水动力条件对藻类生理生态学影响的研究进展

湖泊和水库等水体富营养化通常会引起藻类水华暴发. 已有较多研究总结了光照、温度、营养盐等环境因素对藻类水华发生的影响方面的进展,但缺乏对水动力因素影响藻类生理生态学乃至水华发生等方面的研究总结. 本文通过梳理水动力条件对藻类生长、种群结构的影响及其作用机制,以及临界流速和人工混合对藻类的影响等方面的研究发现:在藻类生理学方面,水动力条件主要影响藻类的生长、细胞形态、营养盐吸收、光合作用活性和酶活性的变化;在藻类生态学方面,不同藻类对应的临界流速有所差异,水动力条件的变化会导致优势种之间的转变;人工混合使局部水体藻细胞密度降低进而改善水质. 对今后的研究热点进行展望:后续仍需进一步研究水动力条件对藻类生理的影响,不仅是酶活性和相关物质的吸收,还应包含胶被、产毒特性和基因序列等方面;应用于实际湖库的临界流速、水体扰动方式、扰动时间、扰动频率和最佳深度的探究,旨在推进藻类水华控制、保障水质安全等方面的相关研究.      

基于模糊神经网络的广东省台风灾害损失预测

台风灾害是我国最严重的海洋灾害之一,研究提高台风灾害损失预测的准确度对防灾减灾具有重要意义。针对目前机器学习算法在处理小样本数据时预测精度不高的问题,提出结合模糊数学的BP神经网络算法对台风灾害损失进行预测。本文选用广东省2005—2016年记录较为完善的25个台风样本数据进行实验,首先利用信息扩散技术对初始数据进行正...     

胶原纤维固化黑荆树单宁吸附Cr(VI)的研究

研究了胶原纤维固化黑荆树单宁对Cr(VI)的吸附.采用不同温度、pH值等条件进行吸附研究,并进一步探讨了固化黑荆树单宁的吸附动力学和吸附柱动力学及其吸附机理.结果表明,该材料对Cr(VI)的吸附平衡符合Freundlich方程,温度对吸附平衡的影响不明显;吸附动力学可用拟二级速度方程来描述,该材料同时具有良好的柱动力学特性;Cr(VI)的吸附过程可能存在3个反应,即Cr(VI)与吸附剂之间发生氧化还原反应生成Cr(III),Cr(III)和-COOH之间发生离子交换反应,以及Cr(III)与单宁的邻位羟基发生螯合.图8表2参10     

微生物转化污泥制备苏云金杆菌生物杀虫剂

以城市污水处理厂的污泥为原料,探索了微生物转化污泥制备苏云金杆菌生物杀虫剂的可行性,并与常规培养基的发酵进程进行了对比.主要考察了苏云金杆菌的代谢特征、菌体形态与杀虫晶体蛋白产量.研究表明:无需任何预处理工序,污泥所含营养成分即可基本满足苏云金杆菌生长需求,且增殖较快,24h即可达活菌数与活芽孢数的最大值:9.48×10⁸CFU·mL^-1和8.51×10⁸CFU·mL^-1,比常规培养基提前12h,数量分别提高17%和21%;36h SEM表征显示,污泥中晶体与芽孢大部分游离,且晶体较大,呈规则的菱形,而常规培养基中苏云金杆菌的代谢进程相对滞后,且晶体较小;至发酵终点污泥中杀虫晶体蛋白含量为2.80 mg·mL^-1,亦略高于常规培养基.采用污泥发酵制备苏云金杆菌生物杀虫剂大大降低了生产成本,且发酵性能优良,为污泥处置开辟了崭新途径.     

Ecotoxicological and microbiological characterization of soils from heavy-metal- and hydrocarbon-contaminated sites

The aims of this study were to characterize soils from industrial sites by combining physicochemical, microbiological, and ecotoxicological parameters and to assess the suitability of these assays for evaluation of contaminated sites and ecological risk assessment. The soil samples were taken from long-term contaminated sites containing high amounts of heavy metals (sites 1 and 2) or petroleum hydrocarbons (site 3) located in the upper Silesia Industrial Region in southern Poland. Due to soil heterogeneity, large differences between all investigated parameters were measured. Microbiological properties revealed the presence of high numbers of viable hetrotrophic microorganisms. Soil enzyme activities were considerably reduced or could not be detected in contaminated soils. Activities involved in N turnover (N mineralization and nitrification) were significantly (P?<?0.05) higher in samples from the metal-contaminated sites than in samples from the hydrocarbon-contaminated site, whereas the opposite was observed for phosphatase activity. The Microtox test system appeared to be the most appropriate to detect toxicity and significant differences in toxicity between the three sites. The Ostracodtoxkit test was the most appropriate test system to detect toxicity in the hydrocarbon-contaminated soil samples. Correlation analysis between principal components (obtained from factor analysis) determined for physicochemical, microbiological, and ecotoxicological soil properties demonstrated the impact of total and water-extractable contents of heavy metals on toxicity.     

