Charge‐transfer chromatographic study of the interaction of commercial pesticides with hydroxypropyl‐β‐cyclodextrin

The interaction between 33 commercial pesticides with hydroxypropyI‐β‐cyclodextrin (HPBCD) was studied by charge‐transfer reversed‐phase thin‐layer chromatography using aqueous sodium chloride solutions as eluents. Each pesticide interacted with HPBCD, their lipophilicity linearly decreased with increasing HPBCD concentration, the pesticide ‐ HPBCD complex (probably inclusion complex) always being more hydrophilic than the uncomplexed pesticide. In many cases the retention of pesticide increased with increasing concentration of salt in the eluent. This effect can be tentatively explained by the suppression of the dissociation of the polar groups in the solute molecules resulting in increased apparent lipophilicity. No significant correlation was found between lipophilicity and complex stability or between salting‐out effect and lipophilicity, that is other than hydrophobic forces are involved in the pesticide ‐ HPBCD interaction.     

Ground water pollution by pesticides at the watershed‐soil catena scale: Lindane at the lower Colorado river basin (Argentina)

The movement of Lindane from application points at the surface soil towards the underground water and further transport within this compartment at the watershed‐soil catena scale, was inspected by measurements of the pesticide concentration in soil water at a controlled experiment where it was applied at a usual label dose. The concentrations of Lindane in soil water and the upper phreatic level were also measured at successive dates in samples obtained from a net of phreatimeter probes distributed over the area (1,500 km²) of the lower Colorado River basin (Bs. Aires, Argentina). The location of cultivated‐irrigated areas within the watershed was inferred from NDVI (Normalized Difference Vegetation Index)‐1 km‐10 day AVHRR images obtained at successive dates during the irrigation season. Feasible paths of underground gravitational water flows were computed by means of a GIS‐simulation model on the basis of local terrain slopes and aspects. The pattern of Lindane distribution over the basin was explained on the basis of the distribution of diffuse sources, the patterns of percolation and groundwater flows and the thermodynamic characteristics of the pesticide.     

Natal dispersal in two mice species with contrasting social systems

We compared the natal dispersal behaviour of two mice species under laboratory conditions. Natal dispersal is a movement of an animal from its birthplace to its breeding area. This behaviour is known to be influenced by the mating system. In polygamous species, males are more likely to disperse, while in most of the monogamous species, both sexes disperse. Our subjects, the house mouse (Mus musculus) and the mound-building mouse (Mus spicilegus) are two sympatric species of the genus Mus. Both are native in Hungary, but they differ in their habitat type mating system and overwintering strategy. The house mouse is a polygynous species and adapted to human environment, known for mature and reproduce early. On the contrary, the mound-building mice are monogamous, and they inhabit extensively used agricultural fields, where they spend the unfavourable winter period in nest chambers under mounds, which they construct from soil and plant material. Successful overwintering for this species demands delayed maturity and reduced dispersion during the winter. Our results showed that the natal dispersal of these two species differ; both sexes of the mound-building mice dispersed later than the house mice, where a difference between sexes also occurs; house mice males dispersed earlier than females. The mound-building mice showed no sexual dimorphism in this behaviour.     

Boldness and body size of male Spanish terrapins affect their responses to chemical cues of familiar and unfamiliar males

Recognition and avoidance of conspecifics based on chemical cues could reduce the risk of aggressive interactions between males. Success in agonistics encounters with unfamiliar males should be lower than with previously known familiar males. Then, males should avoid the chemicals from unfamiliar males with respect to those from familiar males. However, boldness and size could affect the outcome of encounters between males and, consequently, the response to chemical cues of conspecific males. We compared the time spent by male turtles Mauremys leprosa in water pools with chemical stimuli from unfamiliar or familiar males or with their own chemical stimuli. We also performed a behavioral test to estimate boldness of turtles in an antipredatory situation. Turtles avoided the chemicals from unfamiliar males respect to familiar ones and their own odors, but their responses depended on boldness and size of the tested turtle. Bold turtles avoided water with chemicals of unfamiliar males, but not with chemicals of familiar males, whereas shy turtles avoided chemicals of both familiar and unfamiliar males. On the other hand, large males avoided the odor from unfamiliar males, but small males did not avoid water with the odor from other males. Results suggest that male M. leprosa can detect chemicals released to water from conspecific males and discriminate between familiar and unfamiliar males. However, responses to these chemicals depended on boldness and body size of the responding turtle because these factors may affect intrasexual competition.     

Human resilience and environmental degradation: The eco-cultural link in the Sahel

The relationship between human resilience and environmental degradation was studied in the Sahel. The strongest predictors of human resilience were rate of environmental degradation, avoidance, problem solving and locus of control. Compared to pastoralists, agriculturalists were more stressed and marginalized. Women in all groups scored higher on marginalization and stress than men.     

