TOTAL MERCURY IN CHLOROCERYLE AMERICANA (GMELIN, 1788) IN THE BRAZILIAN AMAZON

Abstract

Mercury is a highly toxic global contaminant naturally found in the Amazon, with biomagnification capability in the aquatic trophic chain. The use of piscivorous birds for biomonitoring of mercurial contamination is increasing, mainly due to the non-mobility of the bird in the feathers. The concentrations of total mercury in different tissue of Chloroceryle americana from the Teles Pires River (n = 21, weight 30 g) and Juruena River (n = 24; weight 28 g) samples in the southern Brazilian Amazon during the periods of September 2016 and January 2017. The results obtained evidenced high concentrations of total mercury, on average two times higher in the green kingfisher of the Teles Pires River for all the sampled tissues. The increasing behavior of mercury concentrations between tissues was muscle < liver < feather. High THg concentrations liver were found in C. americana in the Juruena River (0.589 μg.g-1 ± 0.196) and Teles Pires River (1,499 μg.g-1 ± 0,792). A total of 58% of feather samples (5,514 ± 2,351 μg.g-1) and 90% of the Teles Pires River (11,570 ± 5,226 μg.g-1) were higher than the mercury levels associated with reproductive-related adverse effects of 5 μg.g- 1. The THg concentrations suggest special attention for the areas sampled due to the installation projects of dams in the region, as well as the advance of soy monoculture in the southern end of the Amazon, potentiating the bioaccumulation of mercury.