Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants known for their photoinduced toxicity. There are two mechanisms through which this may occur: photosensitization and photomodification. Photosensitization generally leads to the production of singlet oxygen, a reactive oxygen species (ROS), which is highly damaging to biological molecules. Photomodification of PAHs, usually via oxygenation, results in the formation of new compounds (oxyPAHs), and can occur under environmentally relevant levels of actinic radiation. <br /><br /> PAHs and oxyPAHs readily adsorb to the organic phase of particulate matter in the environment such as sediments. It is logical to conclude that sediment transport will also facilitate the transport of these contaminants, and it has been shown that in the course of transport, degradative processes evoke a change in the profile of the PAHs present. Sediment samples taken along a transect from Hamilton Harbour were fractionated, and analyzed using a 2D HPLC method. All sediments contained intact and modified PAHs, although a marked change was noted in the profile of compounds present in the samples, which differ in distance from shore. Fractions of sediment extract were tested for toxicity using a bacterial respiration assay. Toxicity was observed in fractions containing modified PAHs, and was similar to that of intact PAH-containing fractions. <br /><br /> Subsequently, the toxicities of 16 intact PAHs were assessed to <i>Daphnia magna</i> under two ultraviolet radiation (UV) conditions. The toxicity of intact PAHs generally increased in the presence of full spectrum simulated solar radiation (SSR), relative to visible light plus UVA only. To expand the existing data on the effects of PAH photoproducts to animals, fourteen oxyPAHs were also assayed with <i>D. magna</i>, most of which were highly toxic without further photomodification. The data presented highlight the effects of UV radiation on mediating PAH toxicity. The importance of the role of photomodification is also stressed, as several oxyPAHs were highly toxic to <i>D. magna</i>, a key bioindicator species in aquatic ecosystems. <br /><br /> A QSAR model previously developed for <i>Lemna gibba</i> showed that a photosensitization factor (PSF) and a photomodification factor (PMF) could be combined to describe toxicity. To determine whether it was predictive for <i>D. magna</i>, toxicity was assessed as both EC50 and ET50. As with <i>L. gibba</i> and <i>Vibrio fischeri</i>, neither the PSF nor the PMF alone correlated to D. magna toxicity. However, a PSF modified for <i>D. magna</i> did in fact exhibit correlation with toxicity, which was further improved when summed with a modified PMF. The greatest correlation was observed with EC50 toxicity data. This research provides further evidence that models that include factors for photosensitization and photomodification will likely be applicable across a broad range of species. To gain further knowledge of the roles that the variables contributing to the photosensitization and photomodification, a structural equation model was constructed based on the <i>D. magna</i> QSAR. This model accounted for a high amount of variance in six sets of toxicity data, as well as insight into the mechanisms of phototoxicity affecting different aquatic organisms.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants known for their photoinduced toxicity. There are two mechanisms through which this may occur: photosensitization and photomodification. Photosensitization generally leads to the production of singlet oxygen, a reactive oxygen species (ROS), which is highly damaging to biological molecules. Photomodification of PAHs, usually via oxygenation, results in the formation of new compounds (oxyPAHs), and can occur under environmentally relevant levels of actinic radiation. <br /><br /> PAHs and oxyPAHs readily adsorb to the organic phase of particulate matter in the environment such as sediments. It is logical