Arsenic acid

Toxicity to soil microorganisms

Administrative data

Endpoint:

toxicity to soil microorganisms

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: The study is aimed to obtain fungi growth inhibition in the presence of arsenate. Therefore, the concentrations used for this purpose are very high and do not allow to obtain any regulatory endpoint.

Data source

Reference

Reference Type:

publication

Title:

Variation in the toxicity of arsenic compounds to microorganisms and the suppression of the inhibitory effects by phosphate

Author:

DaCosta EWB

Year:

1972

Bibliographic source:

Applied Microbiology 23(1): 46-53

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

The growth of fungi on agar containing various concentrations of arsenic.

Test material

Test material information

Constituent 1

Reference substance name:

Arsenate

IUPAC Name:

Arsenate

Details on test material:

Potassium arsenate was produced by reacting arsenic pentoxide dihydrated (As2O5.2H2O) with KOH to give an analogous pH of 4.4

Sampling and analysis

Analytical monitoring:

no

Test substrate

Vehicle:

no

Details on preparation and application of test substrate:

The arsenate-nutrient media were prepared by autoclaving separately: (i) the appropriate solutions of potassium arsenate and (ii) the nutrient medium.

Test organisms

Test organisms (inoculum):

other: Various fungus

Study design

Total exposure duration:

8 wk

Test conditions

Test temperature:

27°C

Moisture:

Not applicable (agar cultivation medium)

Details on test conditions:

TEST SYSTEM
- Test container (type, material, size): screwed-capped glass phials
- Amount of substrate: agar strip 90 mm long, 25 mm wide and up to 3 mmdeep
- No. of replicates per concentration: 2
- No. of replicates per control: 2

SUBSTRATE INCUBATION
- Method: series of individual subsamples

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : growth

Nominal and measured concentrations:

0, 0.005 M, 0.02 M, 0.08 M (i.e., 0, 0.375, 1.50, and 5.99 g/l)

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

8 wk

Dose descriptor:

EC100

Effect conc.:

<= 0.005 other: M

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth

Remarks on result:

other: Poria monticola (no growth at any As concentration)

Effect concentrations 2

Duration:

8 wk

Dose descriptor:

EC100

Effect conc.:

<= 0.005 other: M

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth

Remarks on result:

other: Poria cocos (no growth at any As concentration)

Effect concentrations 3

Duration:

8 wk

Dose descriptor:

EC100

Effect conc.:

>= 0.08 other: M

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth

Remarks on result:

other: Poria vaillantii

Effect concentrations 4

Duration:

8 wk

Dose descriptor:

EC100

Effect conc.:

<= 0.005 other: M

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth

Remarks on result:

other: Coniophora olivacea (no growth at any As concentration)

Effect concentrations 5

Duration:

8 wk

Dose descriptor:

EC100

Effect conc.:

>= 0.02 - <= 0.08 other: M

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth

Remarks on result:

other: Lenzites trabea