The evolution of mass balance models of persistent organic pollutant fate in the environment

Current approaches to modelling the fate of persistent organic pollutants (POPs) in the environment have evolved in response to four dominant characteristics of these substances; namely: (1) the presence of POPs in virtually all environmental phases and the ease with which they move from one to the other requires multi-compartmental modelling. Describing transport across phase boundaries becomes as, or even more, important as quantifying transport within the phases; (2) POPs may persist in the environment for many decades. For chemicals that 'have time', concepts such as equilibrium partitioning and steady-state become more important than for short-lived substances whose fate is more controlled by the rates of transformation; (3) measuring POPs is difficult and expensive and observed concentrations of POPs are not available in high spatial or temporal resolution. Consequently, high resolution tends not to be a high priority in POP models; and (4) detrimental effects of POPs often manifest themselves in top predators, which has led to a focus on modelling biotic uptake and transfer within food chains. The task of building a POPs model is viewed as combining the four 'building blocks' of partitioning, transport, transformation and source data with the help of the law of the conservation of mass. Process models, evaluative models, models of real local, regional and global fate, as well as biological uptake models are presented and references to numerous examples are provided. An attempt is made to forecast future directions in the field of POPs modelling. It is expected that modelling techniques that do not rely on quantitative emission estimates as well as approaches that take into account spatial, temporal and climatic variability as well as parameter uncertainty will increase in importance. Finally, the relationship between modelling POPs and models of other pollutant issues is addressed, as are potential interactions between POPs and pollutant issues such as eutrophication, acidification and global climate change.     

Vanadium contamination and the relation between vanadium and other elements in wild birds

There is little information on vanadium (V) contamination in wildlife. In the present study, the mean V contents in liver and kidney from 41 wild Japanese water birds were less than 3.69 and 8.11 microg/g dry wt, respectively. The V contents in the liver and kidney of the spotbill duck were more than two times higher than those of other species in Japan. Spotbill ducks obtained in a residential district had a strong correlation between the V contents in the kidneys and those in the livers (R=0.924), and also between V and Ti, Cd, and Li contents in the liver (R>0.8). These results suggest that V accumulation in wild birds reflects the degree of environmental contamination.     

Sensitivity of the terrestrial biosphere to climatic changes: impact on the carbon cycle

The biosphere is a major pool in the global carbon cycle; its response to climatic change is therefore of great importance. We developed a 5 degrees x 5 degrees longitude-latitude resolution model of the biosphere in which the global distributions of the major biospheric variables, i.e. the vegetation types and the main carbon pools and fluxes, are determined from climatic variables. We defined nine major broad vegetation types: perennial ice, desert and semi-desert, tundra, coniferous forest, temperate deciduous forest, grassland and shrubland, savannah, seasonal tropical forest and evergreen tropical forest. Their geographical repartition is parameterized using correlations between observed vegetation type, precipitation and biotemperature distributions. The model computes as a function of climate and vegetation type, the variables related to the continental biospheric carbon cycle, i.e. the carbon pools such as the phytomass, the litter and the soil organic carbon; and carbon fluxes such as net primary production, litter production and heterotrophic respiration. The modeled present-day biosphere is in good agreement with observation. The model is used to investigate the response of the terrestrial biosphere to climatic changes as predicted by different General Circulation Models (GCM). In particular, the impact on the biosphere of climatic conditions corresponding to the last glacial climate (LGM), 18 000 years ago, is investigated. Comparison with results from present-day climate simulations shows the high sensitivity of the geographical distribution of vegetation types and carbon content as well as biospheric trace gases emissions to climatic changes. The general trend for LGM compared to the present is an increase in low density vegetation types (tundra, desert, grassland) to the detriment of forested areas, in tropical as well as in other regions. Consequently, the biospheric activity (carbon fluxes and trace gases emissions) was reduced.     

