The potential benefits and limitations of different test procedures to determine the effects of Ag nanomaterials and AgNO3 on microbial nitrogen transformation in soil

Environmental Sciences Europe

Table 1 EC ₁₀ and EC ₅₀ values for silver nanomaterials and AgNO ₃ on day 28

	Experiment 1		Experiment 2
Test parameters	EC₁₀^a[mg/kg]	EC₅₀^a[mg/kg]	EC₅₀^a[mg/kg]
NM-300K ^b
Nitrate accumulation, lucerne	---	>15	>15
Nitrate accumulation, (NH₄)₂SO₄	0.9 [0.2 to 1.6]	7.3 [5.1 to 11.5]	6.5 [0.3 to 63.5]
Potential ammonium oxidation	0.5 [0.0 to 1.0]	1.6 [0.5 to 4.8]	3.7 [2.1 to 8.3]
Substrate-induced respiration	1.0 [n.d.]	5.0 [n.d.]	13 [n.d.]
NM-302 ^c
Nitrate accumulation, lucerne	---	>100	>100
Nitrate accumulation, (NH₄)₂SO₄	5.6 [4.7 to 6.6]	44.6 [41.2 to 48.5]	Not determined
Potential ammonium oxidation	0.5 [n.d.]	6.0 [n.d.]	17.1 [14.3 to 20.6]
Substrate-induced respiration	2.1 [n.d.]	67.5 [n.d.]	74.7 [42.8 to 174.8]
AgNO ₃ ^b
Nitrate accumulation, lucerne	---	>15	Not determined
Nitrate accumulation, (NH₄)₂SO₄	0.7 [0.50 to 0.8]	2.8 [2.6 to 3.1]	Not determined
Potential ammonium oxidation	1.4 [1.2 to 1.6]	2.9 [2.7 to 3.2]	2.4 [n.d.]
Substrate-induced respiration	---	>15	>15

^aConfidence interval shown in square brackets; ^bfive test concentrations; spacing factor of 3; ^cscreening approach: three test concentrations; spacing factor of 10; n.d., not determinable.