The occurrence of antihistamines in sewage waters and in recipient rivers

Background, aim and scope  Each year, large quantities of pharmaceuticals are consumed worldwide for the treatment and prevention of human and animal diseases. Although the drugs and the metabolites observed in the wastewaters and in the environment are present at concentrations several orders of magnitude lower than the concentrations required to exert their effects in humans or animals, their long-term impact on the environment is commonly not known. In this study, the occurrence of six antihistamines, which are used for the relief of allergic reactions such as hay fever, was determined in sewage treatment plants wastewaters and in recipient river waters. Materials and methods  The occurrence of the antihistamines cetirizine, acrivastine, fexofenadine, loratadine, desloratadine and ebastine in sewage treatment plants wastewaters and in recipient river waters was studied. The analytical procedure consisted of solid-phase extraction of the water samples followed by liquid chromatography separation and detection by a triple-quadrupole mass spectrometer in the multiple reaction mode. Results  Cetirizine, acrivastine and fexofenadine were detected in both influent and effluent wastewater samples at concentration levels ranging from about 80 to 220 ng/L, while loratadine, desloratadine and ebastine could not be detected in any samples. During sewage treatment, the concentration of the antihistamines dropped by an average of 16–36%. Furthermore, elevated concentrations of antihistamines were observed in samples collected during the season of most intensive plant pollen production, i.e. in May. In the river water samples, the relative pattern of occurrence of cetirizine, acrivastine and fexofenadine was similar to that in the wastewater samples; although the concentration of the compounds was substantially lower (4–11 ng/L). The highest concentrations of the studied drugs were observed near the discharging point of the sewage treatment plant. Discussion  The highest concentrations of antihistamines in STP wastewaters correlate with the outbreak of allergic reaction caused by high amounts of plant pollens in the air. The analysis results of the river water samples show that the antihistamines are carried far away from the effluent discharge points. They may account for a part of the mix of pharmaceuticals and of pharmaceutical metabolites that occur downstream of STPs. Conclusions  Antihistamines are poorly degraded/eliminated under the biological treatment processes applied in the wastewater treatment plants and, consequently, they are continuously being discharged along with other drugs to the aquatic environment. Recommendations and perspectives  As a huge quantity and variety of drugs and their metabolites are continuously discharged to rivers and the sea, the compounds should be considered as contaminants that may possess risks to the aquatic ecosystem. Further studies are urgently needed on the environmental fate of the antihistamines and other pharmaceuticals in the aquatic environment. These studies should be concerned with the stability of the compounds, their transformation reactions and the identity of the transformation products, the distribution of drugs and their uptake and effects in organisms. On the basis of these studies, the possible environmental hazards of pharmaceuticals may be assessed.     

Oxidative properties of ambient PM2.5 and elemental composition: Heterogeneous associations in 19 European cities

We assessed the extent to which constituents of PM_2.5 (transition metals, sodium, chloride) contribute to the ability to generate hydroxyl radicals (OH) in vitro in PM_2.5 sampled at 20 locations in 19 European centres participating in the European Community Respiratory Health Survey. PM_2.5 samples (n = 716) were collected on filters over one year and the oxidative activity of particle suspensions obtained from these filters was then assessed by measuring their ability to generate OH in the presence of hydrogen peroxide. Associations between OH formation and the studied PM constituents were heterogeneous. The total explained variance ranged from 85% in Norwich to only 6% in Albacete. Among the 20 centres, 15 showed positive correlations between one or more of the measured transition metals (copper, iron, manganese, lead, vanadium and titanium) and OH formation. In 9 of 20 centres OH formation was negatively associated with chloride, and in 3 centres with sodium. Across 19 European cities, elements which explained the largest variations in OH formation were chloride, iron and sodium.     

Spatio-temporal characteristics of PM10 concentration across Malaysia

The recurrence of forest fires in Southeast Asia and associated biomass burning, has contributed markedly to the problem of trans-boundary haze and the long-range movement of pollutants in the region. Air pollutants, specifically particulate matter in the atmosphere, have received extensive attention, mainly because of their adverse effect on people's health. In this study, the spatial and temporal variability of the PM10 concentration across Malaysia was analyzed by means of the rotated principal component analysis. The results suggest that the variability of the PM10 concentration can be decomposed into four dominant modes, each characterizing different spatial and temporal variations. The first mode characterizes the southwest coastal region of the Malaysian Peninsular with the PM10 showing a peak concentration during the summer monsoon i.e. when the winds are predominantly southerlies or southwesterlies, and a minimal concentration during the winter monsoon. The second mode features the region of western Borneo with the PM10 exhibiting a concentration surge in August–September, which is likely to be the result of the northward shift of the Inter Tropical Convergence Zone (ITCZ) and the subsequent rapid arrival of the rainy season. The third mode delineates the northern region of the Malaysian Peninsular with strong bimodality in the PM10 concentration. Seasonally, this component exhibits two concentration maxima during the late winter and summer monsoons, as well as two minima during the inter-monsoon periods. The fourth dominant mode characterizes the northern Borneo region which exhibits weaker seasonality of the PM10 concentration. Generally, the seasonal fluctuation of the PM10 concentration is largely associated with the seasonal variation of rainfall in the country. However, in addition to this, the PM10 concentration also fluctuates markedly in two timescale bands i.e. 10–20 days quasi-biweekly (QBW) and 30–60 days lower frequency (LF) band of the intra-seasonal timescales. These intra-seasonal fluctuations show strong seasonality with the largest fraction of variance occurring during the boreal summer and the weakest variance during the winter. Generally, the LF intra-seasonal oscillation is stronger compared to the QBW intra-seasonal band.     

