Degradation of recalcitrant organic contaminants by solar photocatalysis.

Biological pre-treated landfill leachates of Djebel Chakir contains some macromolecular organic substances that are resistant to biological degradation. The aim of the present work is to assess the feasibility of removing refractory organic pollutants in biological pre-treated landfill leachate by solar photocatalyse process. Leachate pollutant contents are studied to assess their contribution to leachate pollution and their treatability by solar photocatalyse process. Phenol is chosen as model of pollutants, to evaluate its removal and the efficiency of the photocatalytic system. The experiments were carried out in suspended photocatalytic reactor, using TiO2 Degussa P25, under sunlight illumination (UV-A: 15-31 W/cm2). Under optimum operational conditions, applied to single reactant (phenol), the system presents a TOC removal of 90% (the degradation follows a first-order kinetic). Based on the TOC removal, the results shows that the degradation of biological pre-treated leachate follows a zero-order kinetic. After 5 h of sunlight exposure, 74% of COT is removed. The TOC removal is the best without any correction of the pH and at the TiO2 concentration of 2.5 g/L. The photocatalytic degradation of organic contaminants as well as the formation and disappearance of the by-products were followed by GC/MS. The solar photocatalysis processes induce several modifications of the matrix leading to more biodegradable forms: all the remaining and new compounds generated after the biological pre-treatment of leachate are degraded and other types of organics appear, mainly carboxylic acid, aliphatic hydrocarbons and phtalic acids.     

Removal of trace organic chemical contaminants by a membrane bioreactor

Emerging wastewater treatment processes such as membrane bioreactors (MBRs) have attracted a significant amount of interest internationally due to their ability to produce high quality effluent suitable for water recycling. It is therefore important that their efficiency in removing hazardous trace organic contaminants be assessed. Accordingly, this study investigated the removal of trace organic chemical contaminants through a full-scale, package MBR in New South Wales, Australia. This study was unique in the context of MBR research because it characterised the removal of 48 trace organic chemical contaminants, which included steroidal hormones, xenoestrogens, pesticides, caffeine, pharmaceuticals and personal care products (PPCPs). Results showed that the removal of most trace organic chemical contaminants through the MBR was high (above 90%). However, amitriptyline, carbamazepine, diazepam, diclofenac, fluoxetine, gemfibrozil, omeprazole, sulphamethoxazole and trimethoprim were only partially removed through the MBR with the removal efficiencies of 24-68%. These are potential indicators for assessing MBR performance as these chemicals are usually sensitive to changes in the treatment systems. The trace organic chemical contaminants detected in the MBR permeate were 1 to 6 orders of magnitude lower than guideline values reported in the Australian Guidelines for Water Recycling. The outcomes of this study enhanced our understanding of the levels and removal of trace organic contaminants by MBRs.     

华北平原地下水中有机物淋溶迁移性及其污染风险评价

根据有机污染物的物理化学性质,估算了91种有机物在土壤中的半衰期和有机碳吸附系数,并分析了这些有机物在土壤中的淋溶迁移性。结果表明：对于所研究的污染物,它们的地下水污染指数与其有机碳吸附系数有着很好的负相关性,这为评价地下水中主要有机污染物的污染指数(淋溶迁移性)提供了简易方法。所评价的91种有机物中,38种具有高淋溶和迁移性,易对含水层造成较大范围的污染。通过分析发现,华北平原区域地下水中主要有机物的检出率与其淋溶迁移性有着一定的相关性。因此,地下水污染指数法的应用将有助于预测有机物对地下水的污染风险。     

Use of comprehensive two-dimensional gas chromatography for the broad screening of hazardous contaminants in urban wastewaters.

The list of priority chemicals included in various regulations such as the European Water Framework Directive, as well as the list of hazardous contaminants identified in the aquatic environment, are increasing at an accelerated pace. Therefore, there is a need for broad spectrum methods capable of simultaneously determining hundreds, if not thousands, of contaminants. For the analysis of non-polar or semi-polar contaminants, comprehensive two-dimensional gas chromatography (GC x GC) is more powerful than conventional gas chromatography thanks to a separation on two different stationary phases. This paper reports the use of GC x GC for a broad screening of hazardous contaminants in an urban wastewater plant. Comparison between the raw and treated wastewater has been carried out using a semi-quantitative approach. A variety of drugs, personal care products, pesticides, carcinogens and compounds toxic for reproduction, were identified. Most of these compounds were removed or decreased by this wastewater treatment plant. Preliminary results from this single plant will need to be confirmed by a more extensive study before drawing conclusions on the removal efficiency of 2D-GC amenable compounds.     

