A comparative investigation on the biosorption of lead by filamentous fungal biomass

The removal of lead from aqueous solutions by adsorption on filamentous fungal biomass was studied. Batch biosorption experiments were performed to screen a series of selected fungal strains for effective lead removal at different metal and biomass concentrations. Biosorption of the Pb²⁺ ions was strongly affected by pH. The fungal biomass exhibited the highest lead adsorption capacity at pH 6. Isotherms for the biosorption of lead on fungal biomass were developed and the equilibrium data fitted well to the Langmuir isotherm model. At pH 6, the maximum lead biosorption capacity of Mucor rouxii estimated with the Langmuir model was 769 mg/g dry biomass, significantly higher than that of most microorganisms. Biomass of Mucor rouxii showed specific selectivity for Pb²⁺ over other metals ions such as Zn²⁺. Ni²⁺ and Cu²⁺. This fungal strain may be applied to develop potentially cost-effective biosorbent for removing lead from effluents. The technique of scanning electron microscopy coupled with X-ray dispersion analysis shows that Pb²⁺ has exchanged with K⁺ and Ca²⁺ on the cell wall of Mucor rouxii, thereby suggesting ion exchange as one of the dominant mechanisms of metal biosorption for this fungal strain.     

The effects of UV exclusion on the soluble phenolics of young Scots pine seedlings in the subarctic

The characteristics of UV-absorbing compounds, particularly soluble phenolics, were studied in needles of 63-day-old seed-grown Scots pine (Pinus sylvestris L.) seedlings of two provenances in a UV exclusion field experiment at Pallas-Ounastunturi National Park in Finnish Lapland (68 degrees N, 270 m a.s.l.). The experiment used the following plastic filters in exclosure treatments to manipulate the spectral balance of natural irradiance: (1) 'control' (a polyethene plastic filter); (2) 'UV-B exclusion' (a clear polyester filter); and (3) 'UV-B/UV-A exclusion' (a clear acryl plate). Polyethene transmitted 89% of the ambient levels of total UV (280-400 nm), polyester transmitted 75% of the total UV, but only 0.6% of the UV-B (280-315 nm) component, while acryl plate transmitted 0.2% of UV (280-360 nm). The research also included (4) 'Ambient' plants that were not subjected to any treatment exclosures. After the 58 day UV exclusion, significant (p<0.0001) differences due to treatments were determined for a kaempferol derivative, kaempferol 3-glucoside, and a quercetin derivative, the quantities of which ranged from 0.23 to 0.45, 0.42 to 1.34 and 0.39 to 0.75 micromol g FW(-1), respectively, depending on treatment and provenance. Overall, Scots pine seedlings grown at ambient UV radiation (PAS300, Caldwell's generalized Plant Action Spectrum (PAS) normalized at 300 nm, 72 mW m(-2)) or under a control had significantly (p<0.05) higher quantities of soluble phenolics than seedlings grown under UV-B or UV-B/UV-A exclusion treatments. There were no significant differences in the quantity of soluble phenolics between the two exclosure treatments or between the two Scots pine provenances. The sums of diacylated flavonol glucosides ranging from 3.75 to 4.55 micromol g FW(-1) depending on treatment and provenance, were already present at very low UV-levels under the UV-B/UV-A exclusion treatment. The present study indicated that soluble phenolics, particularly the diacylated flavonol glucosides, may provide an effective preformed protection for young Scots pine seedlings against UV-B and UV-A radiation.     

Distribution of polycyclic aromatic hydrocarbons in soil-water system containing a nonionic surfactant

The effect of a nonionic surfactant, Triton X-100 (TX100), on the distribution of four representative polycyclic aromatic hydrocarbons (PAHs), phenanthrene, fluorene, acenaphthene and naphthalene, in soil-water system was studied on a natural soil. The apparent soil-water distribution coefficient with surfactant (Kd*) for these compounds increased when TX100 equilibrium concentration from zero to around the critical micelle concentration (CMC), followed by a decrease in Kd* at TX100 equilibrium concentration greater than CMC. This is a direct result of surfactant sorption onto soil followed by PAHs partitioning to the sorbed surfactant. The values of carbon-normalized solute distribution coefficient (Kss) with the sorbed TX100 are greater than the corresponding partition coefficients with soil organic matter (Koc), which indicates the soil-sorbed nonionic surfactant is more effective per unit mass as a partitioning medium than the native soil organic matter for PAHs. When Kd* = Kd the corresponding initial concentration of surfactant was defined as critical washing concentration (CWC). Depending on the surfactant initial concentration below or above the CWC, the addition of nonionic surfactant can enhance the retardation of soil for PAHs or promote the removal of PAHs from soil, respectively. The values of Kd* and CWC can be predicted by a model, which correlates them with the compounds' octanol-water partition coefficients (Kow), soil property and the amount of soil-sorbed surfactant.     

Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin or 2,2',4,4',5,5'-hexachlorobiphenyl on vitamin K-dependent blood coagulation in male and female WAG/Rij-rats

Newborns are susceptible to hemorrhages (hemorrhagic disease of the newborn or HDN) due to vitamin K deficiency. Induction of cytochrome P450 in the fetal liver by maternal anticonvulsant therapy such as phenobarbital or phenytoin is considered to be a major cause. An observed increase in late hemorrhagic disease (LHD) in breast fed neonates gave rise to the hypothesis that PCBs and dioxins, P450-inducing contaminants present in human milk, might effect vitamin K-dependent blood coagulation. This hypothesis was studied in rats. Administration of a single oral dose of 0.003, 0.03, 0.3, 3 or 30 nmol 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) per kg bodyweight or 0.75, 4, 20, 100 or 500 micromol 2,2',4,4',5,5'-hexachlorobiphenyl/kg bw (HxCB) to female and male rats resulted in dose-related reductions of the vitamin K-dependent coagulation factor VII. The highest factor VII reduction in female rats was 44%, observed after TCDD exposure. The Lowest Observed Adverse Effect Level (LOAEL) of TCDD on female factor VII levels was 0.3 nmol/kg bw (96 ng/kg). There was a significant inverse correlation between Factor VII levels and induction of hepatic ethoxyresorufin O-deethylating (EROD) activity, reflecting CYP1A1, and total P450 content. HxCB had no effect on female coagulation factors. In contrast, in male rats only exposure to HxCB, which induces mainly CYP2B1 and 2B2, decreased both coagulation factors dramatically up to 88%. The LOAEL of HxCB on factor VII in male rats was 100 micromol/kg bw (36 mg/kg). In general, effects on coagulation factors in male rats exceeded those in females. In addition, sex-dependent differences of TCDD and HxCB were observed on the hepatic vitamin K cycle enzyme activities in female and male rats. Vitamin K-dependent (gamma-glutamyl carboxylase activity was mainly induced in female rats; 2.3-fold in the highest dose group of TCDD. In male rats only vitamin K 2,3-epoxide reductase (KO-reductase) activity was induced 1.7-fold by the highest dose of HxCB. KO-reductase activity in female rats was also increased by TCDD, however, less pronounced than the carboxylase activity. Concluding, the hepatic vitamin K cycle still functions and is not blocked by TCDD or HxCB, thus explaining the observed reduction in factor VII. Finally, the possible role of P450 in vitamin K deficiency is discussed. Based on these results it is suggested to investigate the possible role of PCBs and dioxin-like compounds in LHD in more detail.     

Ambient air pollution induced changes in amino acid pattern of phloem sap in host plants-relevance to aphid infestation

In pollution exclusion experiments on the verge of a widely-used motorway, it has been shown that roadway emissions increase the abundance of the aphid Aphis fabae Scop. on two different host plants, Viburnum opulus L. and Phaseolus vulgaris L. Analysis of phloem sap of excised leaves revealed on increase in almost all of the detected amino acids due to ambient air pollution. To investigate the significance of these changes to aphid development, the patterns analyzed were translated into artificial diets, representing the amino acid composition either of filtered air or ambient air host plants. On 'ambient air' diets, the larvae were significantly larger at birth compared to the progeny on 'filtered air' diets. Also the mean relative growth rates (MRGR) of larvae reared on 'ambient air' diets were significantly increased. At the same time, a conspicuous shorter development time of the larvae could be observed on 'ambient air' diets.     

