[Development of Determination Method of Fluoroquinolone Antibiotics in Sludge Based on Solid Phase Extraction and HPLC-Fluorescence Detection Analysis].

Fluoroquinolone antibiotics (FQs), as the common pharmaceuticals and personal care products (PPCPs), are widespread in the environment. FQs contained in wastewater would be ultimately enriched in sludge, posing a potential threat to the consequent sludge utilization. To optimize the analytical method applicable to the determination of FQs in sludge, the authors selected ofloxacin (OFL), norfioxacin (NOR), ciprofloxacin (CIP) and lomefloxacin (LOM) as the target FQs, and established a method which was based on cell lysis, FQs extraction with triethylamine/methanol/water solution, Solid Phase Extraction (SPE) and HPLC-Fluorescence Detection (FLD) determination. After the investigation, phosphoric acid-triethylamine was decided to be the buffer salt, and methanol was chosen as the organic mobile phase. The gradient fluorescence scanning strategy was proved to be necessary for the optimal detection as well. Furthermore, by the designed orthogonal experiments, the effects of the extraction materials, pH, and the eluents on the efficiency of SPE extraction were evaluated, by which the optimal extraction conditions were determined. As a result, FQs in liquid samples could be analyzed by utilizing HLB extraction cartridge, and the recovery rates of the four FQs were in the range of 82%-103%. As for solid samples, the recovery rates of the four FQs contained reached up to 71%-101%. Finally, the adsorptivity of the sludge from the different tanks ( anaerobic, anoxic and oxic tanks) was investigated, showing gradual decrease in the adsorption capacity, but all adsorbed over 90% of the EQs. This conclusion also confirmed that 50% removal of FQs in the domestic wastewater treatment plant was realized by sludge adsorption.

Mercury distribution in the foliage and soil profiles of the Tibetan forest: processes and implications for regional cycling.

Remote forests are considered a pool of Mercury (Hg) in the global Hg cycle. However, notably few studies have investigated the fate of Hg in the Tibetan forest. In this study, fifty-two foliage samples and seven litter/soil profiles were collected throughout the Tibetan forest. The concentrations of total Hg (THg) in foliage were positively correlated with longitude and negatively correlated with altitude, indicating that the emission of Hg is expected to decrease with increasing distance from emission sources to the Tibetan forest. The deposition flux of THg in the Tibetan forest (with an air-to-forest ground flux of 9.2 µg/m(2)/year) is ∼2 times the flux in clearings, which is suggestive of enhanced Hg deposition by the forest. The depositional Hg is eventually stored in the forest soil, and the soil acts as a net 'sink' for Hg.

Persistent organic pollutants in the Tibetan surface soil: spatial distribution, air-soil exchange and implications for global cycling.

There are limited data on persistent organic pollutants (POPs) in the soils of the Tibetan Plateau. This paper presents data from a survey of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in 40 background surface (0-5 cm) soils of the Tibetan Plateau. Soil concentrations (pg/g, dw) ranged as follows: DDTs, 13-7700; HCHs, 64-847; HCB, 24-564; sum of 15 PCBs, 75-1021; and sum of 9 PBDEs, below detection limit -27. Soil DDT, HCB, PCB and PBDE concentrations were strongly influenced by soil organic carbon content. HCH concentrations were clearly associated with the proximity to source regions in south Asia. The air-soil equilibrium status of POPs suggested the Tibetan soils may be partial "secondary sources" of HCB, low molecular weight PCBs and HCHs and will likely continue to be "sinks" for the less volatile DDE and DDT.

[FMRI study of linguistic cortex in healthy Chinese individuals].

OBJECTIVE: To study the linguistic-functional cortex and identify the effect of age and sex on normal language processing by ER-fMRI and to observe whether a left or right predominance for linguistic-functional cortex exits or not. METHODS: A total of 50 healthy Chinese volunteers with right-hand dominance were divided into 4 groups according to gender and age: Group A, young male (< or =50 yr); Group B, young female ( < OR =50 yr); Group C, old male ( >50 yr); Group D, old female ( >50 yr). Each group finished 2 tasks of reading Chinese words loudly and silently. RESULTS: There were no statistical differences of activated voxel and intensity changes in linguistically functional cortex between healthy male and female individuals of different decades. The activated areas include bilateral frontal lobe, temporal lobe, parietal lobe, occipital lobe and bilateral cerebellar hemisphere. And there were no statistical difference of activated voxel and intensity changes in bilateral activated areas. Although the activated areas were not quite the same between two tasks and more activation elicited by overt-reading, but there was no statistical difference of activated voxel and intensity changes in the same activated areas. CONCLUSION: There is no age and gender difference in linguistic-function regions of healthy individual whose native language is Chinese. It is bilateral-equilibrium and no linguistic hemisphere's predominance exits. This characteristic is different from the left-hemisphere dominance of western languages. Although there is no statistical difference of activated voxel and intensity change between overt-reading and covert-reading, the activated areas of covert-reading are so unreliable that the way of covert-reading to study the linguistic-function regions of human brain is improper to some extent.