Combined effect of tributyltin and benzo[a] pyrene on the levels of sex hormone and vitellogenin in female Sebastiscus marmoratus

Tributyltin（TBT）, an organometal used as an antifouling biocide, has been reported to induce masculinization of fish. Benzo [a]pyrene （BaP）, a widespread carcinogenic polycyclic aromatic hydrocarbon, has been reported that its microsomal metabolites can produce an estrogenic response when tested in vitro. This study was therefore designed to examine the potential in vivo influence of TBT, BaP and their mixture on sex hormone levels in serum of Sebastiscus marmoratus, which were given 2 separate intraperitoneally （ip） injections（a single injection every 7 d） of TBT（0.5, 1, 5 and 10 mg/kg）, BaP（0.5, 1, 5 and 10 mg/kg）, or both in combination（0.5, 1, 5 and 10 mg/kg）; control fish received olive oil vehicle only. Six days after the 2nd injection, serum samples were collected and analyzed for sex hormone levels and alkali labile protein phosphorus （ALPP）, which is related to the yolk precursor protein vitellogenin. The pollutants at all doses significantly reduced serum testosterone, estradiol and ALPP content after 2 injections compared with the corresponding controls. The reduction of the estradiol levels should be response for the decrease of the vitellogenin levels. The results in the present study suggested that aromatase seems not the major target acted by TBT and BaP in fish. This study demonstrated that TBT or BaP exposure both inhibit the reproductive potential in female Sebastiscus marmoratus. Combined effect of TBT and BaP on the serum testosterone, estradiol and ALPP was not antagonism from the anticipation.     

水稻烤田期间N2O排放及其影响因素

水稻田间实验研究了烤田期间的土壤温度、Eh、含水量和裂缝基本性质,矿质态氮以及与氮有关的酶活性的演变规律,及其对N2O排放的影响.试验表明,在水稻分蘖期间烤田,N2O有一个排放高峰,其最高值可达75.6μg·m-2·h-1.在排放高峰后,即使继续烤田,N2O的排放值也将降低.N2O排放与尿素氮肥的施用量没有明显关系.裂缝的生成,改变了N2O的日排放规律.随着烤田时间的延长,脲酶和羟胺还原酶活性呈波动变化,硝酸还原酶活性递减,亚硝酸还原酶活性极低.硝酸还原酶活性与N2O排放之间没有显著相关性.土壤中的脲酶活性与N2O日排放通量呈显著的线性正相关.在烤田期间,NO-3含量呈增加趋势.土壤中的硝态氮含量与N2O排放通量之间呈显著正线性关系.土壤中的铵态氮含量与N2O排放通量之间呈显著负线性相关.     

胶粉的生产利用现状及前景分析

废橡胶作为工业垃圾 ,已为世界所公认 ,介绍了废橡胶回收利用的意义和方法 ,着重阐述了胶粉的生产利用现状 ,并简要分析了胶粉的生产利用前景     

广州地铁工程项目环境影响评价若干问题探讨

以广州地铁六号线环境影响评价为例，结合国内外开展地铁工程项目环境影响评价的经验，对地铁项目环境影响评价的指导思想、评价重点、工程污染再分析及环境影响预测与评价等若干问题进行了探讨，以期为国内地铁工程环境影响评价工作的开展提供一些参考。     

减噪路面的降噪机理及其结构

阐述了减噪路面的降噪机理，并提供了几种减噪路面结构及实测数据，对高速公路设计有着重要的参考意义。     

废旧橡胶粉用于道路改性沥青的研究

从环保的角度出发，利用废旧橡胶粉对道路沥青改性进行了试验研究，分析了废胶粉的细度及掺量对沥青性能的影响，并就橡胶粉改性沥青所采用的胶粉细度、掺量以及改性措施提出了合理的建议。     

北海污水汽提装置运行探讨

介绍北海分公司含硫污水汽提装置改造情况及运行效果，并对装置存在的问题进行分析，提出解决办法。     

岩石工程开挖对山坡体应力场扰动规律的数值分析

应用三雏数值分析方法,研究人工开挖边坡与自然山体边坡体之间的应力场分布特点、演变规律和作用关系,并依据应力场演变规律确定边坡岩体的破坏模式;以便为矿山生产及周边环境的安全评价提供科学依据。     

黄陵至延安高速公路k295+750-k296+050段滑坡稳定性分析与治理

在介绍黄陵至延安高速公路k295+750～k296+050滑坡工程地质情况的基础上,对滑坡的成因和机制进行了分析,并且进行了稳定性计算与评价。最后结合工程实际特点提出了以路肩挡墙作为支挡工程,并辅以刷方减重和地表排水相结合的合理处治方案。     

On-line optical determination of floc size of Fe(Ⅲ) coagulants

This study investigated the floc aggregation, average floc size, floc size variance and floc growth velocity when ferric chloride （FeCl3） and polyferric chloride （PFC） were used to treat the simulated water samples. The factors including coagulant dose, ionic strength and solution pH, which affect the floc aggregation, were studied. Experiments were carried out in a bench-scale reactor using photometric dispersion analyzer （ PDA）. Results showed that there were great differences between the floc aggregation of PFC and FeCl3. The average floc size and fioc growth velocity of PFC were much larger than those of FeCl3. Compared with FeCl3, PFC gave a better coagulation performance in wider range of pH, dosage and ionic strength. It was also found that the coagulation efficiency of PFC did not depend on average floc size but on floc growth velocity.