Geostatistical analyses and hazard assessment on soil lead in Silvermines area, Ireland

Spatial distribution and hazard assessment of soil lead in the mining site of Silvermines, Ireland, were investigated using statistics, geostatistics and geographic information system (GIS) techniques. Positively skewed distribution and possible outlying values of Pb and other heavy metals were observed. Box-Cox transformation was applied in order to achieve normality in the data set and to reduce the effect of outliers. Geostatistical analyses were carried out, including calculation of experimental variograms and model fitting. The ordinary point kriging estimates of Pb concentration were mapped. Kriging standard deviations were regarded as the standard deviations of the interpolated pixel values, and a second map was produced, that quantified the probability of Pb concentration higher than a threshold value of 1000 mg/kg. These maps provide valuable information for hazard assessment and for decision support.     

Impact of the toxicity of Cylindrospermopsis raciborskii (Woloszynska) Seenayya & Subba Raju on laboratory rats in vivo

In vivo laboratory studies of toxicity were performed on Wistar rats using a methanol extract produced by the natural population of Cylindrospermopsis raciborskii (abundance of 2.13 × 10⁵ trichomes mL⁻¹) collected at Aleksandrovac Lake (Serbia). HPLC analysis showed that the extract contains 6.65 μg cylindrospermopsin (CYN) mg⁻¹. The rats were killed 24 or 72 h after a single intraperitoneal injection of C. raciborskii extract in concentrations of 1500, 3000, 6000 and 12,000 μg kg⁻¹ body weight (bw) and an equivalent amount of CYN as present in the highest dose of the extract (79.80 μg CYN kg⁻¹ bw). The genotoxic effect on the livers treated with C. raciborskii was evaluated using comet assay and potential induction of oxidative stress as the toxicity mechanism associated with the presence of CYN in extract. The results from the analyses of DNA damage in the comet tail length, tail moment and percentage of DNA in the tail in the liver indicated that administration of extract and CYN present statistically significant difference when compared with the negative control group. Although an increase in the frequency of selected parameters induced by the CYN was observed in the liver, this damage was less than the damage resulting from the administration of the highest dose of extract. The changes in the biochemical parameters of the hepatic damage showed that the application of single doses of the extract and CYN did not cause serious liver damage in rats. The extract and CYN significantly increased oxidative stress in rats’ liver after a single exposure.

     

Emerging conflict in collaborative mapping: Towards a deeper understanding?

In spatial planning and environmental management, maps are found very helpful in many situations, but in other situations they may also deepen conflicts or be ignored. This paper addresses the question what explains such phenomena, with particular emphasis on, and reference to, collaborative policymaking settings in the Netherlands. We have elaborated the concept of 'frames' and 'framing' to structure and analyze the function of maps in the context of deliberative policymaking. With help of discourse analysis, a method adopted from the policy sciences, we have observed ongoing multi-actor processes and focused on discussions around maps in several case studies. From the observations of both the maps themselves and the discussions and actions with the maps, we have interpreted the meaning and frames represented 'in' the map images, as well as the various perspectives of actors 'on' the collaborative use of the map. We have conceptualized three fundamentally different perspectives or frames on the function of maps in the decision-making process. The cross-frame debate over maps is illustrated with the recollection of one particular map-making example. We conclude that the conflicts observed in a number of case studies can be adequately explained with help of the three identified frames, and provide some recommendations for the profession of mapping.     

An investigation of aqueous activity coefficients at low concentrations

The activity of a chemical in solution determines its tendency to move into other media. At low concentrations (<0.01M) it is generally considered to be linearly related to concentration. A hypothetical model based on the structure of liquid water is discussed which could cause deviations from this linearity in the ppb region, a concentration much lower than that normally investigated thermodynamically, but one of great importance environmentally. Headspace experiments are reported with carbon tetrachloride and chloroform in water at concentrations down to ～10^?3 ppb but no such deviations were discerned.     

油浸变压器排油注氮装置在500kV变电站的设计与应用

在分析500kV变电站主变压器消防系统的现状,比较3类消防系统优缺点的基础上,详细论述了主变排油注氮装置的结构组成、工作原理、参数计算、控制系统设计以及需要注意的事项等,为下一步排油注氮装置的推广应用打下基础.