Recent IAEA intercomparison on the determination of trace elements in simulated air filters

Results of a recent intercomparison on the determination of trace elements in simulated air filter samples are reported. A large scatter of results is obtained for some elements and systematic differences between laboratories are observed. The performance of different methods, in particular neutron activation analysis and atomic absorption spectrophotometry, used by the various laboratories is discussed (air filter analysis; intercomparison; trace elements; control charts).     

Interaction of temperature and salinity on oxygen consumption of the estuarine crab Panopeus herbstii

Marine Biology - The combined effects of temperature and salinity on the rate of oxygen consuption by the estuarine crab Panopeus herbstii Milne-Edwards (Crustacea: Decapoda: Xanthidae) were...     

Intertemporal and intergenerational Pareto efficiency

Efficiency conditions are derived for both private and public goods which provide benefits over time. In deriving these conditions, the paper extends the notion of efficiency to an intertemporal Pareto-optimal concept requiring the maximization of the ith individual's utility at a point of time subject to the constancy of his utility in all future periods and that of all other individuals during the relevant time span. By permitting births and deaths, a generalization of the basic model recasts the analysis into an intergenerational setting. Additional extensions involve learning by doing and perpetual public goods. The paper concludes that several of the conventional practices in public expenditure analysis do not conform to our definition of intertemporal Pareto efficiency.     

Oil/Suspended Particulate Material Interactions and Sedimentation

The interactions of physically dispersed oil droplets with suspended particulate material (SPM) can be important for the transport of bulk quantities of spilled crude oil and polycyclic aromatic hydrocarbons (PAH) to subtidal sediments. The literature regarding oil/SPM interactions is reviewed, and results from whole-oil droplet/SPM interaction kinetics and pure-component (Prudhoe Bay crude oil distillate cut) equilibrium partitioning experiments are presented. The effects of oil type, SPM characteristics, and salinity on the interaction rates are examined, and the importance of whole-oil droplet/SPM interactions on particle agglomeration and settling behavior are discussed. Whole-oil droplet/SPM interactions are retarded as oil droplet dispersion into the water column is inhibited by oil viscosity increases due to evaporation weathering and water-in-oil emulsification. Compared to whole oil droplet/SPM interactions, dissolved-component/SPM adsorption is not as significant for transport of individual components to sediments. The information presented in this paper can be used to augment computer-based models designed to predict oil-spill trajectories, oil-weathering behavior, and spilled oil impacts to the marine environment.