While not wishing to give short shrift to PCBs (Polychlorinated Biphenyls) which have been found in at least three locations in Elmira/Woolwich; their original sources may or may not be unknown. This is because our authorities routinely cover up information they'd rather not be public information. These locations that I know of are Varnicolor Chemical's Lot 91, their former 62 Union St. address and in the fish and Canagagigue Creek itself.
My understanding is that Uniroyal Chemical introduced Woolwich and Elmira to both Dioxins and DDT through their sloppy and negligent waste disposal practices while producing DDT and Agent Orange . Agent Orange consisted of a mixture of 2,4-D and 2,4,5-T and was used as a defoliant and brush killer not only in Vietnam by the U.S. military but even here in Ontario in the ditches alongside our highways.
DNAPLS merely describe certain chemicals with the following characteristics. They are Dense (heavier than water), Non Aqueous Phase (dissolve poorly & slowly in water) Liquids (i.e. they flow by gravity downhill). Hence they are referred to as Dense Non Aqueous Phase Liquids or DNAPLS. Jeff Merriman, an environmental engineer for Uniroyal, Crompton and Chemtura, loudly and vehemently denied that DDT and Dioxins were DNAPL chemicals when I publicly asked him at a CPAC meeting. Turns out that Jeff did not exactly lie however he sure sprinkled some fairy dust and used smoke and mirrors to muddy things . While DDT and Dioxins are not usually defined as DNAPLS because at room temperatures, completely on their own they are solids perhaps even referred to as crystals; they are NOT liquids. Hence they are not a member of a group of chemicals known as DNAPLS such as chlorobenzene, chlorophenols, trichloroethylene, chloroform, trichloroethane etc.. Here's the rub however. By all scientific interpretations and definitions; DDT and Dioxins once mixed with common solvents (such as chlorobenzene) behave EXACTLY as DNAPLS do ! In fact I would refer to them as the DNAPLS from hell.
They sink through aquifers and even some aquitards here in Elmira. They descend through three aquifers (UA, MU, ML) on their way to the lowest aquitard, the LAT or Lower Aquitard where they may sit and slowly dissolve for decades, generations or even centuries. Worse yet there are a number of locations under Elmira where the LAT is missing hence the Municipal Lower Aquifer (ML) rests directly on top of the Bedrock Aquifer (BR). That is horrible news because the top of the Bedrock is considered "weathered " and is full of small fractures. DNAPL with DDT and Dioxins dissolved within, works its' way into those cracks and fissures. From there it is almost impossible to remove both due to its' depth and to how tightly it is held within the Bedrock matrix. Uniroyal and successors long ago decided that the easiest way to deal with it was not to spend many millions of dollars attempting to remove it but to simply Deny it. Pretend that heavier than water chlorobenzene already in the Municipal Lower Aquifer (ML) both dissolved and as DNAPL was not also in the nearby Bedrock Aquifer. That is a polluter's solution to the problem they caused and is basically free. Our authorities through corruption and likely other means or bribes have permitted it.