to conclude that sediment transport will also facilitate the transport of these contaminants, and it has been shown that in the course of transport, degradative processes evoke a change in the profile of the PAHs present. Sediment samples taken along a transect from Hamilton Harbour were fractionated, and analyzed using a 2D HPLC method. All sediments contained intact and modified PAHs, although a marked change was noted in the profile of compounds present in the samples, which differ in distance from shore. Fractions of sediment extract were tested for toxicity using a bacterial respiration assay. Toxicity was observed in fractions containing modified PAHs, and was similar to that of intact PAH-containing fractions. <br /><br /> Subsequently, the toxicities of 16 intact PAHs were assessed to <i>Daphnia magna</i> under two ultraviolet radiation (UV) conditions. The toxicity of intact PAHs generally increased in the presence of full spectrum simulated solar radiation (SSR), relative to visible light plus UVA only. To expand the existing data on the effects of PAH photoproducts to animals, fourteen oxyPAHs were also assayed with <i>D. magna</i>, most of which were highly toxic without further photomodification. The data presented highlight the effects of UV radiation on mediating PAH toxicity. The importance of the role of photomodification is also stressed, as several oxyPAHs were highly toxic to <i>D. magna</i>, a key bioindicator species in aquatic ecosystems. <br /><br /> A QSAR model previously developed for <i>Lemna gibba</i> showed that a photosensitization factor (PSF) and a photomodification factor (PMF) could be combined to describe toxicity. To determine whether it was predictive for <i>D. magna</i>, toxicity was assessed as both EC50 and ET50. As with <i>L. gibba</i> and <i>Vibrio fischeri</i>, neither the PSF nor the PMF alone correlated to D. magna toxicity. However, a PSF modified for <i>D. magna</i> did in fact exhibit correlation with toxicity, which was further improved when summed with a modified PMF. The greatest correlation was observed with EC50 toxicity data. This research provides further evidence that models that include factors for photosensitization and photomodification will likely be applicable across a broad range of species. To gain further knowledge of the roles that the variables contributing to the photosensitization and photomodification, a structural equation model was constructed based on the <i>D. magna</i> QSAR. This model accounted for a high amount of variance in six sets of toxicity data, as well as insight into the mechanisms of phototoxicity affecting different aquatic organisms.

Abstract This study investigated the distributions of polyclic aromatic hydrocarbons (PAHs) in the sediment cores collected from continental shelf of Gaoping submarine canyon. The sediment cores were analyzed for PAHs to reconstruct historical contamination record of these compounds and to find out the possible sources, trends and fluxes. The average concentrations of £U50 and £U16 PAHs ranged from 568 to 816 ng/g and from 169 to 256 ng/g, respectively. Except for sediment cores L10 and L26, the high molecular weight PAHs (4-6 ring PAHs) were found dominant in 1960s-2006, while the low molecular weight PAHs (2-3 ring PAHs) were found dominant before 1960s. Results from diagnostic ratios and hierarchical cluster analysis (HCA) both suggested that sources of PAHs in the cores of southern continental shelf were primarily from petrogenic, while those in the cores of northern continental shelf were from pyrogenic and petroleum combustion. There is a significant increasing of total PAH concentrations between 1930-1950, suggesting that might be an evident during the World War II. Due to increase of importing fossil fuel and the growth of heavy industrials in Gaoping area, the total concentrations of PAHs showed an increasing trend again since 1950s in the core from continental shelf of Gaoping submarine canyon. In