PT01 Assessing Contaminated Soil Sites
Exhibit Hall
8:00 AM - Tuesday, 11 November 2003
(PT002) Forensic Analysis of the pelican die-off on Lake Apopka: Evidence for the contribution of organochlorine poisoning.
Mackay, C1, 1 Exponent, Bellevue, WA, 98007
ABSTRACT- In the fall and winter of 1998, an estimated 400 American white pelicans and numerous other avian species died suddenly at a restoration area on the north shore of Lake Apopka. This region was previously an area of intensive agricultural production that had recently been acquired for the purpose of restoring natural wetlands. Soil analysis indicated the presence of elevated concentrations of dieldrin, toxaphene, and metabolites of DDT. In order to determine whether these organochlorine pesticides could prove to be causative agents in the pelican die-off, we examined four lines of evidence pertaining to the event. First, the migratory patterns of various bird species, including the American white pelican, were examined over the period of the die-off in order to determine the proportion of bird mortalities relative to the number of individuals present. Second, the distributions of measured organochlorine residues in the brains of birds were examined. Third, fluctuating water levels onsite were examined to determine the probability of exposure to lethal concentrations of organochlorines, and fourth, the etiology of the dead birds collected from the site were surveyed to determine whether the findings of pathology investigations were consistent with organochlorine toxicosis. The results of the analysis were inconsistent with organochlorine poisoning being the sole or even the major contributing factor to the bird die-offs.
Key words: Lake Apopka, Pesticides, Forensic Toxiciology, American White Pelican