Isomer specific synthesis using the Suzuki-coupling. Polychlorinated terphenyls as standards for environmental analysis

Defined polychlorinated terphenyl (PCT) single congeners as reference standards are the prerequisite for the development of analytical methods for their determination and quantification in the environment. The selective synthesis of PCTs for environmental analytical purposes by application of the Suzuki-coupling reaction is described. Under easily modified standard reaction conditions of this coupling process the PCTs can be obtained by reaction of benzeneboronic acids with dibromobenzenes mostly in good yields, as described by the synthesis of following PCT congeners: p-PCT (3,3("),5,5(")-tetrachloro-, 2,2("),4,4(")-tetrachloro-, 2('),3,3("),5,5(")-pentachloro-); m-PCT (3,3("),5,5(")-tetrachloro-) and o-PCT (3,3("),5,5(")-tetrachloro-). The terphenyl congeners were characterized by NMR (1H, 13C)- and FT-IR-spectroscopy. Their purity was checked by GC/MS analysis. The experimental and quantum-chemically calculated FT-IR-spectra were compared and it was shown, that the determination of the chlorine substitution pattern in the terphenyl congeners by their typical absorption spectra is possible.     

Adapting cropping systems to climate change in Nepal: a cross-regional study of farmers’ perception and practices

Climate change is a global challenge that has a particularly strong effect on developing countries such as Nepal, where adaptive capacity is low and where agriculture, which is highly dependent on climatic factors, is the main source of income for the majority of people. The nature and extent of the effects of climate change on rural livelihoods varies across Nepal in accordance with its highly diverse environmental conditions. In order to capture some of this variability, a comparative study was performed in two different ecological regions: Terai (lowland) and Mountain (upland) in the western development region of Nepal. The study focuses on perceptions of, and on adaptations to climate change by farmers. Information was collected from both primary and secondary data sources. Climate data were analyzed through trend analysis. Results show that most farmers perceive climate change acutely and respond to it, based on their own indigenous knowledge and experiences, through both agricultural and non-agricultural adaptations at an individual level. The study also shows that there is a need to go beyond the individual level, and to plan and provide support for appropriate technologies and strategies in order to cope with the expected increasing impacts of climate change.     

Designing conservation-development policies for the forest frontier

The conservation of forests in expanding frontier landscapes is critically important to maintain intact forest ecosystems and support forest dependent communities. To conserve frontier forests, policy approaches are needed that conserve forests and advance the well-being of local resource dependent communities. To identify such approaches, the forest conservation and development framework (FCDF) was designed to find place-based conservation-development policies that target system leverage-points influencing land-use practices. To demonstrate the utility of the FCDF, a portfolio of conservation-development policies were identified for Peru’s Manu-Tambopata Corridor (MAT) and evaluated by local land-users. Results of the MAT case study show high levels of interest in the proposed policies, but a wide variation in interest levels relative to personal circumstances and policies proposed. Barriers to implementing conservation-development policies in frontier environments were also identified, including high value land-use alternatives generating high opportunity costs for accepting PES payments (e.g., REDD+), insecure land tenure and conflicting authorizations limiting land-users policy choices, and broad demographic diversity among local land-users. Collectively, this research suggests the FCDF is a useful approach for identifying policies matched to local conditions that advance conservation and human development. This research also indicates policy design in frontier environments is most effective when adapted to local conditions, seeks to identify a mix of complementary policies, and is targeted at key system variables influencing land-use practices (i.e., system leverage-points). Importantly, the MAT case study also highlights how even in rapidly changing frontier landscapes, land-users are interested in policies that advance conservation and development goals.     

