溴氰菊酯对罗非鱼血清中溶菌酶质量浓度及肝脾脏影响

随着溴氰菊酯在农业上的广泛应用,其在水环境中的污染机率也在增加。为了研究溴氰菊酯连续暴露对罗非鱼免疫系统的影响。通过测定血清中溶菌酶质量分数,观察罗非鱼(tilapia)肝脾脏的外观变化,以及计算肝脏和脾脏的脏器系数,评价溴氰菊酯连续染毒对罗非鱼的影响。实验设1.0,2.0,3.0,5.0,10.0μg/L5个质量浓度组和空白对照组,同时每组设置一个平行样。试验开始后的第3天,1.0~5.0μg/L质量浓度组的罗非鱼血清中的溶菌酶质量浓度接近或略小于对照组,10.0μg/L质量浓度组与对照组相比下降明显(P<0.05),降幅达49.3%。实验7~15d期间,1.0~5.0μg/L质量浓度组罗非鱼血清的溶菌酶质量浓度渐渐升高,高于正常鱼体的质量浓度,最高值可达138.06±2.2μg/mL,为对照组的220.9%(P<0.05)。10.0μg/L试验组罗非鱼血清中溶菌酶的质量浓度在试验第7天时降至最低,为26.5±1.9μg/mL,为对照组的42.4%,表现出明显的抑制作用(P<0.01)。随着暴露时间的延长,各试验组在20d时恢复至正常水平,血清中溶菌酶的质量浓度与对照组相比没有明显差异(P>0.05);溴氰菊酯染毒第25天时罗非鱼的肝脏和脾脏的脏器系数与对照组相比均未发生明显的差异,罗非鱼的脾脏外观没有发生异常,但肝脏却发生了明显的病变,试验第25d时10.0μg/L质量浓度组罗非鱼肝脏的异常率达66.67%。试验结果表明,溴氰菊酯对罗非鱼血清中溶菌酶的影响是可逆的,对肝脏会造成一定的病理损伤,对脾脏的影响未检出。     

三丁基锡在水-脂质体间的分配行为

测定了不同酸度条件下三丁基锡(TBT)的正辛醇-水分配系数,并用卵磷脂自行制备脂质体代替正辛醇研究了TBT在人工合成生物膜-水间的分配行为.结果表明TBT在正辛醇和脂膜中的分配均随pH的增大而增大.但将二者进行比较,发现在pH＞pK_a时,TBT在二者中的分配比很接近,此时是疏水性TBTOH占优势;但在低pH下,TBT⁺是主要存在形态,其在脂膜中的分配量要大于在正辛醇中的分配量,说明此时用正辛醇来模拟三丁基锡在生物膜中的分配是不合适的.对离子型有机金     

危险货物办理站安全质量评估方法初探

从铁路危险货物的运输现状出发，通过对影响危险货物办理站安全工作质量的因素的分析，探讨了安全质量的评估方法，并提出了一个新的概念──安全管理难度系数，由此建立起安全质量综合评估模型，以实现对危险货物办理站安全工作的全面衡量。     

玛纳斯河水质参数时空变化规律与趋势分析

干旱区水环境质量的好坏直接决定着绿洲经济建设的水平.通过对玛纳斯河15年来的水质监测资料的分析、研究,从中寻找出该流域的地表及地下水质变化规律与发展趋势.研究结果表明：玛河径流形成区及山前倾斜平原区水质一直保持在一级未受污染级别;山前倾斜平原区地下水中挥发酚以及氮素含量逐年上升,但总体水质仍然保持在一级未受污染级别的范围.     

Simulated interior floods and the flood experience in urban communities

The Hydrologic Engineering Center (HEC-1) model was used to construct synthetic hydrographs for isolated interior urban floods. Flood peak and lag time were very well preserved in simulated flows. Total volume was not adequately expressed. Lag time varied inversely with both urban development and storm intensity. Peak discharge varied with storm intensity, but this variability was well defined only at very high urbanization levels. An 175% increase in storm intensity produced a change of about 15% in peak discharge. Claims for flood damage correlated well with estimates of peak flow and lag time combined. Other measures of flood experience also correlated with the two features. Within the range of storms utilized, urban development factors consistently outranked storm intensity as a determining factor in flood damage.     

长江三峡库区横向扩散系数研究初探

进行长江长寿段示踪剂岸边有限时段连续投放试验,求得横向扩散系数及其与流速、水深、流量、污染物浓度等关系。以长寿湖大沙坝河段为类比试验,预测得到三峡库区在90％保证率的最枯月流量下典型江段的横向扩散系数,并可用于库区的污染带计算。     

SEPTAGE QUALITY AND ITS EFFECT ON FIELD LIFE FOR LAND APPLICATIONS1

ABSTRACT: Maintenance of the more than 24 million septic tanks in the U.S. requires removal and disposal of septage. Disposal options include application to agricultural lands where the nutrients and organic matter can provide soil benefits. However, pathogens and contaminants are also contained in septage. An extensive search turned up very few data on septage quality, and those reveal high variability. The data used by the U.S. Environmental Protection Agency (EPA) in developing regulations had the lowest metal concentrations among the nine data sets that could be compared. Based on these data, EPA assumed that septage could be applied to agricultural land for more than 100 applications before reaching unacceptable cumulative loading of metals. They thus did not establish federal standards for metals in septage, and no monitoring is required under federal rules governing septage disposal. Analysis of the nine data sets we found showed that field site life would be reached in less than 100 applications for most septage and cumulative loading limits established by EPA for sewage sludges will be exceeded in 16 applications for some septage as opposed to the 100 application estimate used by EPA. Determination of acceptable cumulative loading depends on numerous technical and policy considerations. All septage sources reached the more restrictive loading limits such as those established by the New York State Department of Environmental Conservation (NYSDEC) and the recommendations in Cornell publications in less than 100 applications. In one case the cumulative limit for copper was exceeded in a single application. These findings suggest additional data are needed on septage quality and that the federal and state agencies responsible for regulating application of septage to agricultural land should reassess their standards.     

边坡滚石运动的计算模型

边坡滚石是在山区基本建设中常遇到的一种工程灾害，其防护结构的设计依据主要是边坡滚石的运动轨迹，因而要对这种灾害进行防治，首先要确定滚石的运动轨迹。分析了几种主要形式的边坡滚石运动，考虑控制滚石运动的主要影响因素，从工程的角度建立了一套计算边坡滚石运动轨迹的计算公式，并对影响滚石运动的碰撞恢复系数、滚动摩擦系数等重要参数进行了讨论。     

林火对土壤结构的影响

通过对大兴安岭新林林业局 2 0年内不同年数间隔的 10块火烧迹地土壤进行调查取样和室内实验分析 ,发现不同年限、不同强度的火烧迹地土壤结构变化情况如下 :低、中强度火烧对土壤密度和孔隙度的影响不大 ,对土壤分散系数有一定影响 ;高强度火烧对土壤密度、孔隙度和分散系数的影响显著。降雨能使火烧迹地的土壤密度和分散系数升高、孔隙度下降。连年火烧使土壤密度比未烧林地下降 ,而孔隙度和分散系数升高。由此可见 ,高强度火烧对土壤结构破坏严重 ,而低中强度火烧对土壤坚实度和孔隙状况影响不大 ,但对土壤的保水保肥能力有显著影响。