Spectrophotometer Readings for the Presence of 2,4 D
within the Stony Brook/Millstone Watershed
 
 
Date
Control +
Control -
Site 1
Site 2
Site 3
Site 4
Site 5
7/16/97
11nm
8nm
11nm
7nm
12nm
12nm
10nm
7/17/97
11nm
8nm
21nm
10nm
8nm
14nm
9nm
-
Site 1: Mouth of Stony Brook
Site 2: Carnegie Lake at Princeton University Boathouse off of Washington Street
Site 3: Delaware-Raritan Canal off Washington Street
Site 4: Carnegie Lake tributary off Riverside Drive at Vernon Circle (Residential Area)
Site 5: Millstone River
 
 
 
 
 
 
 Analysis and Conclusion:

        The herbicide 2,4 - D was detected at all five sites within the Stony Brook/Millstone Creek Watershed.  Highest levels of 2,4 - D were found at Site 1 (Stony Creek) and Site 4 (Carnagie Lake tributary).  Investigators feel this is due to regular herbicidal usage within community parks and residential areas.  Lower levels of 2,4 -D detected in Lake Carnegie may be caused by increased sedimentation.  Water flow from Site 1 through Site 2 to Site 5 is evident by the decreasing quantity of 2,4 -D detected.  It is further noted the percolation of 2,4-D through the sandy soil of the Stony Brook/Millstone Creek Watershed occurred even though precipitation was minimal. The recorded levels (>20ppb) of surface water contamination are well above EPA standards(<70ppm) for drinking water.  Since the removal of 2,4-D can be accomplished using charcoal filtration it is recommended that persons not associated with the municipal water system should investigate methods of filtering 2,4-D from their ground water supply.

 
 

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