EFFECTS OF PULP MILL POLLUTION ON OYSTERS 
183 
the current at Cape Horn was measured by means of drifting floats. The speed of 
the current was 1.6 feet per second. Previous to low slack water, not over 5,400 
linear feet of current passed the cape; the channel has a cross sectional area of 4,000 
square feet; therefore, not over 21,600,000 cubic feet or 496 (approximately 500) acre- 
feet of water could have been lost. Once again we must bear in mind that the water 
which replaced that lost into Pickering Passage was necessarily polluted with sulphite 
waste liquor, due to the discharge of the pulp liquor at the lower end of Hammersley 
Inlet and its constant presence in the vicinity. 
We have, therefore, an indicated loss from Oakland Bay of 50 acre-feet of water per 
tide, or about 700 acre-feet per week for normal tides, and an additional 500 acre- 
feet for one extreme tide, a total of 1,200 acre-feet per week. In order to use even 
numbers we can consider 1,400 acre-feet per week, or 200 acre-feet per day as the maxi- 
mum average loss. Therefore, the volume of water contained in the bay is 130 times 
the amount lost daily. With this figure we can estimate the equilibrium concentra- 
tion of liquor in Oakland Bay following the continued dumping of any amount of 
liquor. (Table 16.) The continued dumping of 75,000 gallons of liquor per day at 
the mill would result in a concentration of 1 part of liquor to 870 of water at equilib- 
rium. Discharge of 280,000 gallons daily at the mill would result in a concentration 
of 1 to 233 in the bay. 
Table 16 . — Accumulation of sulphite waste liquor in Oakland Bay 
Assumed 
daily 
discharge 
Assumed 
daily 
discharge 
Theoret- 
ical accu- 
mulation 
at equi- 
librium 
Equilibri- 
um con- 
centra- 
tion, liquor 
to sea 
water 
Assumed 
daily 
discharge 
Assumed 
daily 
discharge 
Theoret- 
ical accu- 
mulation 
at equi- 
librium 
Equilibri- 
um con- 
centra- 
tion, liquor 
to sea 
water 
Gallons 
50.000 
75. 000 
100, 000 
150, 000 
Acre-feet 
0. 15 
.23 
.31 
.46 
Acre-feet 
19.48 
29. 86 
40.23 
59. 66 
1-1300 
1-870 
1-646 
1-436 
Gallons 
200, 00 
250. 000 
280.000 
320, 000 
Acre-feet 
.61 
.77 
.86 
.98 
Acre-leet 
79. 06 
99.71 
111.32 
126. 77 
1-261 
1-233 
1-205 
The concentration of liquor in the bay at any one time after operations started 
may be calculated by standard mathematical processes: 
If a = the number of acre-feet of liquor discharged at the mill per day, b, the amount 
of water changed per day by tidal action, and V, the total volume of the bay, then 
V-a-b 
V ' 
•( 1 ) 
represents the proportion of original water left at the end of the first day, and 
' V-a-b ' 
( 2 ) 
that left at the end of t days. Since 
/ V—a — b\ a + b\ 
J-V v ) ’ 
therefore the proportion of pulp liquor plus the amount of new water is 
