SOURCES OF CONTAMINATION IN PUGET SOUND 
Diane E. Strayer and Spyros P. Pavlou 
Envirosphere Company 
A Division of Ebasco Services Incorporated 
Bellevue, Washington 
Introduction 
Effective management decisions concerning the control of toxic 
chemicals which enter Puget Sound require the identification of the 
contributing sources and the quantification of the total input 
associated with these sources, (i.e., the contaminant mass loading). 
Quantitative knowledge of chemical contaminant inputs into the Sound 
coupled with a good understanding of the transport and or fate of these 
materials in the receiving waters of the Sound is critical to: 1) the 
estimation of the net toxic chemical loading that remains following 
inputs, losses via sedimentation or degradation and outflows (i.e., the 
chemical mass balance); 2) the determination of the relationship 
between contaminant input, environmental distribution and effects; and 
3) establishment of a realistic control, compliance, and enforcement 
strategy. 
The total contaminant loading associated with an input source is 
calculated from the contaminant concentration in the discharge and the 
total flow or material volume of the source entering into Puget Sound. 
Although this type of calculation may appear to be straight forward, it 
is in fact quite difficult to characterize the concentration of all 
toxicants in all source discharges to Puget Sound. As an example, 
consider that there are hundreds of chemicals that could potentially be 
discharged from over 350 point sources that discharge either directly 
into Puget Sound or to rivers draining to the Sound. As discussed 
below, other sources of toxicants to Puget Sound are equally difficult 
to characterize. 
The reader is cautioned to remember that the total loadings emphasize 
the relative contribution of different input sources but do not 
indicate the potential for impacts associated with a source. In other 
words, a small loading may be associated with high concentrations that 
could cause localized impacts. Conversely, large contaminant mass 
inputs are not necessarily detrimental when they are associated with a 
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