快速渗透土地处理系统对氮的去除

废水快速渗透土地处理系统可以根据实测地表渗透率(InfiltratonRate)和处理要求来进行设计。水力负荷由设计渗透率确定,通常取其2～10%作为水力负荷率,这取决于现场测定地表渗透率的方法、场地土壤的变异性以及投水期与落干期之比。水力负荷也会影响氮和磷的处理效果。本文提供了以除氮、磷为目的的快速渗滤系统的设计原理和处理运行数据。     

论矿物溶解速率与温度的关系

硅酸盐和氧化物矿物的溶解速率，在远未达到平衡的条件下，其实验活化能（Eexp）随PH值的变化达几十个KJ/mol。在远比零净质子电荷点（PZNPC）更酸性或更碱性的PH条件下，实测的Eexp。值从大于50／mol变化到在pznpc附近但未必在PZNPC点的很小的值。我们通过经验的溶解速率定律与产生正表面电荷的质子吸附的条件平衡常数相结合的方法，解释了这种矿物溶解速率随pH值发生的变化。利用条件平衡常数中的静电势项，对矿物表面各带电位置之间的相互作用加以处理。产生正（或负）表面电行的质子吸附（或解吸）是放热（或吸热）反应。对Eexp贡献15～50KJ／mol；这种贡献取决于带电表面位置的摩尔分数，因而会随PH值发生微弱的变化。随着矿物表面获得明显的正电荷或负电荷，静电势的贡献就会变得越来越重要；因此，它会随PH值发生明显的变化。这种模型法不但解释了Eexp与PH值的关系，而且还得出了下面几条重要的一般性预测成果：1）对于同价阳离子置换有差别的矿物，其从Eexp值也会随pH值的变化而发生类似的变化，2）由于Eexp是大小类似但符号相反的焓的总和，所以可想象到会出现负的Eexp值；3）就带电位置的浓度而言，Eexp与部分反应速率阶（Order）呈线性相关；4）在高温下，溶解速率会对PH值越来越敏感；5）对     

Striving for efficiency,harmony and vitality─A human ecological approach to urban sustainable development

Sustainability can only be assured with a human-ecological understanding of the complexinteractions among environmental,economic and social/cultural factors and with careful planningand management grounded in ecological principles. This paper will probe an integrative methodologyfor achieving environmentally sound, economically productive, and ecologically responsibledevelopment in urban and industrial areas of China through ecological regulation. The central objec-tive is to promote highly efficient resource use rather than high speed development,harmonious sys-tem′s relationship rather than inflexible compartmentalization, and robust and vital self-organizationrather than bureaucrstic control. This ecological order is to be regulated through technological inno-vation,institutional reform, and behavioral incentives that promote positive economic dcvelopmentwhile mitigating negative environmental impacts.     

Endemic Arsenosis Caused by Indoor Combustion of High-As Coal in Guizhou Province, P.R. China

The arsenic (As) content of coal relating with mineralization of gold in Southwest Guizhou Province, China is up to 35,000 ppm. The coal is burned indoors in open pits for daily cooking and crop drying. As a result, arsenic is precipitated and concentrated in corn (5–20 ppm), chili (100–800 ppm) and other foods. Arsenic concentrations in the drinking water of high-As coal areas are lower than 50 ppb. The estimated main sources of As exposure in this area are from polluted food. Approximately, 3000 arsenosis patients were found by 1998, and more than 100,000 people from six counties were under the threat in China. This paper presents the major ingestion pathway of this type arsenosis and relative geochemistry of high-As coal. The project supported by National Natural Science Foundation of China (NSFC 40133010).     

Assessing the Response of Estuarine Intertidal Assemblages to Urbanised Catchment Discharge

Measurement of intertidal rock assemblages was investigated as a potential biological indicator to provide a quantitative estimate of the impact of urbanised catchment discharge on the estuaries of Sydney, Australia, from 1995 to 1999. Based on the presence and characteristics of adjacent human activities, sampling locations were categorised as: Bush; Urban; Urban with Sewer Overflows; and Industry with Sewer Overflows. In Sydney Harbour, variation in assemblage structure was measured between most impact categories, however differences between impact categories were not consistent for each year. Nevertheless, in years of above average rainfall (1998–1999), reference assemblages adjacent to national parks and distant from urbanisation were different to all other putatively impacted assemblages. Variability within assemblages was least at reference locations in each year and greatest at locations adjacent to stormwater canals and sewer overflows, particularly in 1998–1999. Variation in assemblage structure in Sydney estuaries was most strongly correlated with chlorophyll – a concentrations. Univariate analysis also identified highly significant differences for a number of factors, however, interactions between year, impact categories and location for numerous analyses, confounded the differentiation between impact categories. The results suggest that intertidal rock assemblages in Sydney Harbour and surrounding estuaries appear to be responding to the quality and quantity of discharge from urbanised catchments and, furthermore, that assemblages are more suitable than individual taxa to indicate the difference between Bush and anthropogenically disturbed estuarine locations.