Spatiotemporal Variation and Influencing Factors of TSP and Anions in Coastal Atmosphere of Zhanjiang City, China.

Water-soluble anions and suspended fine particles have negative impacts on ecosystems and human health, which is a current research hotspot. In this study, coastal suburb, coastal urban area, coastal tourist area, and coastal industrial area were explored to study the spatiotemporal variation and influencing factors of water-soluble anions and total suspended particles (TSP) in Zhanjiang atmosphere. In addition, on-site monitoring, laboratory testing, and analysis were used to identify the difference of each pollutant component at the sampling stations. The results showed that the average concentrations of Cl-, NO3-, SO42-, PO43-, and TSP were 29.8 µg/m3, 19.6 µg/m3, 45.6 µg/m3, 13.5 µg/m3, and 0.28 mg/m3, respectively. The concentration of Cl-, NO3-, PO43-, and atmospheric TSP were the highest in coastal urban area, while the concentration of SO42- was the highest in coastal industrial area. Moreover, there were significantly seasonal differences in the concentration of various pollutants (p < 0.05). Cl- and SO42- were high in summer, and NO3- and TSP were high in winter. Cl-, SO42-, PO43-, and TSP had significant correlations with meteorological elements (temperature, relative humidity, atmospheric pressure, and wind speed). Besides, the results showed the areas with the most serious air pollution were coastal urban area and coastal industrial area. Moreover, the exhaust emissions from vehicles, urban enterprise emissions, and seawater evaporation were responsible for the serious air pollution in coastal urban area. It provided baseline information for the coastal atmospheric environment quality in Zhanjiang coastal city, which was critical to the mitigation strategies for the emission sources of air pollutants in the future.

[Correlation between anxiety, depression and pefectionistic tendencies in patients before orthodontic treatment].

PURPOSE: To discuss the relationships between the level of anxiety, depression and perfectionism in dental patients before orthodontic treatment. METHODS: A modified Corah Dental Anxiety Scale (MDAS), Self-Rating Depression Scale (SDS), Self-Rating Anxiety Scale (SAS) and Chinese Frost Multidimensional Perfectionism Scale (CFMPS) were used in 170 patients before orthodontic treatment. The data was analyzed by independent sample t test, correlation and multiple regression analysis using SPSS16.0 software package. RESULTS: 24.71% of the patients had obvious dental anxiety with MDAS scores≥11, there was significant difference in the scores of SAS, SDS between dental anxiety group and non-dental anxiety group (P<0.01), the scores of concern over mistakes (CM), personal standards (PS), doubts about actions (DA) and organization (OR) of dental anxiety patients were of significant difference compared with that in the non-dental anxiety group (P<0.05). Concern over mistakes (CM), personal standards (PS) and doubts about actions (DA) had significant positive correlations with the scores of SAS and SDS (P<0.01); while organization (OR) had negative correlation with the scores of SDS (P<0.05); Regression analysis showed that the scores of concern over mistakes (CM), organization (OR) and age seemed to be a strong predictor of the scores of SAS and SDS. CONCLUSIONS: The level of anxiety and depression of dental anxiety patients before orthodontic treatment is higher than non-dental anxiety group, and it has significant correlation with perfectionistic tendencies, for dental anxiety of patients with early intervention should be combined with different age and perfectionism personality characteristics.

[Adsorption kinetic and thermodynamic studies of lead onto activated carbons from cotton stalk].

Low-cost high surface area microporous carbons were prepared from cotton stalk and cotton stalk fiber by H3PO4 activation. The adsorption of lead ions on the carbons was investigated by conducting a series of batch adsorption experiments. The influence of solution pH value, contact time and temperature was investigated. The adsorption kinetics, thermodynamic behavior and mechanism were also discussed. The surface area and pore structure of the activated carbons were analyzed by BET equation, BJH method and H-K method according to the data from nitrogen adsorption at 77K. Boehm titration, Fourier transform infrared spectroscopy (FTIR), the point of zero charge (pH(PZC)) measurement and elemental analysis were used to characterize the surface properties. The results show that the carbons from cotton stalk and cotton stalk fiber have high surface area of 1570 and 1731 m2 x g(-1), and high content of oxygen-containing functional groups of 1.43 and 0.83 mmol x g(-1). The adsorption experiments show that the carbons have high adsorption capacity for lead, and the maximum adsorption equilibrium amount was found to be 120 mg x g(-1). The adsorption amount increased with contact time, and almost 80% of the adsorption occurred in the first 5 min. The pseudo-second-order model describes the adsorption kinetics most effectively. The Freundlich isotherm was found to the best explanation for experimental data. The negative change in free energy (delta G0) and positive change in enthalpy (delta H0) indicate that the adsorption is a spontaneous and endothermic process, and the adsorption of lead ions onto the carbons might be involved in an ion-exchange mechanism.

[Diuron degradation process and change of toxicity by gamma-irradiation].

The radiation-induced degradation process of diuron and change of toxicity by gamma-irradiation were investigated. The contribution to diuron degradation by the radicals is in the order of: *OH > e(aq)(-) > *H. The quantum efficiency ratios of *OH, e(aq)(-) and *H for the degradation of diuron are calculated as 3 : 1 : 2. e(aq)(-) and *H could reduce diuron and its degradation product by loss of the chlorine atoms and the addition reaction. Both the shift and alkaline substitute mutations firstly increase and then decrease with the increase of irradiation time. But, the sample only shows mutagenic potential in Ames assay (TA100 strain) when 22.2 min is selected as the irradiation time. The acute toxicity firstly decreases and then increases with the increase of irradiation time and the more toxic substances are produced.

Treatment of tannery wastewater by electrocoagulation.

Treatment of tannery wastewater by electrocoagulation with low cell current (< or = 1A) and soluble electrodes (mild steel electrodes and aluminum electrodes) was studied. Compared with aluminum electrodes, mild steel electrodes were more effective for the removal of sulfide, with a removal efficiency of over 90%. But during the treatment process, black color precipitate typical to iron(II) sulfides was produced. While aluminum electrodes were effective to eliminate the colority of the effluent, the removal efficiency of sulfide was lower than 12%. The mechanisms of the removal of chemical oxygen demand, ammonia, total organic carbon, sulfide and colority with the two soluble electrodes (mild steel and aluminum electrodes) were discussed in detail. In order to exert the predominance of diffenent types of electrodes, the tannery wastewater was treated using mild steel electrodes first followed by the filter and finally by the aluminum electrodes, the elimination rates of chemical oxygen demand, ammonia, total organic carbon, sulfide and colority were 68.0%, 43.1%, 55.1%, 96.7% and 84.3%, respectively, with the initial concentrations 2413.1 mg/L, 223.4 mg/L, 1000.4 mg/L, 112.3 mg/L and 256 dilution times, respectively. The absorbance spectra and energy consumption during electrocoagulation process were also discussed.