SEWAGE CONTAMINATION OF OYSTER BEDS. pale’ 
TaBLe VII.— Quantitative analysis of water samples collected in Providence River. 
| eon per || B. coli per 
Rees cubic centi- Penns lcubic centi- 
Locality. aaron | . Locality. metennn 
river water. | river water. 
= — SSeS I} as 2 —— 2 
Fields Point: | Bullock Neck: 
Station 3, surface tube...........- 96 | Station 7, surface tube ..-.-.....- 2 
deepitubesoss-eerccscee e. 3@) deep tubes se seonen: 6 
OW SURIACe mb e ses yaeteni- 450 | 4° suriaceitubex. se. cces 3 
deep tube -22.2:..-.:-.: 500 | deepitibes--ce sce eee 2 
1OMsurtacestupeseesssscesae 200 | Hasuriacewiubemeasececces 0 
Geepitu beeen cae sec nels 50 | deep tuned sjscea a. ci- = - 0 
Pomham: $5 surface tubes. 2 2222 .-1-- 1 
Station 1, surface tube.........-.- 75 | deepitubese ence eee cece i) 
deep tube’... =< 55.5020 14 || Rocky Point: 
Ss SULIACe GUDES acco ee ees | Station 1, surface tube .........-. 0 
Geeptubesssecemaciec cess 14 deepitubeswneuseen aces. 0 
Bullock Neck: QMsuriaceuuDes casncecees 0 
Station 2, surface tube............ 24 deep tubess-scaseeece=- 0 
deepitubenesecisss svc. 0 3 SULIBCE TUDE ..-cie c= 0 
6, surface tube.........-.- 20 deepitubesssss2 seen ne 0 
Geen mtb er aeieteisieeere 6) 
1} 
Though the results obtained by this method are by no means as accu- 
rate as might be desired, nevertheless they indicate, as has already been 
proved, a gradual decrease in the amount of pollution in the river as 
it reaches down toward the headwaters of Narragansett Bay. 
The data obtained by the analysis of the foregoing water samples may 
be summed up as follows: The Providence River above Conimicut 
Point is a sewage-polluted body of water, but below this point the 
water of the river and the headwaters of Narragansett Bay are free 
from contamination. The presence of sewage may also be detected in 
Warren River. That section of Mount Hope Bay in which the oyster 
ground is situated appears to be entirely free from pollution. 
The distribution of sewage in Rhode Isiand waters, as indicated by 
the presence of 2. coli in water samples, may- be readily traced from 
the principal sources of contamination. As has already been stated, 
these are three in number—the Providence sewage, Warren mill waste, 
and the sewage from Fall River. Referring once more to the map on 
page 203, it will be observed that equidistant concentric lines radiating 
from three different centers have been drawn across the areas repre- 
senting the Providence River, the Warren River, and Mount Hope 
Bay. The space between these lines represents 1 mile actual distance. 
The series of ares which divide the Providence River into sectors are 
drawn using the point at which the outlet of the Fields Point sewer is 
represented as a center, and with their aid the distribution of sewage 
in the river may be traced as follows: 
The water of the river in the sector included within the are of the 
first circle, at no point more than 1 mile distant from Fields Point, is 
highly polluted. Samples taken from this portion of the river contain 
BZ. coli and other fecal bacteria under all conditions of tide and weather. 
These organisms are also found in the majority of samples collected 
2 miles below the sewer outlet. About 74 per cent of these samples 
contained B. coli. 
