Chlorinated Paraffins in Human Milk from Urban Sites in China, Sweden, and Norway.

Short-, medium-, and long-chain chlorinated paraffins (SCCPs, MCCPs, and LCCPs) were analyzed in human milk from the Yangtze River Delta (YRD) and Scandinavia. Individual samples were collected from Shanghai, Jiaxing, and Shaoxing (China), Stockholm (Sweden), and Bodø (Norway) between 2010 and 2016. Mean concentrations (range) of SCCPs, MCCPs, and LCCPs in samples from the YRD were 124 [

Polyethylene glycol 400 significantly enhances the stimulation of 2-phenoxyethanol on Vibrio qinghaiensis sp.-Q67 bioluminescence.

Previous studies demonstrated long-term stimulation of some commercial personal care products (PCPs) on freshwater luminescent bacteria Vibrio qinghaiensis sp.-Q67 (Q67). However, whether a certain component can affect mixture's hormetic effect is still unknown. In this paper, two of ingredients in PCPs, 2-phenoxyethanol (PhE) and polyethylene glycol 400 (PEG400), were selected as object compounds to explore the relationship between concentration-response (CR) of mixtures and that of a single component. It was found that PEG400 has monotonic CR (MCR) on Q67 both at the short-term (0.25 h) and long-term (12 h) exposures while PhE has MCR at 0.25 h and hormetic CR (HCR) at 12 h. Here, the concentration-response curves (CRCs) of PEG400 at 0.25 and 12 h are overlapped each other and the CRCs of PEG400 are on the right of PhE. If the pEC50 is taken as a toxic index, the toxicities of PEG400 at two times are basically the same, and those of PhE are the same, too, but PhE is twice as toxic as PEG400. For the mixtures of PEG400 and PhE, all rays except R1 have MCRs at 0.25 h while all rays have HCRs at 12 h where the higher the mixture ratio of PhE is, the more negative the maximum stimulation effect is. More importantly, the Emin values of all rays are more negative (1.79-3.17-fold) than that of PhE worked alone, which implies that the introduction of PEG400 significantly enhances stimulative effect of PhE. At 0.25 h, all binary mixture rays but R1 produce a low-concentration additive action and high-concentration synergism. At 12 h, all rays display additive action, antagonism, additive action, and synergism in turn when the concentration changes from low to high. The overall findings suggested toxicological interactions should be considered in the risk assessment of PCPs and their potential impacts on ecological balances.

Identifying the component responsible for antagonism within ionic liquid mixtures using the up-to-down procedure integrated with a uniform design ray method.

Various chemicals in the environment always exist as mixtures. Toxicity interaction within mixtures may pose potential hazards and risks to the environmental safety and human health. Recent studies showed that toxicity interaction by ionic liquid (IL) mixtures can be related to a certain component. To identify the component, we developed a novel procedure integrating an up-to-down process with the uniform design-based ray method (UDUD) and applied it into an IL mixture system of four 1-butyl-3-methylimidazolium ILs (simply [bmim]X) where X=Cl(-), Br(-), CH3OSO3(-) and CH3(CH2)7OSO3(-). It was shown that two mixture rays in the quaternary system exhibited significant antagonistic interaction. In this paper, the UDUD was first employed to design four ternary mixture systems. The microplate toxicity analysis was used to determine the toxicities of various mixtures to a freshwater photobacterium Vibrio qinghaiensis sp.-Q67. The concentration addition was taken as an additive reference to assess the toxicity interactions taking place in mixtures. The results revealed that some ternary mixture rays including [bmim]CH3(CH2)7OSO3 display antagonism while the ternary rays without [bmim]CH3(CH2)7OSO3 exhibit additivity. On these grounds, we again designed all binary mixtures containing [bmim]CH3(CH2)7OSO3, determined their toxicities and assessed toxicity interaction. The results showed that three binary mixture systems produce antagonism. Thus, it may be concluded that [bmim]CH3(CH2)7OSO3 is indeed a key component inducing mixture antagonism.

Source forensics of black carbon aerosols from China.

The limited understanding of black carbon (BC) aerosol emissions from incomplete combustion causes a poorly constrained anthropogenic climate warming that globally may be second only to CO2 and regionally, such as over East Asia, the dominant driver of climate change. The relative contribution to atmospheric BC from fossil fuel versus biomass combustion is important to constrain as fossil BC is a stronger climate forcer. The source apportionment is the underpinning for targeted mitigation actions. However, technology-based "bottom-up" emission inventories are inconclusive, largely due to uncertain BC emission factors from small-scale/household combustion and open burning. We use "top-down" radiocarbon measurements of atmospheric BC from five sites including three city sites and two regional sites to determine that fossil fuel combustion produces 80 ± 6% of the BC emitted from China. This source-diagnostic radiocarbon signal in the ambient aerosol over East Asia establishes a much larger role for fossil fuel combustion than suggested by all 15 BC emission inventory models, including one with monthly resolution. Our results suggest that current climate modeling should refine both BC emission strength and consider the stronger radiative absorption associated with fossil-fuel-derived BC. To mitigate near-term climate effects and improve air quality in East Asia, activities such as residential coal combustion and city traffic should be targeted.

Correction: Emerging per- and polyfluoroalkyl substances (PFAS) in human milk from Sweden and China.

