Occurrence and loss over three years of 72 pharmaceuticals and personal care products from biosolids–soil mixtures in outdoor mesocosms

Municipal biosolids are in widespread use as additives to agricultural soils in the United States. Although it is well known that digested sewage sludge is laden with organic wastewater contaminants, the fate and behavior of micropollutants in biosolids-amended agricultural soils remain unclear. An outdoor mesocosm study was conducted in Baltimore, Maryland, to explore the fate of 72 pharmaceuticals and personal care products (PPCPs) over the course of three years in that were placed in plastic containers made from polyvinylchloride and kept exposed to ambient outdoor conditions. Of the 72 PPCPs tested for using EPA Method 1694, 15 were initially detected in the soil/biosolids mixtures at concentrations ranging from low parts-per-billion to parts-per-million levels. The antimicrobials triclocarban and triclosan showed the highest initial concentrations at 2715 and 1265 μg kg⁻¹, respectively. Compounds showing no discernable loss over three years of monitoring included diphenhydramine, fluoxetine, thiabendazole and triclocarban. The following half-life estimates were obtained for compounds showing first-order loss rates: azithromycin (408–990 d) carbamazepine (462–533 d), ciprofloxacin (1155–3466 d), doxycycline (533–578 d), 4-epitetracycline (630 d), gemfibrozil (224–231 d), norfloxacin (990–1386 d), tetracycline (578 d), and triclosan (182–193 d). Consistent with other outdoor degradation studies, chemical half-lives determined empirically exceeded those reported from laboratory studies or predicted from fate models. Study results suggest that PPCPs shown in the laboratory to be readily biotransformable can persist in soils for extended periods of time when applied in biosolids. This study provides the first experimental data on the persistence in biosolids-amended soils for ciprofloxacin, diphenhydramine, doxycycline, 4-epitetracycline, gemfibrozil, miconazole, norfloxacin, ofloxacin, and thiabendazole.     

防护材料静电衰减性能测试仪的研制

介绍防护材料静电衰减性能测试仪的研制要点及使用效果。阐述了防护材料静电衰减性能测试仪的测试原理,采用可精确控制稳压的±5 k V高压直流电源给试样加压,采用非接触的旋叶式静电检测传感器对加压后试样的静电衰减性能进行实时监测,并研制了静电电荷衰减性能测试仪校准装置从而获得较高的校准准确度,使得研制出的防护材料静电衰减性能测试仪测试结果准确,稳定性好。认为该仪器能够正确评价单层均匀防护材料的静电衰减性能。     

西安脉冲堆氙、钐反应性分析

对西安脉冲堆裂变产物中毒进行了深入地分析研究。利用脉冲堆物理计算程序计算了西安脉冲堆在不同功率下停堆前后氙(135Xe)和钐(149Sm)反应性变化,得到氙毒和碘坑的计算值,并与实测值进行了比较。结果表明,理论计算值与实测值符合较好, 特别是碘坑值,二者只相差5.7×10-5。碘坑反应性值较小,不会影响启动,即西安脉冲堆停堆后,随时都可以安全启动。     

Biodistribution of Liposomes of Terbutaline Sulfate in Guinea Pigs

A series of liposomes was prepared with various lipid (egg phosphatidyl choline [egg PC], phosphatidyl glycerol [PG], dipalmitoyl phosphatidylcholine [DPPC], distearoyl phosphatidyl choline [DSPC], dipalmitoyl phosphatidyl glycerol [DPPG], phosphatidyl ethanolamine [PE], cholesterol [CH], and stearylamine [SA]) compositions, such as egg PC:PG:CH (55:5:40), DPPC:PG:CH (55:5:40), DSPC:DSPG:CH (55:5:40) egg PC:SA:CH (55:5:40), DSPE:DSPG:CH (55:5:40) in molar ratio. Liposomal formulations were administered to guinea pigs intravenously; 3 hr after the treatment, serum samples and various organs (e.g., liver, spleen, lung) were removed and analyzed for drug concentration by a high-performance liquid chromatographic (HPLC) method. Based on the above study, a liposomal preparation with better lung specificity was selected, and the time profile of these liposomes was determined in guinea pigs. Three hours postadministration, a significant difference in blood levels was observed between free terbutaline sulfate and the various liposomal formulations. Localization of the drug in the lungs increased considerably when encapsulated drug was used, and the highest percentage localization was observed with DSPC:DSPG:CH (55:5:40) liposomes. The percentage recovery of the drug in the lungs with egg PC:CH:SA (55:40:5) liposomes did not change significantly when compared with egg PC:CH:PG (55:40:5) liposomes. To establish the time course of disposition of the liposomes, DSPC:SPG:CH (55:5:40) liposomes were selected. Terminal half-life t_1/2 of the drug in blood with free drug solution was about 12 hr, whereas with liposomes, a twofold increase in t_1/2 was observed. The disposition data indicated that the clearance of the drug was delayed by 1.5 times when incorporated into liposomes.     

