巢湖流域和太湖流域沉积物中苄氯菊酯和高效氰戊菊酯的生态风险评价

分析了巢湖流域和太湖流域表层沉积物中苄氯菊酯和高效氰戊菊酯,并结合毒性单元法(Toxic Unit,TU)和物种敏感性分布法(Species Sensitivity Distributions,SSD)评价了两种拟除虫菊酯的生态风险.结果显示,两大流域沉积物中均广泛检测出两类污染物.总体而言,巢湖流域苄氯菊酯含量较高,而太湖流域高效氰戊菊酯含量较高.同时,两种污染物在巢湖流域呈现显著的正相关,但太湖流域二者之间没有相关关系.3种风险评价方法(TU法、沉积物SSD法、水体SSD法)均揭示苄氯菊酯对巢湖流域水生环境影响较大,而高效氰戊菊酯对两个流域影响均较大.因此,需要加强对流域高效氰戊菊酯污染的关注.其中,TU法预测的风险最小,沉积物SSD法预测的风险最大,主要原因在于TU法采用的毒性数据为LC50,而SSD法则选用了NOEC/LOEC,同时沉积物SSD法是出于保护大部分底栖生物为目的的方法.各种方法对于评价沉积物毒害污染物的生态风险均存在不足,尽管沉积物SSD法最为合理,但由于其毒性数据较少,最终预测结果存在一定的不确定性.因此,需要进一步加强对底栖生物毒性的研究和数据积累.     

Mechanism of Deca-BDE-induced apoptosis in Neuro-2a cells: Role of death-receptor pathway and reactive oxygen species-mediated mitochondrial pathway

Decabromodiphenyl ether (BDE-209) is a prevalent polybrominated diphenyl ether (PBDE) congener known to have neurotoxicity. Effects of BDE-209 on Neuro-2a cells were performed in the present study and the possible apoptotic pathway was discussed. Results indicated that BDE-209 induced Neuro-2a cell apoptosis, increased the protein expression of Fas and Fas-associated death domain-containing protein (FADD) and activated the caspase-8 and -3 activities in a concentration-dependent manner, inferring the death-receptor pathway was involved in the apoptotic process. Meanwhile, BDE-209 exposure increased the Bax/Bcl-2 ratio and decreased the cellular mitochondrial membrane potential (MMP) which led to cytochrome C released to the cytoplasm. The intracellular caspase-9 was elevated simultaneously, which caused downstream caspase cascade and triggered cell apoptosis. Moreover, BDE-209 exposure increased cellular reactive oxygen species (ROS) level in a concentration-dependent manner and the addition of N-acetyl-l-cysteine (NAC), known as ROS scavengers, obviously reduced the apoptotic rate and a positive relationship was observed between the degree of apoptosis blocking and the loss of MMP and ROS production. We thus concluded that BDE-209 induced Neuro-2a cell apoptosis via the combination of the death-receptor signaling pathway and the mitochondrial signaling pathway. The elevated ROS production was considered to magnify the intracellular apoptosis signal and played a crucial role in apoptosis of Neuro-2a cells induced by BDE-209.     

大亚湾大中型浮游动物的时空变化及其影响因素

根据2006年7月至2007年l1月在大亚湾四个季节的浮游动物调查资料,分析了大亚湾浮游动物的种类组成、优势种、群落结构、丰度和生物量的时空变化以及环境对其影响.经鉴定共有终生浮游动物105种和阶段性浮游幼虫17个类群.与以往调查资料相比,部分优势种的优势程度顺序发生了改变.由于受到季风、环流和人类活动等的影响,大亚湾...     

我国淡水生物氨氮基准研究

主要采用美国水生生物基准技术,结合美国氨氮水质基准数学模型,利用我国水生生物的氨氮毒性数据,对我国淡水生物氨氮基准进行了研究.共搜集了35种淡水生物的氨氮急性毒性数据和7种慢性毒性数据,得出的氨氮水质基准表现为以水体pH值和温度为自变量的函数,在pH 6.5～9.0、温度0～30℃的取值范围内,我国氨氮急性和慢性基准的...     

