Fatty acids, C8-18 and C18-unsatd., zinc salts

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

A standard solution(Zinc Standard: 10 mg/L) was dissolved in 1 % HNO3 and used.

Vehicle:

yes

Details on test solutions:

160.00 mg/L test solution
The required amount of the test substance 0.1600 g was weighted using a balance(Ohaus, U.S.A.) into 1 L volumetric flask and the test water(ISO medium) was added until the 1 L for preparing of 160.00 mg/L. This solution was sealed and mixed using a magnetic stirrer(Misung Scientific. Co., Ltd., Korea) for 48 h and was filtered through a 0.45 μm PVDF membrane filter(Cuota Lab, Korea).
100.00 mg/L stock solution

Test organisms (species):

Daphnia magna

Details on test organisms:

Species
:
Daphnia sp.(Daphnia magna)
Supplier
:
In the Daphnia sp. breeding room of CentralBio Co., Ltd.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

Hardness(Test water)
:
0 h(Old)
175 mg CaCO3/L
24 h(New)
170 mg CaCO3/L

Test temperature:

Average, range of temperature
:
19.8 ºC (19.6~20.0 ºC)

pH:

Average, range of pH
:
7.78(7.47~7.96)

Dissolved oxygen:

Oxygen(D.O.)
91.9 %(84.8~95.7 %)

Salinity:

Alkalinity(Test water)
:
0 h(Old)
34 mg CaCO3/L
24 h(New)
34 mg CaCO3/L

Nominal and measured concentrations:

nominal concentration = 10.00, 20.00, 40.00, 80.00, 160.00 mg/L
mean measured concentration = 3.77, 7.94, 15.6, 31.4, 63.2 mg/L

Details on test conditions:

A 100 mL sample of each test solution was placed in separation test dish(Φ80×40 H (mm)) in the water bath(20±2 ˚C). D.O. concentration was more than 3 mg/L and pH was within the ranged from 6.00 to 9.00. 20 Daphnia sp.(4 replicates/group, 5 Daphnia sp./replicate) were used for the treatment and control groups for 48 h. During the test period, the water temperature was maintained at 18~22 ˚C(temperature of 0 h control group ±1 ˚C) and the light condition was set on a cycle between 16 h of continuous artificial light and 8 h of continuous darkness. No feed was given for test period.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

ca. 22.057 mg/L

95% CI:

>= 10.807 - <= 55.579

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality

Results with reference substance (positive control):

EC50 = 1.228 (mg/L) (24h)
95 % Confidence limits(mg/L) = 1.014~1.607 (mg/L) (24h)
EC50 = 0.736 (mg/L) (48h)
95 % Confidence limits(mg/L) = 0.630~0.859 (mg/L) (48h)

Validity criteria fulfilled:

yes

Conclusions:

The Daphnia sp.(Daphnia magna) was exposed to treatment group of the test substance, Fatty acids, C8-18 and C18-unsatd., zinc salts for 48 h under the semi-static test. A control group was also observed during this period. The acute immobilisation assessment for Daphnia sp. was performed, and the EC50 was calculated.
During the exposure period, the percentage of immobilised(dead) Daphnia sp. in the control group was less than 10 %. No abnormal symptom in the control group. The D.O. concentration in the control and all treatment groups was more than 3 mg/L at the end of the exposure. Therefore, the result was considered acceptable.
On the basis of the result of the range finding test, the treatment group of the definitive test was composed to 10.00, 20.00, 40.00, 80.00 and 160.00 mg/L including the control group.
At the result of the definitive test, the treatment group(10.00, 20.00, 40.00, 80.00 and 160.00 mg/L) showed the mean measured concentration of 3.77, 7.94, 15.6, 31.4 and 63.2 mg/L. This result was 37.7, 39.7, 39.0, 39.3 and 39.5 % about nominal concentration. Therefore, all results were determined on the basis of the mean measured concentration.
During the exposure period, EC50 about the test substance, Fatty acids, C8-18 and C18-unsatd., zinc salts in Daphnia sp.(Daphnia magna) was 22.057 mg/L(95 % confidence limits: 10.807~55.579 mg/L) at 48 h after exposure.
The highest concentration causing no immobility was determined to 31.4 mg/L at 24 and 3.77 mg/L at 48 after exposure, respectively.
The lowest concentration producing 100 % immobility was determined to 63.2 mg/L at 48 h after exposure. This was not observed at 24 h.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

LC50

Effect concentration:

ca. 22.057 mg/L