Measurements and modeling of pesticide persistence in soil at the catchment scale

Degradation of pesticides in soils is both spatially variable and also one of the most sensitive factors determining losses to surface water and groundwater. To date, no general guidance is available on suitable approaches for dealing with spatial variation in pesticide degradation in catchment or regional scale modeling applications. The purpose of the study was therefore to study the influence of various soil physical, chemical and microbiological characteristics on pesticide persistence in the contrasting cultivated soils found in a small (13 km²) agricultural catchment in Sweden and to develop and test a simple model approach that could support catchment scale modeling. Persistence of bentazone, glyphosate and isoproturon was investigated in laboratory incubation experiments. Degradation rate constants were highly variable with coefficients of variation ranging between 42 and 64% for the three herbicides. Multiple linear regression analysis and Mallows Cp statistic were employed to select the best set of independent parameters accounting for the variation in degradation. Soil pH and the proportion of active microorganisms (r) together explained 69% of the variation in the bentazone degradation rate constant; the Freundlich sorption co-efficient (K_f) and soil laccase activity together explained 88% of the variation in degradation rate of glyphosate, while soil pH was a significant predictor (p < 0.05) for isoproturon persistence. However, correlations between many potential predictor variables made clear interpretations of the statistical analysis difficult. Multiplicative models based on two predictors chosen ‘a priori’, one accounting for microbial activity (e.g. microbial respiration, laccase activity or the surrogate variable soil organic carbon, SOC) and one accounting for the effects of sorption on bioavailability, showed promise to support predictions of degradation for large-scale modeling applications, explaining up to 50% of the variation in herbicide persistence.     

新核素~（237）Th递次衰变曲线分解

按照合成新丰中子核￣（２３７）Ｔｈ的实验数据处理要求，设计了相应的数值方法和计算机程序，采用非迭代方法和随机搜索优化方法分解递次衰变曲线，得到了￣（２３７）Ｔｈ的半衰期，有关结果检验并支持了实验中合成￣（２３７）Ｔｈ的结论。     

人体内^1^3^7Cs的代谢

~(137)Cs 是具有重要生物学意义的裂变产物,因此关于~(137)Cs 在人体内代谢的研究非常重要。本文评述了文献报道的21例受到~(137)Cs 事故照射的中国人的滞留和排泄,主要讨论了长寿命项的生物半排期。14例中国成人(包括男性、女性)的生物半排期的平均值为81 d,国际放射防护委员会(ICRP)推荐的成人~(137)Cs 的生物半排期为110 d。文中还给出了17例中国人的体重与~(137)Cs 生物半排期的关系式。     

Biodistribution of liposomes of terbutaline sulfate in guinea pigs

A series of liposomes was prepared with various lipid (egg phosphatidyl choline [egg PC], phosphatidyl glycerol [PG], dipalmitoyl phosphatidylcholine [DPPC], distearoyl phosphatidyl choline [DSPC], dipalmitoyl phosphatidyl glycerol [DPPG], phosphatidyl ethanolamine [PE], cholesterol [CH], and stearylamine [SA]) compositions, such as egg PC:PG:CH (55:5:40), DPPC:PG:CH (55:5:40), DSPC:DSPG:CH (55:5:40) egg PC:SA:CH (55:5:40), DSPE:DSPG:CH (55:5:40) in molar ratio. Liposomal formulations were administered to guinea pigs intravenously; 3 hr after the treatment, serum samples and various organs (e.g., liver, spleen, lung) were removed and analyzed for drug concentration by a high-performance liquid chromatographic (HPLC) method. Based on the above study, a liposomal preparation with better lung specificity was selected, and the time profile of these liposomes was determined in guinea pigs. Three hours postadministration, a significant difference in blood levels was observed between free terbutaline sulfate and the various liposomal formulations. Localization of the drug in the lungs increased considerably when encapsulated drug was used, and the highest percentage localization was observed with DSPC:DSPG:CH (55:5:40) liposomes. The percentage recovery of the drug in the lungs with egg PC:CH:SA (55:40:5) liposomes did not change significantly when compared with egg PC:CH:PG (55:40:5) liposomes. To establish the time course of disposition of the liposomes, DSPC:SPG:CH (55:5:40) liposomes were selected. Terminal half-life t_1/2 of the drug in blood with free drug solution was about 12 hr, whereas with liposomes, a twofold increase in t_1/2 was observed. The disposition data indicated that the clearance of the drug was delayed by 1.5 times when incorporated into liposomes.     

A new value for the half-life of Be by Heavy-Ion Elastic Recoil Detection and liquid scintillation counting

The importance of ¹⁰Be in different applications of accelerator mass spectrometry (AMS) is well-known. In this context the half-life of ¹⁰Be has a crucial impact, and an accurate and precise determination of the half-life is a prerequisite for many of the applications of ¹⁰Be in cosmic-ray and earth science research. Recently, the value of the ¹⁰Be half-life has been the centre of much debate. In order to overcome uncertainties inherent in previous determinations, we introduced a new method of high accuracy and precision. An aliquot of our highly enriched ¹⁰Be master solution was serially diluted with increasing well-known masses of ⁹Be. We then determined the initial ¹⁰Be concentration by least square fit to the series of measurements of the resultant ¹⁰Be/⁹Be ratio. In order to minimize uncertainties because of mass bias which plague other low-energy mass spectrometric methods, we used for the first time Heavy-Ion Elastic Recoil Detection (HI-ERD) for the determination of the ¹⁰Be/⁹Be isotopic ratios, a technique which does not suffer from difficult to control mass fractionation. The specific activity of the master solution was measured by means of accurate liquid scintillation counting (LSC). The resultant combination of the ¹⁰Be concentration and activity yields a ¹⁰Be half-life of T_1/2 = 1.388 ± 0.018 (1 s, 1.30%) Ma. In a parallel but independent study (Chmeleff et al. [11]), found a value of 1.386 ± 0.016 (1.15%) Ma. Our recommended weighted mean and mean standard error for the new value for ¹⁰Be half-life based on these two independent measurements is 1.387 ± 0.012 (0.87%) Ma.