Combination of biochar amendment and phytoremediation for hydrocarbon removal in petroleum-contaminated soil
Combination of biochar amendment and phytoremediation for hydrocarbon removal in petroleum-contaminated soil
Tao Han 0 1
Zhipeng Zhao 0 1
Mark Bartlam 0 1
Yingying Wang 0 1
Editorial Responsible: Hailong Wang
0 College of Life Sciences, Nankai University , Tianjin 300071 , China
1 Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University , Tianjin 300071 , China
2 Yingying Wang
Remediation of soils contaminated with petroleum is a challenging task. Four different bioremediation strategies, including natural attenuation, biochar amendment, phytoremediation with ryegrass, and a combination of biochar and ryegrass, were investigated with greenhouse pot experiments over a 90-day period. The results showed that planting ryegrass in soil can significantly improve the removal rate of total petroleum hydrocarbons (TPHs) and the number of microorganisms. Within TPHs, the removal rate of total nalkanes (45.83 %) was higher than that of polycyclic aromatic hydrocarbons (30.34 %). The amendment of biochar did not result in significant improvement of TPH removal. In contrast, it showed a clear negative impact on the growth of ryegrass and the removal of TPHs by ryegrass. The removal rate of TPHs was significantly lower after the amendment of biochar. The results indicated that planting ryegrass is an effective remediation strategy, while the amendment of biochar may not be suitable for the phytoremediation of soil contaminated with petroleum hydrocarbons.
Petroleum hydrocarbons; Ryegrass; Biochar; Phytoremediation
Introduction
The rapid development of the global economy has led to
considerable environmental pollution by a wide range of
persistent organic and inorganic pollutants
(Gaskin and Bentham
2010; Zhang et al. 2010)
. Petroleum products are widely used
in modern society and have become one of the most important
environmental pollutants
(Wang et al. 2010, 2012; Zhang et al.
2010)
. Petroleum is a mix of different compounds, consisting
mainly of saturated hydrocarbons, aromatic hydrocarbons,
resins, and asphaltenes
(Liu et al. 2014)
. Petroleum is reported
to cause environmental risks in the soil ecological syste
m
(Wang et al. 2012
), such as inhibition of plant growth, damage
to soil structure, destruction of groundwater quality, and so on
(Cai et al. 2010)
. Moreover, the hazardous chemicals in
petroleum also pose serious threats to human health
(Anyika et al.
2015)
.
Considerable efforts have been made for the remediation of
petroleum-contaminated sites. Phytoremediation is one of the
most favorable remediation techniques since it is both
costeffective and environmentally friendly
(Gaskin et al. 2010;
AlMansoory et al. 2015)
. Plants can have a number of effects,
including degradation, transformation, assimilation,
metabolism, and detoxification of hazardous pollutants from soils and
aquatic and atmospheric sites
(Cai et al. 2010)
. Several plant
species, such as ryegrass, have been successfully applied to
the phytoremediation of soil contaminated with organic and
inorganic pollutants
(Khan et al. 2013; Mimmo et al. 2015; Lu
et al. 2015)
. The question of how to improve the efficiency
and optimize the conditions of phytoremediation is one of the
major concerns. It was reported that both the physicochemical
properties and microbial activities of soil had a strong impact
on the effectiveness of phytoremediation
(Guo et al. 2014)
.
In recent years, the use of biochar as a soil amendment has
been the subject of increasing attention
(Tang et al. 2013)
.
Biochar is formed by burning biomass under hypoxia and low
temperature and is a low-density charred material
(Bastos
et al. 2014; Mukherjee et al. 2014; Tang et al. 2013)
. It was
reported that biochar could change the soil physicochemical
properties
(Brennan et al. 2014)
. For example, it could
increase the soil pH
(Beesley and Marmiroli 2011; Mukherjee
et al. 2014; Schmidt et al. 2014)
, strengthen the water
retaining capacity of soil
(Evangelou et al. 2014; Yao et al.
2012)
, raise the soil fertility
(Mia et al. 2014; Steinbeiss et al.
2009)
, reduce the leaching of soluble macronutrients
(Lucchini et al. 2014; Quilliam et al. 2013a)
, and heighten
carbon sequestration
(Bastos et al. 2014; Méndez et al.
2012)
. These lead to potentially beneficial effects on crop
productivity, plant establishment, and growth; mitigating
climate change by sequestrating C from atmosphere into soil;
and improving moisture, nutrient retention, and microbial
activity
(Brennan et al. 2014)
. Meanwhile, biochar has also been
used as a promising material in environmental remediation
applications
(Qin et al. 2013; Ahmad et al. 2014;
GarciaDelgado et al. 2015)
. For instance, biochar has been applied
as a novel carbonaceous material to adsorb metals in soil and
water
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