Polycyclic aromatic hydrocarbons in benthos of the northern Bering Sea Shelf and Chukchi Sea Shelf

Eighteen polycyclic aromatic hydrocarbons (PAHs) were detected in benthos collected onboard the ‘Snow Dragon’ in the Northern Bering Sea Shelf and Chukchi Sea Shelf during the 6^th Chinese National Arctic Research Expedition (CHINARE 2014). Σ₁₈PAHs for all biota samples ranged from 34.2 to 128.1 ng/g dry weight (dw), with the highest concentration observed in fish muscle (Boreogadus saida) samples close to St. Lawrence Island. The PAH composition pattern was dominated by the presence of lighter 3 ring (57%) and 2 ring (28%) PAHs, indicating oil-related or petrogenic sources as important origins of PAH contamination. Concentrations of alkyl-PAHs (1-methylnaphthalene and 2-methylnaphthalene) were lower than their parent PAH (naphthalene) in all biological tissue, and their percentage also decreased significantly (p<0.05) compared with those in the corresponding sediment. There were no significant relationships between PAH concentrations and trophic levels, which is possibly due to the combined results of the complex benthic foodweb in the subarctic/Arctic shelf region, as well as a low assimilation/effective metabolism for PAHs. According to toxic potency evaluation results from TCDD toxic equivalents (TEQs) and BaP-equivalent (BaPE) values, whelk (Neptunea heros) and starfish (Ctenodiscus crispatus) are two macroinvertebrate species showing relatively higher dioxin-like toxicity and carcinogenic risk.     

湖泊水体中硫酸盐增高的环境效应研究

通过对高原３个硫酸盐浓度差异的湖泊沉积物水界面硫的形态分布、扩散通量和碎屑有机硫通量等估算，揭示了湖泊水体硫酸盐增加以后的环境效应和自然反馈机制．研究认为：水体向沉积物内部扩散和界面硫酸盐还原作用是高硫酸盐浓度水体硫酸盐的主要清除作用，随硫酸盐浓度的增加，它在水体清除硫酸盐作用的贡献逐渐增大，而低硫酸盐含量湖泊水体生物同化吸收作用是水体硫酸盐的主要清除机制，它在硫酸盐浓度不同的水体没有差异．     

A／O工艺处理石油化工废水试验研究

本文介绍了采用Ａ／Ｏ新工艺组合处理高浓度的炼油、化工混合废水中试情况，试验结果表明；Ａ／Ｏ新工艺组合具有抗冲击性能好，产泥量少，在一定条件下，出水各项指标达标排放，还就填料选择、含氮化合物的消化反应、污泥生物相和各池工艺参数相互关系进行了讨论。     

Dissipation,residues, and risk assessment of imidacloprid in Zizania latifolia and purple sweet potato under field conditions using LC-MS/MS

A shortened version of Quick, Easy, Cheap, Effective, Rugged, and Safe method (QuEChERS) for determining the dissipation and residue of imidacloprid present in Zizania latifolia and purple sweet potato was established by using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The average recoveries of imidacloprid in the two crops ranged from 82.12 to 113.79%, with relative standard deviation (RSD) of <7.32%. The dissipation dynamics of imidacloprid in Z. latifolia plants and purple sweet potato plants followed first-order kinetics, with half-lives of 3.2–5.5?days in each of sampling locations. The terminal imidacloprid residues in Z. latifolia and purple sweet potato at each of location were <0.005–0.120?mg kg^?1. According to the risk assessment results, both the acute dietary risk quotient and chronic dietary risk quotient values were <1, indicating that imidacloprid is unlikely to pose health risks to humans with normal recommended use. The present study may serve as a valuable reference for the safe and reasonable use of imidacloprid in Z. latifolia and purple sweet potato fields.     

Biosorption properties of Cd(II), Pb(II), and Cu(II) of extracellular polymeric substances (EPS) extracted from Aspergillus fumigatus and determined by polarographic method

Extracellular polymeric substances (EPS) were extracted from Aspergillus fumigatus using cationic exchange resin technique. The EPS were mainly composed of polysaccharide and low quantities of protein and nucleic acid. Biosorption of Cd(II), Pb(II), and Cu(II) of EPS was investigated as a function of pH using differential pulse polarography and the Ruzic model. Results showed that the EPS biosorption capacity determined using either the direct titration curves i?=?f(C _M) or the method proposed by Ruzic (Analytica Chimica Acta 140:99–113, 1982) were coincident. Cu(II) had the highest affinity with EPS followed by Pb(II) and Cd(II). The total number of binding sites for Cu(II) and Cd(II) increased with pH in the range of 4.0–7.0. Similar trend was observed for Pb(II) at pH?4.0–5.0, while precipitates were observed at pH?6.0 and 7.0. The conditional binding constants of these three metals displayed low levels of fluctuation with pH and ranged from 4.02?±?0.02 to 5.54?±?0.05.     

电絮凝技术处理洗车废水试验

采用电絮凝技术处理洗车废水,以保证处理后出水能够循环利用。考察电流密度、初始pH值、NaCl浓度及电解时间等操作因素对COD与浊度去除效果的影响。结果表明,在最佳处理条件下,出水达到生活杂用水水质标准;另外,去除COD过程符合一级动力学模型,去除单位浓度COD产生4.02×10-3kg湿污泥、3.10×10-4kg干污泥。     

Influence of low molecular weight anionic ligands on the sorption of heavy metals by soil constituents: a review

Environmental Chemistry Letters - The sorption of heavy metals by soil constituents reduces the absorption of these pollutants by crops and vegetables, and thus limit food contamination. Low...     

单甲脒农药对模型池塘生态系统藻类群落结构的影响

在１．５－５０．０ｍｇ／Ｌ的浓度范围内，单甲脒农药对模型池塘生态系统中的浮游植物群落结构有明显影响。尤其在加药的头４ｄ内，藻类种类、数量、多样性指数、种类数比及增长率明显下降，优势比显著上升，敏感种及清洁种减少甚至消失，高浓度（５０．０ｍｇ／Ｌ）的单甲脒在２ｄ内可把藻类全部杀灭。随试验时间的延长，药物不断降解，６ｄ后藻类种类、数量、多样性指数又不断回升。随加药次数的增多，药物对藻类抑制作用明显减弱，藻类的种类、数量、多样性指数等指标不断上升，尤其是藻类数量增加明显，试验后期，藻类数量高低主要受Ｎ、Ｐ浓度大小的影响。     

交联壳聚糖冠醚的合成及其对金属离子的吸附性能

本文合成了交联壳聚糖苯并－１５－冠－５醚和交联壳聚糖苯并－１８－冠－６醚,研究了它们对Ａｇ（Ⅰ）Ｐｄ（Ⅱ）,Ｐｂ（Ⅱ）,Ｃｄ（Ⅱ）,Ｃｒ（Ⅲ）等金属离子的吸附性能和选择性,实验结果表明：无论是在单一金属离子体系还是在二元或三元金属离子体系中,ＣＣＴＳ－ＢＸ和ＣＣＴＳ－ＢＹ对Ａｇ（Ⅰ）和Ｐｄ（Ⅱ）者有较高的吸附选择性。