Polycyclic aromatic compounds in Northwest Atlantic COD (Gadus morhua)

Twenty-seven polycyclic aromatic compounds (PAC) including polycyclic aromatic hydrocarbons (PAH) and polycyclic aromatic sulphur heterocycles were analysed in muscle, liver and ovaries of cod (Gadus morhua) from the Northwest Atlantic. These PAC include the 16 PAH priority pollutants (EPA recommendation), alkylated naphthalenes, phenanthrene-anthracenes as well as dibenzothiophenes (DBT). Aromatics were undetectable in muscle. One of the analysed PAC was detected in one ovary and six in another ovary sample. Liver samples contained between 1 and 9 PAC. Of the parental PAH, only acenapthene (18 ng/g, dry weight), fluorene (28 ng/g) and chrysene (22 ng/g) were detected once each in two liver samples, while fluorene (72 ng/g) was detected once in one of the ovaries. C-2 DBT was the major component in ovaries and liver (8-86 ng/g), while C-3 and C-4 alkylated phenanthrene-anthracene (12-78 ng/g) were the next major components detected in the liver samples. This is the first detailed study of PAH and PAC in finfish from the Northwest Atlantic.     

Flammability of heat transfer fluid aerosols produced by electrospray measured by laser diffraction analysis

Accidental release of pressurized high flash point heat transfer fluids can result in fire and explosion hazard scenarios in the process industry. An experimental investigation on ignition of aerosols of a heat transfer fluid is carried out, and characterization of aerosol and its ignition process by non-intrusive laser diffraction technique is reported. Propagation speed of the aerosol combustion flame front as analyzed from the laser diffraction measurement agrees with high-speed visual camera observation. Flammability of the aerosol, which is based on the chances of the global flame appearance in the aerosol, is mainly controlled by aerosol droplet size and the droplet volume concentration.     

Work–family conflicts of women in the Air Force: their influence on mental health and functioning

This paper examined the effects of work and family stressors and conflicts on Air Force women's mental health and functioning. We analyzed data from a 1993 survey of representative stratified samples of 525 Air Force women from the active duty reserve and guard forces. The analyses of the data are guided by the comprehensive model of work–family conflict that has been tested by Frone, Russell, and Cooper (1992) using a large representative community sample. Structural equation modeling analyses provided support for the work–family conflict model. The analyses also provided support for an extension of the model, which included the separate effects of marital and parental roles on mental health. The extended model demonstrated that job and parental stresses had direct effects on work–family conflicts and that job and marital distress and family–work conflict had an independent adverse effect on mental health. Whereas job and parental involvement had a beneficial effect on distress, they had an adverse effect on work–family conflicts. Copyright © 1999 John Wiley & Sons, Ltd.     

Variability of the Ecological and Morphological Characteristics of Field Vole (Microtus agrestis) in the Southern and Middle Urals

Russian Journal of Ecology - The variability of the ecological and morphological characteristics of the field vole was studied on samples collected in its two localities of the Southern Urals and...     

Estimating the Genuine Progress Indicator (GPI) for the State of Rio de Janeiro,Brazil, from 2002 to 2016, as a tool for public policy decision making

Environment, Development and Sustainability - This paper estimates the genuine progress indicator (GPI) for the state of Rio de Janeiro (RJ), Brazil, from 2002 to 2016 as an alternative indicator...     

Plutonium in sheep faeces as an indicator of deposition on vegetation

In order to study the deposition on vegetation of plutonium arising from the testing of nuclear weapons and discharges from nuclear facilities, sheep faeces were collected from the South-west and North of England. The plutonium content of faeces has been shown to be a reproducible and sensitive indicator of deposition on herbage and, with this technique, plutonium discharged from the Sellafield Works of British Nuclear Fuels LImited can be detected 60 km from the site. On moorland pastures the concentration of ^239+240Pu in faeces, expressed as activity per gram of ash, is roughly equal numerically to the deposit of plutonium on 1 m² of vegetation.Some of the plutonium ingested by a grazing sheep is absorbed and the highest concentrations are found in liver. The liver of a sheep grazing on pasture where the ^239+240Pu concentration in faeces was about 2 pCi (74 mBq) g⁻¹ of ash, was found to contain <1% of the Generalised Derived Limit for mutton and offal, and the meat <0·001%.     

High sensitivity neutron activation analysis of environmental and biological standard reference materials

Neutron activation analysis is a sensitive method with unique capabilities for the analysis of environmental and biological samples. Since it is based upon the nuclear properties of the elements, it does not suffer from many of the chemical effects that plaque other methods of analysis. Analyses can be performed either with no chemical treatment of the sample (intrumentally), or with separations of the elements of interest after neutron irradiation (radiochemically). Typical examples of both types of analysis are discussed, and data obtained for a number of environmental and biological SRMs are presented.