Correction for 'Emerging per- and polyfluoroalkyl substances (PFAS) in human milk from Sweden and China' by Raed Awad et al., Environ. Sci.: Processes Impacts, 2020, 22, 2023-2030, DOI: 10.1039/D0EM00077A.

Emerging per- and polyfluoroalkyl substances (PFAS) in human milk from Sweden and China.

Twenty per- and polyfluoroalkyl substances (PFAS) were determined in human milk from residents of three Chinese cities (Shanghai, Jiaxing, and Shaoxing; [n = 10 individuals per city]), sampled between 2010 and 2016. These data were compared to a combination of new and previously reported PFAS concentrations in human milk from Stockholm, Sweden, collected in 2016 (n = 10 individuals). Across the three Chinese cities, perfluorooctanoate (PFOA; sum isomers), 9-chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS; also known as 6:2 Cl-PFESA or by its trade name "F53-B"), and perfluorooctane sulfonate (PFOS; sum isomers) occurred at the highest concentrations among all PFAS (up to 411, 976, and 321 pg mL-1, respectively), while in Stockholm, PFOA and PFOS were dominant (up to 89 and 72 pg mL-1, respectively). 3H-Perfluoro-3-[(3-methoxy-propoxy)propanoic acid] (ADONA) was intermittently detected but at concentrations below the method quantification limit (i.e. <10 pg mL-1) in Chinese samples, and was non-detectable in Swedish milk. The extremely high concentrations of F53-B in Chinese milk suggest that human exposure assessments focused only on legacy substances may severely underestimate overall PFAS exposure in breastfeeding infants.

Historical development and future perspectives of Environmental Specimen Bank in China: a mini review.

Environmental problems as well as their related ecosystem stress and human health risk in China have raised wide concerns along with the rapid economic development in recent years. Numerous studies with a sharp increase in publication number have addressed the ubiquitous of anthropogenic chemicals in various environmental compartments and human tissues. However, very few data were available to clarify the temporal trend and to give the retrospective analysis of chemical pollution in China. Environmental Specimen Bank (ESB) is a system for the systematic collection and long-term storage of specimens, which has been established since the 1970s in developed counties and recognized as a fundamental complement for environmental monitoring and scientific research. Currently, the value of ESB is becoming more broadly recognized globally, and China is still at the early stage. This article described the history and status and put forwarded the future key points of Chinese ESB development for illustrating the intensive environmental changes in China and the world.

Chemometric model for predicting retention indices of constituents of essential oils.

Quantitative structure-retention relationships (QSRRs) model was developed for predicting the gas chromatography retention indices of 169 constituents of essential oils. The ordered predictors selection algorithm was used to select three descriptors (one constitutional index and two edge adjacency indices) from 4885 descriptors. The final QSRR model (model M3) with three descriptors was internal and external validated. The leave-one-out cross-validation, leave-many-out cross-validation, bootstrapping, and y-randomization test indicated the final model is robust and have no chance correlation. The external validations indicated that the model M3 showed a good predictive power. The mechanistic interpretation of QSRR model was carried out according to the definition of descriptors. The results show that the larger molecular weight, the greater the values of retention indices. More compact structures have stronger intermolecular interactions between the components of essential oils and the capillary column. Therefore, the result meets the five principles recommended by the Organization for Economic Co-operation and Development (OECD) for validation of QSRR model, and it is expected the model can effectively predict retention indices of the essential oils.

A novel model integrated concentration addition with independent action for the prediction of toxicity of multi-component mixture.

Concentration addition (CA) and independent action (IA) have been used to describe the mixture of components having similar and dissimilar mode of action (MOA), respectively. Environmentally relevant mixture does, however, not follow the strictly similar or dissimilar MOA. A novel model, which integrated CA with IA based on the multiple linear regression (ICIM), was proposed for predicting the toxicity of noninteractive mixture. The predictive power of the ICIM model was validated by data set 1 including 13 mixtures of nine components and data set 2 including six mixtures of six components. For data set 1, ten uniform design with fixed concentration ratio ray (UDCR) mixtures was used as a training set to build an ICIM model, and the model was used to predict the toxicity of the test set consisting of three equivalent-effect concentration ratio (EECR) mixtures. For data set 2, the ICIM model based on four UDCR mixtures was used to predict the remaining two EECR mixtures. It is concluded that the ICIM model shows a strong predictive power for the mixture toxicities in the two data sets, and its prediction is better than CA and IA where the two models deviate from the concentration-response data of the mixtures. Thus, ICIM model is a powerful tool to evaluate and predict mixture toxicity, and maybe offer an important approach in risk assessment of mixture toxicity.

[Determination of polycyclic aromatic hydrocarbons in soil by ultra performance liquid chromatography].

An analytical method based on ultra performance liquid chromatography (UPLC) coupled with a photodiode array (PDA) detector has been developed for the simultaneous determination of 16 polycyclic aromatic hydrocarbons (PAHs). The comparison of UPLC and the conventional high performance liquid chromatography (HPLC) has been carried out. The major advantages of UPLC over HPLC include the faster analysis speed, considerably increased sensitivity and significantly improved detection limit. By UPLC, the whole analytical process can be performed in 13.5 min and the limits of detection for the 16 PAHs were between 2 pg and 20 pg.