| Although the effect of ambient air pollution on human health has always been lots of concerns,certain special pollution episodes,such as the influences of barbeque（BBQ）on the environment quality and human health have not been adequately addressed.In addition,food intake,inhalation and dermal contact are three main pathways for human intake of pollutants.Furthermore,previous studies focused on dietary and inhalation exposure for general population,but not dermal exposure.Relative researches on dermal exposure of pollutants for general population lacked,especially using internal exposure to evaluate its dermal exposure.Therefore,the present study selected BBQ as a typical pollution episode and chose PAHs as target compounds to evaluate the contribution of different exposure pathways to human intake of PAHs through estimating external and internal exposure amounts.Particle and gaseous samples were collected at 2-m and 10-m distances from a cluster of four BBQ stoves with charcoal to identify characteristics of size distribution and profile of PAHs in BBQ Fumes.Moreover,20 males were divided into three groups via dietary,dermal,and inhalation exposures,dermal and inhalation exposures,and dermal exposure only,respectively.Pre-exposure urine samples were collected three times at approximately 17 h before barbecue and post-exposure samples were collected in 35 h after barbecue;Cotton cloth samples and food were collected as well,aiming to identify characteristics of PAHs dietary exposure,dermal exposure,and inhalation exposure for general population and evaluate potential health effect of BBQ,as well as to provide theory basis for giving feasible measure and advice to minimize PAHs exposure.The main results were summarized as follows:Concentrations of PAHs decreased with increasing distance from the BBQ stoves,especially for high molecular weight particle-bound PAHs.Numberious high molecular weight particle-bound PAHs were contained at 2-m site and concentration of benzo[a]pyrene（BaP）was 6.3 ng m-3,while 10-m site was also detected with a small amount and BaP concentration was 0.16 ng m-3.The 2-4 rings PAHs predominated in gaseous phase at both2-m and 10-m site,and phenanthrene（Phe）had highest concentration.Particle-bound PAHs of BBQ fumes were dominant in the size range of 0.18-1.8μm,peaked in the accumulation mode.At the 2-m site,acenaphthene（Ace）,fluorene（Flu）and Phe were slightly unimodal in size distribution with a peak in accumulation mode particles（<1μm）,and well distributed in ultrafine and coarse particles.However,anthracene（Ant）,fluoranthene（Fla）,pyrene（Pyr）showed somewhat bimodal distribution patterns.High molecular-weight PAHs（5-6 rings）,except for B[b+k]F,showed unimodal size distribution patterns peaking in the accumulation mode particle fraction.At the 10-m site,particle-bound PAHs were generally unimodal size distributed.High molecular-weight PAHs were mostly unimodal peaking in fine particles and consequently had smaller geometric mean diameters and standard deviations than low molecular-weight PAHs.The values of Fla/（Fla+Pyr）,Ant/（Ant+Phe）,and BaA/（BaA+Chr）implicated that particle-bound PAHs at the 2-m site were predominantly derived from BBQ fumes,primarily generated from wood and charcoal combustion and food-charred emissions,as well as from petroleum combustion.Nevertheless,particle-bound PAHs at the 10-m site were predominated by petrogenic sources,but slightly influenced by BBQ fumes.The present study also demonstrated that Ant/（Ant+Phe）may be a good indicator of distance variability from emission sources,as Ant/（Ant+Phe）values increased with decreasing distance from the source.Dietary exposure was the most dominant exposure route with the greatest amounts of PAH intake and OH-PAH excretion.The intake amounts of Nap,Flu,Phe,and Pyr were estimated to be 5380±440,2150±282,14900±2020,and 3050±788 ng respectively,while the urinary net excreted amounts of hydroxyl（OH）-naphthalene,OH-fluorene,OH-phenanthrene,and OH-pyrene ingested via dietary exposure were 2850±1080,826±499,2010±1240,and 183±181 ng respectively.The results of external and internal exposure methods indicated,dermal exposure was a more important pathway for intake of low molecular-weight PAHs than inhalation.The values of transdermal permeability coefficient(kpg)were estimated in the range of 3.3-6.0 m h-1 for selected PAHs,all greater than 3.0 m h-1,implicating direct dermal exposure of PAHs as an important pathway.The estimated intake amounts of gaseous Flu,Phe,and Pyr were560,2750,and 650 ng via dermal exposure,greater than inhalation intakes of 360,1790,and430 ng,whereas opposite was true for particulate PAHs.As Flu,Phe,and Pyr mainly exist in the gaseous phase,dermal exposure to gaseous Flu,Phe,and Pyr dominated the combined gaseous and particulate phase intakes,compared to inhalation exposure.In addition,net excreted amounts of OH-Nap,OH-Flu,OH-Phe,and OH-Pyr via dermal exposure were 367,63,98,and 28 ng after 2.5 h exposure respectively,comparable to those via combined dermal and inhalation exposure,which were 453,98,126,and 38 ng,indicated the excreted amounts of OH-PAHs were greater via dermal exposure than inhalation.The urinary OH-PAHs excretion amount would be larger if exposed skin area increased.Finally,the ratios of excretion to intake via dermal exposure were 0.11,0.036,and 0.043 for Flu,Phe,and Pyr,respectively,lower than dietary exposure（0.38,0.14,and 0.060）but higher than those for inhalation（0.097,0.016,and 0.025）.In the case of BBQ fumes,dermal exposure was a more important pathway for intake of low molecular-weight PAHs than inhalation,and should not be overlooked. |
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