Cytogenetic status of human lymphocytes after exposure to low concentrations of p,p'-DDT, and its metabolites (p,p'-DDE, and p,p'-DDD) in vitro

Despite that the use of DDT has been restricted for more than 40 years to malaria affected areas, low doses of this pesticide and its metabolites DDE and DDD can be found in the environment around the world. Although it has been shown that these pollutants induce cell and DNA damage, the mechanisms of their cytogenotoxic activity remains largely unknown. This study looks into their possible genotoxic effects, at doses that can be found in body fluids, on human lymphocytes using the cytokinesis-block micronucleus assay and the comet assay. After exposure for 1, 6, and 24 h compounds p,p′-DDT (0.1 μg mL⁻¹), p,p′-DDE (4.1 μg mL⁻¹), and p,p′-DDD (3.9 μg mL⁻¹) showed increase in DNA damage. The most significant results were observed at exposure period of 24 h where number of micronucleated cells increased from control 2.5 ± 0.71 to 23.5 ± 3.54, 13.5 ± 0.71, and 16.5 ± 6.36 for DDT, DDE, and DDD, respectively. Similar effect was observed using comet test where the percentage of DNA in comets tail increased from control 1.81 ± 0.16 to 17.24 ± 0.55, 11.21 ± 0.56 and 9.28 ± 0.50 for each compound, respectively. At the same time Fpg-comet assay failed to report induction of oxidative DNA damage of these pollutants. Additionally, the type of cell death was determined using diffusion assay and necrosis dominated. Our findings suggest that even at low concentrations, these pesticides could induce cytogenetic damage to human peripheral blood lymphocytes and in that manner have the impact on human health as well.     

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) in consumer products in Norway - a pilot study

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are used in numerous industrial and consumer products because of their special chemical properties, for instance the ability to repel both water and oil. A broad variety of PFAS have been introduced into the Norwegian market through industrial use (e.g. via fire fighting foams and paints) as well as in treated customer products such as textiles and coated paper. Our present knowledge of the exact chemical PFAS compositions in preparations using perfluorinated compounds is limited. This lack of knowledge means that it is difficult to provide an accurate assessment of human exposure to these compounds or to the amount of waste that may contain treated products. It is a growing concern that these potentially harmful compounds can now be found throughout the global environment.Samples of consumer products and preparations were collected in Norway, with supplemental samples from Sweden. In 27 of the 30 analyzed consumer products and preparations a number of polyfluorinated substances that were analyzed were detected but this does not exclude the occurrence of unknown PFAS. Notable was that perfluorooctanesulphonate (PFOS), which has been strictly regulated in Norway since 2007, was found in amounts close to or exceeding the EU regulatory level in 4 of the 30 analyzed products, all within the leather or carpet product groups. High amounts of fluorotelomer alcohols (FTOHs) were found in waterproofing agents, carpets and textiles, consistent with earlier findings by Fiedler et al. (2010). The presence of PFAS in a broad range of consumer products can give rise to a constant diffuse human exposure that might eventually result in harm to humans.     

Adaptive management of the Great Barrier Reef and the Grand Canyon world heritage areas

Conventional perceptions of the interactions between people and their environment are rapidly transforming. Old paradigms that view humans as separate from nature, natural resources as inexhaustible or endlessly substitutable, and the world as stable, predictable, and in balance are no longer tenable. New conceptual frameworks are rapidly emerging based on an adaptive approach that focuses on learning and flexible management in a dynamic social-ecological landscape. Using two iconic World Heritage Areas as case studies (the Great Barrier Reef and the Grand Canyon) we outline how an improved integration of the scientific and social aspects of natural resource management can guide the evolution of multiscale systems of governance that confront and cope with uncertainty, risk, and change in an increasingly human-dominated world.     

