NSWC/WOL/TR 76-161 



A good system would consist of an array or line of samplers, 

 downstream from the explosion, controlled by wire in such a way 

 as to collect contaminated water as it flows past. Another 

 approach would be to traverse the surface pool with electronic 

 probes and recording eguipment, such as that developed for 

 monitoring industrial water flows. An alternate procedure 

 would be to measure the concentration of a fluorescent dye 

 tracer, which is directly correlated with the concentration of 

 explosion products. These methods are generally not practical 

 for routine tests because of the cost of equipment and the level 

 of effort required. 



A simpler, but satisfactory approach is to dip water samples 

 from the surface pool by hand after the explosion. One-liter 

 polyethylene containers are a good choice. However, certain 

 precautions are needed. First, a dye tracer should be placed in 

 the water directly above the charge. Also, prior to the test, a 

 background sample should be acquired in the vicinity of the charge. 

 A measurement of current speed and direction is recommended. 



After the test, a minimum of five samples should be 

 collected at the center of the pool at 20- or 30- second intervals. 

 Times should be recorded. A photographic record can be very helpful. 

 As the contents of the pool may not be thoroughly mixed and 

 uniformly distributed at early times, the measured concentrations 

 may be erratic, but they should be adequate to indicate if a 

 problem exists. 



The preparation of samples should be discussed in advance with 

 the chemist who will conduct the analysis. For example, it may 

 be necessary to add nitric acid to the sample to reduce the pH level 

 to 2.0 for satisfactory storage without change. Samplinq procedures 

 have been discussed thoroughly in a publication by Lai. 1 



In most cases, precise measurements and expensive procedures 

 are not needed. This is particularly true if the measured 

 concentrations are low and are well below hazardous levels. Equip- 

 ment developed for field analysis of water samples may be adequate 

 in this case. However, if a product is of special concern 

 because of a potential toxic effect, it will then be necessary to 

 obtain a large number of samples and to use whatever means are 

 needed to obtain accurate data. 



10. Lai, M. G., 1975: A Chemical Monitoring Program of the Explosion 

 Products in Underwater Explosion Tests, NSWC/WOL/TR 75-35, 

 Naval Surface Weapons Center, Silver Spring, Maryland 



10 



