USGS materials

Identification of sources of analytical bias in method development and method validation is another very important application of reference materials in geochemical laboratories. USGS applied simplex optimization in establishing the best measurement conditions when the ICP-AES method was introduced as a substitute for AAS in the rapid rock procedure for major oxide determinations (Leary et al. 1982). The optimized measurement parameters were then validated by analyzing a number of USGS rock reference samples for which reference values had been established first by classical analyses. Similar optimization of an ICP-AES procedure for a number of trace elements was validated by the analysis of U S G S manganese nodule P-i (Montaser et al. 1984). 

The surface layer (0-5 cm depth), A, B and C soil horizons were sampled where available. The B horizon was not sampled by the USGS. Due to the thin and relatively discontinuous nature of the A horizon at many of the Canadian sites and difficulty in distinguishing between H- and A-horizon material, some of the A-horizon samples have organic content greater then the >17% upper pedological limit. Reclassification based on the organic content and other factors will be done... 

The matrices and sources of the sediments listed in Table 4.2 are sometimes unclear. Those that are known are highly weighted toward clastic (quartz- and aluminosilicate-rich) marine sediments from coastal environments. Some of these reference materials, such as MESS-3 (NRC-Canada), MAG-1 (USGS) and the Arabian Sea and Pacific Ocean samples (IAEA 315, and 368), could provide excellent examples of clastic marine sediment representing the main repositories of organic matter in the ocean (Hedges and Keil, 1995). The listed materials fail to include both open-ocean opal and carbonate oozes, as well as pelagic red clays. 

Selected material distributed by the U.S. Geological Survey (USGS) ... 

For most of the laboratories, additional quality control (QC) samples were inserted within each batch of samples sent. These included sample site duplicates, sample splits for analytical duplicates, a suite of USGS-prepared standard reference materials (SRMs), and... 

The Minerals, Metals Sc Materials Society http //www.tms.oig/Tables USGS Minerals Information Zinc http //minerals.usgs.gov/minerals/pubS com-modity/zinc/... 

At the moment, there are no programs or processes in place for recycling the materials that cell phones are made from. According to the USGS, less than one percent of the cell phones thrown away every year are actually recycled in some way. Like many of the parts in obsolete electronics, no one is quite sure what to do with them or howto make a profit in recycling.17... 

USGS. 1984. United States Geological Survey. Element concentrations in soils and other surficial materials of the conterminous United States. USGS Professional Paper 1270. Washington, DC U.S. Government Printing Office. 

Sample Preparation. Copper samples weighing 100 mg were cut from larger samples using a carbide-tipped drill. These samples were cleaned in reagent-grade HCl (IN) and rinsed in triple distilled water to remove surface contaminants. Sample material was placed in polyethylene vials and thermally sealed. Four USGS standards— numbers AGV-1, BRC-1, DTS-1 and W-1— were weighed and placed in similar vials to be used as absolute standards. 

Substitutes for asbestos are constantly being developed (EPA 19891). Nonasbestos friction materials are currently being used in disc brake pads, and substitutes have been developed for drum brake linings. Substitutes include fibers made of carbon, steel, cellulose, ceramics, glass, and wollastonite and organic fibers made from aramid, polyethylene, polypropylene, and polytetrafluoroethylene (USGS 2000). No single substitute was as versatile and as cost effective as asbestos. 

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