Sensitivity of isolated eggs of pond snails: a new method for toxicity assays and risk assessment

The concentration of heavy metals in the environment is normally low. We here address whether using the development of isolated pond snail Radix auricularia eggs would provide a more sensitive endpoint and whether the gelatinous matrix of the egg mass surrounding the eggs indeed protects the snail embryos. In the present study, artificial removal of the gelatinous matrix of egg masses greatly increased the sensitivity of developing eggs to a heavy metal (cadmium). The sensitivity of isolated eggs to cadmium was determined using several convenient endpoints, including mortality, hatching rate, and heart rate, with an acute toxicity test and a subchronic test. In the acute toxicity test, a 96-h LC₅₀ value of 58.26 μg/L cadmium was determined. In the subchronic toxicity test, sublethal effects in terms of a significant reduction in hatching rate could be found in the 25-μg/L treatment, and a significant decrease of heart rate was observed in both treatments (5 and 25 μg/L). The high sensitivity of isolated eggs indicates that such tests can be efficient for toxicity assays and risk assessment, although one needs to keep in mind that the ecologically relevant measure of toxicity will be how eggs are affected when they are still inside the egg mass.     

Factors influencing on the bioaccessibility of polybrominated diphenyl ethers in size-specific dust from air conditioner filters

Size-specific concentrations and bioaccessibility of polybrominated diphenyl ethers (PBDEs) in dust from air conditioner filters were measured, and the factors influencing the PBDE bioaccessibility were determined. Generally, the PBDE concentrations increased with decreasing dust particle size, and BDE209 (deca-BDE) was generally the predominant congener. The bioaccessibility ranged from 20.3% to 50.8% for tri- to hepta-BDEs, and from 5.1% to 13.9% for BDE209 in dust fractions of varied particle size. The bioaccessibility of most PBDE congeners decreased with increasing dust particle size. The way of being of PBDE (adsorbed to dust surface or incorporated into polymers) in dust significantly influenced the bioaccessibility. There was a significant negative correlation between the tri- to hepta-BDE bioaccessibility and organic matter (OM) contents in dust. Furthermore, tri- to hepta-BDE bioaccessibility increased with increasing polarity of OMs, while with decreasing aromaticity of OMs. The tri- to hepta-BDE bioaccessibility significantly positively correlated with the surface areas and pore volumes of dust. Using multiple linear regression analysis, it was found that the OM contents and pore volumes of dust were the most important factors to influence the tri- to hepta-BDE bioaccessibility and they could be used to estimate the bioaccessibility of tri- to hepta-BDEs according to the following equation: bioaccessibility (%) = 45.05 − 0.49 × OM% + 1.79 × pore volume. However, BDE209 bioaccessibility did not correlate to any of these factors.     

Bioanalytical and instrumental analysis of estrogenic activities in drinking water sources from Yangtze River Delta

The estrogenic activities of source water from Yangtze River, Huaihe River, Taihu Lake and groundwater in Yangtze River Delta in the dry and wet season were determined by use of reporter gene assays based on African green monkey kidney (CV-1) cell lines. Higher estrogenic activities were observed in the dry season, and the estrogenic potentials in water samples from Taihu Lake were greater than other river basins. None of the samples from groundwater showed estrogen receptor (ER) agonist activity. The 17β-Estradiol (E2) equivalents (EEQs) of water samples in the dry season ranged from 9.41 × 10^?1 to 1.20 × 10¹ ng E2 L^?1. In the wet season, EEQs of all the water samples were below the detection limit as 9.00 × 10^?1 ng E2 L^?1 except for one sample from Huaihe River. The highest contribution of E2 was detected in Yangtze River as 99% of estrogenic activity. Nonylphenol (NP, 100% detection rate) and octylphenol (OP, 100% detection rate) might also be responsible for the estrogenic activities in water sources. Potential health risk induced by the estrogenic chemicals in source water may be posed to the residents through water drinking.     

纳米ZnO/PS薄膜的制备及光降解性能

利用纳米ZnO与聚苯乙烯(PS)高速共混法制备了一种在紫外光下具有自降解性能的复合薄膜.分析表明,经过KH570处理的纳米ZnO与PS通过化学键的方式桥联在一起.TG分析表明,复合薄膜的耐热性较PS有所提高；SEM图像显示0.5 wt％ ZnO在PS薄膜表面分布均匀,经过UV照射后薄膜表面出现光腐蚀现象.复合薄膜紫外光自降解实验表明:0.5 wt％ ZnO/PS薄膜在15W的紫外灯照射下,15d的自降解率为3.715％.     

