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Application of Mulberry nigra to absorb heavy metal, mercury, from the environment of green space city

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Highlights • The obtained results from the research suggest that aerial organs of Mulberry nigra have had significant difference for mercury accumulation in various concentrations. • According to the results, Mulberry nigra species, seems to be an appropriate species for refining soils contaminated by mercury. • Mercury pollution is most pollution in soil of north of Iran in industrial park area. • Studies in environment heavy metal pollution in soil of urban forestry in most important for human health. • Mulbery nigra is a fast-growing species from medium to high trees, is resistant towards various soils and prefers visors to shade-friendly sites .In this research it was studied that how much a Mulbery nigra could absorb the mercury from the environment.
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Toxicology Reports
journal homepage: www.elsevier.com/locate/toxrep
Application of Mulberry nigra to absorb heavy metal, mercury, from the
environment of green space city
Seyed Armin Hashemi
a,
, Sahar Tabibian
b
a
Department of Forestry, Lahijan Branch, Islamic Azad University, Lahijan, Iran
b
Department of Agriculture and natural resources, Payame Noor University, P.OBox, 19395-3697, Tehran, Iran
ARTICLE INFO
Keywords:
Mulberry nigra
Mercury
Heavy metals
North of Iran
ABSTRACT
Phytoremediation is one of the methods for Bioremediation of the soils which has been noticed in recent dec-
ades. Two years sapling of Mulberry nigra selected and Mercury(II) nitrate solution with 30, 50 and 70 mg/L
concentrations, after add solutions in to soil of sapling Mulberry nigra, eight monthslater leaf, stem and roots
were selected and Measuring mercury was determined by Atomic Absorption Spectrometer. The maximum level
of mercury accumulation in the leaf, stem and root was 55.67, 50 and 65 mg/kg, respectively. Mercury could be
absorbed easily by the plants root and accumulated in the plants.
1. Introduction
Human sources for releasing the mercury to the environment is by
secondary products of various industrial processes like coal burning,
combustion of fossil fuels, mercurial vapor lamps and producing
Chloralkali [1]. Phytoremediation is one of the methods for Bior-
emediation of the soils which has been noticed in recent decades. In this
method, resistant plants are used for rening the soils contaminated by
organic and inorganic components. The advantages of this method
among the others are its simplicity, inexpensiveness and exploiting
possibility in a broad level. Selection of plant has a great importance in
this method. Plant selection depends on climate conditions and also the
level of pollution [2,3]. The mercury is toxic and is absorbed easily by
respiratory system and damages Stomach and intestines. Existence of
this element in the air is harmful. By initiation of industrial era, the
level of mercury has been increased signicantly. The mercury has
harmful eect of the human beings and wildlife as well as various
mediums and food (especially sh) all around the world [4]. The level
of entered mercury into the environment has increased from the be-
ginning of industrial era. The mercury contamination is rst due to man
activities from which 6090% of total mercury released from man ac-
tivities is caused by industrial activities in 19951999. Mercury emis-
sion caused by man activities in Asia has increased from about 30% of
total universal emission to 56% [5,6,7].
The most important way for mercury emission is its emission in the
air. However, the mercury is also released from various sources in the
water and earth. In the case of releasing, the mercury is remained in
various forms and circulates among the air, water, deposits, soil and
plants. The study of heavy metalsdistribution in the dusts of the streets
and the soil of industrial townsworkshops in Jordan suggested that
heavy metal density is more accumulated in surface soil and it is de-
creasing in the lower level of the soil. The man and industrial activities
in the town workshops are possible sources for accumulating the heavy
metals of Zn, Cu, Ni and Pb from which a signicant portion was related
to industrial sources in the town [8].
Mulbery nigra is a fast-growing species from medium to high trees, is
resistant towards various soils and prefers visors to shade-friendly sites.
In this research it was studied that how much a Mulbery nigra could
absorb the mercury from the environment.
2. Method and materials
Two years saplings were transited into greenhouse and were
maintained there for 20 days in order to adapt to new condition. Non-
contaminated soil (applied natural soil in this analysis) was provided
from 0 to 30 depth of one of plantations. Then they were dried and
passed from a 2 mm sieve.in order to provide a soil contaminated by
Mercury(II) nitrate, spraying on the soil by 30, 50 and 70 mg density
was used in this study and the required amount of the solution was
sprayed on the soil gradually, then it was contaminated by the soil
uniformly and the vases were lled by them. The seedlings with the
same age and size were chosen in sucient number and were planted in
the vase. Afterward, the vases were maintained in the greenhouse and
the soil moisture was kept in the capacity level by weighted method.
Watering was done by distilled water when requiring and eight months
after seedlings growth, the aerial organs were harvested and washed by
https://doi.org/10.1016/j.toxrep.2018.05.006
Received 7 August 2017; Received in revised form 6 May 2018; Accepted 13 May 2018
Corresponding author.
E-mail address: hashemi@liau.ac.ir (S.A. Hashemi).
