151
Baumann et al. 2014). Chelating agents and other chemicals are efficient, selective
scavenger and also play an important role in U/DU accumulation, which decrease
the absorption and distribution and increase the elimination of U (Yue et al. 2018).
A number of plants, like Lemna gibba (duckweed), Callitriche stagnalis (waterstarworts), Fontinalis antipyretica and Apium nodiflorum, are reported to have
potential for U remediation (Mkandawire et al. 2004; Pratas et al. 2012; Favas and
Pratas 2013). C. stagnalis and A. nodiflorum are regarded as keystone species for
phytoremediation applications of U for their efficient rooting capabilities and bioproductivity (Favas and Pratas 2013). Further, soil mycorrhiza (including AMF,
arbuscular mycorrhizal fungi) plays a considerable role in phytostabilization of U
(Chen et al. 2008; Gadd and Fomina 2011). Conversely, plant stress and related
ROS (reactive oxygen species) production for radionuclide accumulation are also
evident from different studies (Gupta and Voronina 2018) which are important for
appropriate plant-based remediation practices of uranium.
2 Uranium and Its Application
Uranium has a major application in nuclear power reactors as fuel, while depleted
U is generally used to make military components, but also (formerly) used in paint
and pigment manufacturing units (Berlin and Rudell 1986; WHO 2012). Electricity
production by low-carbon electricity in nuclear power plants increased worldwide
during the last few decades. Currently, nuclear power provides approximately 11%
of global supply of electricity and is expected to rise as it is seen by many countries
as a cost-competitive, near-zero pollutant (including greenhouse gases)-emitting
technology, with a scope for industrialized nation having limited resources of native
resources (WNA 2017). For example, France relies on nuclear for more than 75%
of electricity and the USA, about 20%. Nevertheless, evolution of nuclear power
facilities and related U requirement is undergoing uncertainties worldwide after the
accident in Fukushima (Japan) in March 2011 (NEA 2016). Countries like
Kazakhstan, Canada and Australia produce around 39, 22 and 10% of U, respectively, which amount to more than two-thirds of the global U production (59,531
tonnes from mines) (WNA 2017). The production of U may come from in situ
leaching (ISL; 50%), underground and open pit (46%) or by-products (4%). Apart
from natural leaching, U enters into the environment from nuclear fuel plants and
their tailings, phosphate fertilizers, coal and fuel combustion, etc.
3 Uranium in the Environment
In spite of its ubiquitous presence in the environment, U has peculiar chemical and
physical properties. Radiologically, U is an alpha-particle-emitting, chemically
toxic, non-essential element. Apart from the readily soluble hexavalent form,
Uranium and Plants: Elemental Translocation and Phytoremediation Approaches
Baumann et al. 2014). Chelating agents and other chemicals are efficient, selective
scavenger and also play an important role in U/DU accumulation, which decrease
the absorption and distribution and increase the elimination of U (Yue et al. 2018).
A number of plants, like Lemna gibba (duckweed), Callitriche stagnalis (waterstarworts), Fontinalis antipyretica and Apium nodiflorum, are reported to have
potential for U remediation (Mkandawire et al. 2004; Pratas et al. 2012; Favas and
Pratas 2013). C. stagnalis and A. nodiflorum are regarded as keystone species for
phytoremediation applications of U for their efficient rooting capabilities and bioproductivity (Favas and Pratas 2013). Further, soil mycorrhiza (including AMF,
arbuscular mycorrhizal fungi) plays a considerable role in phytostabilization of U
(Chen et al. 2008; Gadd and Fomina 2011). Conversely, plant stress and related
ROS (reactive oxygen species) production for radionuclide accumulation are also
evident from different studies (Gupta and Voronina 2018) which are important for
appropriate plant-based remediation practices of uranium.
2 Uranium and Its Application
Uranium has a major application in nuclear power reactors as fuel, while depleted
U is generally used to make military components, but also (formerly) used in paint
and pigment manufacturing units (Berlin and Rudell 1986; WHO 2012). Electricity
production by low-carbon electricity in nuclear power plants increased worldwide
during the last few decades. Currently, nuclear power provides approximately 11%
of global supply of electricity and is expected to rise as it is seen by many countries
as a cost-competitive, near-zero pollutant (including greenhouse gases)-emitting
technology, with a scope for industrialized nation having limited resources of native
resources (WNA 2017). For example, France relies on nuclear for more than 75%
of electricity and the USA, about 20%. Nevertheless, evolution of nuclear power
facilities and related U requirement is undergoing uncertainties worldwide after the
accident in Fukushima (Japan) in March 2011 (NEA 2016). Countries like
Kazakhstan, Canada and Australia produce around 39, 22 and 10% of U, respectively, which amount to more than two-thirds of the global U production (59,531
tonnes from mines) (WNA 2017). The production of U may come from in situ
leaching (ISL; 50%), underground and open pit (46%) or by-products (4%). Apart
from natural leaching, U enters into the environment from nuclear fuel plants and
their tailings, phosphate fertilizers, coal and fuel combustion, etc.
3 Uranium in the Environment
In spite of its ubiquitous presence in the environment, U has peculiar chemical and
physical properties. Radiologically, U is an alpha-particle-emitting, chemically
toxic, non-essential element. Apart from the readily soluble hexavalent form,
Uranium and Plants: Elemental Translocation and Phytoremediation Approaches