[Occurrence and Spatial Distribution of Volatile Organic Compounds in Urban Drinking Water Distribution Systems].

Volatile organic compounds (VOCs) in the urban drinking water distribution systems for two coastal cities (S City and L City) in China were analyzed. Health risk assessments of VOCs detected in tap water were performed, and the distribution characteristics of VOCs in the tap water pipe network were also investigated. Among 47 target VOCs, 16 compounds were detected, of which 11 were detected in both S City and L City. Halogenated hydrocarbons were the most commonly detected VOCs, with trihalomethanes (including bromodichloromethane, dibromochloromethane, and bromoform) having the highest detection frequencies (92%-100%). With the exception of bromodichloromethane and dibromochloromethane, the maximum concentrations of detected VOCs in both cities complied with the relevant limits regulated by the standards for drinking water quality (GB 5749-2006). For bromodichloromethane and dibromochloromethane, not only did their concentrations exceed the standard limits of GB 5749-2006 (60 µg·L-1 for bromodichloromethane and 100 µg·L-1 for dibromochloromethane), but their lifetime cancer risks (LCR) were estimated at unacceptable levels (>10-4). Therefore, these two compounds should be given sufficient attention or be classified as priority control pollutants in municipal water supply networks. In addition, the spatial distribution of eight VOCs with high detection frequencies (>90%) in the tap water pipe network of S City was investigated. The concentrations of VOCs (excluding toluene) in this urban drinking water distribution system gradually decreased with increasing distance from the drinking water treatment plant.

Modeling the transport of TiO2 nanoparticle aggregates in saturated and unsaturated granular media: effects of ionic strength and pH.

This study aims to explore the mechanisms governing the transport and retention kinetics of TiO(2) nanoparticle aggregates (NPAs) in flow-through columns of packed sand, particularly under unsaturated conditions. The study was carried out at different pHs (2.6, 7.1, and 9.6) and ionic strengths (ISs) (1.0, 10, and 50 mM). A two-site kinetic attachment model was used to describe transport behaviors of TiO(2) NPAs. At low ISs (i.e., 1.0 and 10 mM) and in neutral/alkaline conditions, high mobility of TiO(2) NPAs was observed in both saturated and unsaturated conditions. However, the retention of TiO(2) NPAs was substantially enhanced at the high IS (50 mM) and in extremely acidity condition (pH = 2.6), because of increased aggregation and straining of TiO(2) NPAs during their transport course. The breakthrough curves (BTCs) of TiO(2) NPAs under unsaturated and saturated conditions almost overlapped, suggesting that decreasing the water saturation did not enhance the retention of TiO(2) NPAs in sand columns. This was probably due to the repulsive interactions existed between negatively charged air-water and TiO(2) NPAs systems that resulted in unfavorable attachment conditions. The two-site kinetic attachment model provided a good description for the BTCs of TiO(2) NPAs both in saturated and unsaturated conditions. The fitted parameters could successfully explain the transport behaviors of TiO(2) NPAs under various solution chemistries.

[Effect of low-dose hydroxyurea with sodium butyrate on globin gene expression in human erythroid progenitor cells].

OBJECTIVE: To investigate the effects of combined use of low-dose hydroxyurea (HU) and sodium butyrate (NaB) on the expression of 7 globin genes (zeta, alpha, epsilon, Ggamma, Agamma, delta, and beta) in human erythroid progenitor cells. METHODS: Human erythroid progenitor cells were cultured using a two-step liquid culture system and treated with HU and NaB either alone or in combination. The inhibitory effects of the agents on the cell growth were monitored with trypan blue exclusion assay, and the changes in the mRNA of the 7 globin genes were detected using RT-PCR. RESULTS: Low-dose HU combined with NaB resulted in significantly lower inhibition rate of the erythroid progenitor cells than routine dose HU and NaB used alone (28.56% and 38.80%, respectively, P<0.05). Compared with untreated cells (0.653-/+0.092 and 0.515-/+0.048), HU combined with NaB significantly increased the expression of Ggamma-and Agamma- mRNA (1.203-/+0.018 and 0.915-/+0.088, respectively, P<0.05), and HU and NaB used alone produced similar effects (1.305-/+0.016 and 0.956-/+0.029 for HU, and 1.193-/+0.070 and 0.883-/+0.012 for NaB, P>0.05). HU and NaB, either used alone or in combination or at different doses, caused no significant changes in the other globin genes (zeta, alpha, epsilon, delta and beta) (P>0.05). CONCLUSION: Low-dose HU combined with NaB can up-regulate gamma globin gene expression, especially Ggamma-mRNA expression, to decrease the growth inhibition on human erythroid progenitor cells in vitro, but produces no significant effect on the expressions of zeta, alpha, epsilon, delta and beta genes.

[Mapping QTLs related to head length, eye diameter and eye cross of common carp (Cyprinus carpio L.)].

A common carp gynogenetic line including 44 individuals derived from the cross Barbless carp x Hebao-cold tolerance red carp was used to construct a linkage map using 445 markers (265 AFLP markers, 127 SSR markers, 37 EST-SSR markers and 16 RAPD markers). Quantitative traits loci (QTLs) associated with head length, eye diameter, and eye cross were identified by composite interval mapping of the software WinQTLCart2.5. Five QTLs were identified for head length on the linkage group of LG2, LG3, LG40, and LG4, which explained 12.39% to 34.29% of the total variation of the head length. All of their additive effects were negative. Two QTLs were associated with eye diameter on the linkage groups of LG39 (qED-39-1) and LG40 (qED-40-1), which explained 9.77% and 5.62% of the total variation of the eye diameter, respectively. The additive effect of qED-39-1 was positive and that of qED-40-1 was negative. Two QTLs were responsible for eye cross on the linkage group of LG28 and LG20, explaining 8.88% and 8.29% of the total variation of the eye cross, respectively. The additive effect of qEC-28-1 was negative and that of qEC-20-1 was positive.