N-(1,4-dimethylpentyl)-N'-phenylbenzene-1,4-diamine

Toxicity to soil microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil microorganisms

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study.

Qualifier:

according to guideline

Guideline:

OECD Guideline 216 (Soil Microorganisms: Nitrogen Transformation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

yes

Total exposure duration:

28 d

Test temperature:

20 °C +/- 2 °C

Moisture:

Soil maisture was kept within a range of ± 5 % of 45 % of the maximum water-holding capacity

Details on test conditions:

The test item was mixed via spiked quartz sand into sieved field soil (Lufa standard soil type 2.3) that was amended with powdered lucerne meal at a concentration of 5.0 g/kg soil dry weight, and incubated for a test period of 28 d at 20 ± 2 °C in the dark. A stock solution was prepared by dissolving the test item in acetone. Test solutions were prepared by a dilution series of the stock solution. The test solutions were used to soak defined amounts of quartz sand which were then mixed into portions of soil. Five test item concentrations, a solvent control (SC) and an untreated control (C) were tested with four replicates, each, and ranged from 10.0 mg test item/kg soil dry weight to 1000 mg test item/kg soil dry weight. Soil moisture of test soils was kept within a range of ± 5 % of 45 % of the maximum water-holding capacity (WHCmax). Soil nitrate concentration was determined in soil extracts on day 0 and day 28.

Nominal and measured concentrations:

0.1, 1.0, 1 0.0, 100 and 1000 mg test item/kg soil dry weight (nominal)

Reference substance (positive control):

no

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

nitrate formation rate

Duration:

28 d

Dose descriptor:

other: LOEC

Effect conc.:

333 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

nitrate formation rate

Details on results:

On day 28, nitrate concentration in soil of the control and solvent control, as weil as in soil treated at 10 mg and 100 mg/kg soil, were increased compared to day 0, while at test-item concentrations of 333 mg/kg soil and above the nitrate concentrations were strongly reduced compared to day 0.
Nitrate concentration in treated soils was significantly increased compared to the solvent control at test-item concentrations of 10 mg and 100 mg/kg soil.
At test-item concentrations of 333 mg/kg soil dw, 666 mg/kg soil dw and 1000 mg/kg soil dw nitrate concentration was significantly decreased compared to the solvent control.
Hence, the LOEC and NOEC were 333 mg test item/kg soil dw and 100 mg test item/kg soil dw, respectively.
Due to the lacking of a dose-effect relationship, no effect concentrations (ECx) could be calculated.

Conclusion:
The test item caused a streng and statistically significant reduction in the nitrate formation in soil at concentrations of 333 mg/kg soil dry weight and above.

The coefficient of variation (CV) for nitrate of control samples was 5.2 % on day 0 and 2.5 % on day 28 of the test. The CV of solvent control samples was 3.9 % (day 0) and 4.2 % ( day 28). Therefore, the validity criterion of a variability of less than 15 % within the control given by the guideline was fulfilled. On day 0, nitrate concentration of test-item treated soils was not significantly different from nitrate concentration of the solvent control. On day 28, nitrate concentration in soil of the control and solvent control, as well as in soil treated at 10 mg and 100 mg/kg soil, were increased compared to day 0, while at test-item concentrations of 333 mg/kg soil and above the nitrate concentrations were strongly reduced compared to day 0. Nitrate concentration in treated soils was significantly increased compared to the solvent control at test-item concentrations of 10 mg and 100 mg/kg soil. At test-item concentrations of 333 mg/kg soil dw, 666 mg/kg soil dw and 1000 mg/kg soil dw nitrate concentration was significantly decreased compared to the solvent control. Hence, the LOEC and NOEC were 333 mg test item/kg soil dw and 100 mg test item/kg soil dw, respectively. Due to the lacking of a dose-effect relationship, no effect concentrations (ECx) could be calculated.

Validity criteria fulfilled:

yes

Remarks:

The coefficient of variation (CV) of control samples was 5.2 % on day 0 and 2.5 % on day 28 of the test. The CV of solvent control samples was 3.9 % (day 0) and 4.2 % (day 28). Since the maximum deviationwas below 15 % the vaidity criterion was fulfilled.

Conclusions:

The test item caused a streng and statistically significant reduction in the nitrate formation in soil at concentrations of 333 mg/kg soil dry weight and above.
At test-item concentrations of 10.0 mg/kg soil dw and 100 mg/kg soil dw nitrate concentration in soil was statistically significantly increased.
The LOEC and NOEC were determined to be 333 mg/kg soil dw and 100 mg/kg soil dw, respectively. Due to the lacking of a dose-response relationship effective concentrations (ECx) could not be calculated.
Based on the above results, the test item, 7PPD is considered to have no adverse long-term effects on nitrate formation in soil at concentrations up to and including 100 mg test item/kg soil dry weight.

Executive summary:

According to the OECD Guideline 216 (Soil Microorganisms: Nitrogen Transformation Test), he study was conducted in order to determine possible effects of 7PPD on soil microorganisms through measuring microbial nitrate formation in treated versus untreated soils after 28 days of incubation. A NOEC of 100 mg/L and a LOEC of 333 mg/L within 28 days related to nitrate formation.

7PPD is considered to have no adverse long-term effects on nitrate formation in soil at concentrations up to and including 100 mg test item/kg soil dry weight.

Description of key information

The test item caused a streng and statistically significant reduction in the nitrate formation in soil at concentrations of 333 mg/kg soil dry weight and above.
At test-item concentrations of 10.0 mg/kg soil dw and 100 mg/kg soil dw nitrate concentration in soil was statistically significantly increased.

The LOEC and NOEC were determined to be 333 mg/kg soil dw and 100 mg/kg soil dw, respectively. Due to the lacking of a dose-response relationship effective concentrations (ECx) could not be calculated.
Based on the above results, the test item, 7PPD is considered to have no adverse long-term effects on nitrate formation in soil at concentrations up to and including 100 mg test item/kg soil dry weight.

Key value for chemical safety assessment

Long-term EC10 or NOEC for soil microorganisms:

100 mg/kg soil dw

Additional information

According to the OECD Guideline 216 (Soil Microorganisms: Nitrogen Transformation Test), he study was conducted in order to determine possible effects of 7PPD on soil microorganisms through measuring microbial nitrate formation in treated versus untreated soils after 28 days of incubation. A NOEC of 100 mg/L and a LOEC of 333 mg/L within 28 days related to nitrate formation.

7PPD is considered to have no adverse long-term effects on nitrate formation in soil at concentrations up to and including 100 mg test item/kg soil dry weight.