巯基化合物在万寿菊镉解毒中的作用

采用水培实验方法研究了万寿菊体内镉积累和解毒与巯基化合物含量的关系。万寿菊植株分别在镉浓度为0、0.1、0.5、2和8 mg/L的营养液中暴露7 d,测定了根、茎、叶中镉、非蛋白巯基(NPT)、半胱氨酸(Cys)、γ-谷氨酰半胱氨酸(γ-EC)、谷胱甘肽(GSH)和植物络合素(PCs)的含量。植物根、茎、叶中镉含量都随着镉暴露浓度的增加而增加。当溶液中镉浓度较低(0.1～2 mg/L)时,茎叶中NPT、PCs、Cys和γ-EC含量随着镉浓度增加而增大;当镉浓度较高(8 mg/L)时,茎叶中PCs含量迅速降低,GSH含量大幅度增高。在根部,这些巯基化合物的含量几乎不受镉处理影响,且含量较低。以上研究结果表明:PCs在万寿菊镉的解毒机制中发挥一定的作用,暴露于高浓度的镉,GSH比PCs起着更为重要的解毒作用。     

Comparison of homologous and heterologous formats in nanocolloidal gold-based immunoassays for parathion residue determination

The effectiveness of homologous and heterologous formats in a nanocolloidal gold-based immunoassay for pesticide residue determination was investigated. Parathion, one of the most toxic organophosphorus pesticides, was used as the target analyte. One-step homologous and heterologous test strips based on a nanocolloidal gold-labeled monoclonal antibody were developed for the rapid detection of parathion residues. The results showed that the heterologous format was more effective than the homologous format, being more sensitive, more specific to parathion and more tolerant of matrix interferences. The best competitive hapten was found to have a moderate heterology and the opposite electronic distribution to the immunizing hapten. The detection limits for parathion using the preferred heterologous strip were 1 μg/L in water samples and 5 μg/kg in soil and food samples.     

Occurrence and distribution of polycyclic aromatic carbons in sludges from wastewater treatment plants in Guangdong, China

In this study, the occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs) were investigated in six sludge samples collected from Guangdong Province, China. Concentrations of PAHs varying from 2,534.1 to 6,926.6 μg kg^???1 (dry sludge) were observed in three municipal wastewater treatment plants with phenanthrene (Phe), fluoranthene, and pyrene being the main compounds. In addition, 682.6 μg kg^???1 PAHs were detected in one sludge sample from a food processing plant, with fluorene, Phe, and chrysene being the main components. No PAHs were detected in sludge samples obtained from two cosmetic plants. The levels and distributional characteristics of PAHs, polychlorinated biphenyls (PCBs), and polycyclic musks (PMs) from the samples were also compared. The results of this comparison indicated that petrochemical refineries and road traffic played important roles in the PAH loads in sludge, while PMs primarily originated from domestic wastewater and industrial wastewater from cosmetic plants. Finally, the presence of 98.8 μg kg^???1 PCBs in sludge suggested diffusional emission sources from electrical components containing PCBs.     

地下渗滤系统处理农村生活污水的研究

在天津武清区一村落构建了2个并行的地下渗滤系统,考察了其对农村生活污水的处理效果。该系统水力负荷为10 cm/d,处理能力为50 t/d。填充介质选用土壤、陶粒、炉渣和两种自然有机质,按5∶2∶2∶1的比例配置的人工土层。结果表明地下渗滤系统对污水中各种主要污染因子均有一定的去除效果,在进水COD和C/N较低的不利条件下,COD、总磷、氨氮、总氮、悬浮物均得到有效去除,出水中各项污染指标平均浓度均达到《城镇污水处理厂污染物排放标准》中的一级A标准;具体到不同的污染指标,添加了不同有机质的2个并行系统的处理效果也有所不同。总体上看,地下渗滤系统作为农村生活污水的处理设施有很好的应用前景。     

Chlorinated and brominated dibenzo-p-dioxins and dibenzofurans in surface sediment from Taihu Lake, China

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) in surface sediment samples from Taihu Lake--an important water supply of the Yangtze River Delta, China--were investigated in the present study. Concentrations of PCDD/Fs ranged from 0.91 to 4.8 pg TEQ g(-1) dw (mean: 2.9 pg TEQ g(-1) dw, TEQ: Toxic Equivalent), which were all higher than the threshold effect level established by interim sediment quality guidelines in Canada (0.85 pg TEQ g(-1) dw). The levels of PBDD/Fs ranged from 0.16 to 1.6 pg TEQ g(-1) dw (mean: 0.52 pg TEQ g(-1) dw) and accounted for 5-33% (mean: 14%) of the total PCDD/Fs and PBDD/Fs TEQ. Comparatively, the abundance of sedimentary PCDD/Fs in the three regions (Meiliang Bay, Gonghu Bay, and Xukou Bay) showed a decreasing trend from the inflow region to the outflow region, while no significant difference was observed among their 2,3,7,8-PBDD/Fs levels, which suggested that the sources of PCDD/Fs and PBDD/Fs differed in this area. Principal component analysis suggested that the historical production/usage of pentachlorophenol and sodium pentachlorophenate was the dominant source of PCDD/Fs in the sediment of these regions. Although the specific sources of PBDD/Fs in the sediment of Taihu Lake were unclear, it was suspected to be due to atmospheric deposition; however, an additional study is needed to confirm this.     

秦皇岛地热能梯级利用状况与前景分析

在对秦皇岛地热能资源现状和开发利用调查的基础上,对秦皇岛地区的地热资源分布特征进行了分类,通过对相应的地热资源利用现状进行调查,掌握了地热能利用的现状以及存在的种种问题和不足。为了更加合理高效地利用地热能资源,进行开发利用前景分析,制定了地热能综合梯级利用的规划建议。