Acetic acid

Toxicity to soil microorganisms

Administrative data

Endpoint:

toxicity to soil microorganisms

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

Up to 18-06-1997

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: The study report has not been received and therefore cannot be reviewed and evaluated in full.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

BBA Part VI, 1-1

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

TEM 123

IUPAC Name:

TEM 123

Details on test material:

The test solutions, TEM 123, included 10% acetic acid and 10% water soluble solution.

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
No data reported.

Sampling and analysis

Analytical monitoring:

not specified

Details on sampling:

Sampling was used to determine the mineral nitrogen content in both soils at 2, 14, 28, 42 and 56 days after application of the test substance. Dehydrogenase activity was determined at 2, 14, 28, 42, 56 and 91 days after application.

Test substrate

Vehicle:

yes

Details on preparation and application of test substrate:

Two different agriculturally utilised soils were selected with different levels of microbial activity. Prior to testing, water holding capacity, water content and pH were determined. Soil 1: dose rate of 5.5 kg/ha. Soil 2: dose rate of 7.5 kg/ha.

Test organisms

Test organisms (inoculum):

soil

Study design

Total exposure duration:

91 d

Test conditions

Test temperature:

Controlled climatic conditions during test.

Moisture:

Controlled climatic conditions during test.

Details on test conditions:

Controlled climatic conditions during test.

Nominal and measured concentrations:

The experiment tested soil microbial activity at TEM concentrations of 1000 L/ha (equivalent to 102 kg as/ha, maximum expected dose) and 10 000 L/ha.

Reference substance (positive control):

yes

Remarks:

Dinosebacetat PESTANAL (Batch No: 12830, active substance: dinoseb acetate - 99%)

Results and discussion

Details on results:

Soils treated with the highest concentration of test substance were initially slightly acidified, though this levelled within 42 to 56 days. There was no influence observed at the lower concentration.
At the lower concentration, no influence on the amount of nitrification was observed, except on day 14. At the higher dose, the nitrogen content of the soil increased due to nitrogen mineralisation. Nitrification was inhibited between days 2 and 42.
At the higher concentration, dehydrogenase activity increased by 25% compared to the control soil. Dehydrogenase activity increased signigicatnly at day 28. At the lower dose, no significant influence was seen until day 56.

Results with reference substance (positive control):

The reference substance induced a nitrogen increase at both concentration levels. Distinct inhibition of the dehydrogenase activity was cause by the dinosebacetat, with reductions after 56 days of up to 30% in soil 1 and 18% in soil 2. Dehydrogenase activity was inhibited in both siols after 91 days.

Reported statistics and error estimates:

In order to convert soil volume to soil dry matter, soil depth of 5cm and density of 1.5 were assumed.
The high influence of the test substance on the dehydrogenase activity of the soil on day 91 should not be taken into account as the comparative control for this result has a reduce value.
Standard deviations for the experiments were tolerable.

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Conclusions:

The results given above, along with acetic acid having a very short half life of less than one day in soil, indicate that the substance is not expected to have any detrimental effects at 1000 kg/ha, the maximum expected dose rate, on soil microflora. No further testing is deemed necessary. At 1000 kg/ha, TEM 123 caused less than 25% effect over 28 days on the nitrification process and dehydrogenase activity in soils.

Executive summary:

Lemnitzer (1997) has been given a Klimisch score of 4 - not assignable (Klimisch et al, 1996) as the study has not been received and therefore has not been properly evaluated. A summary of the study is included in the EU Draft Assessment Report for Acetic Acid (2008).