Abstract
Water quality of the Jansen Lagoon (São Luís, Maranhão State, Brazil) was assessed through histological biomarkers and microbiological parameters. To this end, 29 fish specimens (11 Centropomus undecimalis and 18 Sardinella sp) and eight water samples were collected during the rainy and dry periods of 2013. The lagoon water showed thermotolerant coliform indices above the limit set forth in CONAMA Resolution 357/2005. Histological changes observed in the gills were: lifting of the respiratory epithelium, hyperplasia of the lamellar epithelium, incomplete and complete fusion of several lamellae, disorganization of the lamellae, congestion of blood vessels, aneurysms, hypertrophy of the respiratory epithelium, hemorrhage and rupture of the lamellar epithelium and parasite. The histological alteration index (HAI) average value to Sardinella sp was 31.8 and to C. undecimalis was 22.2. The average HAI value in both species corresponds to category 21–50, with tissue injuries being classified from moderate to severe. The presence of histological injuries and the HAI values indicate that the fish sampled from the Jansen Lagoon are reacting to non-specific xenobiotics present at the site.
Highlights
Aquatic ecosystems are exposed to excessive input of pollutants and contaminants from various sources like domestic and industrial sewage, agricultural processes, heavy metals and others.The uncontrolled discharge of these compounds into the water directly affects aquatic organisms, including fish, which are considered a bioindicator of environmental pollution or contamination [1].Bioindicators are sentinel species used as primary indicators of abiotic or biotic changes presented by a certain environment in the presence of pollutants [2]
A total of 29 fish specimens was collected in the rainy and dry periods of 2013, at a site located at the coordinates 2°29ʹ40ʹ S and 44°18ʹ13ʹ W, in the Jansen Lagoon, these being 11 C. undecimalis in the rainy period of 2013 and 18 Sardinella sp, five in the rainy and 13 in the dry periods of 2013
Microbiological parameters of the Jansen Lagoon were evaluated in two collection periods
Summary
Aquatic ecosystems are exposed to excessive input of pollutants and contaminants from various sources like domestic and industrial sewage, agricultural processes, heavy metals and others. Coliforms are used as indicators of contamination and have been used since the nineteenth century as a basic bacteriological parameter in the definition of standards for the characterization and assessment of water quality in general. Bacteria of this group are the most frequently used as indicators of contamination, because they point out the possibility of the presence of fecal pollution, indicating that the water body receives sewage, directly or indirectly [9]. This study evaluated the water quality of the Jansen Lagoon using microbiological parameters and histological lesions in the gills of two fish species (Centropomus undecimalis and Sardinella sp.) as biomarkers
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