Chorioallantoic membrane as a non-lethal sampling method for polychlorinated biphenyls analysis in the northern diamondback terrapin (Malaclemys terrapin terrapin)

Polychlorinated biphenyls (PCBs) are documented endocrine-disrupting chemicals. This study examined the bioaccumulation of PCBs and the utility of the chorioallantoic membrane (CAM) as a non-lethal sampling technique for PCB analysis in the northern diamondback terrapin (Malaclemys terrapin terrapin), a species endemic to US East Coast salt marshes. To determine the viability of the CAM as a surrogate for PCB burdens within this species, maternal transfer of PCBs to CAM and egg samples was studied. Egg and CAM samples were collected from populations in Cape May County, NJ and Jamaica Bay, NY; liver samples were collected only from NJ terrapins. PCB congeners were detected in all sample types, but less-chlorinated congeners preferentially partitioned in the CAM. Liver and egg sample PCB concentrations were strongly correlated (p=0.002, r _s=0.883), but PCB concentrations of CAM were not strongly correlated to liver (p=0.035, r _s=0.733) and egg samples (p=0.036, r _s=0.484). Examination of homologue groups indicated a strong correlation between penta- and hexachlorinated biphenyls for all sample types. This study shows that maternal transfer of PCB contaminants occurs with selective partitioning of congeners into the CAM, and that analysis of the CAM alone may not reflect total PCB body burdens in this species.     

调水对巢湖浮游植物群落演替模式的影响

建立了巢湖生态动力学模型CAEDYM,并利用2010年的实测出入湖流量、水质、水文、气象等数据对模型进行了参数验证,确定了适用于巢湖水环境特征的生态动力学模型参数.利用模型中的磷循环原理模拟了巢湖水体中磷的生态动力学循环过程和浮游植物群落的季节性演替模式,并模拟了调水对浮游植物群落演替模式的影响.模拟结果表明,巢湖浮游植物优势种的演替模式为:春季绿藻占优势,夏季和秋季蓝藻占优势,冬季硅藻占优势.通过夏季的短期调水可使巢湖各点最终的TN、TP分别平均下降了约18.9%,25.2%.从Chl a的计算结果可知,调水的实施对巢湖西半湖和中部湖区Chl a的改善效果比较明显,可使Chl a的峰值从69μg/L下降到57μg/L,对巢湖的蓝藻有较好的改善效果,且对浮游植物群落的季节性演替影响不大.     

连铸钢坯二冷段喷嘴性能的实验研究

根据非稳态传热学原理,通过对大试样进行单侧加热,另一侧喷水的实验方法,对连铸二冷段喷嘴的热态性能进行了实验研究。根据实际生产条件,对不同喷水压力和不同喷水距离下,喷嘴传热系数关系进行了研究;实验结果表明:相同实验条件下,水喷嘴的传热系数高于气水喷嘴,而在均匀冷却方面,气水喷嘴更具有优势;无论哪一种喷嘴,随着喷水压力的增加,总体趋势传热系数都在增大,而随着喷水距离的增加,传热系数都在降低;同时,相同实验条件下,双喷嘴的冷却效果优于单喷嘴的冷却效果。     

北京地区二噁英类的环境多介质迁移和归趋模拟

以二噁英类为研究对象,利用LevelⅢ多介质逸度模型模拟计算了稳态假设下二噁英类在北京地区空气相、水相、土壤相和沉积物相中的浓度分布及各相间的迁移通量.结果表明:二噁英类在空气和土壤相中的模拟输出浓度(以I-TEQ计,全文同)范围分别为0.32～0.34 pg/m3和0.33～1.14 ng/kg,而相应环境相中的实测值分别为0.33 pg/m3和1.48 ng/kg,二者吻合较好,验证了该模型在北京地区的适用性;北京地区二噁英类的主要迁移过程为空气相—土相沉降和空气相—水相沉降.土壤和大气降解是二噁英类的主要消亡途径,二者占总降解量的99.1%.土壤相是二噁英类的最大储库,其占总量的97.8%.      

酞酸酯在空气和土壤两相间迁移情况的初步研究

以东北某钢铁厂及其周边区域为研究对象,利用气相色谱-质谱(GC-MS)方法分析了空气中15种酞酸酯的浓度,并采用基于实测浓度的逸度模型探讨了酞酸酯在空气和土壤两相间的迁移方向和迁移通量.结果表明,研究区域空气中15种酞酸酯总浓度(∑PAEs)在170—487 ng.m-3之间;DMP(邻苯二甲酸二甲酯)、DEP(邻苯二甲酸二乙酯)和DPP(邻苯二甲酸二戊酯)从土壤相向空气相迁移,迁移通量分别为93.5—117.0 g.month-.1km-2,50.2—108.2 g.month-.1km-2和9.4—15.5 g.month-.1km-2;DiBP(邻苯二甲酸二异丁酯)、DBP(邻苯二甲酸二丁酯)、DEHP[邻苯二甲酸双(2-乙基己基)酯]和DINP(邻苯二甲酸二壬酯)从空气相向土壤相迁移,迁移通量分别为530.6—1395.9 g.month-1.km-2,323.8—2408.8 g.month-1.km-2,1302.7—9839.6 g.month-.1km-2和131.4—205.9 g.month-.1km-2.     

