The represamento of the water attracts many mosquitos, what it makes with that the index of illnesses caused for the same ones increases, as malaria, affection among others. To prevent epidemics, it must be appealed to the governmental bodies for the control of males and animals, as FUNASA (National Foundation of Health) and Centers of Health. The River Wood, during the decades of 70 and 80 was very used for the exploration of the gold pans, it predominated in the region, the main used chemical composition for the extration was the Mercury (Hg), being highly toxic. Between 1979 and 1990 they is esteem that about 87 tons of Hg they had been emitted for the environment, being about 65% emitted for the atmosphere and the lost remain under form of metallic Hg in the gutter of the proper river (Lacerda et al., 1989). Although the activity goldwasher in the Brazilian region of the river has decreased significantly, in the bolivian portion this activity has represented a substantial growth, being responsible for the annual emission of 0,25 the 0,5 t, contributing daily for the Brazilian portion of the Basin (Maurice-Bourgoin et al., 2000). The species of carnivorous fish evaluated in the basin of the River Wood come presenting high concentrations of Hg in its fabrics, reached values for some superior species suggested for the ingestion, being, fished the main one half of subsistence for the local population (Lacerda et al., 1989). Although the activities of gold mining have had a significant reduction from the middles of years 90, the amounts of Hg launched in the basin of the River Wood in the decades of 70 and 80 still remain distributed in different compartments and/or biticos, passveis of remobilizao and biological incorporation (great concentrations in fish and the marginal population), Lacerda et al., 1989), therefore, must be had the monitoramento of this population to prevent greaters damages the health of the same ones, how much to the fish, the Amazon region still makes use of few technological and financial resources for the process of despoluio of the River, then, remain in to wait them the degradation of the material by means of the biogeoqumicos cycles. By the same author: MasterClass. .