Malonic acid

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

Study period:

2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Identification: MALONIC ACIDLot/Batch Number: B-05-3251Purity: 99.68% (C of A)Composition: Malonic acid 99.5% Molecular weight = 104.061g/molChloride content <0.25%Nitrate content <0.1%Sulphate <0.025% Carbonates not det.Acetate <0.3%CAS: 141-82-2, IUPAC:Propandioic acid

Analytical monitoring:

yes

Details on sampling:

Duplicate samples were taken at the start and end of the 48 hour exposure period. Samples were taken from remaining test media after filling test vessels for 0 hours and pooled replicate flasks for 48 hours. Analysis of these samples for the verification of exposure concentrations was performed using HPLC.

Vehicle:

yes

Details on test solutions:

Stock solutions were prepared for both the range-finding and definitive tests by addition of thetest sample directly to Elendt M4 medium in a volumetric flask of adequate volume. Calculatedvolumes of the stock solution were added to nutrient growth medium and made to volume toprepare the test concentrations and provide enough solution for testing and subsequent waterquality measurements.

Test organisms (species):

Daphnia magna

Details on test organisms:

Source: From cultures maintained at Chemex Environmental International Ltd since July 2014 and originally sourced from a clone of genotype 5.Age of Daphnia at start of test: ≤ 24 hours.Feeding regime: Each working day, a suspension of Chlorella vulgaris. The Daphnia in the test were not fed.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

The number of immobilised Daphnia was recorded after 24 and 48-hour exposure periods

Test temperature:

Temperature range within incubator throughout test: 20.2 – 21.2°C

pH:

Initial pH at 0 Hours: 6.81pH range in control and test concentrations throughout test: 6.11 – 7.95

Dissolved oxygen:

Initial Dissolved Oxygen at 0 Hours: 6.89mg/lDO range in control and test concentrations throughout test: 6.23 – 8.03mg/l

Nominal and measured concentrations:

Results for the analytical confirmation of exposure concentrations indicate that the measured concentrations of 32, 58 and 100mg/l remained within 80-120% of nominal while concentrations 10 and 18mg/l did not. 10 and 18mg/l are near to the limit of detection and limit of quantification causing the low recoveries observed. 32, 58 and 100mg/l are at the higher end of the concentration range and as there was no mortality/immobilisation seen at the top concentration the lower concentrations are not critical to any EC calculations. As the majority of the concentrations were in the 80-120% range and these were in the highest concentrations the EC values are reported as nominal concentrations.

Details on test conditions:

Illumination: 16 Hours Light, 8 Hours Dark CycleTest volume: 25mlTest vessel: 40ml glass dishes. To limit aerial contamination of the test vessels and reduce evaporative losses, the vessels were covered with a perspex sheet.Number of replicates: Four replicates at each concentration.Test concentrations: 0 (control), 10, 18, 32, 58 and 100mg/lTest media: Elendt M4 reconstituted Daphnia waterTest organism: Five Daphnia were transferred to each control and test concentration vessel using a wide bore glass tube in the minimum amount of culture water (<0.5ml).

Reference substance (positive control):

yes

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Details on results:

The Daphnia were examined at 24-hours and 48-hours for abnormal behaviour during the determination of immobility. All Daphnia appeared normal with no signs of abnormality. No immobilisation occured in any of the test concentrations, all twenty Daphnia in each unit appeared normal after 48-hours.

Results with reference substance (positive control):

A separate GLP study (ENV 11395) was conducted to monitor the sensitivity of the test animals and test procedures. The reference study gave a 24hour EC50 of 1.4mg/l of potassium dichromate which was within the acceptable range 0.6 mg/l to 2.1 mg/l as specified in Technical Corrigendum to ISO6341.

Reported statistics and error estimates:

Where possible, the EC(r)10, EC(r)50 EC(r)90 values with 95% confidence limits and NOEC(r) were calculated according to the statistical methods of ToxCalc™ Version 5.0 “Comprehensive Toxicity Data Analysis and Database Software”, copyright 1994-1996.

Cumulative immobilisation

Nominal Concentration mg/l	Number immobilised		% immobilisation
	24 hours	48 hours	24 hours	48 hours
0 (Control)	0	0	0	0
10	0	0	0	0
18	0	0	0	0
32	0	0	0	0
58	0	0	0	0
100	0	0	0	0

 

Observations

Nominal Concentration mg/l	Recorded observations
	24 hours	48 hours
0 (Control)	20NS	20NS
10	20NS	20NS
18	20NS	20NS
32	20NS	20NS
58	20NS	20NS
100	20NS	20NS

 

Key to comments

S	Sedimentation	Ms	Movement Slower
D	Debris attached toDaphnia	TM	Trapped in Meniscus (mobile)
LI	Lighter Colouration	TI	Trapped in Meniscus (immobile)
NS	No Signs of Abnormality	SM	DaphniaSmaller
-	AllDaphniaimmobilised

 

Analytical results

Concentration of MALONIC ACID (mg/l) determined by HPLC analysis

Concentration of MALONIC ACID by peak area (mg/l)
Nominal concentration mg/l	Exposure period
	0 hours	48 hours	Mean measured
10	7.077	6.996	7.037
18	14.136	11.776	12.956
32	27.656	24.193	25.925
58	49.172	44.711	46.941
100	87.157	82.630	84.893

 

Average recoveries of MALONIC ACID (mg/l), percentage recovery compared to nominal concentrations.

Percentage recoveries of MALONIC ACID (%)
Nominal concentration mg/l	Exposure period
	0 hours	48 hours	Mean measured
10	70.772	69.962	70.367
18	78.532	65.422	71.977
32	86.425	75.604	81.015
58	84.778	77.088	80.933
100	87.157	82.630	84.893

Validity criteria fulfilled:

yes

Conclusions:

In an acute toxicity study in daphnia magna according to OECD 202, no immobilisation or signs of abnormal behaviour toxicity was observed at any concentration, including the maximum concentration of 100 mg/l (nominal). Malonic acid is therefore considered to be not toxic to daphnia.

Executive summary:

Daphnia magna were exposed to malonic acid at concnetrations of 0 (control), 10, 18, 32, 58 and 100mg/l in an acute toxicity study according to OECD 202. No immobilisation or signs of abnormal behaviour toxicity was observed at any concentration, including the maximum concentration of 100 mg/l (nominal). Malonic acid is therefore considered to be not toxic to daphnia.

Description of key information

Daphnia magna were exposed to malonic acid at concnetrations of 0 (control), 10, 18, 32, 58 and 100mg/l in an acute toxicity study according to OECD 202. No immobilisation or signs of abnormal behaviour toxicity was observed at any concentration, including the maximum concentration of 100 mg/l (nominal). Malonic acid is therefore considered to be not toxic to daphnia.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L