An assessment of urban vulnerability in the Amazon Delta and Estuary: a multi-criterion index of flood exposure,socio-economic conditions and infrastructure

The Amazon Delta and Estuary (ADE) is a region of continental and global ecological importance. Controversy, many of the basic infrastructure and services essential for quality of life and sustainable development of this delta are absent. Using a conceptual model to define socio-economic vulnerability in the urban ADE, a thorough assessment of indicators including sanitation services, housing conditions, household income, population, flood risk and unplanned settlements was conducted in 41 cities at the census sector scale (n = 2938). A multi criterion index was applied to classify urban vulnerability from three dimensions: flood exposure, socio-economic sensitivity and infrastructure. This is the first study to examine urban vulnerability within and between urban areas of the ADE. Results indicated that most of the urban sectors of the ADE are exposed to potential risks due to a combination of flood hazards, poverty and basic structural deficiencies such as insufficient drinking water or inadequate waste water collection, with several sectors being afflicted by similar problems. The assessment of vulnerability indicates that 60–90 % of the urban population live in conditions of moderate to high degree of vulnerability. The ADE cities presented a pattern where vulnerability increases from city center to their newly developed urban areas. Inadequate planning coupled with rapid urbanization has contributed to the development of unplanned settlements in almost half of the urban sectors of the ADE. Combined, these factors contribute to widespread socio-economic vulnerability along the urban spaces of the ADE, increasing exposure to health risks and more frequent seasonal and stochastic events such as storm surges and high flooding levels.     

Trace elements in the shoreline and seabed sediments of the southern Caspian Sea: investigation of contamination level,distribution, ecological and human health risks,and elemental partition coefficient

Environmental Science and Pollution Research - This study assesses the occurrence of trace elements (TEs) in sediments of the southern Caspian Sea. A total of 16 shoreline sediment samples and 15...     

Depleted uranium particles in selected Kosovo samples

Selected soil samples, collected in Kosovo locations where DU ammunition was expended during the 1999 Balkan conflict, have been investigated by secondary ion mass spectrometry (SIMS), X-ray fluorescence imaging using a micro-beam (micro-XRF) and scanning electron microscopy equipped with an energy dispersive X-ray fluorescence detector (SEM-EDXRF), with the objective to test the suitability of these techniques to identify the presence of small DU particles and measure their size distribution and the 235U/238U isotopic ratio (SIMS). Although the results do not permit any legitimate extrapolation to all the sites hit by the DU rounds used during the conflict, they indicated that there can be "spots ' where hundreds of thousands of particles may be present in a few milligrams of DU contaminated soil. The particle size distribution showed that most of the DU particles were <5 microm in diameter and more than 50% of the particles had a diameter <1.5 microm. Knowledge on DU particles is needed as a basis for the assessment of the potential environmental and health impacts of military use of DU, since it provides information on possible re-suspension and inhalation.     

Differential effects of energy and mass influx on the landscape synchrony of lake ecosystems

Interannual variation of 45 annually resolved time series of environmental, limnological, and biotic parameters was quantified (1994-2009) in six lakes within 52,000 km2 to test the hypothesis that influx of energy (E; as irradiance, heat, wind) varies synchronously among sites and induces temporal coherence in lakes and their food webs, whereas influx of mass (m; as water, solutes, particles) reduces synchrony because local catchments uniquely modify hydrologic inputs. Overall, 82% of parameters exhibited significant (P < 0.05) synchrony (S) estimated as mean pair-wise correlation of Z-transformed time series. Influx of E as atmospheric heat and irradiance was both more highly synchronous and less temporally variable (months-to-decades) than influx of m as summer precipitation, snow, or river discharge. Similarly, S of limnological parameters varied from 0.08 to 0.85, with variables known to be regulated by E influx (ice melt, gas solubility) up to twofold more coherent than those regulated by m inputs (organic solutes). Pairs of variables linked by simple direct mechanisms exhibited similar S values (air temperature and ice melt, nutrients and algae), whereas the coherence of other parameters (water temperature, mixing) was intermediate to that of multiple regulatory agents. Overall, aggregate measures of plankton density varied more coherently among lakes than did constituent taxa. These findings suggest that environmental variability is transmitted to most levels of aquatic ecosystems, but that the precise effects depend on whether E or m fluxes predominate, the coherence of each forcing mechanism, and the strength of linkages between exogenous forcing and lake response.