IMPAIRMENT OF GROWTH AND IMMUNE FUNCTION OF AVOCET CHICKS FROM SITES WITH ELEVATED SELENIUM, ARSENIC, AND BORON

Avocets (Recurvirostra americana) hatched from eggs collected from the south Central Valley of California (USA) were studied to determine th e impact of elevated concentrations of selenium, arsenic, and boron on the immune system and growth to maturity. Corcoran ponds were the ref erence site with low selenium (1.2 ppb) and arsenic (29 ppb) (boron no t measured). Westfarmers Pond had elevated concentrations of selenium (319 ppb), arsenic (127 ppb), and boron (109 ppm). Pryse ponds also ha d elevated selenium, arsenic, and boron concentrations (13.9 ppb, 1,10 0 ppb, and 29.4 ppm, respectively). Size at hatch was significantly re duced (P less than or equal to 0.05) in birds from Westfarmers and Pry se ponds. The growth rate was faster, but mean adult size was reduced in birds from Pryse ponds. Avocet chicks from Pryse and Westfarmers po nds exposed solely through in ovo transfer of these elements had signi ficantly increased heterophil:lymphocyte ratios. The phagocytic activi ty of macrophages also was significantly reduced in these birds, and P ryse Pond birds had an increased proliferative ability of lymphocytes in the presence of concanavalin A, a T-cell mitogen. Avocet chicks (le ss than or equal to 5 wk old) were captured from the various ponds and the same morphometric and immune function measurements made. The bird s that were most severely impacted by exposure to these compounds were those that were collected from Pryse ponds.