Potassium perchlorate

Sediment toxicity

Link to relevant study record(s)

Reference

Endpoint:

sediment toxicity: long-term

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Materials and methods are well-documented in the publication. The tests were performed in accordance with U.S. EPA procedures.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

other: U.S. EPA EPA 600-R- 99-064

Version / remarks:

U.S. Environmental Protection Agency, 2000

Deviations:

no

Qualifier:

according to guideline

Guideline:

ASTM E1706 (Test Method for Measuring the Toxicity of Sediment-Associated Contaminants with Freshwater Invertebrates)

Version / remarks:

American Society for Testing and Materials International. 2001

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: U.S. EPA Method 314.0 for the determination of perchlorate concentrations

Deviations:

no

GLP compliance:

no

Specific details on test material used for the study:

Sodium perchlorate monohydrate (CAS 7791-07-3) with a purity of greater than 99.9% was purchased from Aldrich Chemical (Milwaukee, WI, USA) and used as received.

Analytical monitoring:

yes

Details on sampling:

Water samples (125 ml) for perchlorate determination were collected directly from the middle of test chambers using a glass beaker and refrigerated, then shipped on ice to APPL Laboratories (Fresno, CA, USA) for analysis.

Vehicle:

no

Details on sediment and application:

The artificial sediment consisted of 76% fine silica sand, 20% kaolinite clay, and 4% fine peat moss (passed through a 500-μm mesh sieve).

Test organisms (species):

Chironomus dilutus (previous name: Chironomus tentans)

Details on test organisms:

Midges of Chironomus dilutus were obtained from egg masses produced by adult midges in cultures al ABC Laboratories.
The test was inithiated with the addition of 12 midge larvae into 12 replicate test chambers, for a total of 144 midges per treatment. The test chambers were glass jars holding a solution volume of approximately 500 ml and approximately 100 g of hydrated artificial sediment.
Four additional replicate test charnbers were initiated with the addition of 12 midge larvae on day 10 to provide additional male midges during the reproduction evaluation portion of the study.

Study type:

laboratory study

Test type:

flow-through

Water media type:

freshwater

Type of sediment:

artificial sediment

Limit test:

no

Duration:

42 d

Exposure phase:

total exposure duration

Hardness:

140 to 162 mg/L as CaCO3

Test temperature:

21 - 25 °C

pH:

6.5 - 7.0

Conductivity:

303 to 333 μS/cm

Nominal and measured concentrations:

nominal concentrations: 0 (control), 62.5, 125, 250, 500, 100, 2000 mg/L based on the perchlorate ion
measured concentrations: 58.5 to 2080 mg/L based on the perchlorate ion (93 - 104% of the nominal concentrations)

Details on test conditions:

All tests wen: performed at ABC Laboratories (Columbia, MO, USA) under flow-through test conditions witb a proportional diluter system continuously delivering the test solutions at a rate of at least two complete test-system volume replacements per day.
light:dark period 16:8 h
Termperature, dissolved oxygen concentration, and pH were measured in all replicate solutions at test initiation, then weekly and again at test termination.

Key result

Duration:

42 wk

Dose descriptor:

NOEC

Effect conc.:

58.5 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Remarks:

based on perchlorate ion

Basis for effect:

emergence rate

Key result

Duration:

42 wk

Dose descriptor:

LOEC

Effect conc.:

118 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Remarks:

based on perchlorate ion

Basis for effect:

emergence rate

Key result

Duration:

42 wk

Dose descriptor:

EC50

Effect conc.:

208 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Remarks:

based on perchlorate ion

Basis for effect:

mortality

Survival rates:

nominal concentrations of perchlorate (mg/L)	measured concentrations of perchlorate (mg/L)	survival rate (%)
0 (control)	0
62.5	58.5
125	118
250	233
500	489
1000	1020
2000	2080
control with sodium chloride at the same sodium concentration as that in the one or two highest sodium perchlorate treatment concentrations

Most of the surviving larvae from exposure concentrations greater than 233 mg/L were discolored. However, this sublethal effect was not considered in the calculation of the EC50.

Conclusions:

The NOEC was stated to be 58.5 mg/L based on the results of the Chironomus tentans life-cycle chronic toxicity test.
The LOEC was stated to be 118 mg/L based on the results of the Chironomus tentans life-cycle chronic toxicity test.
The EC50 was stated to be 208 mg/L based on the results of the Chironomus tentans life-cycle chronic toxicity test.

Description of key information

The NOEC was stated to be 58.5 mg/L based on the results of the Chironomus dilutus life-cycle chronic toxicity test.

The LOEC was stated to be 118 mg/L based on the results of the Chironomus dilutus life-cycle chronic toxicity test.

The EC50 was stated to be 208 mg/L based on the results of the Chironomus dilutus life-cycle chronic toxicity test.

Key value for chemical safety assessment

EC50 or LC50 for freshwater sediment:

208 mg/kg sediment dw

EC10, LC10 or NOEC for freshwater sediment:

58.5 mg/kg sediment dw