addition, during 1990-2006, the total concentrations of PAHs showed a decreasing trend might result from the environmental protection laws. It is noteworthy that in L28 and L29 sediment cores, the increase of total PAH concentrations recorded during 1990-2006 may be due to the dumping of the sludge from dredged Kaohsiung harbor sediments. Comparing with the sediment quality guidelines (SQG), the PAH concentrations in the northern continental shelf sediment samples were higher than the Threshold Effect Level (TEL) value, suggesting there might be an adverse biological effects caused by PAHs. Keywords¡GPolycyclic aromatic hydrocarbons (PAHs), Kaohsiung harbor, Sediment quality guidelines (SQG)

The emission of polycyclic aromatic hydrocarbons (PAHs) from the diesel engine on a dynamometer by mixing ratio of the fuel (H2/O2 /diesel) was investigated. The engine was operated at a one load steady-state condition of 1,600 rpm with torque and power outputs of 145 Nm and 24.5 kW. In this condition, the measurement of the mixing ratio of the fuel (H2/O2 /diesel) was first recorded without any induction of H2/O2 mixture (Base) into the engine. Then, seven flow rate levels of H2/O2 mixture were used by 10 L/min, 20 L/min, 30 L/min, 40 L/min, 50 L/min, 60 L/min, and 70 L/min, respectively. The concentrations of total PAHs were 106.58, 101.89, 95.30, 90.70, 85.98, 82.35, 72.38, and 67.30 £gg/m3, respectively for Base (0 L/min), 10 L/min, 20 L/min, 30 L/min, 40 L/min, 50 L/min, 60 L/min, and 70 L/min of H2/O2 mixture. The emission factor of total PAHs were 6.00, 5.73, 5.36, 4.99, 4.84, 4.50, 4.07, and 3.78 mg/bhp-hr, respectively for Base (0 L/min), 10 L/min, 20 L/min, 30 L/min, 40 L/min, 50 L/min, 60 L/min, and 70 L/min of H2/O2 mixture. The removal rate of total PAHs were 4.4%, 10.6%, 14.9%, 19.3%, 22.7%, 32.1%, and 36.9%, respectively for 10 L/min, 20 L/min, 30 L/min, 40 L/min, 50 L/min, 60 L/min, and 70 L/min of H2/O2 mixture. This result showed using H2/O2 mixture significantly reduced emissions of PAHs. As the regulated harmful matters, using H2/O2 mixture, CO¡BCO2¡BTHC and PM decreased, whereas the NOx emission increased. The energy saving of the fuels (H2/O2 /diesel), the total oil equivalents combined by fuel consumption of diesel engine and electricity consumption of H2/O2 generator, were 2.42, 2.49, 2.50, 2.48, 2.51, 2.35, 2.18, and 2.17 for Base (0 L/min), 10 L/min, 20 L/min, 30 L/min, 40 L/min, 50 L/min, 60 L/min, and 70 L/min of H2/O2 mixture. The result showed that reduced saving energy of the fuel (H2/O2 /diesel) by 3.2% for 50 L/min, 9.8% for 60 L/min, and 10.4% for 70 L/min, respectively.

This study investigated emission characteristics of polycyclic aromatic hydrocarbons (PAHs) and reductions of regulated harmful matters using Premium diesel fuel (PDF), mixed with a 60 L/min flow rate of H2/O2 mixture and blended with biodiesel 5% (B5), 10% (B10), 20% (B20), and 30% (B30). The diesel engine was operated at steady-state condition of 1,600 rpm, with torque and power outputs of 145 Nm and 24.5 kW, respectively. Measured results show that the emission concentrations of total PAHs were 22.42, 20.11, 17.28, 13.45, and 13.13 £gg/m3 for B0, B5, B10, B20, and B30, respectively, with corresponding emission factors of total PAHs being 1334.53, 1198.82, 986.05, 771.93, and 748.82 £gg/bhp-hr, and reductions of total PAHs being 10.3, 22.9, 40.0, and 41.4%. The results indicated that using biodiesel can reduce PAH emissions. However, the emission factors of carbon monoxide (CO) and total hydrocarbons (THC) were decreased by adding biodiesel, but those of carbon dioxides (CO2), nitrogen dioxides (NOx), and particulate matter (PM) were increased. Annual emissions of total PAHs were estimated to be 140.05, 126.92, 105.21, 81.97, and 79.86 ton/year for B0, B5, B10, B20 and B30, respectively, decreasing with increasing biodiesel. Also, the corresponding annual emissions of BaPeq were 5.88, 5.62, 3.50, 3.03, and 2.83 ton/year, respectively.

