Assessment of organochlorine pesticide contamination in relation to soil properties in the Pearl River Delta, China.

High levels of organochlorine pesticides (OCPs) such as hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) have been found in soil of the Pearl River Delta (PRD), attributable to high pesticide application in this area. Consequently, the occurrence and environmental effect of HCHs and DDTs in the PRD have attracted considerable attention. However, study focusing on the influence of potential factors such as soil property on the environmental fate of HCHs and DDTs in the PRD has been rare.

Degradation of pentachlorophenol by potato polyphenol oxidase.

In this study, polyphenol oxidase (PPO) was extracted from commercial potatoes. Degradation of pentachlorophenol by potato PPO was investigated. The experimental results show that potato PPO is more active in weak acid than in basic condition and that the optimum pH for the reaction is 5.

Degradation of rhodamine B by Fe(0)-based Fenton process with H2O2.

Degradation of rhodamine B by Fe(0)-based Fenton process with H(2)O(2) was investigated. The effects of H(2)O(2) dose, Fe(0) dose, initial concentration of rhodamine B and initial pH value on the degradation of rhodamine B were examined. The results showed that the degradation and mineralization of rhodamine B occurred with low dose of H(2)O(2) and Fe(0).

Removal of rhodamine B using iron-pillared bentonite.

The iron-pillared bentonite (Fe-Ben) was prepared by ion-exchange using the natural bentonite (GZ-Ben) from Gaozhou, China, at room temperature without calcination. Both Fe-Ben and GZ-Ben were characterized by X-ray diffraction, N(2) adsorption and Fourier transform infrared spectroscopy. The results show that the d(001) value and surface area of the bentonite material increased after iron pillaring.

[Source and distribution characteristics of polycyclic aromatic hydrocarbons in agricultural soils in the Pearl River Delta].

260 samples of surface agricultural soils (0-20 cm depth) were collected in the typical areas of Pearl River Delta from October 2002 to November 2005. The concentrations of polycyclic aromatic hydrocarbons (16 US EPA priority PAHs) in the collected soil samples were determined by gas chromatography equipped with a mass spectrometry detector (GC-MS). The results showed that the concentrations of Sigma PAHs in the collected soil samples ranged from 3.

[Distribution of phthalic acid esters in agricultural soils in typical regions of Guangdong Province].

To understand the distribution characteristics of phthalic acid esters (PAEs) in agricultural soils in typical regions of Guangdong Province, surface soil (0-20 cm) samples were collected, and the concentrations of 6 PAEs were determined by gas chromatography. The results showed that the total concentration of the PAEs (sigma PAEs) ranged from not detected to 25.99 mg x kg(-1), and was < or = 1.

The concentrations, distribution and sources of PAHs in agricultural soils and vegetables from Shunde, Guangdong, China.

The concentrations, distribution and sources of 16 polycyclic aromatic hydrocarbons (PAHs) were determined in 30 agricultural soil and 16 vegetable samples collected from subtropical Shunde area, an important manufacturing center in China. The total PAHs ranged from 33.7 to 350 microg/kg in soils, and 82 to 1,258 microg/kg in vegetables.

Spatial distribution of heavy metals of agricultural soils in Dongguan, China.

Distribution and speciation of heavy metals of agricultural soils(85 surface soil samples and 4 soil profiles) in Dongguan were investigated, while total Cr, Cu, Ni, Pb, Zn(abbreviated as Cr, Cu, Ni, Pb, Zn) and available Cu, Zn(Av-Cu, Av-Zn) were analyzed by a flame absorption spectrophotometer(AAS), and total Cd(Cd) was analyzed using graphite furnace AAS. The content of Cd, Cu and Ni was partially much more than the second grade of GB15618-1995 even though the mean contents of all heavy metal were less than the threshold value of the second grade and only the mean content of Pb was more than the value of national background. Results of descriptive statistic showed that the mean content of heavy metals should depend on land utilization and spatial location at some extent.