SECTION 4 
EVALUATION OF CHESTER RIVER OYSTER MORTALITY BIOTOXICITY 
METHODS AND MATERIALS 
Possible Sources of Toxicants 
The Chester River has a typical estuarine portion with widely 
varying temperature and salinity regimes. All of the possible 
sources of toxicants that were examined have their waste mate¬ 
rials entering the river in its tidal portion. These possible 
sources dump materials of widely differing nature. The Chester- 
town sewage plant discharges chlorinated and treated domestic 
sewage. The Campbell's Soup factory sprays its effluent, which 
are wastewaters from preparing chicken, over percolation fields 
and each leached water discharge is chlorinated before it enters 
into Morgan Creek. Tenneco does not discharge any effluent that 
can be made more acceptable by chlorination, as its effluent is 
resultant from manufacture of plasticizers. Instead of chlori¬ 
nating, the factory discharges into a leaching pond at one end 
with a stand pipe overflow on the far end. The volume of ef¬ 
fluent at the time of the study was a small volume compared to 
both the sewage plant and Campbell's Soup plant. 
The proposal called for two separate but related studies: 
(1) a field study on mortality and growth of oysters in the 
Chester River, and (2) a field study to detect possible toxic 
effects on test animals by the effluents of the three plants 
discharging into the Chester River basin. 
Oyster Studies-- 
The oyster portion of the study was conducted in the portion 
of the river from just below Chestertown to just above Kent 
Narrows, which is near the mouth. There were 10 stations in the 
Chester River from 15 May 1978 until 18 September 1978. Fifteen 
trays, each containing 96 oysters, were monitored for mortality. 
Qualitative information on oyster communities' associated orga¬ 
nisms were also recorded. 
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