Predictive modelling of dispersion controlled reactive plumes at the laboratory-scale

A model-based interpretation of laboratory-scale experimental data is presented. Hydrolysis experiments carried out using thin glass tanks filled with glass beads to construct a hypothetical and inert, homogeneous porous medium were analysed using a 2D numerical model. A new empirical formula, based upon results for non-reactive (tracer) experiments is used to calculate transversal dispersivity values for a range of grain sizes and any flow velocities. Combined with effective diffusion coefficients calculated from Stokes-Einstein type equations, plume lengths arising from mixing between two solutes can be predicted accurately using numerical modelling techniques. Moreover, pH and ion concentration profiles lateral to the direction of flow of the mixing species can be determined at any given point downstream, without the need for result fitting. In our case, this approach does not lead to overpredictions of lateral mixing, as previously reported when using parameters derived from non-reactive tracer experiments to describe reactive solute transport. The theory is based on the assumption of medium homogeneity.     

Use of sensitive methods for detection of DNA damage on human lymphocytes exposed to p,p'-DDT: Comet assay and new criteria for scoring micronucleus test

Wide distribution, stability and long persistence in the environment of dichlorodiphenyltrichloroethane (DDT), probably the best-known and most useful insecticide in the world, imposes the need for further examination of the effect of this chemical on human health and especially on the human genome. In this study, peripheral blood human lymphocytes from a healthy donor were exposed to 0.025 mg/L concentration of p,p'-DDT at different time periods (1, 2, 24 and 48 h). For the assessment of genotoxic effect, the new criteria for scoring micronucleus test and alkaline comet assay were used. Both methods showed that p,p'-DDT induces DNA damage in low concentration used in this research. Results of micronucleus test showed a statistically significant (p < 0.05) genotoxic effect of p,p'-DDT on human lymphocytes compared with corresponding control and a different exposure time. A comet assay also showed increased DNA damage caused in p,p'-DDT-exposed human lymphocytes than in corresponding control cells for the tail length. Results obtained by measuring the level of DNA migration and incidence of micronuclei (MN), nucleoplasmic bridges (NPBs) and nuclear buds (NBUDs) indicate the sensitivity of these tests and their application in detection of primary genome damage after long-term exposure to establish the effect of p,p'-DDT on human genome.     

Barriers for implementation of “waste to energy” in developing and transition countries: a case study of Serbia

The aim of this study is to assess boundaries and potential for implementation of waste-to-energy projects in developing and transition countries in order to give realistic future directions for waste-to-energy initiatives. For this purpose, Serbia is taken as an example. In order to highlight the most important issues, which hinder the feasibility of waste-to-energy projects, analysis of the status quo of Serbian municipal solid waste management is performed. In addition, based on the current political and social status of the country, the most important factors that need to be solved as a precondition to waste-to-energy projects are defined. This analysis revealed that aside from technical factors, sociopolitical and cultural obstacles must be eliminated as a prerequisite for successful implementation of waste-to-energy projects. We define the most sustainable pathway for waste-to-energy initiatives in Serbia as well as other similar developing and transition countries, which can complement development of the entire waste management system.     

Quantification of the resource recovery potential of municipal solid waste incineration bottom ashes

Municipal solid waste incineration (MSWI) plays an important role in many European waste management systems. However, increasing focus on resource criticality has raised concern regarding the possible loss of critical resources through MSWI. The primary form of solid output from waste incinerators is bottom ashes (BAs), which also have important resource potential. Based on a full-scale Danish recovery facility, detailed material and substance flow analyses (MFA and SFA) were carried out, in order to characterise the resource recovery potential of Danish BA: (i) based on historical and experimental data, all individual flows (representing different grain size fractions) within the recovery facility were quantified, (ii) the resource potential of ferrous (Fe) and non-ferrous (NFe) metals as well as rare earth elements (REE) was determined, (iii) recovery efficiencies were quantified for scrap metal and (iv) resource potential variability and recovery efficiencies were quantified based on a range of ashes from different incinerators. Recovery efficiencies for Fe and NFe reached 85% and 61%, respectively, with the resource potential of metals in BA before recovery being 7.2%ww for Fe and 2.2%ww for NFe. Considerable non-recovered resource potential was found in fine fraction (below 2 mm), where approximately 12% of the total NFe potential in the BA were left. REEs were detected in the ashes, but the levels were two or three orders of magnitude lower than typical ore concentrations. The lack of REE enrichment in BAs indicated that the post-incineration recovery of these resources may not be a likely option with current technology. Based on these results, it is recommended to focus on limiting REE-containing products in waste for incineration and improving pre-incineration sorting initiatives for these elements.     

