Biomarcadores como ferramentas na avalia??o da qualidade do pescado contaminado com metais tra?o

摘要

Trace metals that present toxicity to vertebrates are cause of concern in environmental monitoring programs due to impact caused by anthropogenic activity. The distribution of these elements is found in different settings: water, sediment and biota. Metals such as Pb, Cd, Hg, As and Cr are related to significant environmental damage, which can contaminate man, primarily by fish consumption. Some biomarkers can be applied via an impact approach, and risk assessment for populations of species susceptible to exposure and toxic effects of trace metals. Acetylcholinesterase, metallothionein, delta-aminolevulinic acid dehydratase, and the micronucleus test can be used together as biomarkers for aquatic organisms that are exposed or affected by toxic metals. The CONAMA Resolution 357/2005 of the Brazilian Ministry of the Environment and the Ordinance 2914/2011 from Ministry of Health set limits for these toxic metals in surface and drinking water respectively. However, it still does not require the determination of chemical species, relative to the bioavailability produced in different arrays, neither to sublethal effects, evaluated by biomarkers, of these metals on aquatic organisms. The purpose of this review is to present the biomarkers (genetic and biochemical) as tools to aid assessment of the quality of fish.