Investigating spatial-temporal contamination for two environments of the Amazon estuary: A multivariate approach

An assessment of environmental quality in Amazonian estuaries utilizing histological and immunohistochemical biomarkers concomitantly with analyses of trace metals in the tissues of Sciades herzbergii, also considering physical chemical analyzes of the water. 352 animals were captured from two sites and during two periods (dry and rainy). Site 1: Sa similar to o Marcos Bay - heavy anthropic influence and Site 2: Caete ' estuary-preserved estuary. In the laboratory, the fish were weighed (g) and measured (cm). Fragments of gills and liver were analyzed using histology and immunohistochemistry (Caspase 3). The specimens from Site 1 presented a low-value condition factor, with the highest concentrations of Al, Cd, and Hg appearing in the muscle, and most severe damages to gills and liver. In contrast, individuals from Site 2 presented a high-value condition factor and showed low metal concentrations in the muscle with only slight tissue lesions. Furthermore, our results demonstrated that seasonal changes affect metal modulation and pathologies in fish at Site 1. The sentinel species chosen in this study is considered a strong bioindicator of pollution and the combination of different biomarkers was efficient in providing a clear view of the signs of exposure to pollutants, and the risks posed to fish health by the presence of metals in the environment, especially in Site 1.

Automated summary

This study assessed environmental quality in Amazonian estuaries by utilizing histological and immunohistochemical biomarkers, along with trace metal analyses in Sciades herzbergii tissues and physical chemical analyses of water. The results showed variations in condition factors and tissue damage levels among samples captured from different locations and seasons, indicating differences in the risks posed to fish health by pollutants.