Ecological niche segregation among five toothed whale species off the NW Iberian Peninsula using ecological tracers as multi-approach

This study aims to assess niche segregation among the five main toothed whales that frequent the NW Iberian Peninsula waters: the common dolphin, the harbour porpoise, the bottlenose dolphin, the striped dolphin and the long-finned pilot whale. We used cadmium (Cd) and stable isotope ratios (δ¹³C and δ¹⁵N) as ecological tracers to assess degree of segregation in diet/trophic level and in foraging habitat, over various time-scales. δ¹³C values highlighted different habitats, while Cd concentrations highlighted feeding differences between oceanic and neritic species. Moreover, δ¹⁵N values suggest different trophic levels of prey targeted within oceanic and neritic species. Hence, results revealed long-term ecological segregation among five toothed whales that coexist in the NWIP and demonstrated the ability of ecological tracers to discriminate ecological niches among closely related species.     

Geologic occurrences of erionite in the United States: an emerging national public health concern for respiratory disease

Erionite, a mineral series within the zeolite group, is classified as a Group 1 known respiratory carcinogen. This designation resulted from extremely high incidences of mesothelioma discovered in three small villages from the Cappadocia region of Turkey, where the disease was linked to environmental exposures to fibrous forms of erionite. Natural deposits of erionite, including fibrous forms, have been identified in the past in the western United States. Until recently, these occurrences have generally been overlooked as a potential hazard. In the last several years, concerns have emerged regarding the potential for environmental and occupational exposures to erionite in the United States, such as erionite-bearing gravels in western North Dakota mined and used to surface unpaved roads. As a result, there has been much interest in identifying locations and geologic environments across the United States where erionite occurs naturally. A 1996 U.S. Geological Survey report describing erionite occurrences in the United States has been widely cited as a compilation of all US erionite deposits; however, this compilation only focused on one of several geologic environments in which erionite can form. Also, new occurrences of erionite have been identified in recent years. Using a detailed literature survey, this paper updates and expands the erionite occurrences database, provided in a supplemental file (US_erionite.xls). Epidemiology, public health, and natural hazard studies can incorporate this information on known erionite occurrences and their characteristics. By recognizing that only specific geologic settings and formations are hosts to erionite, this knowledge can be used in developing management plans designed to protect the public.     

Physicochemical properties of non-living water hyacinth (Eichhornia crassipes) and lesser duckweed (Lemna minor) and their influence on the As(V) adsorption processes

Eichhornia crassipes (Ec) and Lemna minor (Lm) are aquatic plants. They are considered as weeds of the water and approach being a scourge in many parts of the world, choking waterways and hindering transport upon them. At the same time they are known to readily remove heavy metal ions from water. This paper considers the use of non-living plants as novel and inexpensive biosorbent for the removal of As(V) from watersheds. In the first place they were conditioned and characterised to determine their physicochemical and surface properties and in the second place their adsorption properties for As(V) from aqueous solution were evaluated considering the toxicity of this metalloid in the environment. It describes the methodology to prepare the non-living biomasses; the physicochemical characterisation by SEM, XRD, FTIR, TGA analyses and surface characterisation of Ec and Lm by specific surface, hydration kinetic, point of zero charge determination by mass titration, active site density and XPS analysis are described. Both studied biomasses were found to be potential bio-sorbents for arsenic ions from aqueous solution. According to their efficiency to remove arsenic, they can be used in a very low cost metalloid ions removal system.     

Phosphorous cycling and biogeochemistry in a Venezuelan-flooded savanna

In 1970, a programme of land recuperation started in Venezuelan savannas, strongly affected by the seasonality of precipitation; therefore, a network of dykes has been built to alleviate the floods and retain water throughout the dry period. Under the dyked system, the environment has been altered, allowing a change in the herbaceous vegetation towards aquatic species and an increase in primary production. It is assumed that a considerable quantity of nutrients is lost from the ecosystem through the floodgates, a situation that could be worsened with the climate change. This contribution describes the atmospheric input and total output in stream run-off of phosphorous (P) in a flooded savanna. Internal pools of the biogeochemical cycle of P associated with terrestrial compartments are described. In the flooded savanna, a large amount of P is immobilised (29.6?kg?ha^?1) in their above ground biomass by grasses, and in soil microbial biomass. The P budget was nearly balanced, as measured losses were cancelled out by the inputs in rainfall. Soils act as a sink, retaining P coming either from precipitation or from desorption/mineralisation processes. That interruption can be maximised, and losses of P and other nutrients can be minimised with an adequate management of the floodgate.