海口市城区2021—2022年大气PM_(2.5)中主要重金属构成特征及健康风险评价

Composition characteristics and health risk assessment of major heavy metals in atmospheric PM_(2.5) in urban areas of Haikou, 2021-2022

目的 探析海口市大气细颗粒物(fine particulate matter,PM_(2.5))中主要重金属构成特征,并评估其对人体健康的潜在风险。方法 于2021—2022年逐月在海口市典型城区采集环境大气PM_(2.5)样品,利用电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry,ICP-MS)测量样品中砷(As)、镉(Cd)、铬(Cr)、铅(Pb)、锰(Mn)、镍(Ni)、铜(Cu)、钒(V)、锌(Zn)9种重金属元素浓度,并结合健康风险模型进行健康风险评价。结果 2021—2022年海口市大气PM_(2.5)质量浓度为(20.506±13.054)μg/m^(3),范围为4.000~64.000μg/m^(3)。PM_(2.5)浓度呈现明显季节变化:冬季最高,秋、春季次之,夏季最低。9种重金属元素的总浓度范围为0.030~138.000 ng/m^(3),Zn、Mn、Pb含量最高,且在秋、冬两季表现较为突出。富集因子(enrichment factor,EF)分析表明Cd、Zn中度富集(10^(-5)~3.068×10^(-1)),HQ值大小顺序为Mn>Cd>Cr>As>Pb>V>Zn>Cu>Ni,总非致癌风险指数(total non-carcinogenic hazard index,HI)为0.171~0.361。Cr、As、Cd和Ni 4种具有致癌效应的重金属元素呼吸摄入终生增量致癌风险值(incremental lifetime carcinogenic risk,ILCR)范围为2.911×10^(-7)~1.558×10^(-5),ILCR依次降低;总致癌风险指数(total carcinogenic risk index,TR)为1.502×10^(-5)~3.169×10^(-5),HI和TR风险强度大小依次为儿童>成年男性>成年女性。结论 海口市城区大气PM_(2.5)平均浓度低于《环境空气质量标准》(GB 3095-2012)中的24 h平均浓度一级限值(35μg/m^(3)),但与2021年WHO推荐控制标准(15μg/m^(3))还有一定差距。PM_(2.5)中检测的9种重金属元素非致癌健康风险均不显著,但Cr和As具有潜在致癌风险,且对儿童的风险较其他人群更为显著。

Objective To investigate the pollution characteristics of major heavy metals in PM_(2.5) in urban areas of Haikou City,and to assess their potential health risks to humans.Methods From 2021 to 2022,samples of atmospheric PM_(2.5) were monthly collected from the typical urban areas of Haikou,and the concentrations of nine heavy metal elements including arsenic(As),cadmium(Cd),chromium(Cr),lead(Pb),manganese(Mn),nickel(Ni),copper(Cu),vanadium(V),and zinc(Zn)were measured using the inductively coupled plasma mass spectrometry(ICP-MS).The health risk assessment of these heavy metals was conducted using a health risk model.Results The average mass concentration of PM_(2.5) in Haikou was(20.506±13.054)µg/m³,with a range of 4.000 to 64.000µg/m³during the year 2021 and 2022.The PM_(2.5) concentrations showed significant seasonal variations:highest in winter,followed by autumn and spring,and lowest in summer.The total concentration of the nine heavy metal elements ranged from 0.030 to 138.000 ng/m³,with Zn,Mn,and Pb having the highest concentrations,particularly notable during the autumn and winter seasons.Enrichment factor(EF)analysis indicated moderate enrichment(10<EF≤100)for Cd and Zn,suggesting anthropogenic pollution sources;As,Pb,and Cu were slightly enriched(1<EF≤10),influenced by both natural and anthropogenic sources;Cr,Mn,and V showed no significant enrichment(EF≤1).The non-carcinogenic hazard quotients(HQ)for all the nine heavy metals were all less than 1(ranging from 1.735×10^(-5) to 3.068×10^(-1)),with the HQ values ordered as follows:Mn>Cd>Cr>As>Pb>V>Zn>Cu>Ni.The total non-carcinogenic hazard index(HI)ranged from 0.171 to 0.361.The inhalation incremental lifetime carcinogenic risk values(ILCR)for the four elements Cr,As,Cd,and Ni ranged from 2.911×10^(-7) to 1.558×10^(-5),with ILCR decreasing in that order.The total carcinogenic risk index(TR)varied between 1.502×10^(-5) and 3.169×10^(-5),with risk intensities for HI and TR in the order:children>adult males>adult females.Conclusions The average PM_(2.5) concentration in the Haikou urban area is lower than the 24-hour average concentration limit of Grade I(35µg/m^(3))in the"Environmental Air Quality Standard"(GB 3095-2012),but still higher than the control standard recommended by the WHO in 2021(15µg/m^(3)).The non-carcinogenic health risks of the nine heavy metal elements detected in PM_(2.5) are not significant,but Cr and As have potential carcinogenic risks,with children being more vulnerable than other populations.