Ana Carolina Callegario Pereira

Response Mechanisms of Plants to Heavy Metal Pollution: Possibility of Using Macrophytes for Remediation of Contaminated Aquatic Environments

Water contamination by heavy metals is a growing concern among public officials and citizens due to their high potential toxicity to living things and the environment. Macrophytes have been studieds for use in a cleaning up polluted water bodies, due to their favorable characteristics. The various species can respond differently to environments contaminated with heavy metals. They can be sensitive, showing symptoms of toxicity and intolerant of high contamination levels, or tolerant, using extra or intracellular mechanisms to allow them to grow in the presence of these contaminants. In this review, we present the main mechanisms used by plants in response to contamination by heavy metals.

Escória de aciaria na redução da solubilidade e lixiviação de manganês em áreas contaminadas

Steelmaking slag is a waste of steel production and has owned corrective soil acidity and may consequently reduce the mobility of trace elements. The research aimed the capacity of industrial waste steelmaking slag to reduce the solubility and lixiviation of Mn in contaminated soil. In the Soil Pollution Laboratory of the UFRRJ (Seropedica-RJ), leaching experiments were carried using three different residues contaminated with Mn, and two doses of the inertizant residues steelmaking slag. In the columns were applied a known and constant volume of water, established to simulate the maximum precipitation occurred in the last 17 years, in the region where the residue was collected. The highest dose of steelmaking slag (6%) reduced the Mn solubility below the maximum allowed by ABNT, for G1, G2 and Ge, and the treatment with 6% steelmaking slag + barriers chemical was the most effective in reducing the leaching of Mn in all groups. Therefore, the results showed the efficiency of steelmaking slag in the reduction of Mn solubility and lixiviation in all residues.

Use of Cordia Africana in the Phytostabilization of Substrates from Excavations of the Ore Courtyard at the Port of Itaguai, Brazil

The objective of this study was to evaluate the phytostabilization of two substrates contaminated with heavy metals from excavations of the ore courtyard at the port of Itaguai, Brazil. Initially, an inventory of tree species located near the study area was performed to select species for phytostabilization. The species Cordia africana exhibited deeper roots, a larger diameter at chest height (DCH) and crown diameter, as well as higher concentrations of Zn, Cd, and Pb in the trunk, bark, and roots compared to the other investigated species. The tolerance of the selected species to the metals Zn, Cd, and Pb was subsequently assessed through a greenhouse test. The substrates used in the experiment also obtained from excavations at the ore courtyard and showed different levels of heavy metals, indicating either low contamination (Substrate 1) or high contamination (Substrate 2). Alkaline industrial waste steel slag (SS) was used as an amendment to reduce the solubility of heavy metals. Application of the amendment agent to the substrates reduced the bioavailability of heavy metals, favoring the growth of C. africana. This species presents potential for use in phytostabilization programs due to its tolerance for heavy metals and the observed higher accumulation of these metals in the roots and especially the trunk of this species compared to other vegetal parts.