题校正条件价值评估——以福建省鼓山风景名胜区非使用价值评估为例

条件价值(CV)法是评估环境与资源价值的重要手段,后续确定性问题可有效便捷地提高CV结果的有效性。应用10刻度量化表式后续确定性问题对鼓山风景名胜区非使用价值CV评估结果进行校正。问卷采用双边界二分式,面对面调查获得518份有效调查问卷。结果显示:具有正支付意愿的受访者,其付费加入"鼓山保护协会"的确定度呈正态分布,确定度的平均值为6.72;确定度与受访者的收入、受访者对鼓山的熟悉程度呈显著正相关;受访者对起始投标值敏感。当确定度门槛值取7或8时,正支付率从51.5%分别下降至27.8%或23.3%,而平均支付意愿分别从33.24元下降至19.74元或16.36元,采用后续确定性问题校正后CV结果下降了一半左右。     

Variation of cyanobacteria with different environmental conditions in Nansi Lake, China

Nansi Lake is located on the east line of the South-to-North Water Diversion Project in China. A comprehensive study was carried out to investigate the spatial and temporal distribution of cyanobacteria in the lake from June 2008 to May 2011 based on monthly sample monitoring from five stations. The effect of environmental factors on cyanobacterial abundance was also evaluated. The cyanobacterial community contained 15 genera and 23 species. The cyanobacterial abundance of each monitoring station ranged from 0 to 1.53× 10⁷ cells/L with an average of 1.45×10⁶ cells/L, which accounted for 11.66% of the total phytoplankton abundance. The dominant species of cyanobacteria were Pseudanabaena (32.94%) and Merismopedia (19.85%), not the bloom-forming algae such as Microcystis and Anabaena. In addition, the cyanobacterial community structure and water quality variables changed substantially over the survey period. Redundancy analysis (RDA) suggested that temperature and phosphorus were important environmental factors that affected cyanobacteria. Temperature was the most important factor affecting cyanobacterial abundance. The effect of phosphorus on cyanobacterial abundance was more notable in warm periods than in periods with low temperature.     

广东东江流域多氯萘的大气沉降研究

为考察多氯萘(PCNs)通过大气沉降作用对东江流域的影响,利用通用型大气沉降采样器,在东江流域广东省境内代表性地段布设11个采样点,于2010年冬季(1、2月)和夏季(7、8月)分别采集和分析了沉降样品中PCNs的通量及组成.结果表明,东江流域总PCNs日均沉降通量为828 pg.(m2.d)-1,对应毒性当量(TEQ)为0.14 pg.(m2.d)-1,由此估算东江流域广东境内PCNs年沉降总量为8.5 kg,相应TEQ年沉降总量为1.3 g.地域上,广州和东莞地区沉降通量明显高于惠州,同时城镇采样点的沉降通量显著高于农村;季节上,各采样点总体呈现夏季高于冬季的特点;组成上,三氯萘(tri-CNs)是主要的污染物,占总量的50%以上,但广州、东莞的5～8氯萘含量比惠州高.来源分析表明,东江流域PCNs的大气沉降可能受燃烧源与非燃烧源的共同影响;东莞大气沉降中PCNs多来自燃烧源,广州点大气沉降的PCNs以非燃烧源为主.     

塔克拉玛干沙尘暴源区空气微生物群落的代谢特征

采用BIOLOG生态微平板(BIOLOG EcoPlateTM)技术,对采集自塔克拉玛干沙漠南北缘5个地区的空气样品进行研究,目的是了解空气微生物群落碳代谢功能的特点与差异.结果表明,5个地区空气样品的平均吸光度(AWCD)在培养10 d没有达到饱和且差异显著,AWCD值最高的为莎车县,和田县最低,分别为0.24和0.1;碳源利用水平表明这5个地区空气微生物对聚合物类碳源利用率最高,其次是碳水化合物、氨基酸类、羧酸类碳源,而酚类和胺类最低;主成分分析(PCA)发现有20种碳源与PC1显著相关,12种与PC2显著相关,并且这5个地区也被分为两类,和田和皮山聚为一类,乌恰、莎车和轮台聚为一类;典范对应分析(CCA)和相关分析表明一些非生物因素对空气微生物群落碳代谢强度和单一碳源的利用能力具有不同程度的影响,如风速、海拔、湿度等;进一步的研究也表明非生物因素对空气微生物群落利用的能力影响显著,其中β-甲基D-葡萄糖苷、D-半乳糖醛酸和腐胺的光密度值与纬度显著正相关(P<0.05),2-羟苯甲酸和α-D-乳糖与风速显著正相关(P<0.05),D-葡萄胺酸与气压显著正相关(P<0.05)且与海拔为显著负相关(P<0.05).综上可知,塔克拉玛干沙尘暴源区周边地区空气微生物群落碳代谢能力较低,呈现区域性特征,非生物因素显著影响空气微生物群落碳代谢强度及微生物群落对31种单一碳源的利用.