| Chlorinated paraffins?CPs?are now attracting special concerns worldwide as one type of new persistent toxic substances as classified by the Stockholm Convention.China is the globally largest producer,consumer and exporter of CPs at present.Like some other POPs,CPs can be slowly released into the ambient environment during the production and industrial application.As a result,CPs have been determined in various environmental matrices at high levels in China.This compouds can enter into the human body further through inhalation,dust ingestion and dietary intake and may cause adverse effects to human health.SCCPs are suspected to cause cancer in humans and disrupt endocrine function.However,information on the occurrence and distributions of CPs in the environment in China are still very scarce as well as their exposure pathway for human.In the present study,we selected the emerging environmental pollutants chlorinated paraffins as the target compounds.Urban Guangzhou and a mega e-waste recycling industrial park and its surrounding regions were selected as sampling sites.The present study was conducted to?1?examine the size-dependent distribution and inhalation exposure characteristics of particle-bound chlorinated paraffins in indoor air in Guangzhou;?2?evaluate the potential health risk for occupational population and local population in/around the mega e-waste recycling industrial park via dust ingestion and dietary intake.The major results are as follows:Both short chain?SCCPs?and medium chain CPs?MCCPs?were determined in all sizefractioned particle samples with a range of 6.20?17.8 and 5.98?40.5 ng m-3,respectively.Size distributions revealed that individual homologs,SCCPs,and MCCPs shared a similar unimodal distribution pattern peaking in the fine particles with a diameter of 0.56-1.0 ?m.Vapor pressure may be a critical factor governing the size-dependent distribution of CPs.Inhalation exposure doses of SCCPs and MCCPs based on the ICRP model was between 0.86 and 4.22 ng kg-1 day-1 and were much lower than the recommended tolerable daily intake?TDI?values(100 ?g kg-1 day-1)suggested by the International Programme on Chemical Safety,indicated no significant health risk due to CPs in current indoor environments.The total deposition efficiencies were 51.4% for ?SCCPs and 47.9% for ?MCCPs.The majority of inhalable particle-bound CPs deposited in the head airways,and only a small portion deposited in the lungs.The mean concentrations of SCCPs and MCCPs in four kinds of dust collected from ewaste recycling workshops in the industrial park,local residential homes around the industrial park,exterior street surfaces,and control homes were 5600 and 17800,580 and1760,501 and 772,59.0 and 185 ?g g-1,respectively.Estimated total exposures to CPs via dust ingestion were 19.84,2.14,and 14.83 ?g kg-1 day-1 for e-waste workers,local adults and children,respectively.The ?SCCP and ?MCCP concentrations in locally produced staple food samples were in the range of 0.892-605 ?g g-1 lw and 1.22-747 ?g g-1 lw,respectively.Estimated total exposures to SCCPs and MCCPs via dietary intake were 15.4 and 19.5 ?g kg-1 day-1,34.1 and 43.3 ?g kg-1 day-1 for local adults and children,respectively.Children are more susceptible to CP exposure.The main contribution to CP intake was from the diet.The combined health risk was evaluated by the hazard quotient?HQ?.The HQ values ranged from 0.16 to 1.03,indicating a potential health risk for occupational workers and local residents.In this study,the occurrence of SCCPs and MCCPs in the indoor air particulate matter,dust and food samples was systematically investigated and evaluated the human health risk using different exposure models.The results can provide the scientific data for further reseach on exposure risk prevention and control technologies for CPs. |
PDF Full Text Request