[Speciation and Ecological Risk Assessment of Heavy Metal(loid)s in the Municipal Sewage Sludge of China].

To reveal the speciation and pollution status of heavy metal(loid) s (HMs) in the dewatered sewage sludge(SS) of municipal wastewater treatment plants(MWTPs) in China, SS samples were collected from 40 MWTPs located in different regions of China. The total concentrations and geochemical fractions of As, Cd, Cr, Cu, Ni, Pb, and Zn in the SS samples were analyzed. The ecological risks induced by HMs in the SS were assessed based on the toxicity characteristic leaching procedure(TCLP), risk assessment code(RAC), and potential ecological risk index(RI). The median values of HMs in SS followed the order Zn > Cu > Cr > Pb > Ni > As > Cd. The general attainment rates of HMs in SS were satisfactory(>90%). As showed a generally even distribution among all the fractions; Cd and Zn mainly existed in the reducible fraction; Cr mainly occurred in the residual fraction, followed by oxidizable and reducible fractions; Cu mainly occurred in the oxidizable fraction; Ni occurred mainly as exchangeable forms; and Pb mainly occurred in the reducible and residual fractions, with its exchangeable form being the lowest fraction. According to the RAC method, the environmental risks induced by HMs in the SS followed the order Ni > As > Zn > Cd > Cu > Cr > Pb. The ecological risk of Ni was high; Zn, As, and Cd had a medium level of risk; Cr and Cu had a low level of risk; and the risk of Pb was negligible. According to the RI method, Cd and Cu showed the highest potential ecological risk, indicating that these are the primary HM pollutants in the SS. However, if the agricultural application of SS is carried out in accordance with the national standards, the overall level of risk from soil HM pollution is considered relatively low.

Sorption of dodecyltrimethylammonium chloride (DTAC) to agricultural soils.

Quaternary ammonium compounds (QACs) used as cationic surfactants are intensively released into environment to be pollutants receiving more and more concerns. Sorption of dodecyltrimethylammonium chloride (DTAC), one of commonly used alkyl QACs, to five types of agricultural soils at low concentrations (1-50mg/L) was investigated using batch experiments. DTAC sorption followed pseudo-second-order kinetics and reached reaction equilibrium within 120min. Both Freundlich model and Langmuir model fitted well with DTAC isotherm data with the latter better. DTAC sorption was spontaneous and favorable, presenting a physical sorption dominated by ion exchanges. Sorption distribution coefficient and sorption affinity demonstrated that soil clay contents acted as a predominant phase of DTAC sorption. DTAC could display a higher mobility and potential accumulation in crops in the soils with lower clay contents and lower pH values. Sorption of DTAC was heavily affected by ions in solution with anion promotion and cation inhibition.

[Quality Analysis of Peanut Seed by Visible/Near-Infrared Spectra].

In this paper, three representative varieties of peanut seeds were selected for the experiment based on visible/near-infrared reflectance spectroscopy living in the wavelength rang from 600 to 1 100 nm. Firstly, spectral datas ware collected by the near-infrared fiber optic spectrometer, and the spectral features of the original spectral dates were extracted by the wavelet analysis. Then the principal component analysis (PCA) was used for cluster analysis of spectral features. Finally, the four principal components were applied as the inputs, the varieties category as the output and the Mahalanobis distance as the discriminant function of the recognition model, so a linear discriminant analysis model was established. In the 50 samples of each varieties, 30 samples were randomly selected as the training set, and the remaining 20 samples as the predictor set. The recognition model for three peanut varieties have a recognition rate of 95% on average. As the experimental results show that this method is reliable and effectively, and a new method to distinguish and discriminate the quality of peanut seeds was put forword.

Analysis of trace microcystins in vegetables using solid-phase extraction followed by high performance liquid chromatography triple-quadrupole mass spectrometry.

A selective and sensitive method for the simultaneous detection of three common and hazardous microcystins (microcystins-LR, -RR, and -YR) in various vegetables was established using solid-phase extraction followed by high performance liquid chromatography coupled with mass spectrometry. The methanol-water proportion ratio of the extraction solvent and its acidity, as well as the efficiencies of solid-phase extraction, were evaluated to optimize a pretreatment procedure for extracting the microcystins from 10 vegetable matrices. The limits of detection and quantitation were below 7.5 µg/kg (dw) and 25 µg/kg (dw), respectively, in different vegetable matrices. The recoveries of the microcystins in the 10 vegetable matrices ranged from 61.3 to 117.3%, with RSDs of 0.2-18.3%. The established method was used to analyze 28 field vegetable samples collected from the sides of Lake Dianchi, and microcystin-RR was found in almost all samples at concentrations of 36.4-2352.2 µg/kg (dw).

Evaluation of sequential inoculation of Saccharomyces cerevisiae and Oenococcus oeni strains on the chemical and aromatic profiles of cherry wines.

The current study was carried out to elucidate the effect of sequential inoculation of Saccharomyces cerevisiae (RC212, D254) and Oenococcus oeni (SG26, Lalvin 31 and Uvaferm Alpha) on the production of cherry wines, especially on the chemical and aromatic characteristics. SI-D culture required the shortest period (23 d) to complete the fermentation, while other inoculations needed longer time. Analysis from chemical composition showed that titratable acidity and content of l-malic acid exhibited evident differences among the samples after MLF. For volatile compounds, 49 major components were identified, mostly comprising of alcohols, acids and esters. Cherry wines obtained from SI-B and SI-C showed higher contents of total volatile alcohols, and SI-D wines produced the greatest amount of volatile acids. According to the odour active value (OAV), 9 out of 49 studied volatile components had OAV >1 in all the analyzed wines, while six volatile components showed OAV >1 only for some of them. Furthermore, a sensory analysis was performed to compare the sensory profile of these cherry wines, and results evidenced that wines resulting from different inoculations presented diverse sensory profiles. These findings suggest that sequential inoculations posed a great potential in affecting and modulating the aromatic profile of cherry wines.

[Spectral properties of light migration in apple fruit tissue].

The present paper simulates laser wavelength 632 and 750 nm Gaussian beam migration in apple fruit tissue using Monte-Carlo method, and researches the spectral properties of absorption and scattering. It was shown that the special energy distribution characteristics of Gaussian beam influenced the diffusion of the laser in the tissue, the reflection, absorption and transmittance of 750 nm by tissue are lower, there are more photons interacting with tissue within the tissue, and they can more clearly reflect the information within the tissue. So, the transmission characteristics of the infrared light were relatively strong in biology tissue, which was convenient for researching biology tissue.