Hydrogen is generally acknowledged to have a high heat value and emit few pollutants. It has been identified as the fuel with the most potential for the twenty-first century. This study investigates energy saving and pollutant reduction for polycyclic aromatic hydrocarbons (PAHs), hydrocarbons (HCs), carbon monoxide (CO), carbon dioxide (CO2), particulate matter (PM), and nitrogen oxides and a hydrogen (H2) and oxygen (O2) mixture (H2/O2) mixed in a diesel engine combustion chamber. Experimental parameters included a speed of 1600 rpm and a torque of 145 Nm in the steady-state condition. These operating conditions represent a speed of 40km/hr, roughly vehicle speed in an urban area. In this study, premium diesel fuel (PDF) was mixed with H2/O2 at different injection rates. When mixed with PDF, the H2/O2 injection rate was set to 60L/min, while different biodiesel injection rates were used in the diesel engine combustion chamber. In addition, this study used mathematical simulation to model the combustion temperature, combustion efficiency, and combustion gas distribution in the combustion chamber. The results of PDF mixed under different H2/O2 injection rates showed that the brake thermal efficiency (BTE) did not significantly change when the H2/O2 injection rate rose from 0 L/min to 40L/min, but markedly increased when the H2/O2 injection rate increased from 50 L/min to 70L/min. The best BTE of the diesel engine was 35.4% at an H2/O2 injection rate of 60 L/min, roughly 12.6% higher than PDF. The brake specific fuel consumption (BSFC) was 16.287 g/bhp-hr at an H2/O2 injection rate of 60 L/min, 11.72% lower than PDF. The results of the BTE and BSFC showed that an H2/O2 injection rate of 60 L/min enabled the best performance of the diesel engine. Emissions of CO, CO2, THC, PM, and PAHs fell as the H2/O2 injection rate increased, while the NOx emission increased as the H2/O2 injection rate increased. This was because the addition of H2/O2 improved the combustion efficiency of the fuel. The total oil equivalent saving was about 22.13% compared to neat diesel at an H2/O2 injection rate of 70 L/min. The BTE decreased from 37.0% to 35.5% while the BSFC increased to 149.75 g/bhp-hr when the PDF was mixed with biodiesel and the injection rate of H2/O2 was set at 60 L/min. These results showed that the performance of the diesel engine declined slightly. The BTE of the 30% biodiesel + PDF decreased roughly 1.5% compared to pure PDF. The emissions of CO, THC, and PAHs decreased as the percentage of biodiesel mixed with PDF increased, but CO2, NOx, and PM increased as the proportion of biodiesel rose. In the mathematical simulation, H2/O2 was mixed with combustion air at injection rates of 0, 30, 60, and 70 L/min, using C12H26 as the main fuel. The simulation investigated the combustion flame temperature, fuel combustion efficiency, and combustion gas distribution in the diesel engine combustion chamber. The results showed that the combustion temperature and combustion efficiency improved as the H2/O2 injection rate increased.

Water, suspended particle and sediment samples from Gao-ping coastal water column were collected and measured to determine the spatial and temporal distributions of polycyclic aromatic hydrocarbons (PAHs) during August 2010 and June 2011. In addition, principal component analysis (PCA) and hierarchical the cluster analysis (HCA) were performed with chemical fingerprinting to understand the possible sources of PAHs in Gao-ping coast. The correlations between PAHs and several factors such as salinity, temperature and organic carbon were also discussed in the present study. The total PAH concentrations (dissolved and particulate phase) at four sampling campaigns ranged from 2.09 to 45 ng/L. Concentrations of dissolved PAHs ranged from 2.0 to 39 ng/L and the highest average concentrations were found in November 2010 (10.0 ¡Ó 9.90 ng/L). The particulate PAHs ranged from 0.13 to 40 ng/L and the maximum concentration was found in the estuary in August 2010. The total PAH concentrations of sediment ranged from 125-648 ng/g, which were lower than the Effect Range Low (ERL) and Threshold Effect Level (TEL) values, suggesting that few adverse ecological effects would arise from the PAHs in Gao-ping canyon. Results from chemical fingerprinting, PCA and HCA indicate that PAHs in this area were from complex sources such as combustion, petroleum, diagenesis or biogenic sources. Sources of PAHs in dissolved phase were mainly from petrogenic and mixed sources, while particulate PAHs were mainly from a mixed source. However, sources of PAHs in November 2010 and February 2011 were mostly from mixed combustion, suggesting that the PAH concentrations in particulate phase might be affected by atmospheric transport. The results showed that perylene in Gao-ping coast and canyon was mainly from the biogenic source. A significant correlaction was found in PAH fingerprinting between the esturine particles and sediment, indicating that the sediments in Gao-ping canyon might mainly come from Gao-ping River. Correlation analysis showed a significant positive correlation between concentrations of suspended particle and PAHs, while a negative correlation was found between PAH concentrations and temperature. In addition, organic carbon showed a significant correlation with PAHs in sediment samples. The partition coefficients (Koc) values of PAHs were higher than the values from other literatures, suggesting that it might be attributed to soot carbon.

