Bioavailability of pollutants in bacterial communities of Rodrigo de Freitas Lagoon, Rio de Janeiro, Brazil

Abstract

Processes involving heavy metals and other contaminants continue to present unsolved environmental questions. To advance the understanding of geochemical processes that involve the bioavailability of contaminants, cores where collected in the Rodrigo de Freitas lagoon, and analyzed for bacterial activity and metal concentrations. Results would suggest an extremely reducing environment where organic substances seem to be the predominant agents responsible for this geochemical process. Analytical data showed sulphate reduction to be the main agent driving this process, since this kind of bacteria was found to be active in all of the samples analyzed. Esterase enzyme production did not signal the influence of heavy metals and hydrocarbon concentrations and heavy metals were found to be unavailable for biota. However, correlation between results for bacterial biomass and the potentially mobile percentage of the total Ni concentrations would suggest a negative impact.

Seagrass losses concerns: does sediment metal pollution matter?

“…The distribution of acid-volatile sulfides (AVS) and simultaneously extracted metals (SEM) in sediments colonized by R. maritima was evaluated in Rodrigo de Freitas Lagoon (Rio de Janeiro State, Brazil), which is considered one of the most polluted coastal lagoons in SE Brazil, impacted by untreated sewage input and urban runoff. The lagoon is a semi-confined system making water renewal complex and the marine water flux is superficial, leaving deeper layers unaffected (Fonseca et al 2014). Extreme reducing conditions within the lagoon are due to the high concentration of organic matter, low currents and limited exchanges with the sea, making ideal conditions for the accumulation of pollutants, such as trace metals (Kim et al 2011).…”