Stable isotope mass spectrometry in childhood lead poisoning

In order to better understand the relative importance of various sources of lead in childhood lead poisoning, high-precision, isotoperatio, solid-source-mass spectrometry of microgram-sized lead samples was applied to three hospitalized cases in Boston, ranging in age from 1.5 to 14 yr, that had blood-lead levels of 0.7–1.2 μg/g. The lead isotopes in the ambient Boston environment (air, soil, and dust) were also measured. In each case, the isotopic composition (IC) of the child's blood lead was identical with the IC of lead paint taken from the child's residence at a site accessible to the child. Fecal lead samples were also identical to that particular paint. Soil lead IC did not always match the IC of local paints. Paint samples vary widely in their IC's (206/204=17.5–19.4, about 200 times analytical reliability). Dust in homes that never had lead paint contained lead that resembled lead in urban soils. Dust lead IC did not necessarily have the same IC as current automobile lead emissions, but appeared to reflect the long-term accumulation of several sources of urban lead fallout. Limitations and implications of this data are discussed.     

Germination and emergence of soybean under crusted soil conditions

Summary The fluctuations of ODR, moisture content in the crust and the soil beneath the crust and crust strength during emergence period have been presented. The limiting factors of the seed environment under crusted soil conditions have been described and identified. In the early part of the emergence period ODR and in the later part crust strength were the limiting factors. The emergence characteristics of the 12 soybean varieties of varying seed sizes were analysed in detail. The small seeded varieties (Type-1 and Type-49) were less susceptible to the effects of increasing crust strength and maintained distinct emergence advantage over the large seeded varieties. Since the large seeded varieties confronted the hard crust barriers for a longer period of time, their seedling mortality was more than 50 per cent as compared to around 30 per cent in case of small seeded ones.     

The international politics of national parks

National parks are the keystone institutions of environmental conservation. Because national parks make certain lands part of the state itself, international agencies and nongovernmental organizations that promote national parks propose, in effect, to alter the state, as well as the local economy and state relations with social groups. Has international political pressure caused states to create national parks? I consider whether countries highly involved in international politics have the largest proportions of land in national parks. I conclude that many states create minimal park systems as symbolic gestures to the international community. Field researchers may find it easier to explain the success or failure of parks if they identity why state officials decide that adopting international conservation norms will enhance state authority over people and state sovereignty over land.     

Towards a biological basis for predicting nutrient partitioning: the dairy cow as an example

Prediction of nutrient partitioning is a long-standing problem of animal nutrition that has still not been solved. Another substantial problem for nutritional science is how to incorporate genetic differences into nutritional models. These two problems are linked as their biological basis lies in the relative priorities of different life functions (growth, reproduction, health, etc.) and how they change both through time and in response to genetic selection. This paper presents recent developments in describing this biological basis and evidence in support of the concepts involved as they relate to nutrient partitioning. There is ample evidence that at different stages of the reproductive cycle various metabolic pathways, such as lipolysis and lipogenesis, are up or down regulated. The net result of such changes is that nutrients are channelled to differing extents to different organs, life functions and end-products. This occurs not as a homeostatic function of changing nutritional environment but rather as a homeorhetic function caused by the changing expression of genes for processes such as milk production through time. In other words, the animal has genetic drives and there is an aspect of nutrient partitioning that is genetically driven. Evidence for genetic drives other than milk production is available and is discussed. Genetic drives for other life functions than just milk imply that nutrient partitioning will change through lactation and according to genotype - i.e. it cannot be predicted from feed properties alone. Progress in describing genetic drives and homeorhetic controls is reviewed. There is currently a lack of good genetic measures of physiological parameters. The unprecedented level of detail and amounts of data generated by the advent of microarray biotechnology and the fields of genomics, proteomics, etc. should in the long-term provide the necessary information to make the link between genetic drives and metabolism. However, gene expression, protein synthesis etc, have all been shown to be environmentally sensitive. Thus, a major challenge in realising the potential afforded by this new technology is to be able to be able to distinguish genetically driven and environmentally driven effects on expression. To do this we need a better understanding of the basis for the interactions between genotypes and environments. The biological limitations of traditional evaluation of genotype × environment interactions and plasticity are discussed and the benefits of considering these in terms of trade-offs between life functions is put forward. Trade-offs place partitioning explicitly at the centre of the resource allocation problem and allow consideration of the effects of management and selection on multiple traits and on nutrient partitioning.     

