C, δC and total C content in soils around a Brazilian PWR nuclear power plant

Nuclear power plants release ¹⁴C during routine operation mainly as airborne gaseous effluents. Because of the long half-life (5730 years) and biological importance of this radionuclide (it is incorporated in plant tissue by photosynthesis), several countries have monitoring programs in order to quantify and control these emissions. This paper compares the activity of ¹⁴C in soils taken within 1 km from a Brazilian nuclear power plant with soils taken within a reference area located 50 km away from the reactor site. Analyses of total carbon, δ¹³C and ¹³⁷Cs were also performed in order to understand the local soil dynamics. Except for one of the profiles, the isotopic composition of soil organic carbon reflected the actual forest vegetation present in both areas. The ¹³⁷Cs data show that the soils from the base of hills are probably allocthonous.     

Visual Perception of Habitats Adopted for Post-Mining Landscape Rehabilitation

The study presented here focuses on visual preferences expressed by respondents for five relatively natural habitat types used in land reclamation projects in the North-West Bohemian brown coal basins (Czech Republic). Respondents evaluated the perceived beauty of the habitat types using a photograph questionnaire, on the basis of the positively skewed 6-point Likert scale. The order of the habitat types, from most beautiful to least beautiful, was: managed coniferous forest, wild deciduous forest, managed deciduous forest, managed mixed forest, and managed grassland. Higher visual preferences were indicated for older forest habitats (30–40 years old) than for younger habitats (10–20 years old). In addition, respondents preferred wild deciduous forest to managed deciduous forest. Managed grasslands and non-native managed coniferous forests were preferred by older people with a lower level of education and low income living in the post-mining area. On the other hand, native, wild deciduous forest was awarded the highest perceived beauty score by younger, more educated respondents with higher income, living outside the post-mining landscapes. The study confirms differences in the perception of various forms of land reclamation by residents vs. non-residents, and its findings also confirm the need for sociological research in post-mining landscapes within the process of designing rehabilitated landscapes. From the visual standpoint, the results of our study also support the current trend toward using natural succession in the reclamation of post-mining landscapes.     

人口变化及其对空间发展的影响——以德国为例

在分析人口变化如何影响德国的城镇和区域发展的基础上，探讨了在城市与区域规划中如何应对人口变化的主要结果--人口缩减和老龄化的。人口减少对二战以来东德和西德的区域发展有重要影响作用。但是，直到1990年两德统一以前，两德的城市与区域规划一直是建立在人口增长的假设之上。两德统一以后，人口缩减和老龄化对城市和农村发展起到了决定性作用。首先，研究了人口缩减和老龄化的起因和结果，由于人口变化在东德更为显著，因此以东德为例，进行实证分析。其次，重点讨论如何应对人口衰减和老龄化带来的问题。对于城市地区而言，可以采用两种模式--“紧缩式”和“穿孔式”，这两种方式都可以通过减少建筑面积和增加绿色空间或利用强度较小的土地类型来提高生活质量。对于农村地区而言，则需要采取更加严格的方式来应对人口减少和老龄化。一条可行的路径是通过撤销公共服务设施等方式，有计划地舍弃部分村庄，将村民在城镇中进行集中安置     

Characterization of dioxin-like contamination in soil and sediments from the ��hot spot�� area of petrochemical plant in Pancevo (Serbia)

Purpose

Combinatorial bio/chemical approach was applied to investigate dioxin-like contamination of soil and sediment at the petrochemical and organochlorine plant in Pancevo, Serbia, after the destruction of manufacturing facilities that occurred in the spring of 1999 and subsequent remediation actions.

Materials and methods

Soil samples were analyzed for indicator polychlorinated biphenyls (PCBs) by gas chromatography/electron capture detection (GC/ECD). Prioritized soil sample and sediment samples from the waste water channel were analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). Microethoxyresorufin o-deethylase (Micro-EROD) and H4IIE?Cluciferase bioassays were used for monitoring of dioxin-like compounds (DLC) and for better characterization of dioxin-like activity of soil samples.

Results

Bioanalytical results indicated high dioxin-like activity in one localized soil sample, while the chemical analysis confirmed the presence of large quantities of DLC: 3.0?×?10⁵ ng/g d.w. of seven-key PCBs, 8.2 ng/g d.w. of PCDD/Fs, and 3.0?×?10⁵ ng/g d.w. of planar and mono-ortho PCBs. In the sediment, contaminant concentrations were in the range 2?C8 ng/g d.w. of PCDD/Fs and 9?C20 ng/g d.w. of PCBs.

Conclusions

This study demonstrates the utility of combined application of bioassays and instrumental analysis, especially for developing and transition country which do not have capacity of the expensive instrumental analysis. The results indicate the high contamination of soil in the area of petrochemical plant, and PCDD/Fs contamination of the sediment from the waste water channel originating from the ethylene dichloride production.     

Comparative toxicity of imidacloprid, of its commercial liquid formulation and of diazinon to a non-target arthropod, the microcrustacean Daphnia magna

Imidacloprid (IMI) is at the moment the insecticide with the world's fastest growing sales and is considered possible replacement for the widely used organophosphorus pesticide, diazinon, which is subject to phased revocation in many countries. In this study, biochemical, reproductive and survival parameters of the water flea (Daphnia magna) after chronic exposure to IMI, its commercial liquid formulation Confidor SL 200 and diazinon are presented and compared. According to the lowest observed effect concentrations, diazinon is more toxic to the reproduction of D. magna than IMI and Confidor SL 200, which exert similar toxicity. The same was observed for the survival, except that Confidor SL 200 is more toxic than IMI. In polluted aquatic environments, the actual levels of diazinon are potentially chronically hazardous to the reproduction of D. magna (risk quotient >1). According to very few measured environmental levels of IMI, the latter is not expected to be chronically hazardous, unless it is accidentally spilled in a small pond. In such case, the predicted concentrations of IMI would present a potential chronic risk to D. magna, and a potential acute risk to other aquatic invertebrates. In the future, higher environmental levels of IMI are expected due to its increasing use and physico-chemical properties. The literature survey summarized in this work suggests that further ecotoxicological studies with a broader spectrum of aquatic organisms are needed before IMI is classified as safer than currently applied pesticides.     

Feeding frequency and parental division of labour in the double-brooded great tit Parus major

Summary We studied the relative contribution of each sex and total effort expended in feeding nestlings in the great tit Parus major in relation to artificially altered brood size. A recent model suggests that feeding frequency should reflect the optimal trade-off between parental and fledgling survival, the former being negatively, the latter positively, influenced by high feeding frequencies. In both sexes weight loss was linearly related to feeding frequency. Since fledgling survival increases with nestling weight, the conditions of this model are fulfilled. However, in contrast to the predictions of the model, the total feeding frequency for both sexes combined did not differ between control and enlarged broods, but was lower for reduced ones. This outcome was not the result of a physiologically related inability of the parents to increase their delivery rate. Instead, we suggest that parents with enlarged broods could not find sufficient amounts of prey large enough to be economically worth transporting to the nest. Differences in brood-provisioning rates between the sexes may arise because costs and benefits of feeding nestlings may differ. Females lost more weight than males during the nesting period, but maintained a relatively higher weight during the incubation period. The relationship between weight loss and feeding frequency was similar for both sexes. Male and female brood-feeding frequency was related to brood size in a similar way. This is discussed in light of the great tit's mating system and the fact that the great tit is facultatively double-brooded.