Occupational exposure to synthetic musks in barbershops,compared with the common exposure in the dormitories and households

Synthetic musks (SMs) have been widely used as fragrance ingredients in personal care and sanitary commodities. Due to their high volatility and particle-binding affinity, the indoor dust is a major reservoir of SMs, and dust ingestion could be an important exposure way to special populations, such as hairdressers. In spite of the known toxicity of SMs, there is no information regarding the occurrence of SMs in barbershop dusts and the exposure of hairdressers through indoor dust ingestion. In the present study, the levels of two nitro musks and five polycyclic musks were measured from indoor dust samples collected from barbershops, and some other indoor dust samples were also collected from dormitories, bathhouses and households for comparison. The concentrations of ∑SMs in barbershop dusts were 10–100 times higher than those from the other three indoor microenvironments. Polycyclic musks accounted for 89.4% of ∑SMs on average in all samples, of which two compounds, HHCB and AHTN jointly dominated 97.9% of polycyclic musks. The levels of HHCB and AHTN varied from 12.2 to 8.39 × 10⁵ and from 13.2 to 3.49 × 10⁵ ng g⁻¹, respectively. The daily intakes (DIs) of ∑SMs through house dust ingestion were estimated using the model of high dust ingestion and worst-case exposure (P95), and the corresponding exposure rates were 2791, 135 and 727 ng d⁻¹ for the hairdressers, general population and toddlers. SMs were also detected in blood samples collected from the hairdressers and normal adults (n = 50 and 10, respectively). There was no significant difference between these two groups. Despite the absence of higher SM concentrations in hairdresser’s blood, we should not overlook the potential occupational health risks due to their high SMs ingestion rate.     

磷酸活化石墨的氧还原特性以及用于微生物燃料电池阴极

研究了磷酸活化对石墨电极上氧还原反应的影响,并考察了磷酸活化石墨材料应用于微生物燃料电池阴极的可行性。首先以循环伏安和电化学阻抗谱等电化学方法考察了经磷酸活化的石墨材料的氧还原能力,发现经质量分数为85%磷酸活化12 h后其氧还原能力最强;然后将活化石墨材料应用于微生物燃料电池的阴极,进行极化曲线和功率密度曲线的测定。结果表明,磷酸活化阴极微生物燃料电池的最大功率密度可达7.92 W/m3,为未活化石墨阴极微生物燃料电池的3.4倍;同时进行了电化学比表面积的测定及FTIR的分析测定,结果表明,磷酸活化石墨颗粒的比表面积(7.716m2/g)较未活化颗粒(10.940 m2/g)略有减小,但其表面官能团的数量和种类发生了很大变化。表面官能团的变化可能是导致石墨材料氧还原能力增强及MFCs产电性能提高的重要原因。     

巢湖湖岸砂石的磷吸附特性研究

以巢湖湖岸上富含铁、铝、锰等元素的砂石为实验材料,研究其对水体中磷的吸附效果。实验表明:在砂石对磷的吸附过程中,同时存在着物理吸附和化学吸附,且以化学吸附作用为主,符合准二级动力学模型;砂石对磷的作用与溶液初始磷浓度有关,磷释放与吸附的临界浓度点约为0.04 mg/L;砂石对磷的吸附符合Langmuir等温吸附方程,最大吸附量约为1 428.57 mg/kg,对磷的吸附效果比普通沙石要好,且经济易得。     

铁炭微电解预处理高浓度高盐制药废水

采用铁炭微电解法预处理高浓度高盐制药废水,并对反应条件、处理效果、反应动力学和机理进行研究。通过单因素实验初步研究进水pH、铁用量、反应时间和铁炭比对处理效果的影响;通过正交实验表明进水pH对处理效果影响最大,并得到最佳反应条件为:进水pH为4.5,铁投加量40 g/L,铁炭质量比1∶1,反应时间4 h,COD去除率可达40%以上,并可以提高废水的可生化性,后续通过厌氧生物处理出水可达二级污水综合排放标准。通过对各级反应动力学方程进行回归分析,表明微电解处理制药废水基本遵循一级反应动力学。铁炭微电解处理制药废水效果好,并可以提高可生化性,同时具有操作简单和成本低的优点,为制药废水的预处理提供新的途径。     

基于信息熵的灰色模型在地质灾害评价中的应用——以四川青川县为例

地质灾害的发生是由地层岩性、地质构造、地形地貌、气象条件和人类工程活动等诸多因素综合作用的结果,依靠知识与监测无法完全认识其复杂的演变机制,是一种典型的"灰色系统"。基于灰色理论的模型在区域地质灾害危险性评价中得到了广泛的应用,但是由于地质灾害的复杂性,这种以模型为核心的评价方法难以抽象或概化出模型所需的条件,因此出现了评价方与评价对象之间的"不兼容"现象。传统的方法是利用人为的主观判断来获取评价模型所需的条件,不可避免地带来评价的随意性与主观性。通过引入信息熵理论,对传统的灰色模型进行修正,建立了基于信息熵的灰色模型,很好地解决了这个问题。以四川青川县为例,对该模型的正确性进行了应用,取得了较好的效果。     