环境监测策略评价

在环境监测中,监测系统在非预期事件出现时能够发出早期预警是很重要的.这些事件具有突发,或者难以观测到的性质.在设计这类监测系统时,必须在成本和风险之间达到一个适当的平衡.传统意义上有两类和早期预警系统相关联的风险,即没有检测到重要变化的风险和错误预警的风险.本文的目的是阐述一种在考虑了传统类型的风险和成本的情况下来比较不同监测系统性能的方法.这个方法被试用于地衣植被的监测中,并采用预期效应作为性能的度量标准.在估计事件的概率时,应用了空间微观模拟技术(spatial microsimulation)和蒙特卡罗模拟技术.所评估的监测计划基于卫星图像、航空照片、野外采样和土地覆被图.研究的主要结论是,标准化质量度量在环境监测方法可用性的评估中是极为有用的.另外,空间微观模拟技术在效益和成本估计中是可用的.不过要改进算法,还需要应用宏观约束(macroconstraints)来修正模拟模型.     

雄性波罗的海灰海豹(Halichoerus grypus)骨组织的矿物密度

本文利用非侵入计算层析X射线摄影法(pQCT)研究了雄性波罗的海灰海豹(4～23岁龄)骨组织的矿物密度(mg/cm3).资料按照收集的年份分组.A组1850～1955年,有机氯(OCs)大量引入之前的时期;B组1965～1985年,OC污染十分严重的时期;C组1986～1997年,OCs浓度逐渐减小的时期.测量结果的复现性良好,变异系数(CV)为0.1%～2.1%.1986～1997年收集的标本中桡骨小梁的矿物密度比1965～1985年收集的标本的明显要高(p＜0.05).1986～1997年收集的标本中,下颌骨的皮层骨矿物密度明显地低于1850～1955年收集的标本(p＜0.05).这些结果表明小梁和皮层骨在一段时间内的不同响应.在OC污染非常严重的时期(1965～1985年),小梁骨矿物密度最低,而在1985～1997年收集的标本中,皮层骨密度最低,该时段是一个OC污染程度相当低的时期.有关这些效应背后的机制目前尚不知道.但是,可以假定这里涉及到OCs.由于目前缺乏有关研究个体中OCs残留水平的资料,因此不可能评估OCs在这方面的影响.     

Space use in lions, <Emphasis Type="Italic">Panthera leo</Emphasis>, in the Selous Game Reserve: social and ecological factors

Habitat qualities, such as food supply or access to refuges, often influence home-range size. Furthermore, such qualitative differences usually lead to conspecific competition over space, which can be an important factor in determining the distribution of individuals within populations. In carnivores, patterns of resource dispersion are hypothesized to determine home range-size and group size. But in contests over space (or other resources), larger groups usually dominate smaller ones, and group size should therefore also affect home-range size. Here I describe the space use of lions, Panthera leo, in the Selous Game Reserve, Tanzania, and ask whether space use is related to pride size, habitat, or relatedness. Home ranges varied in size, but size showed no correlation to number of adult females in the pride or to habitat type. Lions exhibited a significant preference for riverine and short-grass habitat, and a significant avoidance of acacia woodland. Habitat preference ratios largely reflected prey availability in each habitat. Outer areas, as well as core areas of home ranges, were often used by two or more prides. Overlaps showed no correlation to relatedness among prides or habitat type. Thus, whereas home-range sizes and overlaps were determined by factors that could not be revealed by demographic factors or analyses of habitat composition or genetic structure, lion space use within each home range seemed driven mostly by prey availability, which mainly varies with habitat type.