Preliminary evidence for the metabolism of benzo(a) pyrene by Plantago lanceolata

Polycyclic aromatic hydrocarbons (PAHs) have long been recognised as potential carcinogens in animals in which biotransformation into reactive metabolites can lead to DNA damage. In animals PAHs metabolism mainly occurs in hepatic microsomes and is associated with the cytochrome p-450 mediated mixed functional oxidase (MFO) system. PAH metabolism in plants has been shown to occur via a similar enzyme system, but has received relatively little attention. This study is looking at how the plant species Plantago lanceolata metabolises benzo(a)pyrene (B(a)P), which is one of the PAHs whose metabolism has been studied extensively in animals. The aim of the work is to establish firstly that the B(a)P is taken up and secondly that it is biotransformed by the plant to products possibly similar to those found in animals. This work is achieved by using C-14-B(a)P along with whole body autoradiography, scintillation analysis and chromatography techniques to locate the B(a)P and its metabolites.     

Effect of pH on Pb biouptake by the freshwater alga<Emphasis Type="Italic"> Chlorella kesslerii</Emphasis>

The effect of pH on Pb bioaccumulation by Chlorella kesslerii was studied. Both Pb uptake fluxes and Pb bound to membrane transport sites increased with an increase in pH from 4.0–5.0, were relatively stable in the pH interval 5.0–6.5, and increased again at pH 7.0 and 8.0. Protons affected Pb adsorption to the algal surface by competing directly for surface sites, by modifying the overall algal surface charge and by modifying the chemical speciation of Pb in solution. These results indicate a failure of the free-ion activity or biotic ligand models above pH 6.5, possibly due to the bioaccumulation of hydroxo or carbonato Pb complexes.     

高效液相色谱法测定多环芳烃化合物辛醇/水的分配系数及其对水溶解度的估算

本文采用反相高效液相色谱法间接测定了29种多环芳烃化合物的辛醇/水分配系数,并估算其水溶解度,所得结果与文献值和计算值基本一致。     

碳黑中致突变物研究

用高分辨质谱检出了墨水碳黑有机溶剂提取物中的六种硝基取代多环芳烃化合物,高效液相色谱的保留时间和紫外光谱确证了提取物中的二硝基芘和3-硝基芴酮,根据定量测定结果表明:二硝基芘是提取物中直接致突变活性的主要来源.     

原煤中多环芳烃的分离与测定

本实验以苯为溶剂对不同产地、不同品种的原煤进行了提取。提取液经柱层析分离及薄层层析和纸层析进一步纯化。利用色质联用、荧光光谱和高压液相色谱等方法对提取液中的多环芳烃(PAHs)进行了测定,并用标准样品验证,在原煤中检测出51种多环芳烃,其含量为0.002—44.2ppm。 本文提供了原煤中多环芳烃的本底数据并试图探索不同煤种与多环芳烃含量的相关性。     

Toxicity evaluation of ZnO and TiO2 nanomaterials in hydroponic red bean (Vigna angularis) plant: Physiology, biochemistry and kinetic transport

The toxicity and kinetic uptake potential of zinc oxide(Zn O) and titanium dioxide(TiO_2)nanomaterials into the red bean(Vigna angularis) plant were investigated. The results obtained revealed that Zn O, due to its high dissolution and strong binding capacity, readily accumulated in the root tissues and significantly inhibited the physiological activity of the plant. However, TiO_2 had a positive effect on plant physiology, resulting in promoted growth. The results of biochemical experiments implied that Zn O, through the generation of oxidative stress, significantly reduced the chlorophyll content, carotenoids and activity of stress-controlling enzymes. On the contrary, no negative biochemical impact was observed in plants treated with TiO_2. For the kinetic uptake and transport study, we designed two exposure systems in which Zn O and TiO_2 were exposed to red bean seedlings individually or in a mixture approach. The results showed that in single metal oxide treatments, the uptake and transport increased with increasing exposure period from one week to three weeks.However, in the metal oxide co-exposure treatment, due to complexation and competition among the particles, the uptake and transport were remarkably decreased. This suggested that the kinetic transport pattern of the metal oxide mixtures varied compared to those of its individual constituents.     

Uptake of radioiodide by Paenibacillus sp., Pseudomonas sp., Burkholderia sp. and Rhodococcus sp. isolated from a boreal nutrient-poor bog

Radionuclides, like radioiodine(~(129)I), may escape deep geological nuclear waste repositories and migrate to the surface ecosystems. In surface ecosystems, microorganisms can affect their movement. Iodide uptake of six bacterial strains belonging to the genera Paenibacillus,Pseudomonas, Burkholderia and Rhodococcus isolated from an acidic boreal nutrient-poor bog was tested. The tests were run in four different growth media at three temperatures. All bacterial strains removed iodide from the solution with the highest efficiency shown by one of the Paenibacillus strains with 99% of iodide removed from the solution in one of the used growth media. Pseudomonas, Rhodococcus and one of the two Paenibacillus strains showed highest iodide uptake in 1% yeast extract with maximum values for the distribution coefficient(K_d) ranging from 90 to 270 L/kg DW. The Burkholderia strain showed highest uptake in 1% Tryptone(maximum K_d170 L/kg DW). The Paenibacillus strain V0-1-LW showed exceptionally high uptake in 0.5% peptone + 0.25% yeast extract broth(maximum K_d 1,000,000 L/kg DW). Addition of 0.1% glucose to the 0.5% peptone + 0.25% yeast extract broth reduced iodide uptake at 4℃ and 20℃ and enhanced iodide uptake at 37℃ compared to the uptake without glucose. This indicates that the uptake of glucose and iodide may be competing processes in these bacteria. We estimated that in in situ conditions of the bog,the bacterial uptake of iodide accounts for approximately 0.1%–0.3% of the total sorption of iodide in the surface, subsurface peat, gyttja and clay layers.     

Distribution of Airborne polycyclic aromatic hydrocarbons (PAH) in the area of Thessaloniki,Greece

The aim of this research work is to investigate the temporal and regional behaviour of the PAH in the Thessaloniki's area. During a period of six months, airborne particulate matter was collected twice a week and PAH were determined by HPLC. Profiles as well as concentrations of selected cancerogenic PAH differ in some cases from area to area and have characteristic, temporal changes of concentration.     

Heterogeneous uptake of nitrogen dioxide on Chinese mineral dust

Mineral dust is one of the major aerosols in the atmosphere. To assess its impact on trace atmospheric gases, in this work we present a laboratory study of the effect of temperature on the heterogeneous reaction of NO₂ on the surface of ambient Chinese dust over the temperature range from 258 to 313 K. The results suggest that nitrogen dioxide could mainly be adsorbed on these types of Chinese mineral dust reversibly with little temperature dependence. Similar to a previous study on NO₂ uptake on mineral aerosols, the uptake coefficients are mainly on the order of 10^− 6 for the Chinese dust, when BET areas are taken into account. HONO was observed as a product, and its formation and decomposition on Chinese mineral dust during the uptake processes were also studied. The complete dataset from this study was compiled with previous literature determinations. Atmospheric implications of the heterogeneous reaction between NO₂ and mineral dust are also discussed, in an effort to understand this important heterogeneous process.     

Cadmium in soybeans and the relevance to human exposure

<正>Introduction Cadmium is considered a human carcinogen by the International Agency for Research on Cancer(IARC,1993)and the US National Toxicology Program(NTP,1997).Cadmium contamination of food crops is a persistent issue for both the agricultural industry as well as consumers.This is an issue for agriculture because cadmium can be present in soils naturally or as a result of industrial processes and can contaminate foods that are consumed by humans.Industrial