珠江三角洲稻田土壤砷及其向水稻籽粒迁移特征

采集珠江三角洲区域水稻(Oryze sativa L.)植株的根系、秸秆、稻谷和对应的耕层土壤(0～15锄)样品,分析土壤和水稻植株中砷含量,初步研究土壤砷与土壤基本理化性质的关系及砷在土壤-水稻系统中的迁移规律.结果表明,土壤砷含量在1.83～18.14 mg·kg~(-1)之间,土壤砷与土壤有机质、砂粒含量呈显著负相关,与土壤粉粒含量呈显著正相关.糙米中的砷含量在0.21～0.43mg·kg~(-1)之间,均未超过国家食品卫生标准(0.7mg·kg~(-1)),砷在水稻植株中的分布规律为根>秸秆>颖壳>糙米.糙米砷含量与秸秆砷含量呈极显著正相关,与秸秆中P/As、Si/As摩尔比呈极显著负相关,因此,降低秸秆中As的积累、增加秸秆中P、Si的积累可降低水稻籽粒中的砷含量.     

无锡市柏庄生活垃圾转运站工程设计

介绍无锡市柏庄生活垃圾转运站的工程设计。该工程是苏南地区首座采用上投料水平压缩式的中型垃圾转运站。通过技术分析,认为上投料式水平压缩工艺在工艺技术和环境保护上,较其他工艺具有一定的优势。     

MBBR工艺中不同曝气方式充氧效率的比较及工程应用

通过设定不同的进水方式、曝气量、悬浮填料投加比,对比研究了MBBR工艺中三种曝气方式——均匀曝气、渐进曝气、单侧曝气的充氧效率,并且运用Matlab软件,采用非线性回归法计算测试条件下的饱和溶解氧浓度Cs和氧总传质系数KLα。得出:投加悬浮填料能明显提升原有曝气方式的充氧效率,但首先须保证填料在水中有一定活动强度,否则反会降低充氧效率;均匀曝气本身的充氧效率最佳,不过由于需要更大的气容比来带动填料运动,运行成本高于另外两种方式。     

PVDF ultrafiltration membranes of controlled performance via blending PVDF-g-PEGMA copolymer synthesized under different reaction times

PVDF blended different graft ratio of PVDF-g-PEGMA were systematically studied. Tuning the amphiphilic copolymer synthesis time to control membrane performance. The PVDF membrane with PVDF-g-PEGMA at 19 h possesses most surface oxygen content. The synthesis time of PVDF-g-PEGMA at 9 h is good for high flux UF membrane. Polyvinylidene fluoride grafted with poly(ethylene glycol) methyl ether methacrylate (PVDF-g-PEGMA) was synthesized using atomic transfer radical polymerization (ATRP) at different reaction times (9 h, 19 h, and 29 h). The corresponding conversion rates were 10%, 20% and 30%, respectively. PVDF was blended with the copolymer mixture containing PVDF-g-PEGMA, solvent and residual PEGMA under different reaction times. In this study, we explored the effect of the copolymer mixture additives with different synthesis times on cast membrane performance. Increasing the reaction time of PVDF-g-PEGMA causes more PVDF-g-PEGMA and less residual PEGMA to be found in the casting solution. Incremental PVDF-g-PEGMA can dramatically increase the viscosity of the casting solution. An overly high viscosity led to a delayed phase inversion, thus hindering PEGMA segments in PVDF-g-PEGMA from migrating to the membrane surface. However, more residual PEGMA contributed to helping more PEGMA segments migrate to the membrane surface. The pure water fluxes of the blended membrane with reaction times of 9 h, 19 h, and 29 h are 5445 L·m⁻²·h⁻¹, 1068 L·m⁻²·h⁻¹and 1179 L·m⁻²·h⁻¹, respectively, at 0.07 MPa. Delayed phase inversion can form smaller surface pore size distributions, thus decreasing the water flux for the membranes with PVDF-g-PEGMA at 19 h and 29 h. Therefore, we can control the membrane pore size distribution by decreasing the reaction time of PVDF-g-PEGMA to obtain a better flux performance. The membrane with PVDF-g-PEGMA at 19 h exhibits the best foulant rejection and cleaning recovery due to its narrow pore size distribution and high surface oxygen content.     

塔里木河下游第五次应急输水后地下水恢复量的计算

依据塔里木河下游应急输水前与第五次第一阶段输水后地下水的监测资料,分析了输水前后地下水位的响应特征:地下水位在应急输水前持续下降,呈近似水平状态;输水后则由于接受了河道渗漏的补给,地下水位表现出逐次回升的趋势且受输水的影响,宽度(距离河道)也随之加大。在此基础上,逐断面拟合了第五(I)次输水后地下水位与离河距离的二次多项式方程,同时运用地下水水均衡的原理,推导了计算地下水净恢复量的数学公式,并以此为工具对第五(I)次输水后地下水的净恢复量进行了计算。