The discharge of any toxic chemical might account for the 
mortality pattern. The Tenneco plant waste discharge is one 
possibility based on circumstances that will be considered here. 
The Tenneco plant became operational in 1959. Esterification 
equipment was acquired in 1965. A process for easte treatment by 
bacterial digestion was installed in 1968. At this time, a dam 
was located across the water flowing from the Tenneco plant. As 
a result, a small pond (Tenneco Pond) was formed with 40 x 10^ m^ 
(10 acres or 4 hectares) of surface area. 
Hurricane Agnes occurred in May of 1972 bringing 16.0 cm of 
rainfall in one day (Palmer 1972) to the plant area which was 
flooded. The contents of a waste collection tank were washed 
out. It was estimated that 50-100 gallons (190-380 L) of organic 
waste liquid were washed out into Morgan Creek and then into the 
Chester River. It is possible that the washed-our chemicals 
could be causally related to the oyster mortality. (It is also 
possible that the effect might be the result of one or more other 
factors, including the continual discharge of unidentified organ¬ 
ic compounds which reside after waste treatment, agricultural 
runoff, a "natural phenomenon," etc.). Various pathways for the 
transport of phthalate esters from the Tenneco plant to the oys¬ 
ter mortality area are now discussed. 
The Upper Bay Survey (Palmer, Schubel, and Cronin 1975) 
makes it clear that sparingly soluble organic compounds are speci¬ 
fically associated with the finely has been established with ob¬ 
servations that the presence of such organic compounds is 
precisely correlated by the octanol-water partitioning model, and 
the adsorption of neutral organic compounds by sediment has been 
strongly correlated to the weight fraction of organic carbon 
(Karicknoff et al. 1979). This finding is consistent with the 
known tendency of humic acid to adsorb such compounds rather 
tenaciously. Schnitzer's work (1972) suggests possibly irrevers¬ 
ible adsorption of phthalate esters by clay soils, although there 
is some controversy on the significance of that finding. Regard¬ 
less, the known distribution of neutral organic compounds in the 
marine ecosystem includes biomagnification by life in the marine 
environment, and a corresponding adsorptive magnification effect 
into the natural clay-organic complexes present in marine sedi¬ 
ments. Since dioctylphthalate (DOP) was observed early in the 
study as a conspicuous and major component in Tenneco Pond sedi¬ 
ment, it is important to show whether or how that material would 
be transported from the Tenneco factory to the clay-rich sedi¬ 
ments in the Chester River. These latter sediments according to 
the Chester River Report (Palmer 1972) occupy the deeper terrace 
portions of the river floor and the transitional channels between 
nearshore and the main river channel. Taken in perspective, these 
are the most critical samples where investigation can be focused. 
Such sediments are widely recognized for their ability to adsorb 
compounds for long periods of time, geological epoch in many 
42 
