藻毒素对鱼类肝脏的毒理学效应

以鱼类肝脏为靶器官,研究了藻毒素对鱼类的毒性影响.结果表明,藻毒素在注射和口服两种不同的染毒方式下,均可引起受试鱼类发生急性中毒死亡.对中毒鱼类进行解剖分析发现,受试鱼类的肝/体重比高于对照组.说明无论哪种给药方式,藻毒素都会迅速地、专一地作用于鱼类肝脏,引起鱼类肝脏充血红肿,出现血斑.通过对鱼类肝脏组织碱性磷酸酶(ALP)同功酶谱的分析,可以发现在两种不同染毒条件下藻毒素各剂量组的ALP同功酶谱与对照组相同,均有ALP₁1～ALP₅5条带,只是高剂量组较低剂量组ALP₁～ALP₃ 3条带的着色深,并可使ALP同功酶各组分的相对活性上升.试验结果显示,藻毒素具有极高的细胞选择性和专一生物活性,其在生物机体内所引发的许多细胞学变化主要是对生物体肝脏酶系统的破坏所致,必须引起人们的重视.     

氯代苯胺对斑马鱼的急性毒性及3D-QSAR分析

研究了2-氯-4-硝基苯胺、4-氯-3-硝基苯胺、2-氯-5-硝基苯胺、2,4-二氯苯胺、3,4-二氯苯胺、2,5-二氯苯胺、2,3-二氯苯胺对斑马鱼(Brachydanio rerio)的96 h急性毒性,96 h LC50分别为6.99,2.58,8.63,7.79,6.08,5.23,0.49 mg/L.运用三维定量结构活性相关模型(3D-QSAR)对这些化合物的毒性效应和构效关系进行了分析和评价,估算毒性值与实际观测值相关性较好,相关系数R2＝0.907.      

水污染中的鱼类监测初探

文章阐述了鱼类种群监测和鱼类毒理实验在环境监测方面的应用,并具体介绍了应用化学鱼类监测法、应用浮藻鱼类监测法以及鱼类急性毒性实验法和鱼类致突变试验法。     

不同尺度下人类活动对浑太河流域鱼类和大型底栖动物群落特征的影响

为了确定鱼类和大型底栖动物群落结构对多重人类活动压力响应是否一致,以浑太河流域为例,采用典范对应分析和冗余分析方法,以自然环境因子(包括海拔、坡度、流域面积、经纬度)为协变量,比较流域(各土地利用类型面积所占比例)、河岸带(各土地利用面积所占比例)和河段尺度(水质、水力形态、水文、栖息地质量、底质类型等)下人类活动因子对鱼类和大型底栖动物群落特征的影响. 结果表明:在流域尺度上,林地和农村聚落用地面积所占比例解释了8.09%的鱼类群落特征空间变异,林地、旱地、城镇建设用地和农村聚落用地面积所占比例解释了18.28%的大型底栖动物群落特征空间变异;在河岸带尺度上,城镇建设用地面积所占比例解释了4.26%的鱼类群落特征空间变异,没有环境因子对大型底栖动物群落特征产生显著影响;在河段尺度上,电导率、ρ(TDS)、ρ(NH₄+-N)、ρ(COD_Mn)、河宽、QHEI(a qualitative habitat evaluation index,栖息地评估指数)、ρ(DO)、ρ(TN)、硬度和pH解释了36.60%的鱼类群落特征空间变异,电导率、ρ(TDS)、ρ(NH₄+-N)、ρ(COD_Mn)解释了14.65%的大型底栖动物群落特征空间变异.河段尺度人类活动因子对鱼类群落特征的直接影响最为显著,其次为流域尺度,河岸带尺度的影响最小;流域尺度和河段尺度人类活动因子对大型底栖动物群落特征影响大致相同. 河段尺度的水力形态和水质状况主要受流域尺度土地利用变化的影响,其次是河岸带尺度. 土地利用变化对水力形态的影响较水质更大.      

长江流域鲤鱼和鲟鱼的模型建立与剂量率估算研究

针对长江流域两种典型淡水鱼类-鲤鱼和鲟鱼,通过实验对两种鱼类各部分的浓集性质进行了研究,并建立了相关的的简化解剖学模型(区分了不同组织和器官部分)和外照射环境模型;用蒙特卡罗方法模拟源器官和环境水体对靶器官的能量沉积,采用某厂址水体数据以及实验得到的鱼类不同部位的浓集系数,估算了上述两种鱼类在该环境中所受到的内外照射剂量率,并与ERICA方法进行了比较分析.     

