Avaliação da toxicidade de cianobactérias na água e da presença de microcistinas nos tecidos de peixes de viveiros em Macapá (AP)

Abstract

Aquaculture currently corresponds to food production sector fastest growing in the world. The country has great potential for the development of this activity, among them the North due to great availability of water resources. Thus it must be observed the effects of this activity that deserves attention to enable its improvement and facilitate their operation without affecting the health of the population. The objective of this study was to survey the species of cyanobacteria in the water of ponds and assess their toxic potential and quantifies the microcystin in the meat of two species of fish raised in ponds. Sampling was conducted in December 2013 in six ponds in Macapá. Collection was made of chemical parameters (dissolved oxygen, alkalinity and hardness); physical (temperature, transparency, and pH) as well as the determination of biotic factors (phytoplankton and chlorophyll a). Four fish were collected from specimens of tambaqui (Colossoma macropomum) and tambacu (Colossoma macropomum and Piaractus mesopotamicus) for analyzing the concentration of microcystins in the meat by ELISA immunoassay. In cyanobacteria bloom there was a predominance of Radiocystis fernandoi, Planktothrix agardhii and Microcystis aeruginosa. Chlorophyll a concentrations were above 146.82 μg/L-1 indicating aquatic environments with a high degree of hypertrophy. The concentration of microcystins in fish meat was below the maximum acceptable daily intake (ADI) set by the WHO (0.04 μg microcystin/kg body weight/day-1). It is noticed that prolonged exposure can be considered as a serious health risk since microcystins induces tumors and the continued consumption, even at low concentrations, can lead to higher incidence of liver cancer in the exposed population. It is extremely important to study and monitoring of water and fish quality, and they shall be alert to public health for consumption. This is the first work in the North region investigating the bioaccumulation of microcystins in fish tissues indicating the importance of promoting continuous monitoring of these organisms for human and animal consumption