N-butyltin trichloride

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Not specified

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Short-term toxicity screening test conducted to evaluate the toxicity of organotins to activated sludge and the impact of sludge age on the toxicity of these compounds. Study is well documented and meets generally accepted scientific standards. No analytical confirmation of exposure concentrations. Inhibition of respiration rate was chosen as a short-term screening test for the evaluation of toxicity.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Method: other: American Public Health Association, 1989, Standard Methods for Examination of Water and Wastewater, 17th ed.

GLP compliance:

not specified

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

activated sludge

Details on inoculum:

See below

Test type:

static

Water media type:

freshwater

Limit test:

no

Details on test conditions:

Composition of synthetic wastewater:

Glucose: 787.5 mg/L
(NH4)3PO4: 111.8 mg/L
K2HPO4: 1750 mg/L
KH2PO4: 250 mg/L

Reference substance (positive control):

yes

Key result

Dose descriptor:

IC50

Effect conc.:

134.5 mg/L

Remarks on result:

other: reported as Ki in study

Reported statistics and error estimates:

Ki = inhibition coefficient (concentration of inhibitor giving half of the maximum inhibition) (mg/L)

Validity criteria fulfilled:

not applicable

Conclusions:

The inhibition concentration of the test material was 134.5 mg/L.

Executive summary:

The test material is unlikely to inhibit microorganisms in the activated sludge process because the concentrations giving 50% of the maximum inhibition respiration rate are higher than those often detected in activated sludge treatment plants. The toxicity ofthe test material is reduced as exposure time increases. The inhibition concentration of the test material was 134.5 mg/L.

Description of key information

The inhibition concentration of the test material was 134.5 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

134.5 mg/L

Additional information

The test material is unlikely to inhibit microorganisms in the activated sludge process because the concentrations giving 50% of the maximum inhibition respiration rate are higher than those often detected in activated sludge treatment plants. The toxicity ofthe test material is reduced as exposure time increases. The inhibition concentration of the test material was 134.5 mg/L.