Contaminated Beaches Cleanup

According to EPA s initial plans, cleanup of the Times Beach area was to begin in 1984. However, a number of lawsuits delayed that process until 1990, when the EPA hired the Syntex Corporation to remove and incinerate contaminated soil and restore Times Beach to a safe area. That process was finally completed in July 1997, when the area was reopened as the 409-acre Route 66 State Park. 

The dehalogenation process has been approved by the EPA s Office of Toxic Substances for PCB treatment and has been experimentally implemented for the cleanup of PCB-contaminated soil at the following three Superfund sites Wide Beach in Erie County, New York (1985) Re-Solve in Massachusetts (1987) and Sol Lynn in Texas (1988). The glycolate process has been used to successfully treat contaminant concentrations of PCBs from less than 2 ppm to reportedly as high as 45,000 ppm. Using this technology, Helland et al. (1995) investigated reductive dechlorination of carbon tetrachloride with elemental iron and found that the rate of dechlorination to chloroform and methylene chloride was a fast first-order process. 

A coastal beach in California is polluted with heavy metals. Since it is a protected wildlife habitat, a minimally intrusive electrochemical method is selected for cleanup. Assume that a constant current density of 125 pA cm-2 in a 40 x 6-foot cross section is used in the contaminant pit, which is 40 x 20 x 6 feet deep, (a) What is the total current and voltage required if the pore fluid conductivity is 21.9 mS cm-1 (approx, equivalent to 0.2 M KC1) (b) If the soil is saturated and approx. 50% pore fluid and 50% solids by volume, how long would it take to pass a charge equivalent to the ionic content of the pore fluid (c) How much acid should be added to depolarize the cathode in this time in order to ensure reaction (A) below, instead of water electrolysis, reaction (B) ... 

Cleaning the Times Beach site was a massive estimated 200 million effort that included installation of a temporary incinerator to burn the contaminated soil, and the erection of a 15 ft high barrier around the incinerator to protect that area from regular flooding by the Meramec River. Contaminated soils were dug up, burned, and the resulting waste ash was buried on site. Cleanup of the site was completed by the end of 1997 by the US EPA and Syntex Agribusiness, the company that assumed responsibility for the site s cleanup. More than 265 000 tons of dioxin-contaminated soil from the site and 27... 

Missouri. In 1971, a used oil transporter sprayed oil contaminated with TCDD on riding arenas and roads In Missouri for dust control. The death of about 60 horses and Illnesses In children led to an Investigation by the Centers for Disease Control (CDC). Health effects were attributed to TCDD In the oil In 1974 (4). However, governmental agencies responsible for action were under the mistaken Impression that TCDD had a half-life In the environment of one year and, therefore, carried out only minimal cleanup. In 1982, this problem resurfaced when Times Beach, a community near St. Louis, was evacuated after TCDD concentrations above 1,000 ppb were detected In soil samples. Decisions on this evacuation were carried out under an atmosphere of scientific uncertainty, public emotion, and political pressures within U.S. EPA. At present, there are 43 contaminated sites In Missouri, some of which are being excavated and restored. 

In Times Beach, Missouri, waste oil from 2,4,5-TCP/HCP manufacture, contaminated with 2,3,7,8-TCDD, was used to control dust on roads. The result was the well-known government buy-out of the town. Use of waste oil at several Missouri horse arenas resulted in acute human health effects and the death of sixty-five horses and several small animals. Subsequent use of the horse arena materials as fill at building construction sites resulted in further cleanup problems. 

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