246
A. A. Ansari et al.
(5) phytoremediation controlling both point and nonpoint
sources of pollution (Yang 2009).
The change in the eutrophic conditions is reflected in the
occurrence, pattern of distribution, and diversity of the biotic
community (Ansari et al. 2011c). The limnological studies
of lakes, rivers, and streams have been emphasized owing
to deterioration of water quality because of eutrophication
(Ansari et al. 2011b; Garg et al. 2002; Jha and Barat 2003).
Nutrient removal capacity of some important aquatic plants
such as Eichhornia crassipes, Lemna minor,and Azolla pinnata have been tested individually as well as in combinations in microcosms. Maximum removal was observed in
species mixtures, involving E. crassipes and L. minor (79 %
N) (Tripathi and Upadhyay 2003; Jayaweera and Kasturiarachchi 2004).
Various methods have been investigated for improving
water quality specially the bioremediation of water using
algal colony or other aquatic plants. Plants from the family
Lemnaceae are widely used in ecological engineering projects to purify wastewater and eutrophic waterbodies (Fang
et al. 2007). In phytoremediation plants can be used for pollutant stabilization, extraction, degradation, or volatilization
(Smith et al. 2004). Phytoremediation by kenaf ( Hibiscus
cannabinus L.) was applied to improve eutrophic water quality. The growth of kenaf was satisfactorily achieved in water
environment and nutrients were removed from eutrophic
water body (Ikeda et al. 1999).
The excessive addition of nutrients to water causes quality problems and is one of the major causes of eutrophication in fresh water ecosystems (Ansari and Khan 2002, 2007,
2009a). The eutrophication process directly or indirectly affects the physical, chemical, and biological characteristics
of an aquatic ecosystem (Ansari and Khan 2006a, b). The
potential of various aquatic macrophytes for phytoremediation of various pollutants in water has been determined by
various workers (Chaudhari 2002; Manu and Chaudhari
2002; Chandrashekhar et al. 2003). Phytoremediation, popularly known as green clean, is an emerging technology for
the cleanup of contaminated sites by the use of plants, and
is ecofriendly and low-cost technology compared with traditional engineering remediation methods (Diwan et al. 2008).
The environmental factors viz. nutrients, temperature,
pH, dissolved oxygen, carbon-di-oxide, light, within a
water source have major role in controlling eutrophication
in aquatic bodies and limiting the growth and development
of aquatic plants (Lau and Lane 2002; Shen 2002). The pH
regulates the origin, mobility, and availability of ions and
their different forms in water bodies (Huang et al. 2005). The
uptake of nutrients by aquatic plants shows a direct relation
with pH of the medium (Cordes et al. 2000). The range of
light intensity influences the photosynthesis and acclimation of aquatic macrophytes. The aquatic macrophytes are
reported to remove about 60–80 % nitrogen (Fox et al. 2008)
and about 69 % of potassium from water (Zhou et al. 2007).
Growth responses of aquatic plants indicate eutrophic state
of water (Smith 2007). The effectiveness of aquatic plants
was also evaluated for their capabilities in removing heavy
metals from water (Skinner et al. 2007).
A lot of work has been done and a huge amount of capital
has been invested for the restoration of some major and important water bodies that are besieged under the direct threat
of eutrophication, but results are not very satisfactory. Beside the mechanical purification of water, biological methods such as phytoremediation technologies are required as
they are very low-cost, most effective and sustainable measures to control water eutrophication. The research should
be done to produce cost-effective phytoremediation systems
using aquatic macrophytes for the recovery of nutrients from
eutrophic waters. The role of various limiting factors (viz.
best/worst performance of aquatic plants, nutrient concentrations, temperature, pH, light, seasonality) in developing
a sustainable phytoremediation system should be identified.
The harvested plant material (grown in phytoremediation
system) can be utilized as livestock food, raw material, for
biofuel production and toxicity testing of waters.
17.8 Future Perspectives
Ecological research should be done on important aspects like
causes, consequences, and controls of water eutrophication.
Studies should be conducted on phytoremediation including
offsite nutrient removal by constructed wetlands to abate
both point and nonpoint nutrient pollution and in situ phytoremediation using floating ecoislands system in suitable
environmental conditions with enhanced nutrient removal
capacity. Large treatment ponds can be developed and tested
where limiting factors will be controlled by mechanically
engineered and technological means to enhance the nutrients recovery from eutrophic waters. The work can further
be extended to develop cost-effective methods of large-scale
phytoremediation using aquatic macrophytes.
References
Alvarez-Cobelas M, Cirujano S, Sanchez-Carrillo S et al (2001) Hydrological and botanical man-made changes in the Spanish wetland of
Las Tablas de Daimiel. Biol Conserv 97:89–98
Ansal MD, Dhawan A, Kaur VI et al (2010) Duckweed based bio-remediation of village ponds: An ecologically and economically viable
integrated approach for rural development through aquaculture.
Livest Res Rural Dev 22, Article #129. Retrieved May 8, 2012,
from http://www.lrrd.org/lrrd22/7/ansa22129.htm
Ansari AA (2005) studies on the role of selected household detergents
in the eutrophication of freshwater ecosystem. PhD thesis, Aligarh
Muslim University, Aligarh
A. A. Ansari et al.
(5) phytoremediation controlling both point and nonpoint
sources of pollution (Yang 2009).