Development of adsorbent for the simultaneous removal of organic and inorganic contaminants from aqueous solution

In this study, a modified adsorbent, alginate complex beads, was prepared and applied to the removal of mixed contaminants from wastewater. The alginate complex beads were generated by the immobilization of powdered activated carbon and synthetic zeolites onto alginate gel beads, which were then dried at 110 °C for 20 h until the diameter had been reduced to 1 mm. This dry technique increased the hardness of the adsorbent to assure its durability and application. The adsorption onto the alginate complex beads of organic and inorganic compounds, as target contaminants, was investigated by performing both equilibrium and kinetic batch experiments. From the adsorption isotherms, according to the Langmuir equation, the alginate complex bead was capable of effectively removing benzene, toluene, zinc and cadmium. From kinetic batch experiments, the removal efficiencies of benzene, toluene, zinc and cadmium were found to be 66.5, 92.4, 74.1 and 76.7%, respectively, for initial solution concentrations of 100 mg L(-1). The results indicated that the adsorbent developed in this study has the potential to be a promising material for the removal of mixed pollutants from industrial wastewater or contaminated groundwater.     

Transfer of hydrophobic contaminants in urban runoff particles to benthic organisms estimated by an in vitro bioaccessibility test.

An in vitro bioaccessibility test was applied for assessing the transfer of polycyclic aromatic hydrocarbons (PAHs) present in road dust, into benthic organisms living in a receiving water body. The road dust is supposed to be urban runoff particles under wet weather conditions. Sodium dodecyl sulfate (SDS) solution was used as a hypothetical gut fluid. Pyrene, fluoranthene and phenanthrene were the main PAH species in the SDS extractable fraction of road dust, as well as the whole extract. Benzo(ghi)perylene showed relatively low concentrations in the SDS extract in spite of a high concentration in the original dust. The PAH composition in benthic organisms (polychaetes) did not correspond with that of the surrounding sediment and the PAHs detected were also detected in high concentrations in the SDS extract of road dust. When testing the toxicity of the extracted contaminants by a standardised algal toxicity test, SDS extracts of a detention pond sediment showed higher toxicity than the pore water of the corresponding sediment. Sediment suspension showed a comparative toxicity with 0.1% SDS extract. From the results, the in vitro bioaccessibility test seems more suitable to evaluate the exposed contaminants than the traditional organic solvent extraction method and the SDS extracted fraction is applicable to toxicity tests reflecting the digestive process.     

Ecotoxicological risks from dissolved organic contaminants in a contaminated bay: Combining passive sampling with in vivo bioassays

Innovative and robust methods are needed to evaluate the risks to native aquatic organisms exposed to organic compounds released from contaminated sediments. In the present study, we deployed semi-permeable membrane devices (SPMDs) above sediments in a contaminated harbor at a location in the Laurentian Great Lakes (i.e. Owen Sound Bay) and prepared extracts from these passive samplers for analysis of organic contaminants and for toxicity testing using early life stages of Japanese medaka (Oryzias latipes) and lake whitefish (Coregonus clupeaformis). The concentrations of several classes of organic contaminants estimated from analysis of the SPMD extracts indicated that several polynuclear aromatic hydrocarbon (PAHs) were present in the water column in the inner harbor of Owen Sound Bay at concentrations higher than water quality standards for the protection of aquatic life. Several medaka exposed to the SPMD extract from the inner harbor as well as a positive control compound, benzo[a]pyrene, developed yolk sac edema. However, whitefish did not show the same response. Overall, these data indicate this contamination could contribute to toxicity in sensitive species. The coupling of passive sampling and in vivo bioassays with early life stages of fish shows promise as a method to assess the potential for risks from biologically available fractions of organic contaminants in water. A novel aspect of the present study is the development of a bioassay procedure with early life stages of lake whitefish involving exposures at low temperatures over durations of time that are longer than the bioassays with more conventional model fish species.     

城市水体有机污染类型的三维荧光光谱分析法

运用三维荧光光谱技术对深圳市4种水体的有机污染类型进行了分析研究。实验结果表明,深圳市甲水库主要表现为内源污染;深圳市乙水库主要表现为外源污染;大沙河和校园池塘既有内源污染又有外源污染。有机污染的程度由高到低依次为:大沙河、校园池塘、甲水库、乙水库。     

长江干流主要城市江段微量有机物污染分析

微量有机物对地面水体产生的污染已较普遍，为了解其在长江干流水体中的污染状况与特征，对长江干流主要城市江段水、底质和鱼体中的微量有机污染物进行了检测，根据检测结果，分析和阐述了其微量有机污染物的种类、含量水平及分布特征，并引用美国“多介质环境目标值”评价方法进行了综合评价，结果表明：长江干流主要城市江段水体已普遍受到微量有机物污染，共鉴定出有机物12类308种，主要污染物种为烷烃类、多环芳烃类和脂类；鱼体中微量有机污染物含量普遍高于底质中，而底质中又高于水中；大中型综合工业城市江段污染较为严重，对健康和生态的总环境影响度较大，应引起有关方面的重视。     

The characteristics and measuring technique of refractory dissolved organic substances in urban runoff.

