Tetrabromophthalic anhydride

Toxicity to soil microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil microorganisms

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1979

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study is old, but well reported and used a rational methodology, e.g. counting colonies.

Principles of method if other than guideline:

Effects of the test artcle on soil bacterial and fugal counts were determined after addition of the test article to a natural soil for 28 d. Effects were determined based on colony counts.

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

yes

Details on preparation and application of test substrate:

Acetone used to prepare a solution of the 14C-test article. A stock solution (10% acetone in water) then prepared for addition to soil.

Test organisms (inoculum):

soil

Total exposure duration:

28 d

Remarks:

Soils were sampled at 0, 1, 2, 4, 7, 14 and 28 d for plating. Bacterial and fungal counts determined after 5 d.

Test temperature:

Soil: 28 degrees C at 70% humidity.
Plates: 28 degrees C.

Moisture:

70% of the 0.33 bar level or 14.31 g H2O/100 g dry soil.

Nominal and measured concentrations:

0, Vehicle control, 1, 10 ug/g dry soil

Key result

Remarks on result:

other: Please see text below

Remarks:

Any other information on results.

Overall average bacterial and fungal counts were 6.9 x 10 +7 and 6.6 x 10 +4 / g dry soil, respectively, at the end of the incubation period. Bacterial counts increased during the first 14 d and declined slightly thereafter. The test article had a slight positive effect on the numbers of bacterial in soil which was statistically significant at the 10 µg/g level (p<0.001). Fungal population generally increased during the study, but the effect of treatment was not statistically significant.

Validity criteria fulfilled:

yes

Conclusions:

PHT-4 did not adversely affect the number of bacterial or fungal colonies in soil over a 28-d exposure at concentrations up to 10 ug/g dry soil.

Executive summary:

PHT-4 did not adversely affect the number of bacterial or fungal colonies in soil over a 28-d exposure at concentrations up to 10 ug/g dry soil.

Description of key information

PHT-4 did not adversely affect the number of bacterial or fungal colonies in soil over a 28-d exposure at concentrations up to 10 ug/g dry soil.

Key value for chemical safety assessment

Short-term EC50 for soil microorganisms:

0.01 µg/kg soil dw