Naphthenic acids

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:

experimental study

Adequacy of study:

key study

Study period:

2010

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)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

Daphnia magna

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

Nominal and measured concentrations:

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

mean measured:
Concentrations remained stable over the renewal period (at least 87%).

GC-MS analyses indicated 85-91% of dissolved naphthenic acids contained 10-16 carbon atoms with a prevalence of one and two ring naphthenic acid isomers.

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
- Controlled conditions: temperature, light
- Photoperiod:Light/dark: 16/8
- Light intensity:521 lux

Reference substance (positive control):

no

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:

24 h

Dose descriptor:

EL50

Effect conc.:

ca. 28.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

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

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

Reported statistics and error estimates:

Not specified

Control and test solutions were clear and colourless with no visible signs of un-dissolved test substance, precipitate or surface film throughout the study.

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 Groupwww.petroleumhpv.org. Consortium Registration, May 14, 2012.

Validity criteria fulfilled:

yes

Conclusions:

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: The results of the study showed that WAF has lethal effects on Daphnia magna. The LLC50 is 24 mg/l (load) and LC50 is 20mg/l (measured) for 48 hours of exposure.

The test is performed according to GLP principles and standard test procedures. The quality of the test and test results are highly reliable.

Executive summary:

The effect of the water accommodated fraction (WAF) of naphthenic acids (NA) on the survival of the invertebrate Daphnia magna was measured during a 48 hours exposure period. WAFs were prepared using loading rates of 0, 5, 10, 20, 40 and 80 mg/l naphthenic acids. The measured concentrations were <MQL(control), 3.9, 7.68, 17, 33.3 and 69 mg/l naphthenic acids.

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 on the exposure concentrations and stability of the test substance.

The LLC50 is 24 mg/l (load) and LC50 is 20mg/l (measured) for 48 hours of exposure.

Also effects for 24 hours exposure are reported, and NOEC/LOEC values for both 24 and 48 hours of expposure.

The test is performed according to GLP principles and standard test procedures. The quality of the test and test results are highly reliable.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Environment Canada. Report EPS 1/RM/11. Biological Test Method: Acute lethality test using Daphnia spp, 1990; p 57.

Deviations:

no

GLP compliance:

not specified

Specific details on test material used for the study:

The study of Frank et al. 2009 studied the effect of 8 different NA-like surrogates. Only the results based on Cyclohexanecarboxyclic acid (CHCA) were used as supportive results as it was deemed most coparable to the test substance, because it has more than 8 Carbon atoms, 1 ring and is a monoacid)

Test organisms (species):

Daphnia magna

Details on test organisms:

common name: water flea

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

not specified

Test temperature:

20 +/- 2 °C

pH:

8.1 + /- 0.15

Dissolved oxygen:

not specified

Salinity:

not relevant

Conductivity:

not specified

Nominal and measured concentrations:

nominal concnetrations of CHCA (mg/L): 0, 600, 900, 1200, 1500
nominal concnetrations of CHCA (mg/L): 0, 100, 200, 300

Details on test conditions:

All assays were conducted at 20 ( 2 °C, a 16:8-h light:dark photoperiod cycle, and a light intensity of 400-700 lx.
Test vessels consisted of a 100-mL glass beaker with 80 mL of test solution and four D. magna neonates.
There were four replicates for each test concentration and eight replicates for the control solution, all of which were placed in a randomized block design using a random number generator (Microsoft Office Excel 2003).
Data from the replicates were combined for probit analysis. Control solutions were composed of reconstituted water equal to the volume used in the highest test concentration, plus distilled water, summing to a total volume of 80 mL. The pH of all NA-like surrogate test solutions and controls was adjusted to 8.1 ( 0.15 using NaOH and HCl. Neonates, from females aged 2 to 5 weeks old, were removed from daphnid culture vessels less than 24 h after culturing and were randomly transferred to test vessels in 1 mL of daphnid reconstituted water using a clean glass pipet. Following 48 h exposure, the neonates were examined and identified as alive or dead (identified by lack of movement of the body, appendages, and heart as observed through a microscope. Additional test concentrations were tested when the initial concentration range did not encompass the LC50.

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

109 mg/L

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CI: +/- 38 mg/L

Details on results:

Claculated effect concntrations of the other 7 NA-like surrogates:
NA surrogate (abbreviattion) EC50 +/- 95% CI
hexanoic acid (HA) 116 +/- 153 mg/L
cyclohexanecarboxylic acid (CHCA) 855 +/- 97 mg/L
decanoic acid (DA) 219 +/- 64 mg/L
succinic acid (SA) 3223 +/- 261 mg/L
adipic acid (AA) 2996 +/- 164 mg/L
1,4-cyclohexanedicar-boxylic acid (CHDCA) 2632 +/-128 mg/L
cyclohexylsuccinic acid (CHSA) 1344 +/- 246 mg/L

Reported statistics and error estimates:

Log-probit analysis for the D. magna acute toxicity test data was conducted using theUSEPAProbit Analysis Program Version 1.5 (34), which generated LC50 values with 95% CIs. Significant differences between LC50 values were identified by a lack of overlap between 95% CIs.

Validity criteria fulfilled:

yes

Conclusions:

Based on the acute toxicity test with NA-like surrogates the 48-h EC50 found for Daphnia magna was 109 mg/L +/- 38 mg/L for cyclohexanepentanoic acid (CHPA).

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Principles of method if other than guideline:

Details on testing procedures have been published by Linden et al : E. Linden , B.E. 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

Test organisms (species):

Nitocra spinipes

Water media type:

brackish water

Limit test:

no

Salinity:

7‰

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

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.

Description of key information

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 results of the study showed that WAF has lethal effects on Daphnia magna. The LLC50 is 24 mg/l  (load) and LC50 is 20mg/l (measured) for 48 hours of exposure. A 96-h LC50 of 4.8 mg/L for calcium naphthenate has been determined for the marine copepod, Nitocra spinipes. The naphthenate ion is the ionised form of naphthenic acids so the LC50 value reported here is believed to be valid for naphthenic acids.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

20 mg/L

Additional information

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 results of the study showed that WAF has lethal effects on Daphnia magna. The LLC50 is 24 mg/l (load) and LC50 is 20mg/l (measured) for 48 hours of exposure.

The test is performed according to GLP principles and standard test procedures. The quality of the test and test results are highly reliable.

Bengtsson et al. (1983) reported a 96-hr LC50 of 4.8 mg/l for Nitocra spinipes for calcium naphthenate in brackish water. The naphthenate ion is the ionised form of naphthenic acids so the LC50 value reported here is believed to be valid for naphthenic acids.