2004 Denver Annual Meeting (November 7–10, 2004)

Paper No. 3
Presentation Time: 8:30 AM


ISPHORDING, Wayne C., Earth Sciences, Univ of South Alabama, Mobile, AL 36688, wisphord@jaguar1.usouthal.edu

Pensacola, Florida, unlike many cities in the Gulf Coast, is dependent for drinking water on wells drilled into the underlying confined aquifer. Late in the 1950's, State agencies began observing elevated levels of a number of contaminants in some of the wells. These problems worsened and, in 1959, the 12th Avenue Well was shut down due to low pH’s and elevated sulfate and fluorine. State and local agencies traced the source of the contaminants to a fertilizer manufacturing plant located within the city limits. Sulphuric acid had been produced from pyrite at the facility from1889 until 1920 when it then began manufacturing superphosphate from ores shipped from central Florida phosphate mines. Sulphuric acid was used to convert the ores into superphosphate and the waste products were pumped to unlined waste ponds. Problems with down-gradient contaminants continued and the facility was closed in 1976 and declared a Superfund site in 1987. In 1989 high levels of sulfate, aluminum, and fluorine (and low pH) forced closure of the #8 Well. In 1996, radium was added to the list of monitored contaminants and elevated levels were detected in 2 wells in 1997. The #9 Well was shut down in June, 1998, due to high radium levels, and in April, 2000, the East Well was similarly closed. A class action suit was filed in 2000 alleging that the former manufacturers (Conoco-Agrico) were negligent in permitting contaminants to enter the groundwater. The defendants did not strongly contest that the sulfate, fluorine, aluminum, and low pH’s were derived from down-gradient migration of site waste products. A strong objection was raised, however, as to the source of the 228-radium that had forced closure of two of the wells. The defendants argued that while phosphate ores do contain uranium, and that one of its daughter isotopes is 226-radium, that some other “local” source must be responsible for the 228-radium. The plaintiff’s expert witness, however, clearly demonstrated that the 228-radium could be traced to the presence of thorium in the mineral monazite, which is present in all Florida phosphate ores, and that there was absolutely no local source for the monazite.

In April, 2004 Conoco-Agrico agreed to a $70,000,000 settlement with the affected property owners. As such, it represented the largest settlement of a groundwater dispute, to date, in the United States.