Estuary is a complex region due to the mixing of fresh and sea water as well as the mixing of terrestrial and marine dissolved organic matters (DOM), so that the sorption behavior between hydrophobic organic compounds and dissolved organic matters is very complicated to estimate. By applying fluorescence quenching method, we investigated the influence of the mixing of binary dissolved organic matters from different sources on the binding constant (Kdoc) of pyrene and DOM. Results show that the kinetic of mixing of binary DOMs influences the binding constant, that means if there weren¡¦t enough standing time for mixing of binary DOMs, it would cause some bias in estimating the binding constants of pyrene and DOMs mixture. In this study, we also found that there exists a linear relationship on the binding constants between pyrene and DOMs mixture against mixing ratios. In addition, the mixing mechanism of SRNOM and LHA was dominated by diffusion process from the results of initial mixing efficiency. However, the diffusion process might not be the only mechanism of the mixing reaction of SHHA and LHA, other factors should be considered. Further investigations should be done to find out the dominating factors on the mixing of SHHA and LHA system in the future.

This research used high-volume air sampling (PS-1) and micro-orifice uniform deposit impactor (MOUDI) to measure concentrations of polycyclic aromatic hydrocarbons (PAHs) in the air of a agricultural residue open burning area in Jhushan and Singang station during the rice straw non-burning and burning periods. And PAHs of different size distributions are analyzed. Finally, absolute principal component analyze (APCA) model confer the probable sources of pollution in open burning area. The average PAHs concentrations were 330.04 and 567.81 ng/m3 during the rice straw non-burning and burning period in Jhushan station, the average PAHs concentrations were 427.16 and 571.80 ng/m3 during the rice straw non-burning and burning period in Singang station, respectively, in the rice straw burning period, which were higher than those on the non-burning days. The results of APCA model analysis showed that the contributions of PAHs from mobile source (gasoline and diesel) were 66.50 ¡Ó 7.99 %, burning incense in temple source were 14.83 ¡Ó 6.68 % and burning coal and wood source were 18.67 ¡Ó 6.17 % during the rice straw non-burning period. PAHs from mobile (gasoline) and rice straw non-burning source were 57.27 ¡Ó 6.90 %, mobile source (diesel) were 42.73 ¡Ó 6.89 % during the rice straw burning period in Jhushan station. The results of APCA model analysis showed that the contributions of PAHs from mobile (diesel) and burning incense in temple source were 45.67 ¡Ó 6.43 %, mobile (gasoline) and plastics incinerator source were 54.33 ¡Ó 6.39 % during the rice straw non-burning period. PAHs from burning incense in temple, rice straw, mobile (gasoline and diesel) source were 50.69 ¡Ó 4.55 %, plastics incinerator source were 36.78 ¡Ó 4.24 % and other source were 12.53 ¡Ó 2.71 %¡C

The high-volume air sampling (PS-1) and micro-orifice uniform deposit impactor (MOUDI) were used to measure the concentrations of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere for four seasons at Zuoying and Siaogang in Kaohsiung city, together with the size distributions. Also, the CMB (Chemical Mass Balance) receptor model was employed to determine the potential sources of PAHs. The results show that the highest concentrations of PAHs occurred in winter, being 143.9 ng/m3 and 182.9 ng/m3 at Zuoying and Siaogang, respectively; while the lowest concentrations of PAHs occurred in summer, being 81.4 ng/m3 and 95.2 ng/m3. The low-weight PAHs in the two sites were abundant in gaseous phase, being 55.89 - 95.89 % and 67.07 - 96.61 % at Zuoying and Siaogang, respectively. Meanwhile, the high-weight PAHs were almost present in particulate phase, being 55.24 - 83.50 % and 46.87 - 77.26 % at Zuoying and Siaogang, respectively. The sizes of 50th percentile of cumulative size distribution, d50 of Zuoying and Siaogang were 0.89 £gm and 0.35 £gm, respectively. Hence, most atmospheric PAHs existed in fine-particle ranges (¡Õ1.0£gm). The results of by CMB receptor modeling indicated that the major sources of pollution was exhaust emission (49 - 62 %) in Zuoying, and was burning source (49 - 64 %) in Siaogang.