In situ and laboratory bioassays using Poecilia reticulata Peters, 1859 in the biomonitoring of an acidic lake at Camaçari, BA, Brazil.
The suitability and viability of acute in situ bioassays were investigated in the biomonitoring program of an acidic lake contaminated with sulphur residues. Responses of organisms observed in laboratory and in situ bioassays were also assessed to determine whether or not they were similar and comparable, regarding accuracy and precision. Newborn Poecilia reticulata were employed as test organisms and exposed to the same water samples under in situ and laboratory conditions. Mortality/immobility was the endpoint assessed and dead/immobile organisms were counted at various time intervals during exposure. The mean calculated LT50 values and 95% confidence intervals were 1.61 (1.36-1.87) h in the laboratory bioassays and 0.72 (0.55-0.89) h in the in situ bioassays. Statistical comparison of these values revealed a significant difference (p<0.05). In situ bioassays were more accurate than those carried out in the laboratory, demonstrating higher sensitivity and better reproduction of what occurs in nature, while laboratory bioassays were more precise.
Instituto de Biologia, Federal University of Bahia, Campus de Ondina, 40170-115 Salvador, BA, Brazil. cvmaraujo@yahoo.com.br
Cristiano V M
CV
Araújo
Salomão J
SJ
Cohin-de-Pinho
Jéssica
J
da S Santos
Flávia
F
Delgado
Lúcia C S
LC
Santana
Carla B A
CB
Chastinet
Eduardo M
EM
da Silva
D000143:Acids / Q000032:analysis / Q000633:toxicity; D000818:Animals; D001681:Biological Assay / Q000379:methods*; D001938:Brazil; D004784:Environmental Monitoring / Q000379:methods*; D005618:Fresh Water / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D011036:Poecilia / Q000254:growth & development; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity
D000143:Acids; D014874:Water Pollutants, Chemical