It is considered that refractory dissolved organic substances have caused an increase in the COD concentration in Lake Biwa in recent years. We investigated the organic matter in the first flush of stormwater runoff from a road in the watershed area of the lake, and studied the possibility of improvement in the water environment from that aspect. After percolating the stormwater through soil, we analyzed organic substances fractionated by using GPC-TC. And we examined the effect of removal of organic substances by comparing the peak height before and after percolation. In the result of the experiments, we found that soil infiltration reduced the refractory dissolved organic substance and we successfully designed a system for a simple and easy experimental facility to treat urban runoff.     

Priority organic pollutants in the urban water cycle (Toulouse, France)

Application of the European Water Framework Directive requires Member States to have better understanding of the quality of surface waters in order to improve knowledge of priority pollutants. Xenobiotics in urban receiving waters are an emerging concern. This study proposes a screening campaign of nine molecular species of xenobiotics in a separated sewer system. Five sites were investigated over one year in Toulouse (France) using quantitative monitoring. For each sample, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, nonylphenols, diethelhexylphthalate, linear alkylbenzene sulphonates, methyl tert-butylether, total hydrocarbons, estradiol and ethinylestradiol were analysed. Ground, rain and roof collected water concentrations are similar to treated wastewater levels. Run-off water was the most polluted of the five types investigated, discharged into the aquatic environment. The wastewater treatment plant reduced xenobiotic concentrations by 66% before discharge into the environment. Regarding environmental quality standards, observed concentrations in waters were in compliance with standards. The results show that xenobiotic concentrations are variable over time and space in all urban water compartments.     

Comprehensive assessment of legacy organic contaminants and trends in lake trout from Cayuga Lake,New York: 2011–2017

A seven-year assessment of lake trout contaminants and statistical trend modeling was conducted on Cayuga Lake, New York as the reference monitoring site for the USEPA Great Lakes Fish Monitoring and Surveillance Program (GLFMSP). In all, over 200 individual compounds including polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), organochlorine pesticides (OCPs), polychlorinated napthalenes (PCNs), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) were monitored for the 2011–2017 study period. Legacy contaminants such as PCBs, OCPs, and PBDEs dominate the whole-fish lake trout contaminant profile in the 24–147 ng/g mean concentration range. Total dioxin-like contaminants monitored included PCDD/Fs, CP-PCBs, and PCNs with a mean concentration range of 2.0–516 pg/g. TEQ concentrations for the dioxin-like compounds ranged between 0.3 and 5.3 pg-TEQ/g, and total TEQ averaged 7.2 pg-TEQ/g for whole-fish lake trout. Contaminant trends were modeled using log-linear correlations for both whole-fish lake trout and lake trout eggs. All select compounds modeled for whole-fish lake trout showed significant decreases (average ?53.4%) over the study period. Tissue residue guidelines for the protection of wildlife were uniformly exceeded for both mammals and birds based on mean 2011–2017 total TEQ concentrations measured. All lake trout skin-on fillets from Cayuga Lake analyzed exceed the USEPA human health screening value of 0.15 pg-TEQ/g-ww. Whole-fish lake trout from Cayuga Lake have significantly lower mean total TEQs (6.5 pg-TEQ/g) as compared with the average total TEQ in the Great Lakes (range: 21.9–50.8 pg-TEQ/g) (U = 10.000, p < 0.001), although rates of contaminant decline, contaminant ratios, and half-life (t_1/2) are comparable.     