两种土地利用方式下土壤重金属污染特征与评价

为研究安徽铜陵某矿区耕地和人工林地两种土地利用方式下土壤重金属污染特征，应用Tomlinson污染负荷指数法和生物富集系数评价研究区土壤重金属Cd、Cu污染水平和植物重金属富集水平。结果表明：研究区耕地土壤Cd、Cu全量2.34和161.25 mg/kg，均高于林地Cd、Cu全量1.26和80.15 mg/kg，二者均超农用地土壤污染风险筛选值（GB 15618-2018，pH≤5.5）和铜陵市重金属背景值，耕地和林地污染水平分别为中度污染和轻微污染。耕地糙米Cd（0.95 mg/kg）超标严重，黄山栾树地上部Cd、Cu富集系数均低于水稻地上部。综上，黄山栾树人工林地Cd、Cu污染轻于耕地，退耕还林是研究区更佳的土地利用选择。     

Prenatal diagnosis of Crigler–Najjar syndrome type I by single-strand conformation polymorphism (SSCP)

Crigler–Najjar syndrome type I (CN-I) is a rare and severe inherited disorder of bilirubin metabolism, caused by the total deficiency of bilirubin-UDP-glucuronosyltransferase (UGT) activity. Enzymatic diagnosis cannot be performed in chorionic villi or amniocytes as UGT is not active in these tissues. The cloning of the UGT1 gene and the identification of disease-causing mutations have led to the possibility of performing DNA-based diagnosis. Here we report DNA-based prenatal diagnosis of CN-I in two Tunisian families in whom CN-I patients were diagnosed. As we had previously shown that CN-I was, in Tunisia, associated with homozygosity for the Q357R mutation within the UGT1 gene, we were able to detect this mutation in both families and to show that it was easily recognized by single-strand conformation polymorphism (SSCP) analysis. In both cases, SSCP analysis of fetal DNA showed that the fetus was heterozygous for the Q357R mutation. In one family, the pregnancy was carried to term and a healthy baby was born, whereas, in the other family, the pregnancy is still continuing. Thus the prenatal diagnosis of CN-I is possible, provided disease-causing mutations have been identified. SSCP analysis of DNA prepared either from amniocytes or from chorionic villi is a simple, reliable and fast method for prenatal diagnosis. Copyright © 2002 John Wiley & Sons, Ltd.     

The application of bioassays as indicators of petroleum-contaminated soil remediation

Bioremediation has proven successful in numerous applications to petroleum contaminated soils. However, questions remain as to the efficiency of bioremediation in lowering long-term soil toxicity. In the present study, the bioassays Spirotox, Microtox, Ostracodtoxkit F, umu-test with S-9 activation, and plant assays were applied, and compared to evaluate bioremediation processes in heavily petroleum contaminated soils. Six higher plant species (Secale cereale L., Lactuca sativa L., Zea mays L., Lepidium sativum L., Triticum vulgare L., Brassica oleracea L.) were used for bioassay tests based on seed germination and root elongation. The ecotoxicological analyses were made in DMSO/H2O and DCM/DMSO soil extracts. Soils were tested from two biopiles at the Czechowice oil refinery, Poland, that have been subjected to different bioremediation applications. In biopile 1 the active or engineered bioremediation process lasted four years, while biopile 2 was treated passively or non-engineered for eight months. The test species demonstrated varying sensitivity to soils from both biopiles. The effects on test organisms exposed to biopile 2 soils were several times higher compared to those in biopile 1 soils, which correlated with the soil contaminants concentration. Soil hydrocarbon concentrations indeed decreased an average of 81% in biopile 1, whereas in biopile 2 TPH/TPOC concentrations only decreased by 30% after eight months of bioremediation. The bioassays were presented to be sensitive indicators of soil quality and can be used to evaluate the quality of bioremediated soil. The study encourages the need to combine the bioassays with chemical monitoring for evaluation of the bioremediation effectiveness and assessing of the contaminated/remediated soils.     

全民所有自然资源资产负债表编制的思路框架

编制全民所有自然资源资产负债表是对我国自然资源资产负债表编制理论与方法体系的完善,也是新时期促进生态文明建设的重要举措。在理清全民所有自然资源资产负债表与自然资源资产负债表的区别和联系基础上,提出了符合用途管制和产权设置要求的自然资源资产确认方法以及自然资源保护和利用负债确认方法,初步构建了“主表+分表+基础表”的报表体系,设计出全民所有自然资源资产负债总体情况表、当期实际供应表和当期实际供应流向表三张主表。通过报表编制,反映全民所有自然资源资产家底以及占有、使用、收益、处分等各项所有权权利实现情况,以期为维护国家所有者权益、促进自然资源保护和合理利用、支撑国民经济发展提供基础信息支撑。