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A visiting musician recently asked about the "beautiful lake" she passed on her way into Syracuse. "Oh," I replied, hoping there would be no further questions, "that would be Onondaga Lake." But she pressed on. "Do a lot of people go fishing and boating on it?" I was torn-should I maintain the illusion, or reveal the lake's status as among the most polluted in North America?
Between 1884 and 1986, Solvay Process, which became Allied Chemical (now merged with Honeywell), produced vast quantities of soda ash, sodium bicarbonate, chlorine gas, caustic soda, hydrochloric acid, coal tar distillates (e.g. benzene), chlorinated benzenes, hydrogen peroxide, and myriad related chemicals. In "The Onondaga Lake Quagmire" (PNL 764, May 2007), I discussed several sub-sites of the Onondaga Lake Superfund site which are the legacy of the company's manufacturing operations.
This article describes the millions of tons of wastes dumped directly into the lake. Allied had two primary discharge points: the East Flume and the West Flume (see map). The East Flume caused an enormous buildup of waste material in the southwest corner of the lake: extending approximately 2,000 foot into the lake, approximately 4,000 foot along the lakeshore, and containing waste up to 45 feet thick. It contains over three million cubic yards of Solvay Waste, the white chalky material that comprises the Solvay waste beds in Lakeland and Camillus.
This material increases the salt content of the lake, but is otherwise fairly inert. Unfortunately, the lake deposit is also contaminated with toxic levels of mercury, chlorinated benzenes, benzene, toluene, coal tar, chlorinated dioxins and PCBs.
The West Flume conveyed wastes into Ninemile Creek, which carried them downstream, forming a delta in Onondaga Lake. The delta is primarily contaminated with mercury and lesser concentrations of the contaminants found in the East Flume deposit.
The
Cleanup Plan
NYS negotiated a plan that requires dredging about 1.6 million cubic yards
of the East Flume deposit. Another million cubic yards would be dredged from
other near-shore areas. All of this material would be pumped to a lined landfill
constructed on one of the wastebeds in Camillus. After dredging, each area
would be covered with four feet of clean sand. This should limit the migration
of residual contaminants into the overlying lake waters. The cost is estimated
at $450 million, making it one of the largest Superfund projects in the country.
Two of the most common questions regarding the remediation plan
are:
1) Won't dredging stir up a lot of contamination, causing more harm than good?
2) What's the point of moving contaminated sediments from one place to another?
Historically, dredging was a messy operation that stirred up lots of sediment. Nowadays, stricter environmental regulations make dredging contaminated sediments a much cleaner operation. Barriers called silt curtains are often employed to limit the spread of pollutants during dredging.
Thus, removing contaminated sediment from the lake is good for multiple reasons. The sediments are toxic to the organisms trying to live on the lake bottom ("benthos"). These organisms constitute an important part of the ecosystem. Also, chemicals are slowly released into the lake, poisoning both the fish and organisms-including humans-that eat them. This is particularly true for PCBs, mercury, and dioxins which accumulate up the food chain. Once the sediments are in the landfill, and eventually capped, pollutants are much less likely to escape into the environment. But it is by no means a perfect solution, since some of the pollutants-mercury in particular-will never break down.
Weaknesses in the Plan
The lake sediment remediation focuses on the large East Flume deposit and
smaller areas of contamination around the lake perimeter. This will address,
in large part, the organic chemicals that have been dumped into the lake.
However, it does little to address the mercury contamination spread over the
entire lake bottom. Some of the highest concentrations of mercury are in the
middle of the lake. NYS and Honeywell are counting on "natural recovery,"
meaning that they hope clean sediments coming into the lake from the tributaries
will cover up the mercury contamination. There is little doubt that eventually
the mercury will be buried. However, the forces of nature often do not conform
to the intentions of engineers; the burial process has been modeled to take
about 20 years, but could take hundreds of years.
The Onondaga Nation has pressed for a full cleanup of the lake-the removal of all contaminated sediments, estimated to cost $2.1 billion by the state. While this is a huge sum of money, it no doubt pales in comparison to the profits generated by Solvay Process/Allied Chemical over a century of dumping into the lake.
And so I told my visitor, "The lake is incredibly polluted,
and the company responsible, Honeywell, is moving ahead to clean up some of
the worst contamination. But the Onondagas, they have a plan to really clean
it up."
