47 
In contrast to what was found in the other two locations, 
only a few of the sediment samples collected in Santa Monica 
Bay showed the presence of coliforms, and in these samples the 
numbers were low. This is what one would expect considering 
that essentially all the effluent discharged in the area is 
chlorinated. However, a comparison of Figure 11 with Figure 15 
of the May 1 report shows that in areas where positive samples 
had been obtained previously, negative ones were found on the 
last survey. The only reasonable explanation for this situation 
is that the coliform fieid in this area is either transitory 
timewise because of only sporadic discharge of large coliform 
populations, or else is very unevenly distributed. 
In examining the samples taken from the Santa Monica Bay 
area on the last survey trip, it was found that a large number 
of positive lactose broth tubes failed to confirm on EMB agar. 
An effort was made to determine the cause of these "false posi- 
tive" tubes. Although the work could not be completed because 
of lack of time, it was found that at least part of these faise 
positives were due to lactose fermenting aerobic and anaerobic 
spore formers. More important, it was found that a high per cent 
of the positive lactose tubes that did not confirm on EMB gave 
positive results when transferred to brilliant green bile broth. 
Further examination showed that these positive brilliant green 
tubes did not contain coliforms. Although these findings do 
not bear directly on the question at hand, they certainly indi- 
cate that the use of brilliant green bile medium for confirmation 
test should not be considered in any project dealing with marine 
sediments. 