Monte Carlo analysis of field water flow comparing uni- and bimodal effective hydraulic parameters for structured soil

Soil structure critically affects the hydrological behaviour of soils. In this paper, we examined the impact of areal heterogeneity of hydraulic properties of a structured soil on soil ensemble behaviour for various soil water flow processes with different top boundary conditions (redistribution and drainage plus evaporation and infiltration). Using a numerical solution of the Richards' equation in a stochastic framework, the ensemble characteristics and flow dynamics were studied for drying and wetting processes observed during a time interval of ten days when a series of relatively intense rainfall events occurred. The effects of using unimodal and bimodal interpretative models of hydraulic properties on the ensemble hydrological behaviour of the soil were illustrated by comparing predictions to mean water contents measured over time in several sites at field scale. Although the differences between unimodal and bimodal fitting are not significant in terms of goodness of fit, the differences in process predictions are considerable with the bimodal soil simulating water content measurements much better than unimodal soil. We also investigated the relative contribution of the soil variability of each parameter on the variance of the water contents obtained as the main output of the stochastic simulations. The variability of the structural parameter, weighting the two pore space fractions in the bimodal interpretative model, has the largest contribution to water content variance. The contribution of each parameter depends only partly on the coefficient of variation, much more on the sensitivity of the model to the parameters and on the flow process being observed. We observed that the contribution of the retention parameters to uncertainty increases during drainage processes; the opposite occurs with the hydraulic conductivity parameters.     

Incorporating layer- and local-scale heterogeneities in numerical simulation of unsaturated flow and tracer transport

This study characterizes layer- and local-scale heterogeneities in hydraulic parameters (i.e., matrix permeability and porosity) and investigates the relative effect of layer- and local-scale heterogeneities on the uncertainty assessment of unsaturated flow and tracer transport in the unsaturated zone of Yucca Mountain, USA. The layer-scale heterogeneity is specific to hydrogeologic layers with layerwise properties, while the local-scale heterogeneity refers to the spatial variation of hydraulic properties within a layer. A Monte Carlo method is used to estimate mean, variance, and 5th, and 95th percentiles for the quantities of interest (e.g., matrix saturation and normalized cumulative mass arrival). Model simulations of unsaturated flow are evaluated by comparing the simulated and observed matrix saturations. Local-scale heterogeneity is examined by comparing the results of this study with those of the previous study that only considers layer-scale heterogeneity. We find that local-scale heterogeneity significantly increases predictive uncertainty in the percolation fluxes and tracer plumes, whereas the mean predictions are only slightly affected by the local-scale heterogeneity. The mean travel time of the conservative and reactive tracers to the water table in the early stage increases significantly due to the local-scale heterogeneity, while the influence of local-scale heterogeneity on travel time gradually decreases over time. Layer-scale heterogeneity is more important than local-scale heterogeneity for simulating overall tracer travel time, suggesting that it would be more cost-effective to reduce the layer-scale parameter uncertainty in order to reduce predictive uncertainty in tracer transport.     

Cation exchange in a glacial till drumlin at a road salt storage facility

At a former wood preservation plant severely contaminated with coal tar oil, in situ bulk attenuation and biodegradation rate constants for several monoaromatic (BTEX) and polyaromatic hydrocarbons (PAH) were determined using (1) classical first order decay models, (2) Michaelis–Menten degradation kinetics (MM), and (3) stable carbon isotopes, for o-xylene and naphthalene. The first order bulk attenuation rate constant for o-xylene was calculated to be 0.0025 d^− 1 and a novel stable isotope-based first order model, which also accounted for the respective redox conditions, resulted in a slightly smaller biodegradation rate constant of 0.0019 d^− 1. Based on MM-kinetics, the o-xylene concentration decreased with a maximum rate of k_max = 0.1 µg/L/d. The bulk attenuation rate constant of naphthalene retrieved from the classical first order decay model was 0.0038 d^− 1. The stable isotope-based biodegradation rate constant of 0.0027 d^− 1 was smaller in the reduced zone, while residual naphthalene in the oxic part of the plume further downgradient was degraded at a higher rate of 0.0038 d^− 1. With MM-kinetics a maximum degradation rate of k_max = 12 µg/L/d was determined. Although best fits were obtained by MM-kinetics, we consider the carbon stable isotope-based approach more appropriate as it is specific for biodegradation (not overall attenuation) and at the same time accounts for the dominant electron-accepting process. For o-xylene a field based isotope enrichment factor ε_field of − 1.4 could be determined using the Rayleigh model, which closely matched values from laboratory studies of o-xylene degradation under sulfate-reducing conditions.     

