reaction mass of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-2H -isothiazol-3-one

Toxicity to soil microorganisms

Administrative data

Endpoint:

toxicity to soil microorganisms

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 217 (Soil Microorganisms: Carbon Transformation Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Test material form:

other: Amber liquid

Details on test material:

- Name of test material (as cited in study report):Kathon(TM) 886F biocide

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Rohm and Haas, Batch No. 6111L019

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature
- Stability under test conditions: Stable at room temperature
- Solubility and stability of the test substance in the solvent/vehicle: Soluble and stable
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: No

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: Dilution in water
- Final dilution of a dissolved solid, stock liquid or gel: 1, 10, 50, 100 and 500 mg CMIT/MIT per kg dry weight soil

OTHER SPECIFICS: Purity of test material was 14%

Sampling and analysis

Analytical monitoring:

no

Test substrate

Vehicle:

yes

Details on preparation and application of test substrate:

AMENDMENT OF SOIL
- Type of organic substrate: glucose-amended soil

APPLICATION OF TEST SUBSTANCE TO SOIL
- Method: TS was applied to the soil in aqueous solution. TS and soil were mixed.

VEHICLE:
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Water
- Concentration of vehicle in test medium (stock solution and final test solution): Not applicable
- Evaporation of vehicle before use: Not applicable

Test organisms

Test organisms (inoculum):

soil

Study design

Total exposure duration:

28 d

Test conditions

Test temperature:

20 ± 2 °C

Moisture:

40-70 %

Details on test conditions:

TEST SYSTEM
- Testing facility: Wildlife International
- Test container (type, material, size): Glass container
- Amount of soil: 400 g
- No. of replicates per concentration: 3
- No. of replicates per control: 3
- No. of replicates per vehicle control: n/a

SOIL INCUBATION
- Method: bulk

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Geographical reference of sampling site (latitude, longitude): Grand Forks County, North Dakota, USA (latitude N 47º 48.141’, longitude 097º 37.241’)
- History of site: Pine tree forest
- Treatments with pesticides or fertilizers: No crop protection products or fertilizers for at least 10 years
- Accidental contamination: Not described
- Depth of sampling: 0-6 inches
- Soil texture
- % sand: 71%
- % silt: 12%
- % clay: 17%
- Soil taxonomic classification: Sandy loam soil
- Soil classification system: Not described
- pH (in water): 6.8
- Initial nitrate concentration for nitrogen transformation test (mg nitrate/kg dry weight): 0.138 %
- Maximum water holding capacity (in % dry weigth): 40 to 70 %
- Cation exchange capacity (mmol/kg): Not described
- Pretreatment of soil: Sieving through a 2 mm sieve
- Storage (condition, duration): The soil was stored refrigerated then brought to room temperature to reduce soil moisture content
- Initial microbial biomass as % of total organic C: approximately 1.9 %

DETAILS OF PREINCUBATION OF SOIL (if any): n/a

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Measurements of carbon dioxide release were performed approximately every 2 hours over a 12-hour period.

VEHICLE CONTROL PERFORMED: no

Nominal and measured concentrations:

Nominal concentrations: 1, 10, 50, 100, and 500 mg CMIT/MIT per kg dry weight soil

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

1 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

respiration rate

Effect concentrations 2

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

0.04 mg/kg soil dw

Nominal / measured:

meas. (TWA)

Conc. based on:

act. ingr.

Basis for effect:

respiration rate

Effect concentrations 3

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

38.6 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

respiration rate

Effect concentrations 4

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

1.55 mg/kg soil dw

Nominal / measured:

meas. (TWA)

Conc. based on:

act. ingr.

Basis for effect:

respiration rate

Effect concentrations 5

Duration:

28 d

Dose descriptor:

EC25

Effect conc.:

19.1 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

respiration rate

Effect concentrations 6

Duration:

28 d

Dose descriptor:

EC10

Effect conc.:

7.7 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

respiration rate

Details on results:

- Effect concentrations exceeding solubility of substance in test medium: No

Reported statistics and error estimates:

The respiration rates of the treated soil samples after 28 days were compared to that of the control soil samples and the percent inhibition of each test concentration was calculated using “TOXSTAT Release 3.5”. Statistical procedures were used to calculate EC10, EC25 and EC50 values and 95 % confidence limits.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The nominal 28d NOEC was determined to be 1 mg a.i. /kg dry soil.

Executive summary:

OECD 217, Effects on soil microflora carbon respiration transformation. Results of controls are in acceptable range. The variations between the replicate control sample rates of respiration measured on Day 28 was less than 15 %, fulfilling the validity criterion of the test. Greater than 50 % rate inhibition was demonstrated at test concentrations of 50, 100 and 500 mg CMIT/MIT per kg dry weight soil. The nominal 28d NOEC was determined to be 1 mg a.i. /kg dry soil.