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Potential risk of endocrine disrupting compounds on non-target organisms has received extensive attentions in recent years. The present work aimed to investigate the behavior and effect of a synthetic steroid estrogen quinestrol in duckweed Spirodela polyrhiza L. Experimental results showed that quinestrol could be uptaken, accumulated, and biotransformed into 17 α-ethynylestradiol in S. polyrhiza L. The accumulation of quinestrol had a positive relation to the exposure concentration. The bioaccumulation rate was higher when the duckweed was exposed to quinestrol solutions at low concentrations than at high concentration. While the transformation of quinestrol showed no concentration-dependent manner. Quinestrol reduced the biomass and pigment content and increased superoxide dismutase and catalase activities and malondialdehyde contents in the duckweed. The results demonstrated that quinestrol could be accumulated and biotransformed in aquatic plant S. polyrhiza L. This work would provide supplemental data on the behavior of this steroid estrogen compound in aquatic system. [ABSTRACT FROM AUTHOR]

Trifluoroacetic acid (TFA) was measured at an urban site in Beijing from April 2013 to April 2016 and examined its characteristics and particle/gas distributions. The average monthly atmospheric TFA concentration fluctuated significantly and presented marked seasonal variations. The concentration levels of gas-phase TFA were significantly higher in spring and summer than in fall and winter. The PM 2.5 mass concentration and ambient temperature were important factors affecting the concentration of particulate-phase TFA. Hence, at higher PM 2.5 concentrations and lower temperatures, atmospheric TFA tended to be enriched in particulate matter. Our findings suggest that the percentage of gas-phase TFA in Beijing is higher than that in the steady state; thus, gas-phase TFA can still be transformed to the particulate phase and increase the contribution of TFA to haze formation. [ABSTRACT FROM AUTHOR]