TABLE 3.

Chemical indicators of microbial activity measured in the NC microcosms^a

Indicator	Microbial activity for microcosm with indicated amendment (μmol)
	None	Toluene	NO3−	Toluene + NO3−
CO2	13.22 ± 4.91	30.71 ± 3.99b	39.46 ± 7.82b	33.10 ± 4.84b
NO3−	0.77 ± 1.11	0.49 ± 0.03	84.00 ± 6.98	15.01 ± 3.72
NO2−	NDc	ND	1.79 ± 2.19	1.83 ± 0.06
N2O	ND	ND	9.12 ± 1.03b	1.34 ± 0.32

^aDetermined at the conclusion of the 18-day incubation. Data are means ± standard deviations. 

^bThis value is significantly different (P < 0.05) from that for the nonamended control (CO₂) or those for the nitrate-amended treatments (NO₃⁻, NO₂⁻, and N₂O). 

^cND, not detected.