TOXIC POLLUTION: ORGANIC POLLUTANTS 
by 
Dr. Robert J. Huggett 
Virginia Institute of Marine Sciences 
Dr. Huggett: Thank you, Chris. 
The presentation on toxic pollution will be divided. I will 
talk about the organic pollutants in the Chesapeake Bay, and my 
colleague will talk about inorganics. I will, as will he, 
mention some of the biological impacts resulting from toxics 
that we do know about at this point in time. 
By far, the most abundant organic pollutants in the Chesa¬ 
peake Bay are members of a group of compounds called polynuclear 
aromatic hydrocarbons (PAHs). They are produced by automobiles, 
our home furnaces, and almost any combustion process which uses 
carbonaceous fuels. Some of them are known to be mammalian 
carcinogens, teratogens, and mutagens. And some of them have 
the same effect on fish. 
The concentration of the PAHs in the Bay's bottom sediments 
are greatest near the river mouths in the Southern Bay. In the 
Upper Bay the concentrations tend to increase from the Potomac 
River mouth north to Baltimore Harbor. There is then a decrease 
with another relatively high concentration near the Chesapeake 
and Delaware Canal. At the time of our first sampling (spring 
of 1979), the mouth of the Susquehanna contained low levels of 
PAHs. In the fall of 1979, the Susquehanna had much higher con¬ 
centrations. The first set of samples was taken when the river 
flow was very high. Apparently, everything coming down was 
being flushed out of this area and down into the Bay. Prior to 
and during the fall sampling, there was almost no flow, and what 
was coming over the Connowingo Dam was deposited near the mouth. 
One can pick an individual compound, benzopyrene, perhaps 
the most famous of the PAHs suite, and get the same distribution. 
Basically higher concentrations are near the mouths of our rivers 
and concentrations build up in the Upper Bay. The reason for this 
buildup is likely due to the fact that the sediments in the Upper 
Bay are more fine grained than they are in the Southern Bay. In 
the Upper Bay, there are more silts and clays. Also, there's a 
higher human population in this area. As I mentioned earlier, 
major sources for these PAHs are smokestacks and automobiles. The 
materials enter the atmosphere and are subject to windborne trans¬ 
port. We believe a reason for the higher concentration in the 
Upper Bay is that the contaminated clouds, if you will, come over 
the Bay and the PAHs are rained down. 
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