Spatial & temporal variations of PM10 and particle number concentrations in urban air

The size of particles in urban air varies over four orders of magnitude (from 0.001 μm to 10 μm in diameter). In many cities only particle mass concentrations (PM10, i.e. particles <10 μm diameter) is measured. In this paper we analyze how differences in emissions, background concentrations and meteorology affect the temporal and spatial distribution of PM10 and total particle number concentrations (PNC) based on measurements and dispersion modeling in Stockholm, Sweden. PNC at densely trafficked kerbside locations are dominated by ultrafine particles (<0.1 μm diameter) due to vehicle exhaust emissions as verified by high correlation with NOx. But PNC contribute only marginally to PM10, due to the small size of exhaust particles. Instead wear of the road surface is an important factor for the highest PM10 concentrations observed. In Stockholm, road wear increases drastically due to the use of studded tires and traction sand on streets during winter; up to 90% of the locally emitted PM10 may be due to road abrasion. PM10 emissions and concentrations, but not PNC, at kerbside are controlled by road moisture. Annual mean urban background PM10 levels are relatively uniformly distributed over the city, due to the importance of long range transport. For PNC local sources often dominate the concentrations resulting in large temporal and spatial gradients in the concentrations. Despite these differences in the origin of PM10 and PNC, the spatial gradients of annual mean concentrations due to local sources are of equal magnitude due to the common source, namely traffic. Thus, people in different areas experiencing a factor of 2 different annual PM10 exposure due to local sources will also experience a factor of 2 different exposure in terms of PNC. This implies that health impact studies based solely on spatial differences in annual exposure to PM10 may not separate differences in health effects due to ultrafine and coarse particles. On the other hand, health effect assessments based on time series exposure analysis of PM10 and PNC, should be able to observe differences in health effects of ultrafine particles versus coarse particles.     

Investigations into the transport and pathways of scallop larvae--the use of numerical models for managing fish stocks

The scallop fisheries off the southeast coast of Ireland have historically been considered a valuable resource for coastal communities, and hence their management is important. The scallop fishing grounds consist of a number of scallop beds dispersed throughout the St George's Channel and the southern Irish Sea. The boundaries between stocks and the interconnection in populations of adult scallops, through larval transport, is generally unknown. Until the time of this research, the stocks of scallop in this region had not been assessed. A research project was undertaken to develop novel, spatially explicit and multi-disciplinary approaches to the assessment of the scallop fisheries in the region. The project supported research in three related areas under the broad objective of developing stock assessment protocols and methods in order to promote sustainable management of these fisheries. One of these areas was the development and application of numerical models. The objectives of this modelling research were: (a) to reconstruct the physical environment of the study area; (b) investigate how this environment affects the demographics and nature of scallop; and (c) determine migration-transport pathways of the scallop larvae. From these investigations, light is shed on how the spatial variability in certain parameters of the natural environment determine habitats and the scallop populations. Also, the investigations now enable determinations to be made on the interconnectivities of 'disparate' scallop beds and where larvae are, in general, likely to be found. Thus, through the use of complex computer models, important clues are deduced that enable us to now understand key behavioural components of scallop larvae and their transport pathways. The analysis of these clues is assisting the development of protocols for managing the fish stock in a sustainable manner.     

Ein neuer Biotest mit der HefeSaccharomyces cerevisiae auf aquatische Toxizität

The fermentation activity of the yeastSaccharomyces cerevisiae is used as a bioindicator to detect aquatoxic effects. This is done by measuring the CO₂ production of yeast cells after a multiplication period affected by toxic substances. The concentration of toxicants diminishing the fermentation by 20% is taken as a characteristic value (EC₂₀). Organic compounds (unpolar and polar narcotics), inorganic salts (especially of heavy metals), surfactants and plant pesticides were tested. The results are compared so far as available with data of a ciliata assay usingTetrahymena pyriformis. A congruence of 90% and an equal sensibility of the assays resulted. The results of the yeast assay are therefore representative for ecotoxicological testing. The yeast assay is reproducible, easy to handle, and offers an alternative for sewage testing because sterile handling is not necessary.     

Mating patterns and reproductive success in the bushy-tailed woodrat (Neotoma cinerea), as revealed by DNA fingerprinting

The mating patterns and reproductive success of the bushy-tailed woodrat (Neotoma cinerea) were investigated over a 3-year period (1992–1994) using DNA fingerprinting. Paternity was determined by genetic analysis of 58 juveniles of known maternity from 35 litters. Analysis of DNA fingerprints revealed that all offspring within a litter were fathered by a single male; the statistical probability of detecting multiple males mating with a female was high, indicating that multiple paternity would have been detected had it occurred. However, individual males did not father more than one litter from a given female either within or between years. At least 75% of females and 57% of males successfully produced offspring each year. The finding that all littermates are first-order relatives may contribute to the high level of female cooperation in this species. Received: 28 May 1997 / Accepted after revision: 22 March 1998     

Attitudes and Perceptions about Ecological Resources and Hazards of People Living Aroung the Savannah River Site

Although considerable attention is devoted to environmental monitoring and assessment with respect to both pollutants and the status of particular plant or animal populations, less attention is devoted to assessing people's attitudes about the relative importance of ecological resources. In this paper we examine the attitudes and perceptions about ecological resources of people living around the Department of Energy's Savannah River Site (SRS), in South Carolina. Our overall hypothesis is that people who are directly affected by the possible outcomes and consequences of a particular hazard (i.e., those people employed at SRS) will undervalue the risks and overvalue the potential benefits from future land uses that favor continued site activity, compared to people who live near but are not employed at SRS. We interviewed 286 people attending the Aiken Trials horse show on 14 March 1997. There were few gender differences, although men hunted and fished more than women, women ranked three environmental concerns as more severe than did men, and women were more concerned about the effect of SRS on property values. Maintenance of SRS as a National Environmental Research Park ranked first as a future land use; nuclear production ranked second, followed by hunting and hiking. Only residential development ranked very low as a future land use. There were many differences as a function of employment history at SRS: 1) people who work at SRS think that the federal government should spend funds to clean up all nuclear facilities, and they think less money should be spent on other environmental problems than did non-employees, 2) people who work at SRS ranked continued current uses of SRS higher than did people who never worked at SRS, and 3) people who work at SRS are less concerned about the storage of nuclear material or accidents at the site than are people who never worked at the site.     

