Judge (1970) found that heavy mineral studies were unsatisfactory as 

 indicators of the direction of longshore transport for beaches between Point 

 Conception and Ventura, California, because of the lack of unique mineral 

 species and the lack of distinct longshore trends which could be used to 

 identify source areas. North of Point Conception, grain size and heavy 

 mineral distribution indicated a net southward movement. Cherry (1965) 

 concluded that the use of heavy minerals as an indicator of the direction of 

 coastal sand movement north of Drakes Bay, California, was generally 

 successful. 



(2) Artificial Tracers . Artificial tracers may be grouped into two 

 general categories: radioactive or nonradioactive. In either case, the 

 tracers represent particles that are placed in an environment selected for 

 study and are used for relatively short-term studies of sediment dispersion. 



While particular experiments employ specific sampling methods and 

 operational characteristics, there are basic elements in all tracing 

 studies. These are (a) selection of a suitable tracer material, (b) tagging 

 the particle, (c) placing the particle in the environment, and (d) detection 

 of the particle. 



Colored glass, brick fragments, and oolitic grains are a few examples of 

 nonradioactive particles that have been used as tracers. The most commonly 

 used stable tracer is made by coating indigenous grains with bright colored 

 paint or flourescent dye (Yasso, 1962; Ingle, 1966; Stuvier and Purpura, 1968; 

 Kidson and Carr, 1962; Teleki, 1966). The dyes make the grains readily 

 distinguishable among large sample quantities, but do not significantly alter 

 the physical properties of the grains. The dyes must be durable enough to 

 withstand short-term abrasion. The use of paints and dyes as tracer materials 

 offers advantages over radioactive methods in that they require less 

 sophisticated equipment to tag and detect the grains, nor do they require 

 licensing or the same degree of safety precautions. However, less information 

 is obtained for the same costs, and generally in a less timely matter. 



When using nonradioactive tracers, samples must be collected and removed 

 from the environment to be analyzed later by physically counting the grains. 

 For fluorescent dyes and paints, the collected samples are viewed under an 

 ultraviolet lamp and the coated grains counted. 



For radioactive tracer methods, the tracer may be radioactive at the time 

 of injection or it may be a stable isotope capable of being detected by 

 activation after sampling. The tracer in the grains may be introduced by a 

 number of methods. Radioactive material has been placed in holes drilled in a 

 large pebble. It has been incorporated in molten glass which, when hardened, 

 is crushed and resized (Sato, Ijima, and Tanaka, 1962; Taney, 1963). Radio- 

 active material has been plated onto the surface of natural sediments 

 (Stephens et al., 1968). Radioactive gas (krypton 85 and xenon 133) has been 

 absorbed into quartz sand (Chleck et al., 1963; Acree et al., 1969). 



In 1966, the Coastal Engineering Research Center, in cooperation with the 

 Atomic Energy Commission, initiated a multiagency program to create a workable 

 radioisotopic sand tracing (RIST) program for use in the littoral zone (Duane 

 and Judge, 1969). Tagging procedures (by surface-plating with gold 198-199), 

 instrumentation, field surveys, and data handling techniques were developed 



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