Vol. 16—1962 - NorthEastern Weed Science Society

461
TABLE!
Chemical Water QuaU1?::rof Rockawa::F:PaiPkLake (a)
Analyses
pH
Total Alkalinity
Total Hardness
Color
Chlorine Demand(c)
Biochemical Oxygen Demand(d)
Temperature OF
Dissolved Oxygen
Threshold Odor Number
2,4-DCP
Phenol
2,4-D
9.4
4?5 mg/l as cac0 3
54.5 mg/l as CaC03
20 color units
0.40 mg/l as C1 2
3.5 ms71as 02
73 .
119.5 %saturation
2
0.0
9.0 usll as phenol
8.0 ug!l as 2,4-D
(a) sample taken 6/27/61 and analyzed 6/28/61
(b) average of four samples
(c) contact time = 15 min., chlorine residual (OT)= 0.1 mg/l
(d) 5-day, 200C, B.O.D.
The ~,4-DCP exhibited the same patternpf' occurrence and
persistence as2,4-D in Table II, but at lel~er. concentrations'.
There appeared to be a slight increase of 2t~-PCP to the 10-11
ug/l range after 70' days •. A spot check f'orf,l2,4--DCP was made at
132 days where the concentration was observe~ to be 13 ug/l. A
very low level,. 5.0-15.0 ug/l, of tlbackgrol.U1dl'phenols were
observed.'
Discussion
The use of 2,4-D as an aquatic herbic1~,~ releases 2,4­
dichloropneno1 as an impurity 'from the CO~.OOlia1 formulation.
A oaloulated oonoentration o'f' 4.36 ug/l 2,4~ in the lake
would have resulted from the g:r-anules of 2,!tt.:Dused in this.
study. The possibility also exists that th;B ~h10rinated
phenol would be released asan'intermediater;biologloal
degradation produot of 2,4-D •. There is s o~ eVjidence to
support this statement from a preliminary report on the
effect of some aquatic herbic~des on water Cjua1ity (6) and
f'rom a study of' 2,4-D degradation
, .. by so11 rtLt;croorganisms (5).