HEAVY-METALS IN LAUGHING GULLS - GENDER, AGE AND TISSUE DIFFERENCES

We examined concentrations of lead, cadmium, mercury, manganese, selen ium, and chromium in feathers, liver, kidney, heart, and muscle of kno wn-aged laughing gulls (Larus atricilla) that hatched in Barnegat Bay, New Jersey and were collected at John F. Kennedy International Airpor t, New York 1 to 7 years later. Concentrations differed significantly among tissues, and ''tissue'' entered all the regression models explai ning the greatest variation in metal levels. Age of bird contributed s ignificantly to the models for lead, cadmium, selenium, and chromium. Although there were significant gender differences in all body measure ments except wing length, there were few differences in metal levels. Males had significantly higher lead levels in feathers, and females ha d significantly higher selenium levels in heart and muscle tissue. For lead, 3-year olds had the highest levels in the heart, liver, and kid ney, and levels were lower thereafter. Mercury levels in feathers and heart decreased significantly with age. Cadmium levels increased signi ficantly with age for feathers, heart, liver, and muscle, although the re was a slight decrease in the 7-year olds. Selenium levels decreased significantly with age for all tissues. Chromium levels increased wit h age for liver and heart.