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Dietary intake is an important route of human exposure to chlorinated paraffins (CPs). Cup instant noodles are widely popular food and millions packet of instant noodles are consumed every year. To investigate the levels, congener groups, and health risk of SCCPs and MCCPs in each component of cup instant noodles, samples of nine common brands were collected and analyzed by comprehensive two dimensional gas chromatography coupled with mass spectrometry. The mean concentrations in the noodles were 1.2 × 103 ng/g wet weight (ww) (SCCPs) and 1.2 × 102 ng/g ww (MCCPs), the mean concentrations in the seasoning were 1.4 × 103 ng/g ww (SCCPs) and 1.3 × 102 ng/g ww (MCCPs), and the mean concentrations in the soup were 5.6 × 102 ng/L (SCCPs) and 5.4 × 102 ng/L (MCCPs). The SCCP to MCCP ratio were similar in the soup and soup container, which means CPs in the soup might be migrated from the soup container. Seasoning and noodles from the same brands have similar congener profiles of SCCPs and MCCPs, which may be raised from the manufacturing process or food packaging materials. The dominant SCCP congener groups were C 10–11 Cl 6–7 in noodles and seasoning, and C 10,13 Cl 6–7 in soup. The dominant MCCP congener groups were C 14–15 Cl 6–7 in noodles and seasoning, and C 14–15 Cl 6–7 in soup. A preliminary health risk assessment indicated that the current intakes of SCCPs and MCCPs through cup instant noodles in China did not pose a significant risk to human health. • The order of SCCP concentrations in matched samples was soup < noodles < seasoning. • SCCP concentrations were much higher than those of MCCPs in noodles and seasoning. • Seasoning and noodles from the same brands might have the same CP sources. • SCCPs and MCCPs in cup instant noodles do not pose significant human health risks. [ABSTRACT FROM AUTHOR]

Chlorinated paraffins (CPs) are easily adsorbed into sediments where they pose potential risks to the ecosystem and human health. Few studies have investigated short- and medium-chain CPs (SCCPs and MCCPs) in sediments. The aim of the present study was to comprehensively investigate contamination levels, spatial distributions, sources and risks posed by CPs in sediments from the middle reaches of the Yangtze River. The sediment samples were analyzed by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC–TOFMS). The concentrations of SCCPs and MCCPs ranged from 4.19 to 41.6 ng/g dry weight (dw) and not detected to 14.6 ng/g dw, respectively. No significant correlation was found between the total organic carbon contents and CP concentrations (P > 0.05). The spatial distributions showed that CP contamination levels in the sediments were related to local human activities. The dominant congener groups were C 10-11 Cl 6–7 for SCCPs, and C 14 Cl 7–8 for MCCPs. Correspondence analysis revealed that likely sources of SCCPs were the production and use of CP-42 and CP-52. Principal component analysis indicated that SCCPs and MCCPs in the sediments may come from different sources. Moreover, CPs with nine carbon atoms were quantitated for the first time in sediment samples, and the results indicated they should not be neglected in future analyses. Risk assessments indicated that CPs in the sediments did not pose a great ecological risk currently. [ABSTRACT FROM AUTHOR]

• Thermal evolution of biomarkers trapped by asphaltene structure is distinctly delayed compared with that of free biomarkers. • The potential chemical conversion between asphaltene-occluded n -alkanes and n -alkenes may be related to the different metastable equilibrium of the system. • Steranes and terpanes occluded by asphaltenes can preserve the original characteristics of the diagenesis stage during thermal maturation. • The occlusion space formed by asphaltene aggregates presumably restricts the transformation of active biomarkers during the thermal evolution. Asphaltene-trapped (adsorbed or occluded) biomarkers are considered a valid source of information for crude oil with severe secondary alterations. However, thermal stress might change asphaltene-trapped hydrocarbons to some extent. Therefore, it is indispensable to investigate the thermal evolution behavior of asphaltene-trapped biomarkers. In this study, low-maturity bitumen from the Kuangshanliang area of the Sichuan Basin (China) was selected as a sample. The thermal evolution behavior of free and asphaltene-trapped saturated biomarkers was investigated by thermal simulation experiments. The results revealed, in addition to normal biomarkers, also a series of even carbon number n -alk-(1)-enes in asphaltene-occluded hydrocarbons. All of them were hardly influenced by secondary alterations. Moreover, due to the restriction of macromolecular structure, the thermal evolution of asphaltene-trapped biomarkers lags behind that of free biomarkers. Most biomarker parameters of occluded hydrocarbons changed little with increasing maturity. In particular, the distributions of occluded terpanes or steranes retained the characteristics of early diagenesis of organic matter, even if they suffered from strong thermal alteration. [ABSTRACT FROM AUTHOR]