Toxicology Reports 5 (2018) 644–646
Available online 21 May 2018
2214-7500/ © 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/BY/4.0/).
T
water, then they were dried in the oven by 70 °C. The level of mercury
in plant samples was determined by dry digestion method after samples
digestion with atomic absorption spectrometry. The obtained data from
plants tests were organized in SPSS software. In order to analyze data
for determining metal accumulation level in aerial organs and the root
of plant, ANOVA test and in order to compare the eect of mercury
concentration on the leaf, stem and root, Duncan test were used.
3. Results
Comparison of mercury level among the studied concentrations,
using Duncan test suggested that there is signicant dierence in ac-
cumulation level of mercury among 30, 50 and 70 mg/l concentrations
in probability level of 95%. Such that the highest level of mercury ac-
cumulation was 55.67 mg/kg and the lowest level was 22.2 mg/kg in
20 mg/l density (Fig. 1).
The comparison of mercury among studied concentrations using
Duncan test suggested that there is signicant dierence among 30,
50,70 mg/L by 95% probability in accumulation level of mercury in the
stem m so that the highest level of Mercury accumulation is 50 mg/kg
and the lowest level was 28.6 mg/kg (Fig. 2).
Comparison of the mercury means among the studied
concentrations, using Duncan test suggested that there is signicant
dierence among 30, 50, and 70 mg/L by 95% probability in mercury
accumulation. Such that the highest level of mercury accumulation is
65 mg/kg and the lowest level of mercury accumulation is 35.3 mg/kg
(Fig. 3).
4. Discussion
The obtained results from the research suggest that aerial organs of
Mulberry nigra have had signicant dierence for mercury accumula-
tion in various concentrations. By increasing the concentration of soil
mercury, the amount of its accumulation in aerial organs of leaf, stem of
Mulberry nigra has increased as well. By studying the eect of mercury
on some physiology parameters in eucalyptus and also comparing the
accumulation and mercury transition in this study suggested that the
absorption of this metal in the root is more than it in leaf and stem
[9,10]. About mercury accumulation in Acer velutinum, the results
suggest that various contamination densities have been eective and by
increasing mercury, accumulation level in the root is increased as well
(Fig. 2) concluded in their research that although the mercury is not a
nutrient, could be absorbed easily by the plants root and accumulated
in the plants with some concentrations which is harmful for food chain.
Fig. 1. The mean of mercury absorption in aerial organ of leaf in Mulberry nigra sapling.
Fig. 2. The mean of mercury absorption in the stem of Mulberry nigra sapling.
S.A. Hashemi, S. Tabibian Toxicology Reports 5 (2018) 644–646
645
5. Conclusion
The factors of stems, roots, soil, are a signicant dierence in terms
of mercury accumulation and this signicant dierence shows the
amount of mercury absorption in Mullberry nigra tree species and the
ability of Mullberry nigra in the amount of contamination accumulation
is appropriate. Study revealed that concentrations of lead, zinc, mer-
cury, cadmium and nickel were measured in the leaf of seven species of
deciduous trees (Indian horse-chestnut, maple, Acer cappadocicumGled,
ash, Platanus orientalis, poplar and acacia) in urban areas which the
highest accumulation amount of cadmium and zinc, lead, mercury and
nickel was in poplar, Indian horse-chestnut and acacia, and acacia and
ash, respectively [11,12]. The mercury accumulation in plant tissues in
cell surface also may be toxic and cause growth decrease. Therefore,
preventing mercury absorption by plants roots, could be a strong
strategy for minimizing biologic side eects of this element. In phy-
toremediation topics of heavy metals, tolerance factors of the plant
against metals, plantsroot system, and the capability of transition from
underground organs to aerial organs (transition factor), growth speed
and high biomass must be considered. In this research, according to
mentioned points, Mulberry nigra is an appropriate species for rening
soils contaminated by mercury.
Transparency document
The Transparency document associated with this article can be
found in the online version.
References
[1] I. Raskin, B.D. Ensley, Phytoremediation of Toxic Metals: Using Plants to Clean Up
the Environment, John Wiley & Sons, Inc., New York, 2000.
[2] E. Lombi, F.J. Zhao, S.J. Dunham, S.P. McGrath, Phytoremediation of heavy me-
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[9] A. Shariat, The eect of mercury on some physiology parameters in eucalyptus
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[12] L. Erdei, G. Mezôsi, I. Mécs, I. Vass, F. Fôglein, L. Bulik, Phytoremediation as a
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on Photosynthesis, (2005).
Fig. 3. The mean of mercury accumulation in the root of Mulberry nigra sapling.
