Persistent organic pollutants (POPs) have been associated with a wide range of adverse health effects. Our case-control study was performed to explore the association between placental levels of selected POPs and risks for neural tube defects (NTDs) in a Chinese population with a high prevalence of NTDs. Cases included 80 fetuses or newborns with NTDs, whereas the controls were 50 healthy, nonmalformed newborn infants. Placental concentrations of polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides, polychlorinated biphenyls, and polybrominated diphenyl ethers were analyzed by gas chromatography-mass spectrometry. The medians of PAHs, o,p'-isomers of dichlorodiphenyltrichloroethane (DDT) and metabolites, alpha- and gamma-hexachlorocyclohexane (HCH), and alpha-endosulfan were significantly higher in case placentas than in controls. PAH concentrations above the median were associated with a 4.52-fold (95% confidence interval (CI), 2.10-9.74) increased risk for any NTDs, and 5.84-(95% CI, 2.28-14.96) and 3.71-fold (95% CI, 1.57-8.79) increased risks for anencephaly and spina bifida, respectively. A dose-response relationship was observed between PAH levels and the risk of NTDs, with odds ratios for the second, third, and fourth quartiles, compared with the first, of 1.77-(95% CI, 0.66-4.76), 3.83-(95% CI, 1.37-10.75), and 11.67-fold (95% CI, 3.28-41.49), respectively. A dose-response relationship was observed for anencephaly and spina bifida subtypes. Similar results were observed for o,p'-DDT and metabolites, alpha-HCH, gamma-HCH, and alpha-endosulfan, whereas no dose-response relationship was observed for the last two pollutants. Elevated placental concentrations of PAHs, o,p'-DDT and metabolites, and alpha-HCH were associated with increased risks of NTDs in this population.
To ensure safe and efficient geologic CO2 sequestration (GCS), it is crucial to have a better understanding of CO2–brine–rock interactions under GCS conditions. In this work, using biotite (K(Mg,Fe)3AlSi3O10(OH,F)2) as a model clay mineral, brine-biotite interactions were studied under conditions relevant to GCS sites (95 °C, 102 atm CO2, and 1 M NaCl solution). After reaction for 3–17 h, fast growth of fibrous illite on flat basal planes of biotite was observed. After 22–70 h reaction, the biotite basal surface cracked, resulting in illite detaching from the surface. Later on (96–120 h), the cracked surface layer was released into solution, thus the inner layer was exposed as a renewed flat basal surface. The cracking and detachment of the biotite surface layer increased the surface area in contact with solution and accelerated biotite dissolution. On biotite edge surfaces, Al-substituted goethite and kaolinite precipitated. In control experiments with water under the same temperature and pressure, neither macroscopic fibrous illite nor cracks were observed. This work provides unique information on biotite-brine interaction under acidic hydrothermal conditions.