微波消解-电感耦合等离子体-发射光谱法研究藏香燃后起源颗粒态砷镉铜铅的排放特征

Study of Emission Characteristics of Particulate Arsenic,Cadmium,Copper and Lead Derived From Burning of Tibetan Incenses by ICP-OES Method With Microwave Digestion

燃香产生大量的颗粒物和挥发性物质已经成为室内空气污染的重要来源之一。目前有关燃香对局部大气环境影响的研究主要集中在燃香起源颗粒物浓度、挥发性气体、有机污染物等含量的测定。有关燃香所排放颗粒态重金属的排放率、排放因子以及所排放的颗粒态重金属对室内空气环境质量影响研究未见报道。使用微波消解仪对9种(S1—S9)线型藏香样品及其燃烧后所释放的总悬浮颗粒物进行程序升温消解,并采用电感耦合等离子体发射光谱(ICP-OES)分别在波长188.980,214.439,327.395及220.353 nm下对藏香及其燃烧所释放的总悬浮颗粒物中As,Cd,Cu和Pb含量进行检测,分析藏香燃后起源颗粒态重金属的排放特征,为评估室内藏香密集性使用所排放的颗粒态重金属对人体健康的潜在影响以及制定藏香重金属限量标准提供参考。实验发现:(1)不同种类藏香样品中四种重金属含量不同,平均含量从高到低依次为Cu,Pb,As和Cd元素。不同种类藏香样品中Cd和Pb的来源相似、而As和Cu的来源明显不同。(2)不同种类藏香燃烧后烟尘量不同,最高为94.75 mg·kg^(-1),最低为38.52 mg·kg^(-1)。(3)不同藏香燃烧后的总悬浮颗粒物中As,Cd和Pb的排放量主要取决于它们在藏香样品中的含量,与藏香品种无关;而Cu在总悬浮颗粒物中的排放量受藏香品种影响较大,可能还受到其他因素的影响。(4)藏香燃烧后四种重金属的排放率(E)由高到低依次为Cd,As,Pb和Cu;而排放因子(F)由高到低依次As,Pb,Cd和Cu。(5)藏香燃后所排放的As和Cd可能对局部大气环境质量造成影响,其中来自同一厂家的样品S3,S6及S9的总悬浮颗粒物中As和Cd重金属含量均最高,建议藏香生产企业更加严格控制As和Cd等重金属的来源和含量,以降低藏香燃烧后对室内空气中重金属的污染,进而降低对人体健康危害的风险。

Large amounts of particulate and volatile matter derived from incense burning have become one of the important sources of indoor air pollution.At present,the research about the effect of burning incense on the local air environment mainly focused on determining particulate matters,volatile gases,and organic pollutants after incense burning.The research about the emission efficiencies and emission factors of heavy metals and the effect of particulate heavy metals on indoor air quality after incense burning has not been reported.To better understand the emission characteristics of heavy metals in Tibetan incense,nine kinds(S1—S9)of line-type Tibetan incense powder samples and their total suspended particulates(TSP)after burning were digested by microwave digestion method with programmed temperature procedure,and four primary kinds of heavy metal elements(i.e.As,Cd,Cu,Pb)in these powder samples.Their TSP were determined by the inductively coupled plasma optical emission spectrometry(ICP-OES)with the wavelength 188.980 nm for As,214.439 nm for Cd,327.395 nm for Cu and 220.353 nm for Pb,respectively.The experiment results are listed as follows:(1)The contents of four heavy metals are different in different Tibetan incense samples,and the average content of heavy metal from high to low is in the order of Cu,Pb,As and Cd.The source of Cd and Pb in different Tibetan incense samples is similar,remarkably different from As and Cu.(2)After burning,the amounts of smoke and dust from different Tibetan incense samples are different.The largest and minimum amounts are 94.75 and 38.52 mg·kg^(-1),respectively.(3)The emission amounts of As,Cd and Pb in the total suspended particles from different Tibetan incense samples depend on their contents in the incense sample.However,the emission amount of Cu is not only dependent on the incense samples but also affected by other factors.(4)The emission efficiency of heavy metals in Tibetan incense samples from high to low is in the order of Cd,As,Pb,and Cu.The emission factor from high to low is in the order of As,Pb,Cd,and Cu.(5)The emission of As and Cd from Tibetan incense samples after burning may adversely affect local atmosphere quality.Among these samples,the highest contents of As and Cd in the TSP of S3,S5 and S9 from the same manufacturer.The manufacturer is suggested to control the source and content of As and Cd stricter to decrease the heavy metal pollution in indoor air and the risk to human health after burning Tibetan incenses.