农药助剂对蚯蚓(Eisenia foetida)的急性毒性

为评价农药助剂对土壤生物的毒性效应,分别采用滤纸接触法和人工土壤法测定了不同类别农药助剂对赤子爱胜蚓(Eis enia foetida)的急性毒性.结果表明:19种非离子表面活性剂中,烷基酚聚氧乙烯醚与脂肪醇聚氧乙烯醚毒性较高,滤纸法48 h-LC50为7.630 ～ 39.65μg·cm-2,人工土壤法14 d-LC50为876.5 ～2 786.6 mg· kg-1,其它类型非离子表面活性剂毒性较低.5种阴离子表面活性剂中,十二烷基硫酸钠、十二烷基苯磺酸钙毒性高于木质素磺酸钠、木质素磺酸钙、亚甲基双萘磺酸钠,滤纸法48 h-LC50为6575 ～ 41.89 μg· cm-2,人工土壤法14 d-LC50为1 195.0～1 911.7 mg·kg-1.13种溶剂中,二甲苯、乙苯、甲苯、正丁醇、环己酮表现出较高的毒性,滤纸法48 h-LC50为6.587 ～ 57.62 μg ·cm-2,密封人工土壤法48 h-LC50为181.9 ～781.5 mg·kg-1.采用两种方法测得的5种填料高岭土、白炭黑、硅藻土、凹凸棒土和轻质碳酸钙的毒性均较低.采用两种方法测得的毒性系统偏差接近,重现性均较好,并且滤纸接触法测得的毒力高于人工土壤法.     

二氧化硫与1—己烯的光化学反应动力学

利用ＧＣ／ＭＳ方法研究了ＳＯ２与１－己烯在无氧和有氧体系中光化学反应动力学，确定了ＳＯ２与１－己烯光化学反应的级数，给出了２９３－３３３Ｋ温度范围内总的反应速度常数Ｋ，以及Ｋ与温度的关系、反应的活化能和指前因子。另外，对反应物己醛和２－己酮的生成反应速度常数及其活化能也进行了计算和讨论。     

天然水体沉积物对重金属离子的吸附特性

本文运用表面络合模式，研究了江西乐安江下游黄龙庙沉积物的吸附特性，测定了样品对重金属ＣＵ，ｃＤ的吸附等温线和ＰＨ吸附突跃曲线；应用ＦＩＴＥＱＯ程序计算了沉积物的表面固有吸附常数；对恒定容量模式，扩散层模式和三层模式在天然水体沉积物中的应用进行了比较。     

单甲脒动物代谢的研究

采用气相色谱／傅立叶红外光谱和气相色谱／质谱仪分析大鼠肝脏中单甲脒的代谢产物，证明大鼠经口摄入单甲脒后，在肝脏中迅速代谢，其代谢中间产物为２，４－二甲基苯胺和含酰胺基的化全物。     

6—叠氮—6—脱氧—1,2：3,4—二—氧—异丙叉基—α—D—半乳糖的构象分析

在合成卡那霉类似物的核心结构时，发现６－叠氮－６脱氧１，２；３，４－二－氧－惜内叉基－α－Ｄ－半乳糖的核磁共振数据与普通六元环的船式或椅式构象大不相同，进一步通过分子力学模型ＭＭＰ２的计算，发现它具有扭船式的分子构象（Ｔｗｉｓｔ ｂｏａｔ）。     

Carbon sequestration and soil microbes in purple paddy soil as affected by long-term fertilization

Soil organic carbon (SOC) sequestration impacts on food security and climate change and may be affected by soil microbes in fertilized croplands. A 12-year field experiment under the rice–wheat system was used to evaluate the effect of the long-term fertilization on the SOC accumulation, culturable soil microbes, and their interaction in purple paddy soil. Results showed that varied fertilizations resulted in a significant increase of the SOC content and stock in the plow layer, as well as rise in populations of major soil microbes, including bacteria, actinomycetes, and fungi compared with no fertilization. Soil with combined application of chemical NPK fertilizer and organic amendment (pig manure or rice straw return) on average had the highest organic carbon content and stock, amounts of bacteria, actinomycetes, and fungi, which were 7.8%, 5.8%, 75.8%, 130.5%, and 16.2% higher than the NPK fertilization alone. Fertilization differentially altered populations of the functional anaerobic bacteria in paddy soil. With the combined application of chemical NPK fertilizer and organic amendment, soil displayed higher amounts of anaerobic cellulolytic bacteria, anaerobic fermentative bacteria, hydrogen-producing acetogen, methanogenic bacteria, denitrifying bacteria, and sulphate-reducing bacteria than that with the NPK fertilization alone or no fertilization. Populations of all three major soil microbes showed significantly positive correlations with the SOC content, indicating their interaction was of mutual promotion. Data suggest that the combined application of the NPK fertilizer with organic amendment especially by the rice straw return is recommended to sustain the soil biological fertility and mitigate the emission of the greenhouse gas by the SOC sequestration in purple paddy soil.     

Selenium status of children in Kashin–Beck disease endemic areas in Shaanxi,China: assessment with mercury

Environmental Geochemistry and Health - The causes of Kashin–Beck disease (KBD) in children are multifactorial, and particular consideration has been given to childhood selenium (Se)...     

Selenium and hazardous elements distribution in plant–soil–water system and human health risk assessment of Lower Cambrian,Southern Shaanxi,China

The natural selenium poisoning due to toxic Se levels in food chain had been observed in humans and animals in Lower Cambrian outcrop areas in Southern Shaanxi, China. To find out the distribution pattern of selenium and other hazardous elements in the plant, soil and water of Lower Cambrian in Southern Shaanxi, China, and their possible potential health risk, a total of 30 elements were analyzed and the health risk assessment of 18 elements was calculated. Results showed that the soil, plant and natural water of Lower Cambrian all had relatively high Se levels. In Lower Cambrian, the soil was enriched with Se, As, Ba, Cu, Mo, Ni, Zn, Ga, Cd and Cr (1.68 < I_geo < 4.48, I_geo; geo-accumulation index). In same plants, the contents of Se, Cd and Zn (except Cd in corn and rice, Zn in potato and corn) of Lower Cambrian were higher than that of the other strata. Ba and Ga in natural water were higher than that of the other strata, while K and Cs were opposite. The health risk assessment results showed that the people living in outcrop areas of Lower Cambrian had both high total non-carcinogenic risk of 18 elements (HI = 16.12, acceptable range: < 1) and carcinogenic risk of As (3.98E−04, acceptable range: 10⁻⁶–10⁻⁴). High contents of Se, As, Mo and Tl of Lower Cambrian may pose a health risk to local people, and food intake was the major pathway. For minimizing potential health risk, the local inhabitants should use the mix-imported food with local growing foods.

     

二氧化硫与环己烷的光化学反应

本文研究了ＳＯ２与环己烷在无氧及有氧体系中的光化学反应，观察到了白色烟雾有生成并凝聚，利用ＧＣ和ＧＣ／ＭＳ法确定了部分反应产物－环烯烃、醇、酮、二元酸酯、呋喃衍生物以及硫酸二甲酯等有机化合物，探讨了影响光化学反应的几种因素及反应机理。