Naphthenic acids, lithium salts

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

key study

Study period:

2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to standard test guideline OECD 202

Justification for type of information:

See IUCLID section 13 for read across justification

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Sampling: Concentrations were measured at time 0, 24 (fresh and old) and at 48 h (old).

Vehicle:

no

Details on test solutions:

- Preparation: WAFs were prepared independently by adding the appropriate amount of test substance to 4L of mineral medium and stirring for 24 ± 1 h at a speed creating a vortex of 30-50% of the depth of the solution.
- Observations: Control and test solutions were clear and colourless with no visible signs of undissolved test substance, precipitate or surface film throughout the study.

Test organisms (species):

Daphnia magna

Details on test organisms:

- Age: <24 h old

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

Renewal at 24 h of exposure

Post exposure observation period:

Not relevant

Hardness:

150 g/L

Test temperature:

20.6-22°C

pH:

6.8-8.9

Dissolved oxygen:

6.8-8.8 mg/L

Salinity:

Freshwater

Conductivity:

Not reported

Nominal and measured concentrations:

- Nominal WAF loading rates: 0 (control), 5, 10, 20, 40 and 80 mg/L naphthenic acids
- Mean measured:

Details on test conditions:

TEST SYSTEM
- Test vessel: 200 mL
- Test volume: 100 mL
- No. of organisms per vessel: 5 organisms (<24 h old) per vessel
- No. of vessels per concentration (replicates): No data

TEST MEDIUM / WATER PARAMETERS
- Culture medium: Aged laboratory well water

OTHER TEST CONDITIONS
- Photoperiod: Light/dark: 16/8
- Light intensity: 521 lux

OBSERVATIONS
- Observations: Immobility and floating of the organisms was assessed every 24 hours.

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

EL50

Effect conc.:

ca. 28.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

ca. 24 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL 21-27

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

ca. 23.8 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

ca. 20 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

mobility

Remarks on result:

other: 95% CL 17-23

Duration:

48 h

Dose descriptor:

NOELR

Effect conc.:

ca. 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOELR

Effect conc.:

ca. 20 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

ca. 7.68 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

ca. 17 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

mobility

Details on results:

- Observations: Floating of daphnia was seen from 20 mg/L nominal concentration
- Results: Based on mobility, the 48 hour EL50 is approximately 24 mg/L (95% CL 21-27 mg/L) and the EC50 is approximately 20 mg/L (measured arithmetic mean) (95% CL 17-23 mg/L).

Results with reference substance (positive control):

Not reported

Reported statistics and error estimates:

No confidence limits are reported in the HPVIS document. The 95% CL are taken from the ‘Naphthenic acids category analysis and hazard characterizaton’. Report submitted to the US EPA by the American Petroleum Institute petroleum HPV testing Group. www.petroleumhpv.org. Consortium Registration, May 14, 2012.

Validity criteria fulfilled:

yes

Remarks:

Acceptability criteria (guideline requirements) were met.

Conclusions:

The results of the study showed that WAF has lethal effects on Daphnia magna. The LL50 is 24 mg/L (load) and LC50 is 20mg/L (measured) for 48 hours of exposure.

Executive summary:

The survival of the waterflea (species: Daphnia magna) is evaluated during 48 hours of exposure to the water accommodated fractions (WAF) of naphthenic acids. Test was performed according to OECD TG 202, in a semi static set up with medium renewal after 24 hours. WAFs were produced with loading rates 0 (control), 5, 10, 20, 40 and 80 mg/L naphthenic acids. The mean measured concentrations were: <MQL (control), 3.9, 7.68, 17, 33.3 and 69 mg/L naphthenic acids, and concentrations were stable during the renewal period (at least 87%). Test conditions were suitable. The test is performed according to GLP principles and standard test procedures. The test was performed in controlled conditions. At 24 and 48 hours, the number of surviving organisms was assessed. Results were expressed as % mortality. The effect concentrations were calculated. Analytical results are available and document the exposure conditions and stability of the test substance. The quality of the test and test results are highly reliable. The results of the study showed that WAF has lethal effects on Daphnia magna. The LL50 is 24 mg/L (load) and LC50 is 20mg/L (measured) for 48 hours of exposure. Effects concentrations at 24 hours and the 24 and 48 hour NOEC/NOELR and LOEC/LOELR values are also reported.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

