Biodegradability of
Organic Chemicals Isolated from Rivers
F. J. LUDZACK, Chemist
M. B. ETTINGER, Chief
Chemistry and Physics Section
U. S. Public Health Service
Robert A. Taft Sanitary Engineering Center
engine
, Ohio
Cincinnati
The studies to be described are selective studies of the biodegradability of
materials recovered and analytically defined as surface water pollutants. One of
the chemicals, o-chloronitrobenzene, was known to travel a long distance in surface water because it had been followed down the Mississippi River from St. Louis
to the Gulf.
Acetophenone, naphthalene, tetralin, ethyl benzene, and BB' -dichlorodiethyl
ether were isolated from the Kanawha River (1) at a site believed to be near their
sources.    Information was sought as a basis for judging possibilities of following
them downstream.
Extended travel in surface water was indicated by our colleagues for phenyl -
ether and tert-butyl benzene. Potassium cyanate persistence was studied on a
short-term basis by Resnick, et al (2); extended observation time was desired.
In general these studies were grouped to give a basis for estimating stream behavior and to relate laboratory results with field observations. Subsequent to this
work, field observations during winter conditions traced dichloroether and certain other tested chemicals down the Kanawha and Ohio Rivers to Cincinnati.
TEST METHODS
The chemicals were added to 5-gal carboys of Ohio River water in concentrations from 19.0 to 25.0 mg/1. Vigorous shaking was used for mixing, but no attempt was made to obtain uniform dispersion of the relatively insoluble materials.
Carbon dioxide production at room temperatures was used as the primary index of
oxidizability with apparatus and technique previously described (3). A phosphate
buffer was added to maintain a pHof7.2± 0.1. Nitrogen analysis, alkalinity,
and pH were checked weekly. Changes in odor characteristics of the undiluted
substrate were noted but threshold odor numbers were not determined. Extracts of
the samples were examined by infrared but disappearance of the test chemical was
not followed on all samples. Data were limited to general characteristics that
could be obtained with a minimum of manipulation time.
One per cent of volume of settled sewage was added weekly to provide nitro -
gen, trace nutrients, and new organisms. Ammonium chloride was added when
nitrogen results were low.
Samples were redosed to check possible acclimation when carbon dioxide results indicated a high degree of oxidation or an extended plateau. One-half of
the contents of the oxidation bottle was siphoned off, including a major proportion
of settled or side-wall solids. The carboy was then refilled with buffered Ohio
River water, and redosed as before. The discarded fraction was used for extraction, microbiological tests, or other analyses.
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