Phytoremediation of Effluents Contaminated with Heavy Metals by Floating Aquatic Macrophytes Species

Abstract

The progress of urbanization and technologies led to the rise of anthropogenic activities, which consequently have high production of pollutants, affecting ecosystems, including aquatic biomes. One of the contaminating forms that cause environmental impact is heavy metals, which are produced in large quantities by inappropriate disposal of batteries, residential, industrial, agricultural and mining waste. Such components generate bioaccumulative effects, classifying them as dangerous elements that must be removed from environment. However, in species such as plants, this bioaccumulative effect can be exploited, aiming a biotechnological and bioengineering application to remove metals, called phytoremediation, employing floating aquatic macrophytes, which have high potential due to their properties retaining contaminants. Results obtained were conclusive for adaptation of Eichhornia crassipes and Salvinia auriculata as better phytoremediation agents, respectively, while Lemna minor and Pistia stratiotes fit better in biomonitoring, which have resistance to certain concentrations of metal when related to Cd, Hg, Zn, Ni and Pb.

A review: Water pollution by heavy metal and organic pollutants: Brief review of sources, effects and progress on remediation with aquatic plants

“…However, the effects of heavy metal pollution in water shall be discussed under the following; plants, aquatic animals and humans. The toxicity of heavy metals to aquatic plant, animal and human is depended on the solubility and bioavailability of the metals, organism tolerance, pH, and presence of other ions that interfere with bioavailability, among other issues that may interfere with the result of contact with the element [37].…”

Phytoremediation of Polluted Waterbodies with Aquatic plants: Recent Progress on Heavy Metal and Organic Pollutants

“…Some plants counteract the damages of heavy metals while some at certain concentration increase in nutrient. For example, when E. camaldulensis species was exposed to 45 μmol/L cadmium there was an increase of carotenoids (related to the tolerance to oxidative stress), and there is also an increase in the thickness of the epidermis and root endoderm according to the increased doses of the metal and the decrease in the thickness of the mesophyll and leaf limb related to the decrease of the photosynthetic capacity [37,51]. The tolerance could be due to some phytocompounds such as anthocyanins, thiols, and antioxidant scavenging enzymes [52].…”

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“…Knowledge of the ideal plant age for higher absorption/accumulation in relation to the period of exposure is a key aspect for better implementation and usage of this technique. Gomes (2012) and De Souza and Silva (2019) emphasize that longer periods of exposure to contaminants are a negative point of this process; however, information about exposure time is largely unknown. Like any other remediation process, the use of plants is designed to reduce contaminant levels to levels that are safe and compatible with human health (Andrade et al, 2007).…”