共基质生物刺激技术去除城市河道底泥难降解有机污染物研究

随着城市河道外源污染的有效控制,河道污染底泥的治理在全面解决水体污染中的地位日渐突出。受污染底泥中的难降解有机物长期残留在环境中,对生物和人类健康造成风险。研究采用共基质生物刺激方法,在深圳河污染底泥中单独投加乙酸钠和甲醇,通过试验,利用微生物的共代谢行为,考察有机物去除效果。研究结果表明:(1)深圳河底泥中投加共基质乙酸钠和甲醇后,刺激底泥微生物增殖,进而促进底泥生物降解;(2)使用共基质生物刺激技术可有效去除有机污染物,但对底泥还原状态和黑臭问题并无改善,这可通过后续向底泥投加化学氧化剂加以解决。     

水在雪中下渗的数学模拟

对于融雪水在雪中下渗过程的模拟，虽然已有大量研究，但理论较多，模拟实例很少，边界条件一般也由资料外推而来，而且由于建模中某些参数的简化，使具体应用条件变得模糊。本文在现有理论的基础上，利用全套实测资料对积雪表面融化和融雪水下渗进行了全过程多日模拟，并对模拟结果进行了检验。结果证明，该模型及其具体计算方法在当雪中水流流量大于0.05cm3/cm2/h时完全符合实际水流下渗过程，但低于此值时则不适合。     

新疆内陆河流域融雪期积雪深度变化影响因素研究

采用因子分析法结合多元线性回归分析法对影响融雪期积雪深度变化的因素进行分析.结果表明:融雪期积雪深度与热能因子(地表温度,气温,净辐射)呈负相关,与水汽因子(水汽压,相对湿度,降雨)呈弱的负相关.空气流动因子(日均风速)对其影响较微弱;在此基础上对各因素的影响强弱,按大小进行排序,各因素对融雪期积雪深度变化影响的排序为:热能因子＞水汽因子＞空气流动因子.建立的回归方程通过了显著性检验表明:利用因子分析法与多元线性回归分析法结合,分析融雪期积雪深度的变化影响因素是可行的.     

积雪最低含水饱和度的野外测定

在野外对处于融化期的自然积雪的最低含水饱和度进行了测定。结果显示，当下渗水流流速在毛管力起着不可忽视作用的约3×10-8～1.39×10-7ms-1时，所对应的积雪平均含水饱和度为0.05～0.07。流速在约10-8ms-1以下时，达到最低含水饱和度，平均值为0.02～0.03。在毛管力起作用的范围内，积雪的不同层位的含水饱和度有较大差异，而且差异随流速的减小而显著增加。     

A larval medaka (Oryzias latipes) acute toxicity assay combined with solid-phase extraction to efficiently determine the toxicity of organic contaminants in river water.

Using a larval medaka (Oryzias latipes) acute toxicity assay combined with solid-phase extraction, we proposed a method for efficiently determining the fish toxicity of organic contaminants in river water. Organic toxicants were 10, 20, 50 and 100-fold concentrated from 4 L of the sample with adsorption cartridges. The lethal effect was observed by exposing every ten individuals of 48-72 h old larval medaka to 20 mL of each solution for 48h. The median lethal concentration rate (LCR50) was used as an indicator for the toxicity. With the developed toxicity test method, more than seven times difference was found in the LCR50 of the river water samples. LCR50 distribution profiles were compared with 125 samples in two typical rivers. The result revealed a lower toxicity level in the mainstream than in the confluences, and a lower toxicity level in Sagami River than in Ayase River. LCR50 proved unique as a toxicity indicator, which was impossible to speculate from the conventional water quality indicator of the dissolved organic carbon concentration. As an effective screening test for priority settings, the method can help us with an efficient planning for the environmental investigation and management.     

弯曲性分叉河道中污染物扩散性的初步研究

弯曲性分叉河道中水流特征复杂,对污染物扩散有很大影响。为了定量分析其水流特征对污染物扩散的影响,采用有限元方法求解弯曲性分叉河道中的污染物扩散数学模型,研究其中污染物扩散的状况。主要针对河道回流、绕流对污染物扩散的影响进行了详细数值模拟计算,并分别给出了可视化结果及平均的扩散距离。计算结果表明:边界层稍微减弱污染物的扩散,弯道分离使污染物扩散呈现多向扩散,而回流和绕流尾迹区使污染物很难扩散,从而有利于泄漏污染物的收集和集中治理。     

撒融雪剂除冰对桥梁破损的影响

撒融雪剂除冰引起的钢筋锈蚀是北方跨河桥梁结构破坏的重要原因。通过对北京市通州区的一些跨河桥梁的氯化物含量的测试,初步探讨了造成该地区桥梁钢筋锈蚀的主要原因,并从设计方面提出解决问题的办法。     

高寒山区融雪模型的改进与应用研究

以台兰河流域为研究区,采用改进的含融雪结构的新安江模型,利用2003-2009年逐日水文气象资料进行水文模拟。结果表明:改进的融雪计算方法能够很好的应用于含融雪结构的新安江模型中,并能在径流模拟研究中取得令人满意的结果。