Naphthenic acids

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

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 203 (Fish, Acute Toxicity Test)

Deviations:

yes

Remarks:

A brief temperature excursion outside the boundaries of 22±1°C.

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

Pimephales promelas

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Remarks on exposure duration:

renewal every 24 hrs

Post exposure observation period:

not relevant

Hardness:

134 mg/l

Test temperature:

21.6-23.6°C

pH:

8-8.4

Dissolved oxygen:

7.1-9.3 mg/l

Salinity:

the test medium is fresh water

Nominal and measured concentrations:

Nominal WAF loading rates: 0 (control), 1.3, 2.5, 5, 10 and 20 mg/L naphthenic acids

mean measured: 0 (control), 0.9, 2.08, 3.22, 6.04 and 13.8 mg/l naphthenic acids

Concentrations remained stable over the renewal period (at least 89%).

GC-MS analyses indicated 82-90% of dissolved naphthenic acids contained 10-16 carbon atoms with a prevalence of one and two ring napthenic acid isomers.

Details on test conditions:

TEST SYSTEM
- Controlled conditions: temperature, light
- Light/dark: 16/8 (523 lux)

TEST MEDIUM / WATER PARAMETERS
- Modified well water

Reference substance (positive control):

not specified

Duration:

24 h

Dose descriptor:

LL50

Effect conc.:

> 20 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

48 h

Dose descriptor:

LL50

Effect conc.:

ca. 11 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

ca. 9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CL 6.6-12

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

> 13.8 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

mortality (fish)

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

ca. 7.22 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

ca. 5.62 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CL 2.5-11

Duration:

96 h

Dose descriptor:

NOELR

Effect conc.:

ca. 5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: scientific judgement of the dose-response pattern

Duration:

96 h

Dose descriptor:

LOELR

Effect conc.:

ca. 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: scientific judgement of the dose-response pattern

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

ca. 3.22 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

other: scientific judgement of the dose-response pattern

Duration:

96 h

Dose descriptor:

LOEC

Effect conc.:

ca. 6.04 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

dissolved

Basis for effect:

other: scientific judgement of the dose-response pattern

Reported statistics and error estimates:

Not specified

Sublethal observations / clinical signs:

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:

Fish mortality (species: Pimephales promelas) is evaluated during 96 hours of exposure to the water accommodated fractions (WAF) of naphthenic acids. Test was performed according to OECD TG 203, in a semi static set up with medium renewal every 24 hours. WAFs were produced with loading rates 0 (control), 1.3, 2.5, 5, 10 and 20 mg/L naphthenic acids. The measured concentrations were 0 (control), 0.9, 2.08, 3.22, 6.04 and 13.8 mg/l naphthenic acids and they were stable during the renewal period. Test conditions were suitable. There was a slight temporary deviation in temperature, but this had no further consequences.
The results of the study showed that WAF has lethal effects on the fish Pimephales promelas. The LLC50 is 9 mg/l (load) and LC50 is 5.62 mg/l (measured arithmetic mean) for 96 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 survival of the fish species Pimephales promelas was measured during a 96 hours exposure period. A semi static set up was used with medium renewal every 24 hours. WAFs were prepared using loading rates of 0.9, 2.08, 3.22, 6.04 and 13.8 mg/l naphthenic acids. The measured concentrations were 0 (control), 0.9, 2.08, 3.22, 6.04 and 13.8 mg/l naphthenic acids and they were stable during the renewal period.

The test was performed in controlled conditions. At 0, 24, 48, 72 and 96 hours the mortalities was assessed. Results were expressed as % mortality. The effect concentrations were calculated.

Analytical results are available and document on exposure concentrations and stability of the test substance during the renewal periods of 24 hours.

The LLC50 is 9 mg/l NA and LC50 is 5.62 mg/l.

 

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 fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

not available

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

no guideline followed

Principles of method if other than guideline:

The study was performed prior to the adoption of the test guideline OECD Guideline 203 (Fish, Acute toxicity test).

GLP compliance:

not specified

Analytical monitoring:

not specified

Details on test solutions:

The dilution water used in all tests was a synthetic soft water (Chu 14, modified) made up from distilled Λvater to the following quality :
Ca 11.3 ppm
K 11.4 ppm
Mg 3.9 ppm
Na 7.6 ppm
SOí 1S.6 ppm
SiOÍ 12.5 ppm
NO3 0.14S ppm
Fe 0.34 ppm

Test organisms (species):

Lepomis macrochirus

Details on test organisms:

The test fish was the common bluegill sunfish, Lepomis macrochirtis Raf. Specimens were obtained originally from the Pennsylvania Fish Commission and stored in a pond managed by the Academy. The pond water was similar in chemical characteristics to the synthetic water used in the tests. The fish ranged in length from 5.3 to 7.2 cm including tail and averaged 2.5 to 3.9 g in weight. These figures were obtained from measurements of 100
fish selected at random from the stock of test animals before tests were begun. In any one test container no single fish varied more
than 50 per cent in total length from any other (recommendation by Hart et al., 1945).

