)0 
or five miles from the outfall. These slicks apparently do not 
disperse nor break up rapidly and the occurrence of high comts 
at great distances from the point of sewage discharge may relate 
to their presence. 
That coliforms are not uniformly distributed in the surface 
waters even within the main sewage field is clearly seen from 
the results of three experiments in which surface samples were 
collected over a small area within the main sewage field. The 
first of these experiments was run at Whites Point were a grid 
of 23 samples covered a square about 1,000 feet on a side located 
roughly 1,000 feet up coast from the outer Whites Point boil. The 
position of the grid overlapped the path of travel of a dye patch 
started at the inner boil some five hours previously. The location 
of the grid is shown in Figure 7; the counts obtained on the grid 
samples are the basis of the contours also shown in Figure 7. 
From the extreme variation in the counts observed (Fig. 7 and 
Fig. 12), one might conclude that the boat was passing in and out 
of the sewage field during the collection of the samples. However, 
calculations based on the chlorinities of the samples showed that 
the per cent sewage varied only 2% fold, from 0.6% to 1.02%, making 
this argument invalid. From the per cent sewage and the MPN of 
the samples, the original of "100% sewage count™ can be calculated 
(Table 8). 
It can be seen that the highest "100% counts" are within the 
range of what might be expected for an unchlorinated primary 
effluent, suggesting that no mechanisms are at work that might 
tend to concentrate coliforms as compared to the liquid phase of 
sewagee On the other hand, the low "100% counts", and there are 
