利用生理提取试验(physiologically based extraction test,PBET)法研究石家庄市建设大街15个公交站点表层尘土中Cr、Mn、Cu、Zn、Cd、Pb的生物可给性,并采用美国环保局人体健康风险模型对6种重金属的健康风险进行评价。结果表明:与河...利用生理提取试验(physiologically based extraction test,PBET)法研究石家庄市建设大街15个公交站点表层尘土中Cr、Mn、Cu、Zn、Cd、Pb的生物可给性,并采用美国环保局人体健康风险模型对6种重金属的健康风险进行评价。结果表明:与河北省土壤元素背景值相比,Mn和Cr在各站点的含量未超过背景值,Cu、Zn、Cd、Pb在各站点含量均超过背景值,其中Cd的富集程度最大。重金属溶解态量在胃和肠阶段差异较大,除在运河桥客运站Cr的溶解态量肠阶段大于胃阶段外,各重金属在所有站点溶解态量胃阶段均高于肠阶段。在所有站点中,Cu、Zn、Cd、Pb、Mn、Cr的生物可给性分别为40.57%~90.31%、45.67%~77.57%、61.03%~84.14%、49.05%~82.99%、59.46%~85.32%、11.36%~54.17%。儿童的非致癌风险商(HQ)和致癌风险商(CR)高于成人。6种重金属在各站点的HQ均小于1,在安全阈值之内。Cr和Cd在各站点的CR在1×10^-6~1×10^-4范围内,对儿童及成人存在一定致癌风险,但尚可接受;Pb在各站点的CR小于1×10^-6,对儿童及成人的致癌风险甚微,可忽略。展开更多
Reaction rate constants and products of 1-octen-3-one,3-octen-2-one and 4-hexen-3-one with ozone were studied in a 100-L fluorinated ethylene propylene(FEP) Teflon film bag using absolute rate method at 298 ± 1 K...Reaction rate constants and products of 1-octen-3-one,3-octen-2-one and 4-hexen-3-one with ozone were studied in a 100-L fluorinated ethylene propylene(FEP) Teflon film bag using absolute rate method at 298 ± 1 K and atmospheric pressure.The rate constants were(1.09 ± 0.12) × 10-17,(3.48 ± 0.36) × 10-17 and(5.70±0.60) × 10-17 cm3/(molecule·sec),respectively.According to the obtained rate constants,the effects of carbonyl were discussed.The carbonyl group in β position has a net withdrawing effect with respect to an olefinic bond,then causing the decline of rate constants.The quantum chemical calculation was used to explain the results of rate constants.The products of ozonolysis were mainly aldehydes,which have significant influence on the formation of SOA,and hence play an important role in the atmosphere.In this work,we detected the main products of reaction and proposed the reaction mechanism by combining the results of quantum chemical calculations.Atmospheric lifetime for three unsaturated ketones reacted with ozone was 36.4,11.4 and 6.9 hr for 1-octen-3-one,3-octen-2-one and 4-hexen-3-one,respectively.展开更多
文摘利用生理提取试验(physiologically based extraction test,PBET)法研究石家庄市建设大街15个公交站点表层尘土中Cr、Mn、Cu、Zn、Cd、Pb的生物可给性,并采用美国环保局人体健康风险模型对6种重金属的健康风险进行评价。结果表明:与河北省土壤元素背景值相比,Mn和Cr在各站点的含量未超过背景值,Cu、Zn、Cd、Pb在各站点含量均超过背景值,其中Cd的富集程度最大。重金属溶解态量在胃和肠阶段差异较大,除在运河桥客运站Cr的溶解态量肠阶段大于胃阶段外,各重金属在所有站点溶解态量胃阶段均高于肠阶段。在所有站点中,Cu、Zn、Cd、Pb、Mn、Cr的生物可给性分别为40.57%~90.31%、45.67%~77.57%、61.03%~84.14%、49.05%~82.99%、59.46%~85.32%、11.36%~54.17%。儿童的非致癌风险商(HQ)和致癌风险商(CR)高于成人。6种重金属在各站点的HQ均小于1,在安全阈值之内。Cr和Cd在各站点的CR在1×10^-6~1×10^-4范围内,对儿童及成人存在一定致癌风险,但尚可接受;Pb在各站点的CR小于1×10^-6,对儿童及成人的致癌风险甚微,可忽略。
基金supported by the National Key Research and Development Program of China(No.2016YFC0202200)the National Natural Science Foundation of China(Nos.41571130022 and 91544227)+1 种基金Beijing Nova Program(No.2018113)the Youth Innovation Promotion Association Chinese Academy of Sciences(CAS)(No.2017042)
文摘Reaction rate constants and products of 1-octen-3-one,3-octen-2-one and 4-hexen-3-one with ozone were studied in a 100-L fluorinated ethylene propylene(FEP) Teflon film bag using absolute rate method at 298 ± 1 K and atmospheric pressure.The rate constants were(1.09 ± 0.12) × 10-17,(3.48 ± 0.36) × 10-17 and(5.70±0.60) × 10-17 cm3/(molecule·sec),respectively.According to the obtained rate constants,the effects of carbonyl were discussed.The carbonyl group in β position has a net withdrawing effect with respect to an olefinic bond,then causing the decline of rate constants.The quantum chemical calculation was used to explain the results of rate constants.The products of ozonolysis were mainly aldehydes,which have significant influence on the formation of SOA,and hence play an important role in the atmosphere.In this work,we detected the main products of reaction and proposed the reaction mechanism by combining the results of quantum chemical calculations.Atmospheric lifetime for three unsaturated ketones reacted with ozone was 36.4,11.4 and 6.9 hr for 1-octen-3-one,3-octen-2-one and 4-hexen-3-one,respectively.
