The objective of this work was to evaluate the Hg levels in target organs of one species of kingfisher, Chloroceryle amazona, in three South American rivers in Brazilian Amazonia and Pantanal. We determined Hg in liver, muscle and feathers, in relation to size, weight and age of the birds, and Hg in the river water, and in relation to the deforestation dynamics of the areas, reconstructed in a time series of 40 years. The highest Hg were measured in the suspended particulate (8.6 ± 3.7 ng/L) and filtered portions (0.9 ± 0.4 ng/L) of the Teles Pires River in comparison with Juruena River (4.1 ± 3.6 and 0.8 ± 0.2 ng/L, respectively). The highest Hg among tissues was in the following order: feathers (4.97 ± 0.86 ng/L) > liver (0.80 ± 0.018 ng/L) > muscle (0.41 ± 0.11 ng/L). The highest levels in the feathers and muscle were found in the Teles Pires River samples (F=7.78, p=0.03; F=17.16, p=0.01 respectively). On the other hand, liver showed the highest Hg concentration in the samples of the Juruena River (F=3.83; p = 0.04). There is a significant correlation between THg concentrations in feathers and muscle (R²=0.76, p=0.01) in both rivers. Likewise, we found a significant positive correlation between the animal’s length and Hg concentrations in liver (R²= 0.10, p=0.04) and feathers (R²= 0.13; p=0.02). The satellite images showed severe changes in the landscape, with the withdrawal of native vegetation for agriculture or livestock. Considering the total area of buffers, created within the collection area in each river, the Teles Pires River (cerrado-Amazonian transition area) lost about 25% of its original coverage, whereas the Juruena river (Amazon forest) lost is 18% and the Paraguay (cerrado) / humid zone / shrub vegetation) around 35.92%, between the years of 1988- 2018. Our results suggest C. amazona as a potential sentinel species for the monitoring of environmental Hg contamination in Amazonia and Pantanal. In addition, our data point to a possible relationship between deforestation and Hg values in river water and biota.

Peer reviewed