SEWAGE CONTAMINATION OF OYSTER BEDS. 914 
Tas._E I1.—Analysis of water samples collected off Pomham. 
Red colo- 
bps Dextrose | nies on lit- . Other fecal 
Date:and station. fermented.| mus lac- B. coli. bacteria. 
tose agar, | 
February 26, flood tide. 
Station 1, surface tube 4 + + + 
deep tube... + + + 4+ 
2, surface tube + 4 — + 
deep tube... = ae BEN Gps sero sees 
3, surface tube ot + te | loser seeeeicn 
CED MLIRD OS seis cloves ae eect simaie cas sisrcieicheleiasiee + Te attr qvafleetonaleceeeree 
March 2, tide falling. 
Stationel-surfacey Cube se. .'< - oe cicl= = =e cate oso claw ciaievaieisie 4 + eS All| ee eine ee 
CHEE DAUUND C Seta sre see ce ew nism cieraciniaie econ — — a Peet ce eects 
OESSEITTA CORLL DO reson eae nis e close eee e oc oeianeee + (a) aS FEE oe ee ae 
Geepitiibe sacs. .s-cbebe secon ccceececeeersness + + Bai? Mle Srcencisinsae 
By GeVHeNOS ADO “Sa aaa cacocaseansooscaues sonacde + (a) afea  ilepNatstayjeteicteins 
GDS WH Ns 5 Ge asosnonbodsesoesebacusbagansS =e (@) et SSacoeeeaaaa 
March —, tide falling. 
PEMCIOTI Ml VARTA CCNOUDE a= sac op climciele ieee mise steiciels olareie + (a) Sea) es Bieerdien See 
hate UDI De as eee eo aseerad ane alermecoreeaons + (a) SE A aecieeeeee 
Ds SMMC) (AH) Oe Baar pene acsoe Bemmee cate aemrer + + i yy lent monseoers 
(GOrSGI AD eGo oe a soon Soeeeee aamOrOnape pe saesee + _ = a. 
Powe CORDUND Cisne aee ia sicae niete clei mi oletsene asia + + 4+ + 
GLa WON 8s6 on Bose ona sopeeueudessseedassaras aF + tee = 
a Not made. 
The data given in Tables I and IT show clearly that the water of the 
river in the immediate neighborhood of Fields Point and also at Pom- 
ham, 14 miles below this point, is polluted by sewage to a very con- 
siderable extent, since it is possible to isolate B. coli from practically 
every sample collected within this area. This statement seems to be 
trustworthy whether the tide is making upstream or falling, or 
whether the samples are collected when there is a stiff breeze from the 
southerly direction, thus tending to drive an increased amount of 
water up the river, or during a flat calm. 
An attempt to estimate the number of bacteria per cubic centimeter 
in the water about Fields Point was made by inoculating nutrient gel- 
atin plates from two of the samples collected April 10 and keeping 
them three days at room temperature. Four plates were made from 
each sample, and the average count of colonies developing was esti- 
mated as follows: Station 2, surface water, 1,500,000 bacteria per 
cubic centimeter; station 3, surface water, 2,000,000 bacteria per cubic 
centimeter. Thus the quantitative as well as qualitative analysis 
points to high organic pollution of these waters. 
The second series of samples was collected from a section of the 
river from 2 to 25 milesfrom Fields Point. These samples were taken 
at five stations, as follows: Station 1 over the northern part and sta- 
tion 2 at the southern end of the oyster grounds off Sabins Point; 
on the Pawtuxet shore, station 3 in the shallow water covering the 
sand beach west of the Rhode Island Yacht Club house, station 4 off 
the end of the club wharf, and station 5 in shallow water again, from 
the shore near the end of Pawtuxet Neck. Four trips were made to 
the first two of these stations; but one to those on the western shore 
of the river. The result of these analyses is included in Table II. 
