Suitability of different salt marsh plants for petroleum hydrocarbons remediation

The suitability of the salt-marsh species Halimione portulacoides, Scirpus maritimus, Juncus maritimus and an association of the last two for remediation of petroleum hydrocarbons (PHC) in soil was investigated. An outdoor laboratory experiment (microcosm-scale) was carried out using contaminated soil collected in a refinery, as a complement of another study carried out in the refinery environment (mesocosm-scale). Soil samples with old contamination (mainly crude oil) and with a mixture of the old and recent (turbine oil) contamination were tested. Studies in both micro- and mesocosm-scale provided results coherent in substance. The presence of S. maritimus caused removal of old contamination which was refractory to natural attenuation (after 7 months of exposure, efficiency was 13% when only old contamination was present and 40% when the soil also contained recent contamination). H. portulacoides (only included in the microcosm-scale study) revealed also potentiality for PHC remediation, although with less efficiency than S. maritimus. Degradation of recent contamination was also faster in the presence of plants (after 7 months: 100% in the presence of S. maritimus vs. 63% in its absence). As these species are common in salt marsh areas in Atlantic coast of Europe, it is probable they will be also useful for recovering coast sediments. In contrast, J. maritimus and association did not reveal capability to remove PHC from soil, the presence of J. maritimus inhibiting the capability of S. maritimus.     

Safety management by use of laser mass spectrometry of polychlorinated biphenyls (PCBs) in the processed gas and work environment of a PCB disposal plant

This study demonstrates the applicability of laser mass spectrometry for safety management of the processed gas and the work environment in a polychlorinated biphenyl (PCB) disposal plant. By utilization of laser ionization/ion trapping storage/time-of-flight mass spectrometry (LI-IT-TOFMS), we analyzed gaseous PCBs from scrap capacitors with on-line detection. It was confirmed that few contaminants were detected in the spectrum. By the effect of laser-induced selective ionization, it was considered that there was little interference with the mass range of PCBs. The accuracy of LI-IT-TOFMS when analyzing environmental gas was almost the same as that for the PCB standard gas. It was possible to perform on-line analysis of the work environment for over 2000 h (120 000 data points). LI-IT-TOFMS was thus shown to be a very useful method for ensuring the safety of the work environment in disposal plants for PCBs.     

Polycyclic Aromatic Hydrocarbons: Need for Assessment of Health Risks in India? Study of An Urban-Industrial Location in India

This paper reports the PAHs levels in the atmosphere of an urbanised industrial site of India. A high-resolution capillary gas chromatograph with a mass spectrometric detector (HRCGC-MS) and a high performance liquid chromatograph (HPLC) equipped with a fluorescence detector were used for the identification and quantitation of PAHs. The atmospheric levels of PAHs were higher (4.66 ng/m³ yearly average) than most of the concentrations previously reported in the literature. Indian sites were found more contaminated with potently carcinogenic: four and above ringed PAHs. Based on a good correlation between the levels of lead, vanadium, BaP and BghiP, the vehicular emission appears to be a major source of the PAHs. Further, the higher levels of observed PAHs could be attributed to the vertical distribution of the aerosols, the preference of the PAHs for the particulate phase and the greater availability of the substrate in the atmosphere for their sorption. This paper also discusses the need for development of a PAHs monitoring protocol and related health effect studies in developing countries such as India.     

A comparative study on the uptake of polycyclic aromatic hydrocarbons by Anodonta californiensis

Uptake of polycyclic aromatic hydrocarbons (PAHs) by the freshwater bivalve mollusc Anodonta californiensis was examined in the presence and absence of surfactant in order to gain further insight into mixture toxicity and to predict whether certain mixtures have negative and/or positive effects on aquatic organisms. In the presence of surfactant, the uptake of anthracene or chrysene was higher than that of naphthalene, given the same concentration in the solution. In the absence of surfactant, the trend was similar, but the uptakes were increased by approximately 100% compared to those in the presence of surfactant. On the uptake of naphthalene, the presence of anthracene showed only minor influence. The uptake of anthracene was affected by both naphthalene and chrysene. The uptake of chrysene was influenced by neither naphthalene nor anthracene. There was no observable displacement of divalent cations from the surface of the gill membrane by any of the PAHs studied.     

