Salt toxicosis in ruddy ducks that winter on an agricultural evaporation basin in California

Andrew G. Gordus, H L Shivaprasad, Pamela K. Swift

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Agricultural evaporation basins are used as a means to dispose of highly saline underground-tile-drainage water in the San Joaquin Valley (California, USA). The hypersaline water conditions encourage high aquatic invertebrate production, primarily brine shrimp (Artemia franciscana), which attract birds to those sites. Cool winter temperatures (<4 C) and hypersaline water conditions (>70,000 μmhos/cm) resulted in feather salt encrustation and salt toxicosis in ruddy ducks (Oxyura jamaicensis). During December 1998 and January 1999, approximately 200 dead and sick ruddy ducks were collected from an evaporation basin and five healthy control ruddy ducks were collected from a freshwater wetland. Brains contained ≥1,890 ppm sodium (wet tissue mass) in seven dead birds and contained ≤1.150 ppm sodium in the control birds. Liver arsenic, lead, and mercury concentrations were <1 ppm in all birds examined. Manganese, molybdenum, and copper liver concentrations did not differ significantly (P > 0.05) between the two groups of ducks. The dead ducks had significantly higher liver selenium, cadmium, iron, and zinc than the controls, but the concentrations were not sufficient to cause toxicity. Significant gross and microscopic lesions in most of the dead birds included conjunctivitis, lens opacity and cataract formation, vascular congestion in various organs most notably in the meninges of the brain, and myocardial and skeletal muscle degeneration.

Original languageEnglish (US)
Pages (from-to)124-131
Number of pages8
JournalJournal of Wildlife Diseases
Volume38
Issue number1
StatePublished - Jan 2002

Keywords

  • Brain sodium
  • Evaporation ponds
  • Hypersaline water
  • Oxyura jamaicensis
  • Ruddy duck
  • Salt encrustation
  • Salt toxicosis

ASJC Scopus subject areas

  • veterinary(all)

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