Table 4.

Negative effects of CNMs in soil microorganism.

Reference	CNM	Organism	Treatment	Effect
Kang et al., 2007	SWNTs	Escherichia coli	1–50 μg/mL	Strong antimicrobial properties.
Fang et al., 2007	C60 aggregates	Bacillus subtilis (Gram-positive) and Pseudomonas putida (Gram-negative)	0.01 mg/L	Significantly impacted levels of iso-and anteiso-branched fatty acids in Bacillus subtilis (Gram-positive).
Johansen et al., 2008	Fullerenes C60	Microbial communities and protozoans	0–50 mg/kg	Results after 14 days showed a threefold decrease in the number of fast-growing bacteria.
				No significant changes in protozoan population.
Liu et al., 2009	SWCNT dispersed and SWCNT agglomerates in saline solution	Gram-negative Escherichia coli, Pseudomonas aeruginosa, and gram-positive Staphylococcus aureus, Bacillus subtilis	5 g/mL	Higher antibacterial activity of dispersed SCNT to gram-positive bacteria in comparison with the agglomerates.
Chung et al., 2011	MWCNT	Microbial communities	0, 50, 500, and 5000 μg/g	Enzyme activity decreased after 30 min of the incubation.
				Microbial biomass and extracellular enzyme activity decreased (up to ∼50%).
Rodrigues et al., 2013	Carboxyl-functionalized SWCNTs	Bacterial and fungal communities	0.5 mg/L	Alteration on Pseudomonas putida (Gram-negative) phase transition temperatures and levels of unsaturated fatty acids.
				Higher doses had a maximum biomass loss at 3 days and the fungal community was unable to recover even after 14 days.
Jin et al., 2014	SWCNT	Gram- positive, Gram-negative bacteria, and fungal populations	0.03 to 1 mg/g	Decreased biomass of microbial groups and fungal populations.
Chung et al., 2015	Graphene oxide	Microbial communities/soil enzymes	0.5–1 mg/kg	Decreases of up to 50% in the enzyme activities after 21 days of incubation.
Kerfahi et al., 2015	Raw and acid treated or functionalized MWCNTs	Microbial communities	0–5000 mg/kg	Bacterial community composition was affected but recovered after 8 weeks.