110
concentration of silver nanoparticles in soil affects the functional composition of
microbial communities and related ecosystem. They found that different shapes and
concentration of nanomaterial also changed the carbon utilization pattern of present
microbial community. Recently, Rahmatpour et al. (2017) also measured significant
reduction of soil urease and phosphatase activity at >20 mg.kg
−1
due to Ag nanoparticles. The author revealed that the inhibition of soil enzymatic activity and microbial community structure depends on nanoparticles concentration and soil type.
They found no change in soil respiration at low concentration of silver nanoparticles.
4.5.2 Carbon Nanomaterials
The application of carbon nanomaterials has been increased due to their exceptional
optical and mechanical properties. The carbon nanomaterials have shown mixed
effect on microbial communities. Oyelami and Semple (2015) studied the effect of
single- and multi-walled carbon nanotube on soil microbial flora. They found that
the amount of glucose in microbial biomass decreased with increasing concentration of carbon nanomaterial in soil but inconsistent with carbon nanomaterial concentration in the range of 1 to 1000 mg.g
−1
. They observed that increasing
concentration does not impact microbial activity in specific pattern. Previously,
Tong et al. (2007) also found that at 1–1000 mg C 60 fullerenes per kg soil had no
impact on total phospholipid content of microbial population after 180 days of incubation. They reported that fullerenes have not changed the microbial community
structure and microbial activity at this concentration range.
Further, Nyberg et al. (2008) found no negative impact of C 60 fullerenes at 50 g.
kg
−1
on microbial community but carbon nanomaterial influenced the food chain
through affecting the growth of primary and secondary producer. In contrast,
Johansen et al. (2008) reported that C 60 fullerene reduced the number of fastgrowing bacteria which directly influenced the number of bacteria feeding on the
protozoan community. They found that fullerene absorbed the essential nutrients
like vitamins and minerals from soils, which limited the growth of soil microbes.
Chung et al. (2011) also reported that multi-walled carbon nanotubes (MWCNT)
reduced the soil enzyme activities at 500 mg.kg
−1
concentration. Further, Tong et al.
(2012) studied the effect of single-walled carbon nanotube (SWCNT) on microbial
community structure. They repeatedly used raw SWCNT at 1000 μg.g
−1
soil and
polyethylene glycol or m-poly amino benzene sulfonic acid functionalized SWCNT
at 10 and 50 μg.g
−1
soil concentration to challenge E. coli and microbial community
for 6 weeks. They found that repeated application of SWCNT affected the soil
microbial community and soil metabolic activity decreased less with functionalized SWCNT.
Carbon nanomaterial showed both positive and negative impact on microbial
community at various concentration levels. It was found that multi-walled carbon
nanotubes (MWCNT) at lower concentration in the range of 10–1000 mg.kg
−1
showed no remarkable effect on sandy loam soil microbial community but at higher
H. Chhipa
concentration of silver nanoparticles in soil affects the functional composition of
microbial communities and related ecosystem. They found that different shapes and
concentration of nanomaterial also changed the carbon utilization pattern of present
microbial community. Recently, Rahmatpour et al. (2017) also measured significant
reduction of soil urease and phosphatase activity at >20 mg.kg
−1
due to Ag nanoparticles. The author revealed that the inhibition of soil enzymatic activity and microbial community structure depends on nanoparticles concentration and soil type.
They found no change in soil respiration at low concentration of silver nanoparticles.
4.5.2 Carbon Nanomaterials
The application of carbon nanomaterials has been increased due to their exceptional
optical and mechanical properties. The carbon nanomaterials have shown mixed
effect on microbial communities. Oyelami and Semple (2015) studied the effect of
single- and multi-walled carbon nanotube on soil microbial flora. They found that
the amount of glucose in microbial biomass decreased with increasing concentration of carbon nanomaterial in soil but inconsistent with carbon nanomaterial concentration in the range of 1 to 1000 mg.g
−1
. They observed that increasing
concentration does not impact microbial activity in specific pattern. Previously,
Tong et al. (2007) also found that at 1–1000 mg C 60 fullerenes per kg soil had no
impact on total phospholipid content of microbial population after 180 days of incubation. They reported that fullerenes have not changed the microbial community
structure and microbial activity at this concentration range.
Further, Nyberg et al. (2008) found no negative impact of C 60 fullerenes at 50 g.
kg
−1
on microbial community but carbon nanomaterial influenced the food chain
through affecting the growth of primary and secondary producer. In contrast,
Johansen et al. (2008) reported that C 60 fullerene reduced the number of fastgrowing bacteria which directly influenced the number of bacteria feeding on the
protozoan community. They found that fullerene absorbed the essential nutrients
like vitamins and minerals from soils, which limited the growth of soil microbes.
Chung et al. (2011) also reported that multi-walled carbon nanotubes (MWCNT)
reduced the soil enzyme activities at 500 mg.kg
−1
concentration. Further, Tong et al.
(2012) studied the effect of single-walled carbon nanotube (SWCNT) on microbial
community structure. They repeatedly used raw SWCNT at 1000 μg.g
−1
soil and
polyethylene glycol or m-poly amino benzene sulfonic acid functionalized SWCNT
at 10 and 50 μg.g
−1
soil concentration to challenge E. coli and microbial community
for 6 weeks. They found that repeated application of SWCNT affected the soil
microbial community and soil metabolic activity decreased less with functionalized SWCNT.
Carbon nanomaterial showed both positive and negative impact on microbial
community at various concentration levels. It was found that multi-walled carbon
nanotubes (MWCNT) at lower concentration in the range of 10–1000 mg.kg
−1
showed no remarkable effect on sandy loam soil microbial community but at higher
H. Chhipa