Phytoremediation

Ecophysiological and anatomical changes due to uptake and accumulation of heavy metal in Brachiaria decumbens

by Marcelo Gomes

The growth and developmental characteristics of grasses and their high biodiversity make such plants suitable for... more The growth and developmental characteristics of grasses and their high biodiversity make such plants suitable for remediation of areas contaminated by heavy metals. Nevertheless, heavy metal toxic effect on the plants may cause alteration in their metabolic pathways, such as photosynthesis, respiration, and growth, modifying plant anatomy. This work aimed to evaluate the effect of levels of soil contamination (0, 7.5 % and 15 % m3 m-3) on biomass production, on photosynthetic characteristics and on anatomical changes in roots and leaves of brachiaria (Brachiaria decumbens Stapf.). After seeds were planted, seedlings were uprooted and replanted in vases containing soil at different contamination levels, being left to rest for 120 days. At the end of that time, plants presented reduced yield of root and shoot dry matter, contents of chlorophyll a, chlorophyll b, total chlorophyll and potential photosynthesis with increased of soil contamination. The cell layers of endodermis and exodermis in the root tissues and the cell walls of the xylem and cortical parenchyma all thickened as contamination increased. In the leaf tissues, the adaxial and abaxial epidermis presented increased thickness while the leaf blade presented reduced thickness as contamination increased with consequent change in the root growth rate. In general, the effects of heavy metal increased with the metal concentration. Some results indicate that B. decumbens seems to have some degree of heavy metal tolerance.

Arsenic-Sensitivity in Anadenanthera peregrina Due to Arsenic-Induced Lipid Peroxidation

by Marcelo Gomes

Physiological and anatomical responses of eucalyptus seedlings exposed to cadmium

by Marcelo Gomes

Pollution caused by heavy metals, mainly by cadmium (Cd), is generated by mining and industrial activities, and by the... more Pollution caused by heavy metals, mainly by cadmium (Cd), is generated by mining and industrial activities, and by the use of phosphated fertilizers and sewage sludge in agriculture. Aiming to investigate the Cd effects on physiological and anatomical features, eucalyptus seedlings in Cd-increasing concentrations in nutrient solution. Seedlings of Eucalyptus camaldulensis remained for 20 days in 1L vases with Clark solutions, and the treatments with 0, 15, 25, 45 and 90 mmol Cd L-1 supplied as CdSO4. Water potential, water potential and pigment content evaluations were carried out on dates 1, 3, 6, 12 and 20 days after treatments induction (DAE). Evaluations of mass production, Cd contents and anatomical characteristics were made with vegetal matter collected in the end of the experimental period. There was a decrease on dry matter production, even in the lowest Cd concentration. Total chlorophyll content decreased with the increase of Cd content in nutrient solution at 20 days after exposure (DAE) whereas carotenoid contents were the highest at 45 and 90 mmol Cd L-1. Lipid peroxidation in leaves increased with increasing Cd levels at 20 DAE, whereas in root, the effect of Cd was less pronunciated. Water potential increased at all Cd concentration at 12 and 20 DAE. Root tissues thickness also increased increased as Cd levels increased, but mesophyll and leave blade thickness decreased. Thus, the results indicate that the exposure time and higher doses of Cd accentuate damages in E. camaldulensis for most of the evaluated traits. Some changes observed reveal the tolerance potential of E. camaldulenses to Cd-exposition.

Utilization of Willow ( Salix humboldtiana Willd) as a species for phytorremediation of zinc industry waste

by Marcelo Gomes

An experiment was carried out in a greenhouse to evaluate the effect of contaminated soil by zinc industry wastes in... more An experiment was carried out in a greenhouse to evaluate the effect of contaminated soil by zinc industry wastes in heavy metal levels and in root and shoot nutritional status of young willow plants. One year old plantlets were transferred and cultivated for thirty days in 6 L pots containing 0, 15 e 30 % (v/v) of contami-nated soil with (mg kg-1 soil) 18600 of Zn, 140 of Cd, 450 of Cu and 410 of Pb. Plants grown in this conta-minated soil showed high levels of metals in leaves, ranging from (mg kg-1 DW): Zn = 362 to 878 and Cd = 19 to 35, and exhibited Zn and Cd phytotoxicity symptoms. Except for Mn, Fe and S; nutrient (P, K, Ca, Mg and N) levels in plants were not affected by the contaminated soil, showing a low heavy metal influence on
their nutritional status.

Trace element accumulation in woody plants of the Guadiamar Valley, SW Spain: A large-scale phytomanagement case study

by Teodoro Marañón

Environmental Pollution 152 (1): 50-59 (2008) 

Phytomanagement employs vegetation and soil amendments to reduce the environmental risk posed by contaminated sites.... more Phytomanagement employs vegetation and soil amendments to reduce the environmental risk posed by contaminated sites. We investigated the distribution of trace elements in soils and woody plants from a large phytomanaged site, the Guadiamar Valley (SW Spain), 7 years after a mine spill, which contaminated the area in 1998. At spill-affected sites, topsoils (0–25 cm) had elevated concentrations of As (129 mg kg−1), Bi (1.64 mg kg−1), Cd (1.44 mg kg−1), Cu (115 mg kg−1), Pb (210 mg kg−1), Sb (13.8 mg kg−1), Tl (1.17 mg kg−1) and Zn (457 mg kg−1). Trace element concentrations in the studied species were, on average, within the normal ranges for higher plants. An exception was white poplar (Populus alba), which accumulated Cd and Zn in leaves up to 3 and 410 mg kg−1 respectively. We discuss the results with regard to the phytomanagement of trace element contaminated sites.

Field Note: Successful Establishment of a Phytoremediation System at a Petroleum Hydrocarbon Contaminated Shallow Aquifer: Trends, Trials, and Tribulations

by Rachel Cook

Arsenic-Sensitivity in Anadenanthera peregrina Due to Arsenic-Induced Lipid Peroxidation

by Queila Garcia

Published in International Journal of Applied Science and Technology

The Role of Glutathione Transferases in the Detoxification of TNT

by Helen Sparrow

Removal of aqueous phenanthrene by brown seaweed Sargassum hemiphyllum: Sorption-kinetic and equilibrium studies

by (Jake) Ming Kei Chung

Selecting Plants to Minimise Radiocaesium In the Food Chain

by Abraham Escobar-Gutierrez

Caesium (Cs) is an alkali metal with chemical properties similar to potassium (K). It has no known role in plant... more Caesium (Cs) is an alkali metal with chemical properties similar to potassium (K). It has no known role in plant nutrition and it is not toxic to plants at the micromolar concentrations occurring naturally in soil solutions. However, two radioisotopes of Cs (134Cs and 137Cs) are of environmental concern due to their relatively long half-lives, emissions of β and γ radiation during decay, and rapid incorporation into biological systems. There is considerable interest in remediating sites contaminated by these isotopes using phytoextraction and, since the produce from radiocaesium-contaminated areas may enter the food chain, the introduction of ‘safe’ crops that do not accumulate Cs. This article reviews the molecular mechanisms of Cs uptake by plants, and provides a perspective on strategies to develop: (1) plants that extract Cs efficiently from soils (for the phytoremediation of land), or (2) ‘safe’ crops that minimise the entry of radiocaesium directly into the human food chain.