Levels and distributions of organochlorine pesticides in the soil-groundwater system of vegetable planting area in Tianjin City, Northern China.

To study the influence of long-term pesticide application on the distribution of organochlorine pesticides (OCPs) in the soil-groundwater system, 19 soil samples and 19 groundwater samples were collected from agricultural area with long-term pesticide application history in Northern China. Results showed that the composition of OCPs changed significantly from soil to groundwater. For example, ∑DDT, ∑HCH, and ∑heptachlor had high levels in the soil and low levels in the groundwater; in contrast, endrin had low level in the soil and high level in the groundwater.

Analysis of spatial distribution characteristics of dissolved organic matter in typical greenhouse soil of northern China using three dimensional fluorescence spectra technique and parallel factor analysis model.

The aim of the present work is to study the soil DOM characteristics in the vegetable greenhouse with a long-term of cultivation. Results showed that the soil DOM mainly consisted of three components, fulvic acid-like (C1), humic acid-like (C2) and protein-like (C3), with C1 as the majority one. The distribution of DOM in space was also studied.

[Studies on fluorescence spectral characteristics of fulvic acid (FA) from Xingkai Lake sediments].

Four samples (sample No. HXXD, HXXX, HXDX and HXDB) were taken from Xingkai Lake Sediments in Heilongjiang province and fluorescence spectral characteristics of Fulvic acid (FA) from sediments were studied. Conventional and excitation-emission matrix (EEM) all indicated that FA from HXXD sediment exhibited primary peaks at longer wavelengths.

[Analysis on the forms and release potential of nutrients in sediments from lakes in the West Jiangsu Province].

To probe the effect of nitrogen and phosphorus (P) in sediment on aqueous nutrient concentrations, forms of phosphorus, sediment water interface diffusion fluxes and phosphorus release and adsorption of 10 lakes in the west Jiangsu province were studied. Sediments were sequentially extracted by the modified Ruttenberg's method, and the result showed that inorganic phosphorus in sediments of the lakes was the major fraction of total phosphorus, but the proportion of bioavailable phosphorus was relatively low. Compared with the lakes in northern Jiangsu, the Fe-P was relatively high in sediments of lakes in southern Jiangsu.

[Fluorescence spectroscopic characteristics of dissolved organic matters (DOM) from Jingpo Lake water].

Six samples (sample J1-J6) from Jingpo Lake in Heilongjiang province were analyzed by fluorescence and fluorescence excitation-emission matrix regional integration (FIR) to determine the different characteristics of dissolved organic matters (DOM). The results with the traditional method just analyzing the excitation, emission and synchronous fluorescence spectra indicated that DOM molecular condensation degree was highest at sample J4 and sample J5, however, the study with the three-dimensional-excitation emission matrix spectra (3EEMs) method showed that the content of protein-like material was higher in sample J6 than others. In the second method, 3EEMs was divided into five regions, among which Region I, Region II, and Region IV were related to protein-like material, Region II was related to fulvic acid-like material, Region V was related to humic acid-like organics, and then these regions were integrated named as A(I), A(II), A(III), A(IV) and A(V).

Strip-based immunoassay for the simultaneous detection of the neonicotinoid insecticides imidacloprid and thiamethoxam in agricultural products.

A semiquantitative strip immunoassay was developed for the rapid detection of imidacloprid and thiamethoxam in agricultural products using specific nanocolloidal gold-labeled monoclonal antibodies. The conjugates of imidacloprid-BSA, thiamethoxam-BSA and goat anti-mouse IgG were coated on the nitro-cellulose membrane of the strip, serving as test lines and control line, respectively. The flow of the complexes of gold labeled antibodies and insecticides along the strip resulted in intensive color formed on the test lines inversely proportional to the concentrations of imidacloprid and thiamethoxam.

[Regional heterogeneity of lake eutrophication effects in China].

Although biomass of algae (Chl-a) were in variant levels between different lake regions in China under the same nutrients conditions, it demonstrated that efficiencies of TN/TP used by algae had regional differences. In order to clarify the differences, curve estimation in SPSS was used to analyze the linear relationship between Ig Chl-a and Ig TN/lg TP. The slopes of these linear equations were identified as the efficiencies of TN/TP used by algae.

[Occurrence of PFOA and PFOS in the aquatic environments and their ecological toxicities in the aquatic environments].

Based on current researches, described the sources, toxicities, analytical methods and occurrence of PFOA and PFOS in wastewater treatment plants, lakes, rivers, coastal areas and tap waters in different countries in the world. According to the limited concentrations of PFOA + PFOS in effluents of wastewater treatment plants (WTPs) put forward by Germany, the concentrations of PFOA + PFOS in WTP effluents in Singapore, Germany, Korea and England were assessed. The results showed that the concentrations of PFOA + PFOS in WTP effluents in Singapore were higher than the liminted concentration of 300 microg/L.

[Study on ecoregion techniques of lake nutrients in Yunnan-Guizhou plateau Lake regions].

The primary objective of this research is to present an ecoregion model based on the principle components analysis (PCA), the cluster analysis (CA), the discriminant analysis (DA) and the spatial autocorrelation analysis (SAA), which were applied to establish the ecorigion of lake nutrients in Yunnan-Guizhou Plateau Lakes. First, the principle components analysis method was used not only to reduce the dimensionality of the feature space, but also to deal with new indexes. The accumulation contribution ratio of the four new indexes achieved 93.

[Effects of land management measures on nutrients emission].

The SWAT model, coupled with a GIS, was applied to simulate the effects of fertilizer application, contour planting and returning land for farming to forestry on nutrients discharges. The results showed that when nitrogen fertilizer of agricultural land increased from 630 to 955 kg/hm2, and phosphorus fertilizer increased from 200 to 300 kg/hm2, nitrogen and phosphorus nutrient emissions have shown a growing trend. Nitrate nitrogen loads reached to 3 776.

[Effects of parameter spatial distribution on non-point pollution source model].

The SWAT model was used to simulate the effects of parameter spatial distribution on flow and nutrients loadings in the Daning river watershed. It was first calibrated and validated using the measured data for the period of 2000 - 2004. Then the model was used to simulate the effects of watershed delineation scenarios on flow and nutrients loadings, using six watershed delineations, each with a different number of sub-watersheds.

[Simulation of nonpoint source pollution load in Maoping River watershed].

The nitrogen and phosphorous transport in the Maoping River watershed was modelled using the SWAT model, which simulates the water cycle and the transformation of nutrients. The model was first calibrated by comparing the observed and the simulated data from May to October 2004, and then validated. The Nash-Sutcliffe coefficient (R2), the mean square root error (RMSE) and the relative error(CV) were used to test the agreement between observed and simulated data.