改良MTT法在鱼类细胞毒性实验中的使用条件

文章利用斑点叉尾鮰鱼卵巢细胞(CCO)、鲤鱼上皮癌细胞(EPC)、草鱼肾细胞(CIK)探讨改良四噻唑蓝(MTT)比色法在测定污染物对鱼类细胞急性毒性实验中的最佳条件。通过实验发现其最佳实验条件为570nm波长下,MTT作用4h,MTT终浓度1mg/mL,最佳接种量的确定因每种细胞的特性而不同,生长速度快的细胞接种量较少。     

Predicting the Thermal Effects of Dam Removal on the Klamath River

The Klamath River once supported large runs of anadromous salmonids. Water temperature associated with multiple mainstem hydropower facilities might be one of many factors responsible for depressing Klamath salmon stocks. We combined a water quantity model and a water quality model to predict how removing the series of dams below Upper Klamath Lake might affect water temperatures, and ultimately fish survival, in the spawning and rearing portions of the mainstem Klamath. We calibrated the water quantity and quality models and applied them for the hydrometeorological conditions during a 40-year postdam period. Then, we hypothetically removed the dams and their impoundments from the models and reestimated the rivers water temperatures. The principal thermal effect of dam and reservoir removal would be to restore the timing (phase) of the rivers seasonal thermal signature by shifting it approximately 18 days earlier in the year, resulting in river temperatures that more rapidly track ambient air temperatures. Such a shift would likely cool thermal habitat conditions for adult fall chinook (Oncorhynchus tshawytscha) during upstream migration and benefit mainstem spawning. By contrast, spring and early summer temperatures could be warmer without dams, potentially harming chinook rearing and outmigration in the mainstem. Dam removal might affect the rivers thermal regime during certain conditions for over 200 km of the mainstem.     

IAFSA-GRNN在油田集输管道CO2腐蚀速率预测中的应用

为提高油田集输管道CO₂腐蚀速率预测的准确性,针对原始广义回归神经网络(GRNN)预测精度低的问题,提出改进的群智能算法优化原始GRNN的预测模型;分别使用GRNN模型、人工鱼群算法(AFSA)优化的GRNN(AFSA-GRNN)模型和自适应改进的AFSA-GRNN(IAFSA-GRNN)模型预测X65管线钢的CO₂腐蚀速率。结果表明:采用AFSA和IAFSA优化光滑因子S后,能大大提高GRNN模型的预测精度,预测结果的平均相对误差由36.09%分别减小至7.20%和6.90%;与AFSA相比,IAFSA优化的GRNN不仅具有更高的预测精度,还具有更快的收敛速度。AFSA-GRNN在第164次迭代计算时收敛,而IAFSA-GRNN在第109次迭代计算时收敛,说明AFSA经自适应优化能提高优化过程的收敛速度和GRNN的预测精度。     

Estrogenic Compounds Downstream From Three Small Cities in Eastern Nebraska: Occurrence and Biological Effect1

Abstract: Recent studies have detected estrogenic compounds in surface waters in North America and Europe. Furthermore, the presence of estrogenic compounds in surface waters has been attributed, in some cases, to the discharge of wastewater treatment plant (WWTP) effluent. The primary objective of the current study was to determine if WWTP effluent contributes estrogens to the surface waters of Nebraska. A second objective of this study was to determine if estrogens were found in concentrations sufficient enough to manifest feminizing effects on fish. These objectives were satisfied by deploying polar organic chemical integrative samplers (POCIS) and caged fathead minnows at eight field sites. Deployment sites included: three reference sites (Pawnee Creek, the Little Blue River, and the Middle Loup River), two sites upstream of the WWTPs at Grand Island and Columbus, and three sites downstream of the WWTPs at Grand Island, Columbus, and Hastings. Following the seven day deployments, POCIS extracts were analyzed for estrone, 17β‐estradiol, estriol and 17α‐ethinylestradiol using liquid chromatography tandem mass spectrometry (LC/MS/MS). 17β‐estradiol was detected in POCIS from six of the eight field sites with the greatest quantities recovered in POCIS deployed downstream from the Grand Island and Hastings WWTPs. Estrone was detected only in the POCIS deployed downstream from the Grand Island and Hastings WWTPs. Estrogenic effects were detected in caged minnows analyzed for the hepatic mRNA expression of two estrogen‐responsive genes, vitellogenin (vg1) and estrogen receptor α (ERα). Fish deployed at the site where the greatest quantities of estrogens were recovered (Hastings) had significantly higher expression of both vg1 and ERα than fish deployed at any of the other sites. These results confirm that WWTP effluent contributes biologically significant levels of estrogens to Nebraska surface waters.