Acute toxic hazard evaluations of glyphosate herbicide on terrestrial vertebrates of the oregon coast range

GOAL, SCOPE AND BACKGROUND: The degree to which dose responses of model organisms (lab rodents) can adequately predict dose responses of free-ranging wild mammals or amphibians is unknown, and the relative sensitivity of such species to body loading of a toxicant such as glyphosate is seldom reported. For relative effects of dosage, we compare sensitivity of nine wild vertebrate species to effects of high doses of glyphosate in Swiss-Webster laboratory mice both by gavage and by intraperitoneal injection. We also evaluate sublethal effects of herbicide exposure on behavior and reproductive success of one mammal and one amphibian species. METHODS: Comparisons of acute toxicity of glyphosate were made with intraperitoneal dosings of technical glyphosate isopropylamine salt to nine species of terrestrial vertebrates (five amphibians, four mammals) and compared with responses in Swiss-Webster laboratory mice. Animals collected from sites that had no recent herbicide application were allowed 7-14 days to equilibrate in captivity before treatment. RESULTS: Median lethal dose ranged from 800 to 1,340 mg kg(-1) in mammals, and 1,170 to >2,000 mg kg(-1) in amphibians, with Oregon vole being the most sensitive. White lab mice were in the middle of the mammalian range. Tailed frog, at >2,000 mg kg(-1) was the least sensitive. Calibration of IP sensitivity to oral administration by gavage indicated that roughly four times as much glyphosate must be administered to obtain a comparable estimate of lethality. Administration by gavage in highly concentrated solutions tended to cause physical injury, hence may prove less useful as a relative indicator of toxicity. When sublethal dosages were given to roughskin newts or chipmunks, mobility and use of cover appeared largely unaffected. DISCUSSION: Direct toxic effects of spraying glyphosate under normal forest management seem unlikely for the nine species examined. Nor could we detect significant indirect effects of exposure on behavior and use of cover features in two species. There may be effects on other aspects of the field biology of these animals, such as reproductive rates, which we did not investigate. Recent field data indicate that changes in habitat quality following herbicide application can result in high reproductive activity in species associated with the grasses and forbs that proliferate following field applications. CONCLUSIONS: When compared to field data on body burdens of wild mammals exposed after aerial application of glyphosate at maximum rates in forests, there seems to be a large margin of safety between dosages encountered and those causing either death or limitation of movement, foraging or shelter. RECOMMENDATIONS AND PERSPECTIVES: Margins of safety for small mammals and amphibians appear to be large under any probable exposure scenarios, however our results indicate high variability in responses among species. Uncertainty introduced into field studies from unknown sources of mortality (e.g, likely predation) must be considered when interpreting our results.     

Degradation of PVC Containing Mixtures in the Presence of HCl Fixators

Degradation of a model polymer mixture (PVC/PS/PE) and a waste polymer mixture in the presence of HCl fixators (Red Mud, precipitated CaCO₃ and dolamite) was studied using thermal gravimetric analysis (TGA) and a cycled-spheres-reactor. The experiments in cycled-spheres reactor model were performed by stepwise pyrolysis. Liquid products and HCl from each step were collected separately. For the model polymer mixture, the precipitated CaCO₃ showed the best effect on the fixation of evolved HCl and the reduction of chlorine content in the liquid products whereas RM yielded the best result for the waste polymer mixture. In addition, using HCl fixator also affected the degradation of both types of polymer mixture, leading to the formation of more gaseous and less residue.     

Transforming ecology and conservation biology through genome editing

As the conservation challenges increase, new approaches are needed to help combat losses in biodiversity and slow or reverse the decline of threatened species. Genome-editing technology is changing the face of modern biology, facilitating applications that were unimaginable only a decade ago. The technology has the potential to make significant contributions to the fields of evolutionary biology, ecology, and conservation, yet the fear of unintended consequences from designer ecosystems containing engineered organisms has stifled innovation. To overcome this gap in the understanding of what genome editing is and what its capabilities are, more research is needed to translate genome-editing discoveries into tools for ecological research. Emerging and future genome-editing technologies include new clustered regularly interspaced short palindromic repeats (CRISPR) targeted sequencing and nucleic acid detection approaches as well as species genetic barcoding and somatic genome-editing technologies. These genome-editing tools have the potential to transform the environmental sciences by providing new noninvasive methods for monitoring threatened species or for enhancing critical adaptive traits. A pioneering effort by the conservation community is required to apply these technologies to real-world conservation problems.     

Projected declines in global DHA availability for human consumption as a result of global warming

Ambio - Docosahexaenoic acid (DHA) is an essential, omega-3, long-chain polyunsaturated fatty acid that is a key component of cell membranes and plays a vital role in vertebrate brain function. The...     

The fate of secondary metabolites in plants growing on Cd-, As-, and Pb-contaminated soils—a comprehensive review

Environmental Science and Pollution Research - The study used scattered literature to summarize the effects of excess Cd, As, and Pb from contaminated soils on plant secondary metabolites/bioactive...