Environment and virulence factors of Vibrio cholerae strains isolated in Argentina

AIMS: To determine the presence of Vibrio cholerae in different areas of Argentina in three sample types, to determine the composition of planktonic communities in areas at which this pathogen was detected and to characterize the virulence properties and antimicrobial resistance of the recovered environmental isolates. METHODS AND RESULTS: Water and plankton samples were collected in marine, brackish and freshwater environments. Vibrio cholerae non-O1, non-O139 was isolated in 36.1% of the samples analysed. The micro-organism was detected in freshwater but not in marine or brackish samples. No relationship was found between isolation of V. cholerae and presence of any species of plankton. All the isolates presented very similar virulence profiles by PCR, lacking ctxA and tcpA El Tor and containing hlyA (98.7%), rtxA (99.0%), toxR (98.7%) and stn-sto (1.9%). Resistance to ampicillin was found in both Tucumán (21%) and Buenos Aires isolates (45%). CONCLUSIONS: We identified two geographic areas in Argentina where V. cholerae was present: freshwaters of the rivers from Tucumán and the Río de la Plata. SIGNIFICANCE AND IMPACT OF THE STUDY: The identification of V. cholerae strains in the environment, carrying both virulence factors and resistance to antimicrobial agents, highlight the need for a continuous and active surveillance of this pathogen.     

Application of a Multi-Criteria Decision-Making Approach for Ranking Environmental Risks Caused by Petrochemical Industries: A Case Study of a Sodium Carbonate Production Unit

The occurrence of accidents in petrochemical industries that cause environmental catastrophes has persuaded experts to use risk-oriented approaches. The approach is to rank the key elements of risk assessment by which the priority of each risk is specified compared to the other ones. The present study was performed to test the applicability of a multi-criteria decision-making approach for prioritizing environmental risks of a petrochemical complex in southwestern Iran. Accordingly, all risky activities of the Sodium Carbonate Production Unit (SCPU) were identified initially. Afterward, the relevant environmental components affected by the risky activities were specified. According to the specification, the most significant risks were shortlisted using experts’ judgment based on three criteria: “impact intensity,” “occurrence probability,” and the “extent of contamination dispersion in the environment.” The shortlisted environmental risks were then prioritized by the Method “Elimination et Choice Translating Reality (Elimination and Choice Expressing Reality)” abbreviated as ELECTRE. Based on the obtained results, “decreased air quality” and “manpower health threatening” are the top-priority risks while “poor quality of groundwater” was identified as the least priority risk. In a general conclusion, a multi-criteria decision-making approach is quite useful for assessing environmental risks of petrochemical industries.     

Genomic regions involved in productivity of two interspecific poplar families in Europe. 1. Stem height, circumference and volume

Interspecific hybrids of Populus species are known for their superior growth. In this study, we examined the effect of the genetic background and contrasting environmental conditions on growth and searched for quantitative trait loci (QTL) affecting growth traits. To this end, two hybrid poplar families resulting from controlled crosses, Populus deltoides ‘S9-2’ × P. nigra ‘Ghoy’ (D × N, 180 F₁) and P. deltoides ‘S9-2’ × P. trichocarpa ‘V24’ (D × T, 182 F₁), were grown at two contrasting sites, Northern Italy and Central France. At the end of the second growing season, tree dimensions (stem height, circumference, and volume) were assessed. The performances of both families significantly differed within and between sites. Tree volume was significantly larger at the Italian site as compared to the French site. Genotype by environment interactions were significant but low for both families and for all growth traits. Tight correlations among the individual growth traits indicated that there may be a common genetic mechanism with pleiotropic effects on these growth traits. In line with previous studies, linkage groups I, VII, IX, X, XVI, XVII, and XIX appeared to have genomic regions with the largest effects on growth traits. This study revealed that (1) both families have high potential for selection of superior poplar hybrids due to the pronounced heterosis (hybrid vigor) and the large genetic variability in terms of growth and (2) the choice of site is crucial for poplar cultivation. Dillen and Storme contributed equally to the work. An erratum to this article can be found at