水质中多种挥发性有机物的同时测定

在采用双柱双检测器的基础上，对水中24种挥发性有机物进行了同时测定。当进样体积为5ml时，最低检测限为0．5俐L，线性范围及测定范围为0．5～50倒L，1μg/L和20μg/L浓度水平的加标回收率在80．0％-110％之间，变异系数为0．6％～9．2％，实验结果令人满意。     

Constructed wetlands treating highway runoff in the central Mediterranean region

Two free water surface (FWS) and two subsurface flow (SSF) pilot-size constructed wetlands treating highway runoff (HRO) were monitored over a period of two years (September 2005-August 2007). One FWS and one SSF were designed with a hydraulic retention time (HRT) of 12h, named FWS12 and SSF12, respectively, with each one capable of treating a maximum HRO of 12.6 m(3) d(-1). The other couple, named FWS24 and SSF24, respectively, was designed with an HRT of 24h, with each receiving a maximum HRO of 6.3 m(3) d(-1). The influent flowed from a highway section with a total surface 2752 m(2) on the island of Crete, Greece, in the heart of the South-Central Mediterranean region. Influent and effluent were monitored for COD, TSS, total N (TN), NO(3)(-) and total P (TP) concentrations. Furthermore, removal efficiencies were examined for heavy metals (Cu, Ni, Pb, Zn) for both years, while polycyclic aromatic compounds (PAHs) were examined for the period between September 2006 and August 2007. The influent had a two-year average COD value of 101 mg l(-1), whereas the mean values for TSS, TN, N-NO(3)(-) and TP were 203, 4.30, 1.25 and 4.17 mg l(-1), respectively. For Cu, Ni, Pb and Zn the respective two-year mean influent concentrations were 56, 114, 49 and 250 microg l(-1). Mean concentration of total PAHs in runoff (summation operator PAHs, 16 compounds) were 12.01 microg l(-1). The performance among the four beds was not significantly different according to ANOVA analysis followed by Tukey test (at p<0.05) for almost all the above physicochemical parameters, suggesting that all systems performed in a similar way. All studied systems, achieved a mean of two-year removal efficiencies of 47% for COD, 89% for TSS, 49% for TN, 58% for N-NO(3)(-), 60% for TP, 47% for Cu, 23% for Ni, 33% for Pb, 61% for Zn and 59% for summation operator PAHs (16 compounds).     

表面活性剂促进污泥产酸及用于生物除磷的研究进展

表面活性剂可以提高污泥发酵产生的挥发性脂肪酸的产量。经过污泥水解发酵产生的挥发性脂肪酸,既能作为生物除磷系统所需的优质碳源,使城市污水达到稳定深度除磷的要求,又减少了剩余污泥对环境的污染。将城市污水厂污泥生物转化为挥发性有机酸并用于生物除磷,丰富了污水生物处理和污泥处理与资源化等研究内容。     

活性炭吸附回收挥发性有机物的研究进展

活性炭吸附法是目前使用范围最为广范、技术最为成熟的回收挥发性有机物（VOCs）的方法。该法与冷凝法联用，可达到经济、高效回收VOCs的目的。介绍了变压吸附和变温吸附等常见的活性炭吸附回收VOCs的工艺，分析比较了各工艺的特点，并指出了存在的问题。在总结现有研究进展的基础上，预测了活性炭吸附回收VOCs技术的发展趋势。     

Linking chemical extraction to microbial degradation of 14C-hexadecane in soil

Chemical extractions have been shown to measure the biodegradable fraction of aromatic contaminants in soil; however, there is little research on the chemical prediction of aliphatic hydrocarbon degradation. The aim of this study was to investigate the potential for cyclodextrin extractions to predict hexadecane biodegradation in soil. Soils were amended with 10 or 100 mg kg⁻¹ of a model alkane n-hexadecane and 100 Bq g⁻¹¹⁴C-n-hexadecane. Correlations between the extents of mineralisation and extractions of the ¹⁴C-contaminant were determined. Solvent shake extractions and aqueous CaCl₂ extractions were poor predictors of hexadecane bioaccessibility. However, the novel HP-α-CD shake extraction showed close correlation (r² = 0.90, n = 36, p < 0.05) to the mineralisation data. This novel extraction technique has the potential to be used to assess the biodegradable aliphatic hydrocarbon fraction in contaminated soils.     

Potential use of DNA adducts to detect mutagenic compounds in soil

In this study, three different soils with contrasting features, spiked with 300 mg benzo[a]pyrene (BaP)/kg dry soil, were incubated at 20 °C and 60% water holding capacity for 540 days. At different time points, BaP and DNA were extracted and quantified, and DNA adducts were quantified by ³²P-postlabelling. After 540 days incubation, 69.3, 81.6 and 83.2% of initial BaP added remained in Cruden Bay, Boyndie and Insch soils, respectively. Meanwhile, a significantly different amount of DNA-BaP adducts were found in the three soils exposed to BaP over time. The work demonstrates the concept that DNA adducts can be detected on DNA extracted from soil. Results suggest the technique is not able to directly reflect bioavailability of BaP transformation products. However, this new method provides a potential way to detect mutagenic compounds in contaminated soil and to assess the outcomes of soil remediation.