UPSTREAM OF BENEDICT BRIDGE DOWNSTREAM OF BENEDICT BRIDGE 
O O 
OJ — 
I- 
•ID 6rV ‘d-_£od 
ro cvj — O rO (\j — 
O O 
CO 
o 
o 
O O o o 
in 
ro OJ — 
jd 61V 
4 d-_gOd 
76 
Figure 4. Concentrations of orthophosphate-P in surface waters of the Patuxent 
River upstream and downstream of Benedict Bridge versus time of year. 
