Zhen Wang

Pollution status of 16 polycyclic aromatic hydrocarbons (PAHs) was investigated in coastal water of Bohai Sea, China, and ecological risks of the 4 typical PAHs (naphthalene, phenanthrene, fluoranthene, and benzo(a)pyrene) were assessed using probabilistic risk assessment approach. The average concentration of total 16 PAHs was 3504 ng/L, and 3- and 4-ring PAHs were the dominant species. The probabilistic risks of the four typical PAHs were calculated using probability density function curve and joint probability distribution curve. The maximum acceptable ecological risks of 95% of the species being unaffected for the 4 compounds were 0.004, 0.035, 0.135, and 0.010, respectively. The joint ecological risk of the four PAHs was higher than the summation of their individual ecological risks, revealing that the summation of the calculated ecological risk of PAH mixtures underestimated their integrated ecological risks when they co-existed in aquatic environment.

The concentration of polycyclic aromatic hydrocarbons (PAHs) in the urban air of Dalian, China was monitored from November 2009 to October 2010 with an active high-volume sampler and a semipermeable membrane device (SPMD) passive sampler. The samples were analyzed for the sixteen US EPA priority monitoring PAHs using GC/MS. The concentrations of ∑PAHs in particle and gas phases ranged from 3.2–90.6 ng m⁻³ and 40.8–155 ng m⁻³, respectively. The PAHs of 3–4 rings covered 89.2% of the total concentrations (gas phase + particle phase). Furthermore, the gas-particle partitioning phenomena and the results measured from the field versus those predicted by the Junge-Pankow adsorption model, octanol-air partitioning coefficient (K _OA) based absorption model, the absorption into the organic matter plus the adsorption to the soot carbon model using the soot-air partitioning coefficients (K _SA) were discussed in this article. The dominant contributors of PAHs in the gas phase of active samples and SPMD passive samples were similar. The SPMD mainly sequestrated gas phase PAHs. The linear correlation coefficients between C _SPMD and C _air-gas were 0.7316 and 0.7403; C _SPMD and C _air-total were 0.7397 and 0.7409 at Dalian Jiaotong University sampling site and Dalian Meteorological Observatory sampling site, respectively. The quantitative structure-property relationship (QSPR) of the sampling rate of SPMD for PAHs was studied, which can be predicted by the core–core repulsion energy and the energy of the highest occupied molecular orbital of PAH molecules.

Samples of gas- and particle-phase polycyclic aromatic hydrocarbons (PAHs) were collected at three sampling stations (Xiaomai Island, Laohutan, and Zhangzi Island) in the north Yellow Sea, China during November 2008 and September 2009 to study their atmospheric transport potential and the gas/particle distributions. The composition of PAHs was dominated by gaseous compounds. The percentages of the particle-phase PAHs to the total concentrations were found to be higher during the heating period than the non-heating period. The ratios of naphthalene and acenaphthene to phenanthrene, chrysene and dibenzo(a,h)anthracene showed an increasing trend from Xiaomai Island to Zhangzi Island, which can be called as the local atmospheric distillation of PAHs. Gas/particle partitioning coefficients (K _p) and their relationship with the sub-cooled liquid vapor pressures (pº_L) of PAHs were investigated. The regressions of logK _p versus logpº_L gave significant correlations for all samples of the three sites with r ² values in the range 0.56–0.66 (p < 0.01). Both Junge–Pankow adsorption model and octanol–air partition coefficient absorption model tended to underestimate the sorption for most PAHs, but the absorption model appeared to be more suitable for predicting the particle fraction of PAHs than the Junge–Pankow model.

To evaluate the gas-particle partitioning behavior of polycyclic aromatic hydrocarbons (PAHs) in the urban air of Dalian, China, both gas phase and particle phase ambient air were monitored with active high-volume sampler from November 2009 to October 2010. The average total concentration of 16 US EPA priority monitoring PAHs (particle + gas) (∑PAHs) was 112 ng m⁻³ and the most abundant PAH was Phenanthrene. ∑PAHs and the gas-particle partitioning coefficients (K _p) of PAHs displayed seasonal variation in the order of winter > autumn > spring > summer. ∑PAHs was much higher during the heating period than non heating period. ∑PAHs in gas phase were all higher than those in particle phase in the four seasons. The PAHs sources identification was attempted using diagnostic ratios. The relationship between the concentration of PAHs in the air and meteorology parameters were analyzed using SPSS packages. The concentrations of PAHs in the air decreased with the increase of ambient temperature, and increased with the increase of atmospheric pressure. The gas-particle distribution was examined through several different approaches such as the relationship of logK _p with the ambient temperature, with the logarithm of the sub-cooled vapor pressure (logP _L ⁰), and the octanol-air partitioning coefficient (logK _oa) of PAHs. The slopes obtained from regressing logK _p vs. logP _L ⁰ was −0.687∼−0.821 in heating periods, which was in the range between −0.6 and −1, indicating the partitioning of PAHs to particle phase in the urban air of Dalian was absorption as well as for adsorption mechanism. However, the average slope value was −0.502 in the non heating periods, which was shallower than -0.60, indicating that the absorption mechanisms contributed more to the partitioning process. The exposure risk of PAHs was evaluated with four methods, the results of which indicated that the quality of the urban air of Dalian was better.

A novel method for distinguishing heavy fuel oils from crude oils is proposed in this study. This method comprises gas chromatography-mass spectrometry analysis and principal component analysis (PCA) of the diagnostic ratios of selected polycyclic aromatic hydrocarbons (PAHs). The method was applied to 15 heavy fuel oils (B1 to B15) and 32 crude oils (C1 to C32) for distinction. Oil samples were collected from Turkmenistan, Korea, China, Vietnam, Morocco, Algeria, Sultan, Yemen, Saudi Arabia, Argentina, Russia, Indonesia, Brazil, Equatorial Guinea, Angola, and Mauritania. The discriminative power of PCA was enhanced through the selection of typical PAH diagnostic ratios, which could be used to distinguish petrogenic from pyrogenic PAHs. The two principal components (PC1 and PC2) account for over 75% of the variance. The method was confirmed to be highly efficient for distinguishing heavy fuel oils from crude oils, with a rapid and objective procedure under comprehensive considerations.