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

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was a well-documented study that meets basic scientific principles

Justification for type of information:

See IUCLID section 13 for read across justification

Reason / purpose for cross-reference:

read-across source

Principles of method if other than guideline:

Details on testing procedures have been published by Linden et al: E Linden , BE Bengtsson, O Svanberg, G Sundström. The acute toxicity of 78 chemicals and pesticide formulations against two brackish water organisms, the bleak (Alburnus alburnus) and the harpacticoid copocod (Nitocra spinipes). Chemosphere. 8: 843-851

GLP compliance:

not specified

Specific details on test material used for the study:

No details reported

Analytical monitoring:

not specified

Details on sampling:

No details reported

Vehicle:

not specified

Details on test solutions:

No details reported

Test organisms (species):

Nitocra spinipes

Details on test organisms:

No details reported

Test type:

not specified

Water media type:

brackish water

Limit test:

no

Remarks on exposure duration:

None

Post exposure observation period:

No details reported

Hardness:

No details reported

Test temperature:

No details reported

pH:

No details reported

Dissolved oxygen:

No details reported

Salinity:

7‰

Conductivity:

No details reported

Nominal and measured concentrations:

No details reported

Details on test conditions:

No details reported

Reference substance (positive control):

not specified

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

4.8 mg/L

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CL 3.8-6.2

Details on results:

The 96 hour LC50 of calcium naphthenic to Nitoctra spinipes was 4.8 mg/L based on mortality (95% CL 3.8-6.2 mg/L).

Results with reference substance (positive control):

No details reported

Reported statistics and error estimates:

No details reported

Validity criteria fulfilled:

not specified

Conclusions:

A 96-h LC50 of 4.8 mg/L for calcium naphthenate has been determined for the marine copepod, Nitocra spinipes by the Brackish Water Toxicology Laboratory (Sweden). The naphthenate ion is the ionised form of naphthenic acids so the LC50 value reported here is believed to be valid for naphthenic acids.

Executive summary:

A 96-h LC50 of 4.8 mg/L for calcium naphthenate has been determined for the marine copepod, Nitocra spinipes by the Brackish Water Toxicology Laboratory (Sweden). The naphthenate ion is the ionised form of naphthenic acids so the LC50 value reported here is believed to be valid for naphthenic acids. Data are taken from published literature (Bergtsson 1983). The study was a well-documented study that meets basic scientific principles and has been assigned a Klimisch score of 2 (reliable with restrictions). Details on testing procedures have been published by Linden et al (1979).

Description of key information

Lithium naphthenate consists of lithium salts of naphthenic acids. Therefore, data have been presented for both the organic anion and the lithium cation. Studies are included for naphthenic acids as well as lithium salts of docosanoic acid (C22) and dilithium adipate (C6).

Both lithium docosanoate (C22) and dilithium adipate (C6) showed 48 hour EL50/EC50 of >100 mg/L. For naphthenic acids, the 48 hours EL50 was determined to be 24 mg/L and EC50 was 20 mg/L (HPVIS 2010). In addition, a 96-h EC50 of 4.8 mg/L for calcium naphthenate has been determined for the marine copepod, Nitocra spinipes. Taking a worst-case approach for the results of the key studies, the short-term toxicity (48 hour EC50) of lithium naphthenate to freshwater invertebrates is determined to be 20 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

20 mg/L

Marine water invertebrates

Marine water invertebrates

Effect concentration:

4.8 mg/L

Additional information

Lithium naphthenate consists of lithium salts of naphthenic acids. Therefore, data have been presented for both the organic anion and the lithium cation. Studies are included for naphthenic acids as well as lithium salts of docosanoic acid (C22) and dilithium adipate (C6).