Comparison on gestation and lactation exposure of perfluorinated compounds for newborns

Perfluorinated compounds (PFCs) are worldwide present in the environment and the general population. Animal studies have shown developmental toxicity of these compounds. To investigate the PFCs exposure of neonates from mother during gestation and lactation, we analyzed twelve PFCs in matched maternal serum, cord serum and breast milk samples collected from 50 pairs of women and their newborns between June and July 2009 in Jinhu, China. Eight PFCs were detected in serum samples, and five of them were also detectable in breast milk. A significant intercorrelation between PFCs concentrations in matched maternal serum, cord serum and breast milk was observed (p<0.01, r=0.435-0.911). The median partition ratio was from 0.39:1 (PFDA) to 1.74:1 (PFTrDA) for seven PFCs through the placenta, and was from 0.02:1 (PFOS) to 0.09:1 (PFOA) for five PFCs through the lactation. A high transport efficiency of PFOA both through placental barrier and lactation was observed. The postnatal exposure of PFCs through lactation was higher compared to prenatal exposure, especially for PFOA.     

完全自营养脱氮过程中的影响因素

基于正交实验考察了溶解氧（DO）、初始NH4＋-N浓度、pH对SBR自营养脱氮性能的影响。结果表明,DO和NH4＋-N浓度对好氧氨氧化速率影响大,pH对好氧氨氧化速率的影响小;DO、NH4＋-N浓度对亚硝酸氧化速率的影响较大,pH对亚硝酸氧化速率的影响较小;DO、NH4＋-N浓度和pH对厌氧氨氧化菌（ANAOB）的活性影响较小。好氧氨氧化菌（AOB）直接影响到CANON系统的总氮去除能力,是CANON系统的控制反应,DO是关键控制因子。实验确定的CANON系统优化运行条件为,DO（0．3±0．05）mg／L、初始NH4＋-N浓度150mg／L和pH7．4。     

Remote sensing of aquatic vegetation distribution in Taihu Lake using an improved classification tree with modified thresholds

Classification trees (CT) have been used successfully in the past to classify aquatic vegetation from spectral indices (SI) obtained from remotely-sensed images. However, applying CT models developed for certain image dates to other time periods within the same year or among different years can reduce the classification accuracy. In this study, we developed CT models with modified thresholds using extreme SI values (CT(m)) to improve the stability of the models when applying them to different time periods. A total of 903 ground-truth samples were obtained in September of 2009 and 2010 and classified as emergent, floating-leaf, or submerged vegetation or other cover types. Classification trees were developed for 2009 (Model-09) and 2010 (Model-10) using field samples and a combination of two images from winter and summer. Overall accuracies of these models were 92.8% and 94.9%, respectively, which confirmed the ability of CT analysis to map aquatic vegetation in Taihu Lake. However, Model-10 had only 58.9-71.6% classification accuracy and 31.1-58.3% agreement (i.e., pixels classified the same in the two maps) for aquatic vegetation when it was applied to image pairs from both a different time period in 2010 and a similar time period in 2009. We developed a method to estimate the effects of extrinsic (EF) and intrinsic (IF) factors on model uncertainty using Modis images. Results indicated that 71.1% of the instability in classification between time periods was due to EF, which might include changes in atmospheric conditions, sun-view angle and water quality. The remainder was due to IF, such as phenological and growth status differences between time periods. The modified version of Model-10 (i.e. CT(m)) performed better than traditional CT with different image dates. When applied to 2009 images, the CT(m) version of Model-10 had very similar thresholds and performance as Model-09, with overall accuracies of 92.8% and 90.5% for Model-09 and the CT(m) version of Model-10, respectively. CT(m) decreased the variability related to EF and IF and thereby improved the applicability of the models to different time periods. In both practice and theory, our results suggested that CT(m) was more stable than traditional CT models and could be used to map aquatic vegetation in time periods other than the one for which the model was developed.     

Dynamic changes in functional gene copy numbers and microbial communities during degradation of pyrene in soils

This study investigates the dynamics of pyrene degradation rates, microbial communities, and functional gene copy numbers during the incubation of pyrene-spiked soils. Spiking pyrene to the soil was found to have negligible effects on the bacterial community present. Our results demonstrated that there was a significant difference in nidA gene copy numbers between sampling dates in QZ soil. Mycobacterium 16S rDNA clone libraries showed that more than 90% mycobacteria detected were closely related to fast-growing PAH-degrading Mycobacterium in pyrene-spiked soil, while other sequences related to slow-growing Mycobacterium were only detected in the control soil. It is suggested that nidA gene copy number and fast-growing PAH-degrading Mycobacterium could be used as indicators to predict pyrene contamination and its degradation activity in soils.