Efeito da engorda artificial das praias do Meireles e Iracema sobre as condições de qualidade da água

Abstract

Recently, the beaches of Meireles and Iracema underwent the process of artificially increasing the sand strip. This intervention can temporarily or permanently change the quality of the water and, consequently, cause negative impacts on marine fauna and flora habitats. This work aims to evaluate the effects of that work on the water quality conditions and to know if these effects change the class in which this body of water is framed according to CONAMA Resolution no 357/2005 for class 1 saline waters. Three oceanographic campaigns were carried out: before, during and one year after the completion of the work, in 12 different oceanographic stations, where surface and bottom samples were collected. The methodologies used in sampling and laboratory determinations are scientifically recognized. Mean pH concentrations at all points on the surface smoothly exceeded the maximum allowed value, with mean values ranging between 8.97 ± 0.11 and 8.93 ± 0.07, which was not presents significant damage to marine ecology or human health. The average DO concentrations were always above the minimum required value for all campaigns. For total organic carbon (TOC), only one sample from the initial phase exceeded the maximum allowable value (MPV). No sample analyzed exceeded the VMP for thermotolerant coliforms, keeping the conditions suitable for bathing, however exceeding the VMP for the cultivation of bivalve molluscs with mean values ranging between 78,33 ± 191,88 and 130 ± 318,43 org/100 mL. All samples analyzed for floating materials, oils and greases, substances that produce odor and turbidity, dyes from human sources and objectionable solid waste were “virtually absent”, regardless of the study phase. According to the results, it is possible to affirm that, until the last campaign, the work did not significantly impact the water body class.