Particles inorganics, measurement

The association between mean SQG quotients and toxic effects measured in the test batteries were not as clear for sites that yielded moderate SED-TOX scores. Indeed, mean SQG quotients ranged from 0.21 to 76.1 at these sites, indicating a wide range of contamination levels in the moderately toxic sediments. A variety of scenarios may explain this lack of correspondence for sediments falling into the moderate class of hazard potential, for example (1) toxicity may have occurred in sediments with low mean SQG quotients due to the potential effects of unmeasured contaminants or potentially toxic substances such as ammonia, butyl tin, and sulphur, which are not accounted for with SQGs (2) some contaminants may not have been present in bio-available forms (e.g. complexation with sediment particles, inorganic... 

Airborne particulate matter, which includes dust, dirt, soot, smoke, and liquid droplets emitted into the air, is small enough to be suspended in the atmosphere. Airborne particulate matter may be a complex mixture of organic and inorganic substances. They can be characterized by their physical attributes, which influence their transport and deposition, and their chemical composition, which influences their effect on health. The physical attributes of airborne particulates include mass concentration and size distribution. Ambient levels of mass concentration are measured in micrograms per cubic meter (mg/m ) size attributes are usually measured in aerodynamic diameter. Particulate matter (PM) exceeding 2.5 microns (/i) in aerodynamic diameter is generally defined as coarse particles, while particles smaller than 2.5 mm (PMj,) are called fine particles. 

The transfer of P from the continents to the ocean is separated into two distinct pathways. The flux of reactive P (F25) is estimated via measurements of dissolved organic and inorganic P in rivers. A small correction (33% after Kaul and Froelich, 1984) is added to the measured values to account for P released from particles within the estuaries. This P is transported directly to the surface ocean and is... 

Dynamic SIMS is used for depth profile analysis of mainly inorganic samples. The objective is to measure the distribution of a certain compound as a function of depth. At best the resolution in this direction is < 1 nm, that is, considerably better than the lateral resolution. Depth profiling of semiconductors is used, for example, to monitor trace level elements or to measure the sharpness of the interface between two layers of different composition. For glass it is of interest to investigate slow processes such as corrosion, and small particle analyses include environmental samples contaminated by radioisotopes and isotope characterization in extraterrestrial dust. 

The internal surface area of a porous inorganic membrane is often significantly affected by the heat treatment temperature. Leenaars, Keizer and Burggraaf (1984) have shown that, even if the crystallite size of the membrane precursor particles remains essentially the same (from the X-ray line-broadening measurements), the surfaee area of a transition-phase alumina membrane decreases with increasing calcination temperature. Con-... 

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