Impacto da contaminação sob atributos químicos de solo de manguezal no município de São Francisco do Conde – Bahia

Abstract

Mangrove is a transitional coastal ecosystem located between terrestrial and marine environment. The mangrove ecosystems consist of arboreal vegetation adapted to fluctuating salinity, which colonizes muddy soils, slightly consolidated, rich in organic matter and low oxygen content.Mangroves grow better in between the tropics of Cancer and Capricorn (23 ° 27 'N and 23 ° 27' S), especially in the vicinity of the equator.This study evaluated the impact of the contamination in some chemical properties of a mangrove area. The study was conducted in São Francisco do Conde located between latitude 12° 37'45 "S and longitude 38 ° 40'50" W, Subaé River Basin, São Francisco do Conde - BA. The problem area was divided in three sub areas, according to the proximity with the river flow. Composite samples, made up of three simple samples were collected from the problem area, at the depth of 0 to 0.2m.The samples were analyzed for field pH, pH(H2O), pH(KCl), electrical conductivity, fertility analyzes, Pb, Mn, Fe, Cd and Zn concentrations, organic C, nitrogen and particle size analysis.The organic C content in the mangrove area in contact with the river was higher than in areas farther from shore.The field pH values were much higher than the laboratory pH(H2O) and pH(KCl) indicating an acidification process mostly like organic matter, or sulphur oxidation during the samples drying process. The soil pH of the disturbed area, mangrove fringe was lower than in the other two sites. The of Pb and Zn concentration of the experimental areas were higher values than those recommended by environmental regulatory agencies.