泾河流域现代洪水泥痕沉积学特征研究

文中通过对泾河流域深入调查研究,在泾河干流和支流河槽发现了三处印迹明显的现代洪水泥痕。通过对洪痕泥沙粒度和磁化率特征分析表明泾河流域的洪痕的磁化率特征与黄土L1相似。粒度组成以粉沙为主,粘粒、沙粒含量较低。其沉积性质为粉质亚粘土,与流域内的黄土、古土壤性质相近。泾河洪水发生时泥沙含量高,在悬移搬运中流速大,故沉积较快,分选性较差。该研究可对于泾河流域的防洪减灾、水利水电工程设计和水土流失防治具有重要科学意义。     

赤泥和有机肥对镉、铅在水稻中吸收分布的影响

通过大田正交试验,研究添加赤泥和有机肥对Cd、Pb在土壤-水稻系统中分布规律的影响。结果表明,添加赤泥或有机肥后,水稻根际土壤pH值升高0.36~1.90个单位,根际土壤中Cd、Pb含量分别降低2.73%~26.25%和7.15%~34.26%,糙米中Cd和Pb含量分别降低23.24%~55.90%和11.76%~29.41%,其中单施赤泥效果最好,其次是配施,单施有机肥最差。添加赤泥和有机肥后,水稻各器官中Cd和Pb含量显著降低,不同生育期Cd和Pb的贡献率明显改变,且添加量及施肥方式(单施、配施)也有显著影响。与CK相比,降Cd效果最好的是单施赤泥4 000 kg·hm~(-2),降幅为55.90%;降Pb效果最好的是赤泥(4 000 kg·hm~(-2))与有机肥(1 000 kg·hm~(-2))配施,降幅为29.41%。由于土壤中Cd(超标65倍)、Pb(超标7倍)污染程度较高,糙米中Cd、Pb含量仍超过食品污染物限量(GB 2762—2012)。因此,在重金属污染程度较高的稻田,仅通过添加土壤调理剂不能达到安全生产的目的。     

Effect of dietary cholesterol levels on growth performance,body composition and gene expression of juvenile mud crab Scylla paramamosain

A 56‐day feeding trial was conducted to investigate the effect of dietary cholesterol (CHOL) levels on growth performance, body composition and gene expression of juvenile mud crab (Scylla paramamosain). Four isonitrogenous and isoenergetic diets were formulated with 0.4%, 0.8%, 1.2% and 1.6% CHOL supplemented, and the final dietary CHOL concentrations were 0.72%, 1.11%, 1.49% and 1.83% respectively. Each dietary treatment was performed with three replicates (28 crabs per replicate, initial body weight 0.04 g). At the termination of the experiment, although the survival had no statistic difference in all treatments, the mud crabs fed the lowest CHOL diet had the lowest survival rate. The weight gain (WG) of mud crab significantly increased with dietary CHOL level up to 1.11% and then significantly decreased with dietary CHOL level further increased. The total‐cholesterol (T‐CHOL) content in whole body had an increasing trend with the dietary CHOL level increased. Besides, dietary CHOL supplement generally increased the hepatic superoxide dismutase (SOD) activity, and the mud crabs fed diets CHOL1.11 and CHOL1.49 showed significantly higher value than those fed other diets. The hepatic aspartate aminotransferase (AST) activity decreased slightly with dietary CHOL level up to 1.11% and then significantly increased with CHOL level further increased. The mRNA expression of ecdysone receptor (EcR) gene in the eyestalk obviously increased with dietary CHOL level up to 1.11% and then significantly decreased with dietary CHOL further increased. These results suggested that about 1.11% dietary CHOL seem fulfil to maintain good growth performance and healthy condition for juvenile S. paramamosain.     