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

18° +/- 1 °C

pH:

no pH value reported

Dissolved oxygen:

5 to 9 ppm

Duration:

96 h

Dose descriptor:

other: TLm

Effect conc.:

5.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Sublethal observations / clinical signs:

	High treshold conc. (ppm)	concentration % survival	96 -hour TLm (ppm)	Low treshold concentration (ppm)	Concentration % survival
Naphthenic acid	7.0	0	5.6	3.5	100

Validity criteria fulfilled:

yes

Conclusions:

The 96h-TLm value fro Lepomis macrochirus has been experimentally determined for naphthenic acid solutions.
This value is equivalent to a LC50 value.
The short term toxicity to fish for naphthenic acid is LC50 =5.6ppm

Reference 3

Endpoint:

short-term toxicity to fish

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:

no guideline followed

Principles of method if other than guideline:

Method/Guideline: Hart, et al. 1945; Doudoroff et al. 1951
The testing process is outlined in the following scientific articles:
Hart, W.B., P. Doudoroff, and J. Greenbank. 1945. The evaluation of the toxicity of the industrial wastes, chemicals and other substances to freshwater fishes - The Atlantic Refining Company, Philadelphia, Pa., 315 pp.
Dourdoroff, P., B.G. Anderson, G.E. Burdick, P.S. Galstoff, W.B. Hart, T. Patrick, E.R. Strong, E.W. Surber, and W.M. VanHom. 1951. Bioassay methods for the evaluation ot acute toxicity of industrial wastes to fish. Sew. and Ind. Wastes. 23(11):1380-1397.

GLP compliance:

not specified

Analytical monitoring:

not specified

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

24° +/- 1°C

Dissolved oxygen:

5-9ppm

Nominal and measured concentrations:

Test concentrations were control, 7.5, 8.7, 10, 11.5. 13.5. 15.5. 18.0, 21.0, and 24.0 ppm naphthenic acids.

Duration:

96 h

Dose descriptor:

other: TLm

Effect conc.:

>= 16.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Sublethal observations / clinical signs:

Concentration of Naphthenic Acids, ppm	Number of adults tested	% Dead at 96 hours
0 (Control #1)	10	0
0 (Control #2)	10	0
7,5	10	0
8,7	10	40
10	10	20
11,5	10	0
13,5	10	20
15,5	10	30
18	10	80
21	10	100
24	10	100

The article reported that pH and dissolved oxygen concentrations were taken during the test, but these data were not reported.

Validity criteria fulfilled:

yes

Conclusions:

The 96-hour TLm was reported to be 16.3 ppm under the presented testing conditions.

Description of key information

Fish mortality (species: Pimephales promelas) has been evaluated during a 96 hours of exposure to the water accommodated fractions (WAF) of naphthenic acids. The LLC50 is 9 mg/l  (load) and LC50 is 5.62 mg/l (measured arithmetic mean) for 96 hours of exposure.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

5.62 mg/L

Additional information

Fish mortality (species: Pimephales promelas) was evaluated during 96 hours of exposure to the water accommodated fractions (WAF) of naphthenic acids.The tested substance is representative for the naphthenic acids of this dossier.Test was performed according to OECD TG 203, in a semi static set up with medium renewal every 24 hours. WAFs were produced with loading rates 0 (control), 1.3, 2.5, 5, 10 and 20 mg/L naphthenic acids. The measured concentrations were 0 (control), 0.9, 2.08, 3.22, 6.04 and 13.8 mg/l naphthenic acids and they were stable during the renewal period. Test conditions were suitable. There was a slight temporary deviation in temperature, but this had no further consequences.

The results of the study showed that WAF has lethal effects on the fish Pimephales promelas. The LLC50 is 9 mg/l (load) and LC50 is 5.62 mg/l (measured arithmetic mean) for 96 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.

Toxicity endpoints reported in the literature largely report nominal lethal concentrations with varying amounts of supporting information on test conditions. The available data show that naphthenic acids are toxic to fish. Cairns et al. (1965) reported the 96-hour TLm of 16.3 mg/l for adult zebra fish (Brachydanio rerio) and of 5.62 mg/L for bluegill (Lepomis macrochirus Raf.). Furthermore data collected by API under the HPV program support these findings.

Based on the above information the LC50 of 5.62 mg/L is warranted and has been used for the PNEC deriviation (conservative approach).