The toxicity of PM_(2.5)does not necessarily change synchronously with its mass concentration.In this study,the chemical composition(carbonaceous species,water-soluble ions,and metals)and oxidative potential(dithiothr...The toxicity of PM_(2.5)does not necessarily change synchronously with its mass concentration.In this study,the chemical composition(carbonaceous species,water-soluble ions,and metals)and oxidative potential(dithiothreitol assay,DTT)of PM_(2.5)were investigated in 2017/2018 and 2022 in Xiamen,China.The decrease rate of volume-normalized DTT(DTTv)(38%)was lower than that of PM_(2.5)(55%)between the two sampling periods.However,the mass-normalized DTT(DTTm)increased by 44%.Clear seasonal patterns with higher levels in winter were found for PM_(2.5),most chemical constituents and DTTv but not for DTTm.The large decrease in DTT activity(84%−92%)after the addition of EDTA suggested that watersoluble metals were the main contributors to DTT in Xiamen.The increased gap between the reconstructed and measured DTTv and the stronger correlations between the reconstructed/measured DTT ratio and carbonaceous species in 2022were observed.The decrease rates of the hazard index(32.5%)and lifetime cancer risk(9.1%)differed from those of PM_(2.5)and DTTv due to their different main contributors.The PMF-MLR model showed that the contributions(nmol/(min·m^(3)))of vehicle emission,coal+biomass burning,ship emission and secondary aerosol to DTTv in 2022 decreased by 63.0%,65.2%,66.5%,and 22.2%,respectively,compared to those in 2017/2018,which was consistent with the emission reduction of vehicle exhaust and coal consumption,the adoption of low-sulfur fuel oil used on board ships and the reduced production of WSOC.However,the contributions of dust+sea salt and industrial emission increased.展开更多
为探究农业-城市复合流域汛期初期水质特征并解析其主要元素的来源贡献,以小东江为例,研究汛期初期水质变化及主要指标来源,为区域水污染防治提供科学依据。通过分析水质指标、八大离子及主要微量元素分布特征,结合绝对主成分–多元线...为探究农业-城市复合流域汛期初期水质特征并解析其主要元素的来源贡献,以小东江为例,研究汛期初期水质变化及主要指标来源,为区域水污染防治提供科学依据。通过分析水质指标、八大离子及主要微量元素分布特征,结合绝对主成分–多元线性回归模型(absolute principal component-multiple linear regression,APCS-MLR)和正定矩阵因子分解(positive matrix factorization,PMF)模型解析污染来源。结果表明:汛期初期,小东江水质为Ⅳ类,水质变化呈双重效应。上游支流受农业面源影响,导致TP、AN质量浓度升高,而下游干流受城市生活污水和溢流影响,导致EC、TDS和Cd等增加。汛期初期降雨对下游水质有稀释作用,但上游农业面源污染的加剧导致水质恶化。Se质量浓度高于生活饮用水标准限值(<10μg/L),TDS与Sr、V、Ca2+等指标呈极显著相关性(P<0.001),TP与AN及阴阳离子间存在显著相关性(P<0.01)。APCS-MLR和PMF模型分析结果表明,农业面源污染对TP和AN的贡献率分别为41.42%和42.22%,大气沉降对SO42-的贡献率为60.89%,生活污水对Cl-的贡献率为78.98%。综上,农业面源和下游生活污水是汛期初期小东江的主要污染来源,亟须加强汛期初期农业面源及下游城市生活污水管理。展开更多
基金supported by the Science and Technology Program of Fujian Province,China(No.2023R1014002)the National Natural Science Foundation of China(No.41471390).
文摘The toxicity of PM_(2.5)does not necessarily change synchronously with its mass concentration.In this study,the chemical composition(carbonaceous species,water-soluble ions,and metals)and oxidative potential(dithiothreitol assay,DTT)of PM_(2.5)were investigated in 2017/2018 and 2022 in Xiamen,China.The decrease rate of volume-normalized DTT(DTTv)(38%)was lower than that of PM_(2.5)(55%)between the two sampling periods.However,the mass-normalized DTT(DTTm)increased by 44%.Clear seasonal patterns with higher levels in winter were found for PM_(2.5),most chemical constituents and DTTv but not for DTTm.The large decrease in DTT activity(84%−92%)after the addition of EDTA suggested that watersoluble metals were the main contributors to DTT in Xiamen.The increased gap between the reconstructed and measured DTTv and the stronger correlations between the reconstructed/measured DTT ratio and carbonaceous species in 2022were observed.The decrease rates of the hazard index(32.5%)and lifetime cancer risk(9.1%)differed from those of PM_(2.5)and DTTv due to their different main contributors.The PMF-MLR model showed that the contributions(nmol/(min·m^(3)))of vehicle emission,coal+biomass burning,ship emission and secondary aerosol to DTTv in 2022 decreased by 63.0%,65.2%,66.5%,and 22.2%,respectively,compared to those in 2017/2018,which was consistent with the emission reduction of vehicle exhaust and coal consumption,the adoption of low-sulfur fuel oil used on board ships and the reduced production of WSOC.However,the contributions of dust+sea salt and industrial emission increased.
文摘为探究农业-城市复合流域汛期初期水质特征并解析其主要元素的来源贡献,以小东江为例,研究汛期初期水质变化及主要指标来源,为区域水污染防治提供科学依据。通过分析水质指标、八大离子及主要微量元素分布特征,结合绝对主成分–多元线性回归模型(absolute principal component-multiple linear regression,APCS-MLR)和正定矩阵因子分解(positive matrix factorization,PMF)模型解析污染来源。结果表明:汛期初期,小东江水质为Ⅳ类,水质变化呈双重效应。上游支流受农业面源影响,导致TP、AN质量浓度升高,而下游干流受城市生活污水和溢流影响,导致EC、TDS和Cd等增加。汛期初期降雨对下游水质有稀释作用,但上游农业面源污染的加剧导致水质恶化。Se质量浓度高于生活饮用水标准限值(<10μg/L),TDS与Sr、V、Ca2+等指标呈极显著相关性(P<0.001),TP与AN及阴阳离子间存在显著相关性(P<0.01)。APCS-MLR和PMF模型分析结果表明,农业面源污染对TP和AN的贡献率分别为41.42%和42.22%,大气沉降对SO42-的贡献率为60.89%,生活污水对Cl-的贡献率为78.98%。综上,农业面源和下游生活污水是汛期初期小东江的主要污染来源,亟须加强汛期初期农业面源及下游城市生活污水管理。
