Adsorption of trichlorphon on phyllosilicate minerals:Effect of low-molecular-weight organic acids

The use of trichlorphon in large quantities causes a large number of organic pollutants to enter water, sediments, and soils. Phyllosilicate minerals are considered effective adsorbents for organic pollutants. However, the adsorption behavior of organic pollutants on soil minerals affected by low-molecular-weight organic acids(LMWOAs) is not fully understood. In this study, the effect of LMWOAs on the adsorption behavior of trichlorphon on phyllosilicate minerals was investigated using a combination of adsorption measurements and molecular spectroscopic techniques(attenuated total reflection-Fourier transform infrared spectroscopy(ATR-FTIR) and X-ray photoelectron spectroscopy(XPS)). The adsorption of trichlorphon onto kaolinite(KAO) and montmorillonite(MON) was suppressed by increasing pH, indicating that electrostatic interaction played a key role in adsorption, especially at low pH. In the presence of citric acid(CA), there was an obvious promotion of trichlorphon adsorption on KAO and MON. In the presence of oxalic acid(OA), the adsorption of trichlorphon on KAO was promoted, whereas the adsorption on MON was inhibited, especially at pH 4.0. The presence of CA and OA increased the adsorption by increasing the exposure of hydrophobic sites of KAO and MON. The results from ATR-FTIR and XPS also indicated that the hydrophobic Si–O sites of phyllosilicate minerals were the preferred adsorption sites for trichlorphon in the presence of CA and OA, probably driven by the hydrophobic effect. However, the weak effect of OA on MON caused an increase in the electrostatic repulsion between MON and trichlorphon molecules, thus inhibiting adsorption. This study is significant for a deeper understanding of self-purification of soil and sediment systems in the presence of organic pollutants.

The Use of Sludge from Cow Manure Biodigester as Fertilizer and Carrier of Cordyceps sp. for White Grub Pest Control

Processing cow manure into biogas is a solution to reduce air pollutant, because it reduces the smell of the manure up to 70%. Besides producing biogas, the sludge of biodigester can also serve as solid and liquid fertilizer. The solid fertilizer can be used as carder of entomopathogenic fungi to control the pest which lives underground. The research aimed to investigate the benefits of biodigester sludge as fertilizer and carrier of entomopathogenic fungi （Cordyceps sp.） to control white grub pest. The use of organic fertilizer and pesticide in the cultivation can minimize the environmental hazard. The method used in the study was completely randomized design with four treatments, which were the addition of Cordyceps sp. corn media as much as 0, 10, 20 and 30 g/kg of sludge. Every addition was repeated three times to corn planted in a tub. To examine the effect of the treatments, the data were analyzed with ANOVA and Duncan test was applied when differences occurred between treatments. The results of the research showed that the nutrients contained in the manure which had been processed into biogas were not lost. The plants cultivated in the planting medium supplemented with sludge grew healthier, bigger, taller and had stronger and longer roots. On the contrary, the plants cultivated without sludge addition were vulnerable to white grub attack. The Cordyceps sp., which was added into the sludge, was effective to control the white grub. The concentration of Cordyceps sp. as much as 20 g/kg of sludge in corn planting medium was the most effective concentration to control white grub pest.

Chlorinated hydrocarbons in animal tissue samples from the Arctic Area

This study presents our preliminary results of the concentrations of chlorinated hydrocarbon contaminants in muscle, liver of caribou and intestine tissues of seal collected from the Arctic Area by China Arctic Scientific Expedition in April 1995. Hexachlorocyclohexanes (α, β, γ and δ HCH), DDT group (p,P′ DDE, o,P′ DDT, p,P′ DDD and p,P′ DDT) and polychlorinated biphenyls (PCBs) were analyzed. The concentrations of ∑HCH ranged from 3 13 ng/g to 7 02 ng/g and those of ∑DDT ranged from 0 16 ng/g to 1 28 ng/g. 14 individual PCB congeners, each in the range of 0 01 0 12 ng/g, were detected and the concentration of ∑PCB was from 0 14 ng/g to 0 60 ng/g. Also, the results were compared with the data reported previously.

Minimization of methabenzthiazuron residues in leaching water using amended soils and photocatalytic treatment with TiO_2 and ZnO

In the present work, potential groundwater pollution by methabenzthiazuron （MTBU） and the effect of three different amendments （composted sheep manure, composted pine bark and spent coffee grounds） on its mobility were investigated under laboratory conditions. The efficiency of ZnO and TiO2 suspensions in the photocatalytic degradation of MTBU in leaching water was also investigated. The relative and cumulative breakthrough curves were obtained from disturbed soil columns. The presence and/or addition of organic matter drastically reduced the movement of the herbicide. On other hand, photocatalytic experiments showed that the addition of ZnO and TiO2 strongly enhances the degradation rate of this herbicide compared with the results of photolytic experiments under artificial light. ZnO appeared to be more effective in MTBU oxidation than TiO2. The results obtained point to the interest of using organic wastes and heterogeneous photocatalysis for reducing the pollution of groundwater by pesticide drainage.

Disruption of iron homeostasis and resultant health effects upon exposure to various environmental pollutants:A critical review

Environmental pollution has become one of the greatest problems in the world, and the concerns about environmental pollutants released by human activities from agriculture and industrial production have been continuously increasing. Although intense efforts have been made to understand the health effects of environmental pollutants, most studies have only focused on direct toxic effects and failed to simultaneously evaluate the long-term adaptive, compensatory and secondary impacts on health. Burgeoning evidence suggests that environmental pollutants may directly or indirectly give rise to disordered element homeostasis, such as for iron. It is crucially important to maintain concerted cellular and systemic iron metabolism. Otherwise, disordered iron metabolism would lead to cytotoxicity and increased risk for various diseases, including cancers. Thus, study on the effects of environmental pollutants upon iron homeostasis is urgently needed. In this review, we recapitulate the available findings on the direct or indirect impacts of environmental pollutants, including persistent organic pollutants（POPs）, heavy metals and pesticides, on iron homeostasis and associated adverse health problems. In view of the unanswered questions, more efforts are warranted to investigate the disruptive effects of environmental pollutants on iron homeostasis and consequent toxicities.