Social organization of female sperm whales and their offspring: constant companions and casual acquaintances

Summary Associations among female sperm whales, Physeter macrocephalus, and their dependent offspring, off the Galapagos Islands were studied between 1985 and 1989. The whales were found in groups containing about 23 individuals, with each individual having approximately 12 constant (over years) companions. These permanent units associated with one another for periods of 6.5 days, although the rate and duration of these associations seemed to vary between years, perhaps because of differences in the food supply. The principal function of the closed units may be care of the offspring, and units in the same general area may derive benefit from feeding in a coordinated manner.Offprint requests to: H. Whitehead     

Photocatalytic soot degradation under UV and visible light

Environmental Science and Pollution Research - Particulate matter is one of the most persistent global air pollutants that is causing health problems, climate disturbance and building...     

Analysis of coupled model uncertainties in source-to-dose modeling of human exposures to ambient air pollution: A PM2.5 case study

Quantitative assessment of human exposures and health effects due to air pollution involve detailed characterization of impacts of air quality on exposure and dose. A key challenge is to integrate these three components on a consistent spatial and temporal basis taking into account linkages and feedbacks. The current state-of-practice for such assessments is to exercise emission, meteorology, air quality, exposure, and dose models separately, and to link them together by using the output of one model as input to the subsequent downstream model. Quantification of variability and uncertainty has been an important topic in the exposure assessment community for a number of years. Variability refers to differences in the value of a quantity (e.g., exposure) over time, space, or among individuals. Uncertainty refers to lack of knowledge regarding the true value of a quantity. An emerging challenge is how to quantify variability and uncertainty in integrated assessments over the source-to-dose continuum by considering contributions from individual as well as linked components. For a case study of fine particulate matter (PM_2.5) in North Carolina during July 2002, we characterize variability and uncertainty associated with each of the individual concentration, exposure and dose models that are linked, and use a conceptual framework to quantify and evaluate the implications of coupled model uncertainties. We find that the resulting overall uncertainties due to combined effects of both variability and uncertainty are smaller (usually by a factor of 3–4) than the crudely multiplied model-specific overall uncertainty ratios. Future research will need to examine the impact of potential dependencies among the model components by conducting a truly coupled modeling analysis.     

Equivalent leak definitions for Smart LDAR (leak detection and repair) when using optical imaging technology

Controlling fugitive emissions from leaks in petrochemical industry process equipment now requires periodic monitoring of valves, flanges, pumps etc., typically on a quarterly basis. Previous studies have shown that over 90% of the reducible emissions come from approximately 0.1% of the components, i.e. the large leakers. A new, and more cost-effective approach for controlling these large leakers would entail more frequent monitoring of process equipment, allowing for the detection and repair of the highly leaking components that contribute the most to emissions. This approach has been called "Smart LDAR." New optical imaging instruments, which significantly reduce monitoring costs, are now available to implement such an alternative work practice. This work describes the determination of the leak detection sensitivity (equivalency threshold) that an optical imaging instrument must achieve to ensure that it will provide at least the equivalent emission control of the current leak detection and repair practice. Equivalency thresholds were developed for various monitoring intervals. The U.S. Environment Protection Agency's Monte Carlo simulation approach was used to perform the analysis and to demonstrate that optical imaging, which is capable of identifying all of the largest leakers, can provide better control of fugitive emissions.     

Book reviews

ENGLISH STRUCTURE PLANNING

Eds: D. T. Cross and M. R. Bristow

Pion Ltd., London, 1983. £16.00.

AN INTRODUCTION TO URBAN RENEWAL

Michael S. Gibson and Michael J. Longstaff

London: Hutchinson, 1982. 384 pp.

INTEGRATED URBAN MODELS

S. H. Putman

Pion Ltd., 1983, 332 pp.

EXPLANATION PREDICTION AND PLANNING: THE LOWRY MODEL

M. T. Webber

Pion Ltd., London, 1984, 214 pp.

THE GOVERNMENT AND ADMINISTRATION OF METROPOLITAN AREAS IN WESTERN DEMOCRACIES

Alan Norton

Institute of Local Government Studies, University of Birmingham, 1983, 57 pp.

THE MANAGEMENT OF SEMI‐NATURAL WOODLAND

County Planning Officers’ Society (available from Hampshire County Planning Dept., price £2.00).     

The distribution and transformations of iodine in the environment

Iodine in the atmosphere is derived largely from seawater. It is probable that the biological production of methyl iodide is important in this transfer. Subsequent photolytic dissociation and oxidation of the methyl iodide, together with other inputs, with partial sorption of the products by aerosols, results in the atmospheric iodine being distributed between various gaseous and particulate forms. Atmospheric iodine is the major source of the iodine in soils, and the process of enrichment continues throughout soil formation and development until ultimately an equilibrium concentration is attained. The retention of iodine in soils is due mainly to the organic matter and hydrous oxides of iron and aluminum. In humid areas, only small proportions of the total soil iodine are soluble in water or available for uptake by plants. The atmosphere is also a direct source of iodine for plants, and in some situations may be more important than the soil. Iodine may be lost from soils by leaching, volatilization, and removal in crops, but the magnitude of these processes is difficult to assess. However, the amounts of iodine reported in groundwaters, and in rivers and lakes remote from human activity, suggest that some leaching of iodine is widespread. Increased amounts of iodine occur in rivers receiving effluent from sewage works. Milk and milk products are now major dietary sources of iodine because their content is often increased by concentrate feedingstuffs supplemented with iodine and/or by the use in dairies of iodophor detergents and sterilants.