Abstract: Cabbage seedlings grown in vitro were exposed to
excess levels of heavy metals, including Cd, Mo, and Zn. High metal
levels affected plant growth at cotyledonary stage. Seedlings under
Cd, Mo, and Zn treatments could not produce root hairs and true
leaves. Under stress conditions, seedlings accumulated a higher
amount of anthocyanins in their cotyledons than those in the control.
The pigments isolated from Cd and Zn stressed seedling cotyledons
appeared as pink, while under Mo stress, was dark pink or purple.
Moreover, excess Mo stress increased antioxidant enzyme activities
of APX, CAT, SOD. These results suggest that, under excess Mo
stress, the induced antioxidant enzyme activity of cabbage seedlings
may function as a protective mechanism to shield the plants from
toxicity and exacerbated growth.
Abstract: The use of sewage sludge and effluents from
wastewater treatment plants for irrigation of agricultural lands is on
the rise particularly in peri-urban areas of developing countries.
The reuse of nutrients and organic matter in treated wastewater
and sewage sludge via land application is a desirable goal. However,
trace or heavy metals present in sludge pose the risk of human or
phytotoxicity from land application. Long-term use of sewage
sludge, heavy metals can accumulate to phytotoxic levels and results
in reduced plants growth and/or enhanced metal concentrations in
plants, which consumed by animals then enter the food chain. In this
research, the amount of heavy metals was measured in plants
irrigated with wastewater and sludge application. For this purpose,
three pilots were made in a Shush treatment plant in south of Tehran.
Three plants species, spinach, lettuce and radish were selected and
planted in the pilots.First pilot was irrigated just with wastewater of
treatment plant and second pilot was irrigated with wastewater and
sludge application .Third pilot was irrigated with simulated heavy
metals solution equal 50 years of irrigation. The results indicate that
the average of amount of heavy metals Pb, Cd in three plant species
in first pilot were lower than permissible limits .In second pilot,
Cadmium accumulations are high in three species plants and more
than the standard limits. Concentration of Cd , Pb have exceed their
permitted limits in plants in third pilot . It was concluded that the use
of wastewater and sludge application in agricultural lands enriched
soils with heavy metals to concentrations that may pose potential
environmental and health risks in the long-term.
Abstract: The presence of toxic heavy metals in industrial
effluents is one of the serious threats to the environment. Heavy
metals such as Cadmium, Chromium, Lead, Nickel, Zinc, Mercury,
Copper, Arsenic are found in the effluents of industries such as
foundries, electroplating, petrochemical, battery manufacturing,
tanneries, fertilizer, dying, textiles, metallurgical and metal finishing.
Tremendous increase of industrial copper usage and its presence in
industrial effluents has lead to a growing concern about the fate and
effects of Copper in the environment. Percolation of industrial
effluents through soils leads to contamination of ground water and
soils. The transport of heavy metals and their diffusion into the soils
has therefore, drawn the attention of the researchers.
In this study, an attempt has been made to delineate the
mechanisms of transport and fate of copper in terrestrial
environment. Column studies were conducted using perplex glass
square column of dimension side 15 cm and 1.35 m long. The soil
samples were collected from a natural drain near Mohali (India). The
soil was characterized to be poorly graded sandy loam. The soil was
compacted to the field dry density level of about 1.6 g/cm3. Break
through curves for different depths of the column were plotted. The
results of the column study indicated that the copper has high
tendency to flow in the soils and fewer tendencies to get absorbed on
the soil particles. The t1/2 estimates obtained from the studies can be
used for design copper laden wastewater disposal systems.
Abstract: The use of un-activated bentonite, and un-activated
bentonite blended with limestone for the treatment of acid mine
drainage (AMD) was investigated. Batch experiments were
conducted in a 5 L PVC reactor. Un-activated bentonite on its own
did not effectively neutralize and remove heavy metals from AMD.
The final pH obtained was below 4 and the metal removal efficiency
was below 50% for all the metals when bentonite solid loadings of 1,
5 and 10% were used. With un-activated bentonite (1%) blended with
1% limestone, the final pH obtained was approximately 7 and metal
removal efficiencies were greater than 60% for most of the metals.
The Langmuir isotherm gave the best fit for the experimental data
giving correlation coefficient (R2) very close to 1. Thus, it was
concluded that un-activated bentonite blended with limestone is
suitable for potential applications in removing heavy metals and
neutralizing AMD.
Abstract: Two seperate experiments by barley and alfalfa were
conducted to a 2×8 factorial completely randomised design, with four
replicates. Factors were inoculation (M) with Gomus mosseae or uninoculation
(M0) and seven levels of contaminants (Co, Cd, Pb and
combinations) plus an uncontaminated control treatment (C). Heavy
metals in plant tissues and soil were quantified by Inductively
Coupled Plasma Optical Emission Spectrometer (ICP-OES) (Variant-
Liberty 150AX Turbo). Phytoextraction coefficient of contaminants
calculated by concentration of heavy metals in the shoot (mgkg-1) /
concentration of heavy metals in soil (mgkg-1). In the barley, the
highest rate of phytoextraction coefficient of Pb, Cd and Co was in
M0Pb, M0PbCoCd and MCo, respectively (P