Charcoal burning as a source of polyaromatic hydrocarbons in waterpipe smoking

Polyaromatic hydrocarbons (PAH) content from seven commercial waterpipe charcoals were determined during the smoking process to estimate how much PAHs would not be trapped by the water trap and could reach the lungs of the smokers. Naphthalene, 2-methylnaphthalene, acenaphthylene, acenaphthene, phenanthrene and fluoranthene were the most abundant PAH compounds produced during smoking. Naphthalene was the highest in all of the smoke contents and levels of 5 to 405 μg/15 minutes could be inhaled by the smoker. The amounts of PAHs produced during the smoking events in absence of tobacco varied greatly among different brands of charcoal. The amount and composition of the emitted PAH were not related to the amount and composition of the original chemicals in the charcoal prior to burning. Our findings suggest that public health agencies should regulate smoked charcoal products alongside tobacco.     

紫外光(UV)光解油田采出水中多环芳烃

为了探讨紫外光光解人工模拟油田采出水中多环芳烃的降解效率,利用自制反应装置对油田采出水中多环芳烃(PAHs)的紫外光光解做了一个初步研究。研究结果证明,紫外光光解对油田采出水中的多环芳烃萘和芴有显著的降解能力。实验室的测试表明,与紫外UVA(365 nm)、UVB(308 nm)的光照相比,紫外UVC(254 nm)在光照60 min的条件下,2种多环芳烃各自的去除率都近似达到了99%。可见,在光解效力和暴露时间两方面,紫外UVC对采出水中萘和芴的去除具有相对稳定和比较高的效率。     

Modelling of iron cycling and its impact on the electron balance at a petroleum hydrocarbon contaminated site in Hnevice, Czech Republic

Over a period of several decades multiple leaks of large volumes from storage facilities located near Hnevice (Czech Republic) have caused the underlying Quaternary aquifer to be severely contaminated with nonaqueous phase liquid (NAPL) petroleum hydrocarbons. Beginning in the late 1980's the NAPL plume started to shrink as a consequence of NAPL dissolution exceeding replenishment and due to active remediation. The subsurface was classified geochemically into four different zones, (i) a contaminant-free zone never occupied by NAPL or dissolved contaminants, (ii) a re-oxidation zone formerly occupied by NAPL, (iii) a zone currently occupied by NAPL, and (iv) a lower fringe zone between the overlying NAPL and the deeper underlying contaminant-free zone. The study investigated the spatial and temporal variability of the redox zonation at the Hnevice site and quantified the influence of iron-cycling on the overall electron balance. As a first step inverse geochemical modelling was carried out to identify possible reaction models and mass transfer processes. In a subsequent step, two-dimensional (forward) multi-component reactive transport modelling was performed to evaluate and quantify the major processes that control the geochemical evolution at the site. The study explains the observed enrichment of the lower fringe zone with ferrihydrite as a result of the re-oxidation of ferrous iron. It suggests that once the NAPL zone started to shrink the dissolution of previously formed siderite and FeS by oxygen and nitrate consumed a significant part of the oxidation capacity for a considerable time period and therefore limited the penetration of electron acceptors into the NAPL contaminated zone.     

Toxic Environmental Releases from Medical Waste Incineration: A Review

Toxic releases from medical waste incineration comprising organic emissions such as polychlorinated dibenzo-dioxin/furan (PCDD/Fs) and polycyclic aromatic hydrocarbons (PAHs), inorganic emissions and ashes containing toxic metals have been reviewed. Attempts made by various investigators to reduce/eliminate emissions have also been included. Legislations concerning emission standards for medical waste incinerators have been discussed.     

Lead and polycyclic aromatic hydrocarbons (PAHs) in surface soil from day care centres in the city of Bergen, Norway

Surface soil (0-2cm) quality in 87 day care centres in the city of Bergen, Norway has been studied. Approximately 45% of the day care centres contained Pb and PAH values above recommended action levels. There are clear variations between different areas of the city. The old central part of the city hosts most of the contaminated day care centres. In suburban areas most of the day care centres have Pb and PAH concentrations below action levels. City fires, gas work emission, lead-based paint, and traffic are probably important anthropogenic contamination sources, together with uncontrolled transportation of soil from contaminated to clean areas. Geological or other natural sources are probably not an important contributor to the high levels of lead and PAH.     

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.     

Estimation of the annual scavenged amount of polycyclic aromatic hydrocarbons by forests in the Pearl River Delta of Southern China

Leaves of six main tree species from the Pearl River Delta (PRD) in Southern China were collected to identify the interspecific variability, the spatial variability and the seasonal variations of polycyclic aromatic hydrocarbons' (PAHs) concentrations, and to calculate the amount of PAHs removed by leaves. PAHs concentrations in pine needles were much higher than in broad-leaves and leaves from urban/industrial areas (Baiyunshan and Heshan) exhibited two times greater concentrations than leaves from the rural area (Dinghushan). Seasonal variations of PAHs in leaves occurred with lesser concentrations in September. Leaves in PRD scavenged 3.7 ± 0.9 t PAHs y⁻¹, accounting for about 10% of the total amount emitted in this region. This result suggests that forests play an important role in the fate of PAHs.     

Partitioning of polycyclic aromatic hydrocarbons to solid-sorbed nonionic surfactants

The partition of hydrophobic organic compounds (HOCs) into solid-sorbed surfactant has a crucial role in describing and predicting the distribution of HOCs in solid-water-surfactant systems. The experimental results of this study indicated that the partition coefficients of polycyclic aromatic hydrocarbons (PAHs) into the solid-sorbed surfactant (Ksm) increased with an increase in the sorption amount of surfactants onto solid and reached a stable maximum value (Km sm) at the sorption of surfactants in saturation state, at which the solid surface was completely covered with the surface micelle (or admicelle). The fitted Km sm values for PAHs with different surfactants were found to have a good linear relationship with the corresponding partition coefficient of PAHs to surfactant micelles in solution (Kmc), and then a model was developed to describe and predict the distribution of PAHs in solid-water-surfactant systems. These results are of practical interest for developing effective and safe surfactant-enhanced remediation technologies.     

稠环芳烃在Pluronic嵌段共聚物胶束水溶液中的增溶

三种Pluronic嵌段共聚物（F108,P94和L64）胶束水溶液对萘、蒽、芘的增溶研究表明,它们在胶束和水相间的分配系数Kv值大小的顺序为：P94＞F108＞L64,这是由于具有较长PPO嵌段的Pluronic共聚物分子形成了较大内核的胶束,这种胶束有利于稠环芳烃的增溶。当指定Pluronic胶束体系时,Kv值随着稠环芳烃分子憎水性的增强（即分子苯环数目增加）而增大。这些规律同样反映在吸附等温线中。     

批量平衡法研究芳香族酮类化合物在东北黑土中的吸附

本文用批量平衡法研究－系列芳香族酮类化合物在东北黑土中的吸附,采用Ｆｒｅ－ｎｕｎｄｌｉｃｈ吸附等温方程求得土壤吸附常数（ｋｆ）,研究表明：１２种芳香族酮类化合物的吸附等温线有线性和非线性两种形式,对化合物的土壤有机碳吸附常数（ｌｇＫｏｃ）进行定量结构－性质（ＱＳＰＲ）分析,发现芳香族酮类化合物的土壤有机碳吸附常数与正辛醇／水分配系数相关不显著,土壤有机碳吸附常数与分子极化率（ａ）有较好的相关性,这