The change in the eutrophic conditions is reflected in the
occurrence, pattern of distribution, and diversity of the biotic
community (Ansari et al. 2011c). The limnological studies
of lakes, rivers, and streams have been emphasized owing
to deterioration of water quality because of eutrophication
(Ansari et al. 2011b; Garg et al. 2002; Jha and Barat 2003).
Nutrient removal capacity of some important aquatic plants
such as Eichhornia crassipes, Lemna minor,and Azolla pinnata have been tested individually as well as in combinations in microcosms. Maximum removal was observed in
species mixtures, involving E. crassipes and L. minor (79 %
N) (Tripathi and Upadhyay 2003; Jayaweera and Kasturiarachchi 2004).
Various methods have been investigated for improving
water quality specially the bioremediation of water using
algal colony or other aquatic plants. Plants from the family
Lemnaceae are widely used in ecological engineering projects to purify wastewater and eutrophic waterbodies (Fang
et al. 2007). In phytoremediation plants can be used for pollutant stabilization, extraction, degradation, or volatilization
(Smith et al. 2004). Phytoremediation by kenaf ( Hibiscus
cannabinus L.) was applied to improve eutrophic water quality. The growth of kenaf was satisfactorily achieved in water
environment and nutrients were removed from eutrophic
water body (Ikeda et al. 1999).
The excessive addition of nutrients to water causes quality problems and is one of the major causes of eutrophication in fresh water ecosystems (Ansari and Khan 2002, 2007,
2009a). The eutrophication process directly or indirectly affects the physical, chemical, and biological characteristics
of an aquatic ecosystem (Ansari and Khan 2006a, b). The
potential of various aquatic macrophytes for phytoremediation of various pollutants in water has been determined by
various workers (Chaudhari 2002; Manu and Chaudhari
2002; Chandrashekhar et al. 2003). Phytoremediation, popularly known as green clean, is an emerging technology for
the cleanup of contaminated sites by the use of plants, and
is ecofriendly and low-cost technology compared with traditional engineering remediation methods (Diwan et al. 2008).
The environmental factors viz. nutrients, temperature,
pH, dissolved oxygen, carbon-di-oxide, light, within a
water source have major role in controlling eutrophication
in aquatic bodies and limiting the growth and development
of aquatic plants (Lau and Lane 2002; Shen 2002). The pH
regulates the origin, mobility, and availability of ions and
their different forms in water bodies (Huang et al. 2005). The
uptake of nutrients by aquatic plants shows a direct relation
with pH of the medium (Cordes et al. 2000). The range of
light intensity influences the photosynthesis and acclimation of aquatic macrophytes. The aquatic macrophytes are
reported to remove about 60–80 % nitrogen (Fox et al. 2008)
and about 69 % of potassium from water (Zhou et al. 2007).
Growth responses of aquatic plants indicate eutrophic state
of water (Smith 2007). The effectiveness of aquatic plants
was also evaluated for their capabilities in removing heavy
metals from water (Skinner et al. 2007).
A lot of work has been done and a huge amount of capital
has been invested for the restoration of some major and important water bodies that are besieged under the direct threat
of eutrophication, but results are not very satisfactory. Beside the mechanical purification of water, biological methods such as phytoremediation technologies are required as
they are very low-cost, most effective and sustainable measures to control water eutrophication. The research should
be done to produce cost-effective phytoremediation systems
using aquatic macrophytes for the recovery of nutrients from
eutrophic waters. The role of various limiting factors (viz.
best/worst performance of aquatic plants, nutrient concentrations, temperature, pH, light, seasonality) in developing
a sustainable phytoremediation system should be identified.
The harvested plant material (grown in phytoremediation
system) can be utilized as livestock food, raw material, for
biofuel production and toxicity testing of waters.
17.8 Future Perspectives
Ecological research should be done on important aspects like
causes, consequences, and controls of water eutrophication.
Studies should be conducted on phytoremediation including
offsite nutrient removal by constructed wetlands to abate
both point and nonpoint nutrient pollution and in situ phytoremediation using floating ecoislands system in suitable
environmental conditions with enhanced nutrient removal
capacity. Large treatment ponds can be developed and tested
where limiting factors will be controlled by mechanically
engineered and technological means to enhance the nutrients recovery from eutrophic waters. The work can further
be extended to develop cost-effective methods of large-scale
phytoremediation using aquatic macrophytes.
References
Alvarez-Cobelas M, Cirujano S, Sanchez-Carrillo S et al (2001) Hydrological and botanical man-made changes in the Spanish wetland of
Las Tablas de Daimiel. Biol Conserv 97:89–98
Ansal MD, Dhawan A, Kaur VI et al (2010) Duckweed based bio-remediation of village ponds: An ecologically and economically viable
integrated approach for rural development through aquaculture.
Livest Res Rural Dev 22, Article #129. Retrieved May 8, 2012,
from http://www.lrrd.org/lrrd22/7/ansa22129.htm
Ansari AA (2005) studies on the role of selected household detergents
in the eutrophication of freshwater ecosystem. PhD thesis, Aligarh
Muslim University, Aligarh