泥沙比例对不同规格菲律宾蛤仔幼贝潜沙行为的影响

为探明不同泥沙比例的底质对不同规格菲律宾蛤仔Ruditapes philippinarum潜沙的影响,在水温13~15℃的室内实验室条件下,研究了4种规格(壳长为13、17、23、25 mm)的蛤仔幼贝在5种泥沙比例的底质(泥沙比为全沙、3∶7、1∶1、7∶3、全泥)中的潜沙情况。结果表明:4种规格蛤仔在5种底质中的48h潜沙率以全沙组最高,其他含泥组均比全沙组明显降低(P0.05),且含泥组间无显著性差异(P0.05);底质相同时,规格越小蛤仔的潜沙速度越快,平均48 h潜沙率越高;方差分析表明,蛤仔规格、底质及两者的交互作用均对蛤仔的潜沙率有显著影响(P0.05);底质中总有机碳含量与48 h潜沙率呈极显著直线负相关(P0.01),说明底质的粒径和化学成分共同影响蛤仔的潜沙速度。研究表明,滩涂养殖时选择10~15 mm蛤仔苗种,投放在沙比例较大的海区将利于蛤仔快速潜沙。     

Preliminary study on zeolite materials used to control of heavy metal pollution during the culture of mud clam Tegillarca granosa L.

To control heavy metal pollution during the culture of the mud clam, Tegillarca granosa L., the isothermal static adsorption capacities of three adsorption materials [natural zeolites, zeolites synthesized from kaolin and zeolites synthesized from coal fly ash (ZFA)] towards Cu²⁺, Cd²⁺, Cr⁶⁺, Zn²⁺, Pb²⁺ and Hg²⁺ in seawater were investigated. The adsorption capacity of the best material was investigated during the culture of mud clam in an artificially polluted environment. Results showed that the ZFA adsorption capacity was the highest and conformed to the Freundlich model. The theoretical maximum adsorption capacities of the adsorbent towards Cu²⁺, Cd²⁺, Cr⁶⁺, Zn²⁺, Pb²⁺ and Hg²⁺ in seawater were 3.057, 1.123, 0.325, 13.101, 6.116 mg g^?1 and 6.527 μg g^?1 respectively. For seawater artificially polluted by six heavy metals, heavy metal adsorption by ZFA followed the order Zn²⁺ > Cd²⁺ > Hg²⁺ > Cu²⁺ > Pb²⁺ > Cr⁶⁺. For the mud clam culturing experiment that simulated a continuously polluted water source, the Cu²⁺, Cd²⁺, Cr⁶⁺, Zn²⁺, Pb²⁺ and Hg²⁺ contents of mud clam tissues decreased by 40.9%, 25.8%, 9.6%, 28.2%, ?27.8% and 25.7%, respectively, after 21 days of culturing compared with the contents before the experiment.     

Bioprospecting Red Sea Coastal Ecosystems for Culturable Microorganisms and Their Antimicrobial Potential

Microorganisms that inhabit unchartered unique soil such as in the highly saline and hot Red Sea lagoons on the Saudi Arabian coastline, represent untapped sources of potentially new bioactive compounds. In this study, a culture-dependent approach was applied to three types of sediments: mangrove mud (MN), microbial mat (MM), and barren soil (BS), collected from Rabigh harbor lagoon (RHL) and Al-Kharrar lagoon (AKL). The isolated bacteria were evaluated for their potential to produce bioactive compounds. The phylogenetic characterization of 251 bacterial isolates based on the 16S rRNA gene sequencing, supported their assignment to five different phyla: Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, and Planctomycetes. Fifteen putative novel species were identified based on a 16S rRNA gene sequence similarity to other strain sequences in the NCBI database, being ≤98%. We demonstrate that 49 of the 251 isolates exhibit the potential to produce antimicrobial compounds. Additionally, at least one type of biosynthetic gene sequence, responsible for the synthesis of secondary metabolites, was recovered from 25 of the 49 isolates. Moreover, 10 of the isolates had a growth inhibition effect towards Staphylococcus aureus, Salmonella typhimurium and Pseudomonas syringae. We report the previously unknown antimicrobial activity of B. borstelensis, P. dendritiformis and M. salipaludis against all three indicator pathogens. Our study demonstrates the evidence of diverse cultured microbes associated with the Red Sea harbor/lagoon environments and their potential to produce antimicrobial compounds.     