S.A. Hashemi, S. Tabibian Toxicology Reports 5 (2018) 644–646
646

Supplementary resource (1)

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A PROPER inventory of atmospheric emissions from natural sources is basic to our understanding of the atmospheric cycle of the trace metals (and metalloids), and is also needed for assessing the extent of regional and global pollution by toxic metals1. It is generally presumed that the principal natural sources of trace metals in the atmosphere are wind-borne soil particles, volcanoes, seasalt spray and wild forest fires2–6. Recent studies have shown, however, that particulate organic matter is the dominant component of atmospheric aerosols in non-urban areas7–10 and that over 60% of the airborne trace metals in forested regions can be attributed to aerosols of biogenic origin11,12. Here I estimate that biogenic sources can account for 30–50% of the global baseline emissions of trace metals. For most of the toxic metals, the natural fluxes are small compared with emissions from industrial activities, implying that mankind has become the key agent in the global atmospheric cycle of trace metals and metalloids.
Article
An estimate of the global emission of mercury from anthropogenicsources in 1995 has been prepared. Major emphasis is placed onemissions from stationary combustion sources, non-ferrous metalproduction, pig iron and steel production, cement production andwaste disposal. About three quarters of the total emission,estimated to be about 1900 tonnes, was from combustion of fuels, particularly coal combustion in China, India, and South and NorthKorea. In general, the Asian countries contribute about 56% to the global emissions of mercury to the atmosphere. Europe and North America seem to contribute less than 25%. The major chemical form of mercury emitted to the atmosphere is gaseouselemental mercury, contributing with about 53% to the totalemissions, followed by gaseous bivalent mercury with 37%. The Hg emissions on particles contribute only about 10% to the total emissions. Again, Asia contributes about 50% to the totalemissions of all individual chemical forms of mercury.
Article
A review of the available information on global Hg cycling shows that the atmosphere and surface ocean are in rapid equilibrium; the evasion of Hg0 from the oceans is balanced by the total oceanic deposition of Hg(II) from the atmosphere. The mechanisms whereby reactive Hg species are reduced to volatile Hg0 in the oceans are poorly known, but reduction appears to be chiefly biological. The rapid equilibrium of the surface oceans and the atmosphere, coupled with the small Hg sedimentation in the oceans makes deposition on land the dominant sink for atmospheric Hg. About half of the anthropogenic emissions appear to enter the global atmospheric cycle while the other half is deposited locally, presumably due to the presence of reactive Hg in flue gases. We estimate that over the last century anthropogenic emissions have tripled the concentrations of Hg in the atmosphere and in the surface ocean. Thus, two-thirds of the present Hg fluxes (such are deposition on land and on the ocean) are directly or indirectly of anthropogenic origin. Elimination of the anthropogenic load in the ocean and atmosphere would take fifteen to twenty years after termination of all anthropogenic emissions.
Article
Karak Industrial Estate (KIE) was investigated for its heavy metals content. Samples of dust, street dust and soil were analyzed for their content of Fe, Cu, Zn, Ni and Pb after digestion with nitric acid. The results of the analysis were used to determine major sources and magnitude of heavy metals pollution. The ranges of heavy metal concentrations in the investigated area were 58.8–94.8, 1.8–84.9, 15.4–136.9, 1.7–6.5 and 2.1–314.1 mg kg−1 dry soil for Fe, Cu, Zn, Ni and Pb, respectively. The concentrations of heavy metals in soils are greater on the surface but decreased in the lower part as a result of the basic nature of this soil. There are two possible sources of heavy metals (Zn, Cu, Ni and Pb) anthropogenic and industrial activities from the work place in KIE. Significant contribution from industrial sources at KIE was evident at nearby places.
Article
A pot experiment was conducted to compare two strategies of phytoremediation: natural phytoextraction using the Zn and Cd hyperaccumulator Thlaspi caerulescens J. Presl & C. Presl versus chemically enhanced phytoextraction using maize (Zea mays L.) treated with ethylenediaminetetraacetic acid (EDTA). The study used an industrially contaminated soil and an agricultural soil contaminated with metals from sewage sludge. Three crops of T. caerulescens grown over 391 d removed more than 8 mg kg(-1) Cd and 200 mg kg(-1) Zn from the industrially contaminated soil, representing 43 and 7% of the two metals in the soil. In contrast, the high concentration of Cu in the agricultural soil severely reduced the growth of T. caerulescens, thus limiting its phytoextraction potential. The EDTA treatment greatly increased the solubility of heavy metals in both soils, but this did not result in a large increase in metal concentrations in the maize shoots. Phytoextraction of Cd and Zn by maize + EDTA was much smaller than that by T. caerulescens from the industrially contaminated soil, and was either smaller (Cd) or similar (Zn) from the agricultural soil. After EDTA treatment, soluble heavy metals in soil pore water occurred mainly as metal-EDTA complexes, which were persistent for several weeks. High concentrations of heavy metals in soil pore water after EDTA treatment could pose an environmental risk in the form of ground water contamination.
The effect of mercury on some physiology parameters in eucalyptus occidentalis, the magazine of science and technology of agriculture and natural sources
  • A Shariat
A. Shariat, The effect of mercury on some physiology parameters in eucalyptus occidentalis, the magazine of science and technology of agriculture and natural sources, Water Soil Sci. 53 (2010) 112-121.