不同环境条件下三丁基氧化锡对火腿许水蚤(Schmakeria poplesia)的毒性效应

为探讨不同环境条件下三丁基氧化锡(TBTO)对桡足类的毒性效应,通过世代培养30日龄火腿许水蚤(Schmakeria poplesia)的多因素协同作用急性毒性实验,测定了温度、盐度、单胞藻浓度和桡足类密度等环境因素对TBTO毒性效应的影响。结果显示:TBTO对火腿许水蚤雌、雄个体的毒性效应无显著差异,96h-LC50值分别为0.41和0.42μg·L-1;随着温度的升高,TBTO毒性效应增强;与盐度25条件相比,盐度15和35条件下火腿许水蚤对TBTO的敏感性相对较高;单胞藻浓度升高导致TBTO对桡足类毒性效应降低;另外,桡足类暴露敏感性还受到其密度的影响。以上结果表明,环境因素对污染物的生物毒性效应产生较大影响,在毒理学研究中应根据实际环境情况设定合理的环境条件,以保证最终生态风险评价结果的科学性。     

全氟辛烷磺酸盐(PFOS)胁迫对翡翠贻贝抗氧化酶的影响

为了解全氟辛烷磺酸盐(PFOS)对海洋贝类抗氧化防御系统的毒性效应及致毒机理,在实验室条件下研究了PFOS对翡翠贻贝的96h急性毒性,同时探讨PFOS胁迫和净水恢复过程中翡翠贻贝外套膜和内脏团组织中抗氧化指标(SOD活性、GSH和MDA含量)的变化。结果显示,PFOS对翡翠贻贝的96h半致死浓度(LC50)为68.3mg·L-1,安全浓度为6.83mg·L-1。在PFOS胁迫阶段,1mg·L-1浓度组外套膜SOD活性显著性升高(p<0.05),内脏团SOD酶活性显著降低(p<0.05);而PFOS浓度高于1mg·L-1时,外套膜SOD活性显著性降低(p<0.05),内脏团SOD活性显著升高(p<0.05)。PFOS胁迫对翡翠贻贝外套膜和内脏团中GSH含量均有显著的诱导作用(p<0.05),PFOS胁迫15d后各浓度组GSH含量均受到显著的抑制(p<0.05)。翡翠贻贝外套膜MDA含量受PFOS胁迫后显著升高(p<0.05),内脏团MDA含量的变化呈先降低、后升高的规律。净水释放阶段,翡翠贻贝两组织中SOD活性在释放7d后均恢复至对照组水平,GSH含量和MDA含量呈显著升高的趋势(p<0.05)。研究结果表明,PFOS暴露能够引起翡翠贻贝外套膜和内脏团氧化胁迫,但这种损伤的效果不明显,释放短时间后即可自我恢复。     

北方地区城市污水厂冬季运行管理

以沈阳市北部污水处理厂5年的实际运行管理为例,阐述北方地区城市污水处理厂冬季运行时应注意的问题及对策。     

固定化微生物技术在环境工程中的应用研究进展

综述了固定化微生物的制作方法及载体的选择,并对固定化技术在废水、大气和土壤等环境工程中的应用和研究进展状况进行了简介,同时对固定化技术的应用前景及存在的问题进行了评述。     

单级生物脱氮的特性研究

以 PVA为载体 ,采用冷冻法混合固定硝化菌和反硝化菌 ,研究硝化菌与反硝化菌的比例、有机碳源、p H值、碱度、温度和DO等因素对单级脱氮过程的影响 .试验结果表明 :当硝化菌 /反硝化菌 =1.5∶ 1～ 3.6∶1 (W∶W)时 ,脱氮速率最快 .在甲醇、乙醇、醋酸和葡萄糖 4种有机碳源中 ,以乙醇为碳源时脱氮速率最快 .最适的温度、pH值和 DO分别是 30℃、8.2和 2 mg/L～ 6mg/L.碱度与氨氮的比例越高 ,脱氮速率越快 ,但当碱度 /氨氮 >9.0时 ,脱氮速率趋于稳定 .     

污染物总量控制目标的确定

污染物总量控制是我国环境管理工作的一大进步。本文从其涵义入手,简要介绍了污染物总量控制指标体系的建立及污染物总量控制目标的确定方法。     

地衣对建筑物的生物破坏作用

大量的证据表明地衣可以诱发和加速矿质基质的物理、化学风化过程,着生于建筑物表面的地衣能对建筑材料导致明显的生物破坏.其中,地衣菌丝在矿质基质中的穿插生长、原植体随环境变化表现出的膨胀收缩、冻融交替等机制对建筑物造成机械破坏.而地衣分泌的草酸等简单有机酸以及大量的高分子有机化合物诱发和促进矿质基质的生物-化学风化过程.受其影响,矿质建材中原生矿物遭受溶解、蚀变,并产生多种次生矿物.最终破坏建筑物的坚固程度、缩短其使用寿命、减低其美学价值.     

关于RosinRammler粒径分布函数的研究

Rosin Ramm ler分布函数是最常用的描述粉尘粒径分布的一种形式 ,本文对表达式中系数 a与指数 n之间的关系进行了分析 ,导出了二者之间的关系式。     

蒙脱石颗粒吸附剂的制备及除锌研究

以蒙脱石为原料,粉煤灰为激发剂,添加一定量的黏结剂混合造粒制成复合颗粒吸附剂,用于处理含Zn2+废水,实验研究了蒙脱石/粉煤灰混合比例、焙烧温度、添加剂用量等因素对复合颗粒强度和吸附性能的影响。研究结果表明,制备复合颗粒较佳的工艺条件为:蒙脱石与粉煤灰的混合比为6∶4,焙烧温度105℃,硅酸钠的添加比例为15%(蒙脱石/粉煤灰混合物质量)。制成的颗粒吸附剂不仅吸附效果好,而且其散失率较低。     

Relationships between distributions of longevous population and trace elements in the agricultural ecosystem of Rugao County,Jiangsu, China

Soil, plant, and water, as well as trace elements they contain, can influence human health through the food chain. A survey was conducted on distributions of trace elements in soils, plants, and drinking water in Rugao County, Jiangsu Province, China, an agricultural area with a high level of centenarians and nonagenarians. The ratio of people over 90 years old per 100,000 inhabitants (90-rate) based on village (about 4,000 residents in 4 km²) was correlated with trace elements in soil, drinking water, and rice by means of correlation analysis and/or principal component analysis. Although the average 90-rate in the whole area was as high as 277, the rates were not uniform across the entire region. The 90-rate in the area of loamy and strongly-developed Anthrosols and Cambosols was about 330, significantly higher than the 255 in the areas of sandy and strongly-developed Cambosols and of clayey and weakly-developed Cambosols. The concentrations of available Se, B, Ni, and Mo in soils of the area with the high 90-rate were markedly greater than those in the area with the low 90-rate. This was demonstrated by highly positive correlations between the 90-rate and available Se (r = 0.33), B (r = 0.21), Ni (r = 0.17) and Mo (r = 0.17) at the p < 0.01 level and high loadings of available Se (0.851), B (0.535), Ni (0.594) and Mo (0.394) in the longevous factor. Similar relationships between the available elements in soils and elements in water and rice were found. These results suggest that: (1) the available forms of elements in soil were more crucial to elemental bio-availability in the ecosystem and human health than total elements in soil; and (2) the element association above might have affected the 90-rate positively and could be an important environmental geochemical factor influencing the longevity of humans.