天然水体中铝浓度的预测方法探讨

本文概括了天然水体中铝的形态分类和地球化学行为,综述了天然水体中Ａｌ＾３＋和有机铝的浓度的预测方法,提出了由矿物浓度积,无机铝和有机铝经验关系式,有机铝模型辅以配体浓度和热力学常数预测天然水体中各形态铝的浓度的方法。     

投菌生物接触氧化法处理洁霉素废水的机理研究

研究了“水解酸化－二段生物接触氧化－混凝”工艺处理高浓度洁霉素废水处理系统中好氧微生物膜特性,分布规律、降解作用,高效降解菌的选育,投加菌在反应器中能否保持优势等问题,以探讨用投菌生物接触氧化法处理洁霉素废水的机理,对本系统好氧微生物膜进行后仍存于反应器中并占有优势,最优势菌株经鉴定属气单胞菌属、通过对中试好氧处理出水进行定性定量分析,寻找其引起剩余ＣＯＤｃｒ值的原因。     

Application of microcosm and species sensitivity distribution approaches in the ecological hazard assessment of 4-tert-butylphenol

In order to evaluate the ecological hazard of 4-tert-butylphenol (4-TBP), species abundances and physicochemical properties were monitored for 63 days in a microcosm system containing planktonic algae, rotifers, shrimps and Daphnia. The 63 days-NOEC (no observed effect concentration) of 4-TBP for this system was calculated. At the same time, species sensitivity distribution curves were constructed based on the toxicity data of EC₁₀, EC₅₀ and NOEC derived from laboratory single-species toxicity tests, which further gives no obvious hazard concentrations for 95% species in the ecosystem (HC₅). In both the microcosm and the single-species tests, the shrimp (Neocaridina sp.) was the most sensitive species to 4-TBP exposure, while most algae species were relatively insensitive compared to the zooplankton. For the microcosm exposed to 4-TBP, significant changes occurred to the community structure instead of the community function, resulting in a NOEC_microcosm of 265.38?μg?L^–1 which approached the EC₁₀-based HC₅ (0.376?mg?L^–1). Nevertheless, EC₅₀-based HC₅ was higher than the NOEC_microcosm, and the NOEC-based HC₅ was lower. The data showed that the EC₁₀-based HC₅ was protective at the similar level with the result of microcosm for 4-TBP, providing supportive data for chemical risk assessment.     

天然针阔混交林优势种群间联结关系

运用２ ×２ 联列表,通过方差分析、χ２ 检验、联结系数Ｃ、Ｏｃｈｉａｉ 系数、Ｃｚｅｋａｎｏｗｓｋｉ 系数和Ｊａｃｃａｒｄ 系数等系列方法,测定了天然针阔混交林１５ 个优势种群间的总体联结关系,各种对间联结显著性和关联系数．研究表明：中亚热带针阔混交林的种间联结测定使用上述系列技术效果很佳．运用方差分析揭示出多物种整体间的联结关系;χ２ 检验揭示出成对物种间联结的性质和程度;Ｏｃｈｉａｉ、Ｃｚｅｋａｎｏｗｓｋｉ 和Ｊａｃｃａｒｄ 系数可表明种对的联结程度和相伴随出现的机率．结果表明：多物种间的整体联结关系为显著的正联结;χ２ 统计量检验了１０５ 个种对,其中９ 个种对呈现极显著的正联结;２ 个种对为显著的正联结;４ 个种对呈现显著的负联结．马尾松（ Ｐｉｎｕｓ ｍａｓｓｏｎｉａｎａ）与常绿阔叶林优势树种间的联结关系很弱,反映出天然针阔混交林的成熟性     

Change in Fish Fauna as Indication of Aquatic Ecosystem Condition in Río Grande de Morelia–Lago de Cuitzeo Basin, Mexico

Chirostoma charari and C. compressum, and they are presumed extinct. Twelve (63%) of the remaining species had declines in distribution. Sixteen (80%) of the 20 localities sampled had lost species. The greatest declines occurred in Lago de Cuitzeo proper and in the lower portion of the Río Grande de Morelia watershed. Species losses from the lake were attributable to drying and hypereutrophication of the lake because of substantial reductions in the amount and quality of tributary inputs, whereas losses from the Río Grande de Morelia watershed were the result of pollution from agricultural, municipal, and industrial sources, especially in the region around the city of Morelia. Three localities in the upper portion of the Río Grande de Morelia watershed—Cointzio reservoir, La Mintzita spring, and Insurgente Morelos stream—contained most of the remaining fish species diversity in the basin and deserve additional protection. Fish faunal changes indicated major declines in the health of aquatic ecosystems in the Morelia–Cuitzeo basin.     

飞灰颗粒物介导活性氧氧化损伤与金属离子浸取浓度的关系研究

本文利用脱氧核糖氧化法考察了飞灰颗粒物氧化能力与络合剂及盐酸浸取颗粒物上金属浓度的关系。结果表明,代表氧化损伤程度指标的脱氧核糖氧化物,通过硫代巴比妥酸似丙二醛加合物显色反应,其吸光度值与飞灰颗粒物被浸取剂盐酸及氨三乙酸作用后的金属离子铁、锌、镉、铅和锰的浓度显著相关。基于铁在自然环境中的高含量及在活性氧催化反应中的特殊性,本文认为二乙三氨五乙酸、乙二胺四乙酸及柠檬酸浸取液中的金属浓度不能很好地表