Lithium naphthenate is produced through the reaction of naphthenic acids with lithium hydroxide. Naphthenic acids consist of a main acidic (naphthenic) fraction (70-95%) and a smaller non-acidic (petroleum) fraction (5-30%). The acidic fraction contains typically C8-C20 with 0-3 rings and the non-acidic fraction has a carbon range mainly of C12-C22 and no single constituent >10%. The lithium hydroxide added to the naphthenic acids will neutralise the components within the acid fraction to form lithium salts while any components present in the non‑acidic fraction of naphthenic acids (the unsaponifiable matter) will be unchanged by the manufacturing process. Therefore, lithium naphthenate is expected to consist of 70 - 95% lithium salts of naphthenic acids (C8-C20, 0-3 rings), with 5 - 30% unsaponifiable matter unchanged from the naphthenic acids starting material.

Dilithium adipate (C6) has a shorter chain length than the acids present in lithium naphthenate (C8) and is a dicarboxylic acid, while fatty acids present in lithium naphthenate are monocarboxylates. Although no dicarboxylic acid salts were identified in the GC-MS analysis for lithium naphthenate, the dataset for dilithium sebacate shows that the substance follows similar trends in properties to the longer chain monocarboxylic acid lithium salts and supports the read across between lithium salts of different carboxylic acids. Dilithium adipate, as a lithium salt of a carboxylic acid two shorter than those present in lithium naphthenate, presents a worst-case scenario for the shortest chain length present in the target substance, bracketing one end of the range of potential properties of constituents present in the UVCB.

Lithium docosanoate (C22) has a longer chain length as the longest chain length acids present in the acidic fraction of lithium naphthenate (C20). Therefore, lithium docosanoate, as a lithium salt of a carboxylic acid two longer than those present in lithium naphthenate, brackets the other end of the range of potential properties of constituents present in the UVCB.

HPVIS (2010)

The survival of the waterflea (species: Daphnia magna) is evaluated during 48 hours of exposure to the water accommodated fractions (WAF) of naphthenic acids. The test was performed according to GLP principles and OECD TG 202, in a semi static set up with medium renewal after 24 hours. Analytical results are available and document the exposure conditions and stability of the test substance. The results of the study showed that the WAF has lethal effects on Daphnia magna. The LLC50 is 24 mg/L (load) and LC50 is 20 mg/L (measured) for 48 hours of exposure.

Harlan (2013)

The acute toxicity of lithium docosanoate to Daphnia magna was determined in a GLP-compliant, limit test (Harlan 2013) following OECD guideline 202. The acute toxicity of lithium docosanoate toDaphnia magnashowed no effects at a water accommodated fraction loading rate of 100 mg/L. Therefore, the 48 hour LC50 is determined to be > 100 mg/L.

WIL (2015)

The effect of dilithium adipate on the mobility of the Daphnia magna was investigated according to an OECD 202 guideline and EC method C2 study. The test concentrations were considered to be maintained and the results are reported based on nominal concentrations. The study met all the validity criteria for the test. As no effects on the mobility ofDaphnia magnawere observed in the test the EC50 is > 100 mg/L dilithium adipate.

Bergtsson (1983)

A 96-h LC50 of 4.8 mg/L for calcium naphthenate has been determined for the marine copepod,Nitocra spinipesby the Brackish Water Toxicology Laboratory (Sweden). The naphthenate ion is the ionised form of naphthenic acids so the EC50 value reported here is believed to be valid for naphthenic acids. Data are taken from published literature (Bergtsson 1983). The study was a well-documented study that meets basic scientific principles; details on testing procedures have been published by Linden et al (1979).

Conclusion

Lithium naphthenate consists of a lithium salt of naphthenic acid. Therefore, data have been presented for both the organic anion and the lithium cation. Studies are included for naphthenic acids as well as lithium salts of docosanoic acid (C22) and dilithium adipate (C6).

Both lithium docosanoate (C22) and dilithium adipate (C6) showed 48 hour EL50/EC50 of >100 mg/L. For naphthenic acids, the 48 hours EC50 was determined to be 24 mg/L and EC50 was 20 mg/L (HPVIS 2010). In addition, a 96-h EC50 of 4.8 mg/L for calcium naphthenate has been determined for the marine copepod, Nitocra spinipes. Taking a worst-case approach for the results of the key studies, the short-term toxicity (48 hour EC50) of lithium naphthenate to freshwater invertebrates is determined to be 20 mg/L.