Article

Archives of Environmental Contamination and Toxicology

, Volume 41, Issue 4, pp 501-507

Mercury in Eggs and Feathers of Great Egrets (Ardea albus) from the Florida Everglades

  • D. G. RumboldAffiliated withSouth Florida Water Management District, Mail Code 6442, 3301 Gun Club Rd., West Palm Beach, Florida 33406, USA
  • , S. L. NiemczykAffiliated withSouth Florida Water Management District, Mail Code 6442, 3301 Gun Club Rd., West Palm Beach, Florida 33406, USA
  • , L. E. FinkAffiliated withSouth Florida Water Management District, Mail Code 6442, 3301 Gun Club Rd., West Palm Beach, Florida 33406, USA
  • , T. ChandrasekharAffiliated withFlorida Department of Environmental Protection, Central Laboratory, 2600 Blair Stone Road, Tallahassee, Florida 32399-2400, USA
  • , B. HarkansonAffiliated withSouth Florida Water Management District, Mail Code 6442, 3301 Gun Club Rd., West Palm Beach, Florida 33406, USA
  • , K. A. LaineAffiliated withSouth Florida Water Management District, Mail Code 6442, 3301 Gun Club Rd., West Palm Beach, Florida 33406, USA

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Abstract

Great egret (Ardea albus) eggs and nestling feathers were collected for total mercury (THg) and methylmercury (MeHg) analysis from two colonies in the Florida Everglades in 1999 and 2000. THg was present in all eggs at a mean concentration of 0.39 ± 0.19 μg/g fresh weight (n = 33, range = 0.08–0.86 μg/g). Egg-THg levels did not differ significantly between colonies or years. MeHg concentration in eggs was 0.35 ± 0.18 μg/g fresh weight (n = 20, range = 0.05–0.82 μg/g,), and on average represented 85% of the THg found in the egg. Concentration of THg in feathers from egret nestlings, age 11–31 days, ranged from 1.4 to 8.6 μg/g dry weight. Feather-THg levels also did not differ significantly between colonies or years. THg concentrations in feathers, normalized based on bill length, were positively correlated to THg concentrations in eggs from the same clutch. Levels of THg in both eggs and feathers were lower in 1999 and 2000 than values reported for similar samples collected in 1993–95, indicating that MeHg exposure has decreased in the southern Everglades since the mid-1990s. THg levels in eggs and nestling feathers for the period of this study were below levels associated with toxic reproductive effects. Clutch size, fledging success, and brood size observed in this study were consistent for this species in the Everglades. Collectively, these results suggest that MeHg was not adversely affecting the reproductive performance of this population during the study.