TY - JOUR
T1 - Synergistic and antagonistic interactions among organic and metallic components of the ambient particulate matter (PM) for the cytotoxicity measured by Chinese hamster ovary cells
AU - Wang, Yixiang
AU - Puthussery, Joseph V.
AU - Yu, Haoran
AU - Verma, Vishal
N1 - Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2020/9/20
Y1 - 2020/9/20
N2 - Although PM2.5 toxicity is known to be related to its chemical composition, the effect of interactions among various particles' components on the toxicity is not well explored. To understand these interactions, especially metals and organic compounds on PM2.5 cytotoxicity, we chose several redox-active substances known to be present in the ambient particles such as metals (Cu, Fe, and Mn) and quinones [9,10-phenanthraquinone (PQ), 1,2-naphthoquinone (1,2-NQ), 1,4-naphthoquinone (1,4-NQ), and 5-hydroxy-1,4-naphthoquinone (5,H-1,4-NQ)]. Cytotoxicity was assessed through a Chinese hamster ovary (CHO) cells assay and expressed by a median lethal concentration (LC50). Two methods were employed to assess the interactions. In the first method, we tested the impact of nontoxic level of a component on the LC50 of other components. In the second method, we mixed two components in different concentration ratios to expose the cells and calculated a mixture toxicity index (MTI). MTI is a composite value to quantify the nature of interactions such that the interactions are considered synergistic when MTI > 1, additive when 0 < MTI ≤ 1 and antagonistic when MTI < 0. The interactions between quinones and metals were largely synergistic by both methods. To further assess the environmental relevance of these mixtures, we extracted organic compounds termed as water-soluble Humic-like substances (HULIS) from real ambient PM samples and mixed them with individual metals. A similar pattern, as observed from the interaction of quinones and metals, was found. Moreover, the interactions became more synergistic as the relative concentration of metals with respect to water-soluble HULIS was decreased in these mixtures. With environmentally relevant mass concentration ratios of organics to metals (75–7500), the interactions were strongly synergistic (MTI = 1–115). These results indicate the importance of incorporating the interaction among various PM components for estimating the net toxicity of ambient PM2.5.
AB - Although PM2.5 toxicity is known to be related to its chemical composition, the effect of interactions among various particles' components on the toxicity is not well explored. To understand these interactions, especially metals and organic compounds on PM2.5 cytotoxicity, we chose several redox-active substances known to be present in the ambient particles such as metals (Cu, Fe, and Mn) and quinones [9,10-phenanthraquinone (PQ), 1,2-naphthoquinone (1,2-NQ), 1,4-naphthoquinone (1,4-NQ), and 5-hydroxy-1,4-naphthoquinone (5,H-1,4-NQ)]. Cytotoxicity was assessed through a Chinese hamster ovary (CHO) cells assay and expressed by a median lethal concentration (LC50). Two methods were employed to assess the interactions. In the first method, we tested the impact of nontoxic level of a component on the LC50 of other components. In the second method, we mixed two components in different concentration ratios to expose the cells and calculated a mixture toxicity index (MTI). MTI is a composite value to quantify the nature of interactions such that the interactions are considered synergistic when MTI > 1, additive when 0 < MTI ≤ 1 and antagonistic when MTI < 0. The interactions between quinones and metals were largely synergistic by both methods. To further assess the environmental relevance of these mixtures, we extracted organic compounds termed as water-soluble Humic-like substances (HULIS) from real ambient PM samples and mixed them with individual metals. A similar pattern, as observed from the interaction of quinones and metals, was found. Moreover, the interactions became more synergistic as the relative concentration of metals with respect to water-soluble HULIS was decreased in these mixtures. With environmentally relevant mass concentration ratios of organics to metals (75–7500), the interactions were strongly synergistic (MTI = 1–115). These results indicate the importance of incorporating the interaction among various PM components for estimating the net toxicity of ambient PM2.5.
KW - Chinese hamster ovary (CHO) cells
KW - Cytotoxicity
KW - Humic-like substances
KW - Interactions
KW - Metals
KW - Mixture toxicity index
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U2 - 10.1016/j.scitotenv.2020.139511
DO - 10.1016/j.scitotenv.2020.139511
M3 - Article
C2 - 32474273
AN - SCOPUS:85085245393
SN - 0048-9697
VL - 736
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 139511
ER -