改性白泥/PVC复合材料的研究

以白泥和PVC为主要原料,采用铝酸酯偶联剂对白泥进行表面处理,研制了改性白泥/PVC复合材料。优化了偶联剂用量和白泥用量,当偶联剂用量为0.5份(相对于白泥用量)、白泥用量25份(相对于PVC用量)时,复合材料的冲击强度、拉伸强度、弯曲强度和维卡软化温度均较高。研究发现改性白泥对PVC有明显增韧增强作用,通过对改性白泥的红外光谱和复合材料的微观形态分析,阐述了偶联剂改性白泥增韧增强PVC材料的机理。     

太湖重金属污染沉积物中的铁硫地球化学特征及其与相关重金属的关系

To understand the geochemical characteristics of iron and sulfur and the extent of iron-sulfide minerals influencing heavy metal behaviour in metal-polluted sediments of Talhu Lake, two sites, in Meiliang Bay （ML） and Wuli Lake （WL）, were selected to study the fractionation of iron, sulfur and related heavy metals. There were relatively high concentrations of Fe^2＋ and low concentrations of total S^2- in porewaters, indicating that conditions in these sediments favored iron reduction. The concentrations of acid volatile sulfides in sediments were 1.9-9.6 μmol g^-1 at ML and 1.0-11.7 μmool g^-1 at WL, both in the range of values detected in unpolluted lakes. Pyrite-S was 10.2-49.4 μmol g^-1 at ML and 10.3- 33.0 μmol g^-1 at WL, accounting for more than 69% of the reduced inorganic sulfur at both sites. The low degree of sulphidization （〈 14%） and pyritization （〈 10%） indicate that sulfate may be the limiting factor for pyrite formation. The extractability of Mn, Cu, Pb, Zn, Ni, and Cr in sediments all suggest that sulfides are not the major binding phase for these metals during early diagenesis. Sulfur may play a modest role in the geochemistry of iron and traced metals in the sediments.     

含油污泥堆腐处理技术研究

含油污泥主要来源于原油的勘探、开采和运输过程,在回收石油过程中由于采用加热后助剂提取方法,使油泥中大量微生物失活,为生物修复处理带来新的困难。针对这种含油污泥,采取投加固体菌剂的方法增加微生物种群,通过投加客土、肥料、水分及改变pH,调控微生物的营养和生存环境。利用正交实验L934方法选择了较理想的含油污泥生物修复条件。实验结果表明,处理含油污泥时投加客土是影响处理效果的重要因素,较理想的处理条件为:在自然温度条件下,客土投加量10%￣20%、肥料5%、菌剂5%(湿重)、水分30%(烘干基)和pH7.0。当TPH初始浓度为20.6￣22.3g·kg-1时,60d后其去除率>49%。在实验过程中,堆料的O2含量的变化能够反映出生物降解过程中微生物的活性及总石油烃(TPH)的处理效果变化趋势。     

赤泥和脱水矿泥协同生态处置区盐分和重金属随雨水淋溶的迁移特征

为探究在平果铝土矿赤泥和脱水矿泥协同生态处置区盐分和重金属随雨水淋溶的迁移规律,以及对周边土壤的影响,在生态处置区和周边土壤不同深度的土层埋设淋溶盘进行田间小区试验,对每月淋溶液中的重金属和盐分含量进行监测,最后收集不同深度的基质样品,对其重金属和盐离子含量进行测定。结果表明：5—10月,赤矿泥(赤泥和脱水矿泥按照干质量比1∶3进行翻堆混匀而成)基层Na盐的平均淋溶量达到51.2 mg·m^-2·月-1,其中8月份Na的淋溶量达到108 mg·m^-2·月-1。生态处置8个月后,赤矿泥pH从9.06降低到8.70,电导率(EC)降低了80.0%,Na盐含量降低了70.4%。赤矿泥基层中的Na盐随着雨水淋溶侧面迁移至周边土壤,导致周边1.5 m范围内的土壤pH和EC值显著增加(P<0.05),但迁移影响范围在3 m内。赤矿泥基层中的Cd、Cr和As随雨水淋溶的流失量在0.22 mg·m^-2·月-1以下。经过8个月的雨水淋溶,赤矿泥和周边土壤中Cd和As的含量没有显著变化。研究表明,赤矿泥基层用于矿区生态处置有利于改善赤矿...