脂肽类生物表面活性剂液体发酵条件的响应面优化

通过Plackett-Burman和Box-Behnken实验对解淀粉芽孢杆菌XZ-173液体发酵生产表面活性素进行了响应面优化研究。首先使用Plackett-Burman实验对影响表面活性素产量的17个因素进行显著性筛选,结果表明,MnSO4、CuSO4、温度和转速为显著性因素。再运用Box-Behnken实验对这4个显著因素的取值进一步优化,得到各因素优化后的数值分别为4.4 mg/L(MnSO4)、0.18 mg/L(CuSO4)、29℃(温度)和163 r/min(转速)。响应面分析结果表明:该菌株产生表面活性素的最佳培养基为:葡萄糖15 g/L,蛋白胨5 g/L,L-谷氨酸钠6 g/L,KH2PO40.8 g/L,MgSO40.4 g/L,KCl 0.4 g/L,酵母提取物3 g/L,L-苯丙氨酸2.5 mg/L,MnSO44.4 mg/L,CuSO40.18 mg/L,FeSO40.12 mg/L;最适培养条件:pH 7.5,温度29℃,转速163 r/min,接种量5%,装液量50 mL/250 mL,摇床培养36 h。在优化后的条件下,表面活性素实际产量为336 mg/L,实际实验结果与模型预测结果相一致。表面活性素采用HPLC技术分离,发现其在浓度仅为50 mg/L时EI24就可达到70%以上,反映了表面活性素优异的乳化活性以及广阔的应用前景。     

抗压实验法厌氧颗粒污泥机械强度的测定及影响因素分析

通过首先对厌氧颗粒污泥样品进行筛分,然后测定其机械强度,解决了实际操作过程中现有抗压实验法出现的精确度与重现性较差的问题。通过对不同来源厌氧颗粒污泥样品机械强度的测定、对比分析发现,厌氧颗粒污泥的机械强度大小与反应器的规模、反应器所采用水力负荷存在一定的正相关性,且与其主要金属元素（Ca、Fe和Mg）含量的大小存在着密切的关系。     

Baseline soil levels of PCDD/Fs established prior to the construction of municipal solid waste incinerators in China

In order to determine the baseline contamination by polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in different areas in China, prior to the construction of municipal solid waste incinerators (MSWIs), a total of 32 representative soil samples was collected near 16 incinerators and analyzed for their PCDD/F concentrations. The PCDD/F baseline concentrations in the soil samples ranged from 0.32 to 11.4 ng I-TEQ kg⁻¹ (dry matter), with average and median value of 2.73 and 2.24 ng I-TEQ kg⁻¹ (dry matter), respectively, and a span between maximum and minimum recorded value of 36. The PCDD homologues predominated in 26 out of 32 soil samples, with the ratio (PCDDs)/(PCDFs) ranging from 1.1 to 164; however in the other 6 samples, PCDF homologues were larger, with the same ratio varying from 0.04 to 0.8. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to examine PCDD/F amount and profile in these soil samples, and their possible associations with known emission sources: in this process 6 really distinct isomer fingerprints were identified. Background PCDD/F levels and profiles were comparable to those found in soils from China and other countries and indicate a rather low baseline PCDD/F contamination of soils. The present data provide the tools for future assessment of a possible impact of these MSWIs.     

基于“事故树-层次分析法”的高校学生宿舍火灾风险分析

高校学生宿舍的消防安全是高校安全管理的重要内容之一。对学生宿舍的消防进行风险分析对高校的安全管理具有重要意义。本文采用层次分析法对高校宿舍的消防安全进行风险分析。在进行层次分析法之前,引入了事故树,通过事故树寻求指标层中各类重要因素,从而提高了层次分析的准确性和有效性。分析结果表明：采用事故树-层次分析法,可定量地分析各个因素对建筑火灾风险的影响大小,对制定建筑火灾的防范措施具有一定的指导意义。分析结果表明：消防设施、火灾荷载和安全疏散设备对学生宿舍的火灾安全有着重要的影响,应该引起安全管理人员的重视。