Naphthenic acids

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

key 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:

During 5 days fish were exposed to naphtenic acids. BCF was determined

GLP compliance:

not specified

Radiolabelling:

not specified

Vehicle:

not specified

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

The test organisms were Oncorhynchus mykiss reported in the article as rainbow trout

Route of exposure:

aqueous

Test type:

semi-static

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

4 d

Total depuration duration:

5 d

Test temperature:

15°C

pH:

8.2

Dissolved oxygen:

not reported

TOC:

not reported

Salinity:

not reported

Nominal and measured concentrations:

measured concentration

Details on estimation of bioconcentration:

Based on the analyses of 19 fish, the mean concentration of NAs in the fish kept in the NAs solution from days 2 to 9 inclusive, was 5.6 ±1.9 mg k g - 1 . The fish were exposed to solutions containing 3mg/L Merichem naphthenic acids, the bioconcentration factor for NAs is approximately 2 at
pH 8.2.

Lipid content:

%

Conc. / dose:

3 mg/L

Temp.:

15 °C

Type:

BCF

Value:

ca. 2 L/kg

Basis:

other: fish flesh (wet weight)

Time of plateau:

2 d

Calculation basis:

steady state

Depuration of naphthenic acids occurred quickly when the rainbow trout were placed in naphthenic acids-

ree water. Within 1 d of being transferred to clean water, the naphthenic acids concentration dropped to 0.3 ±0.3 mg kg/1, which based on a t-test was significantly less than (P<0.05) the naphthenic acids concentration (4.2 ± 0.7 mg /kg) in the fish that remained in the solution of naphthenic acids. Two days after being transferred to clean water, the naphthenic acids concentration in the fish was 0.1 ±0.2 mg/kg, which was again significantly less than (P<0.05) the naphthenic acids concentration (5.0 ± 2.8 mg /kg) in the fish that remained in the solution of naphthenic acids.

Validity criteria fulfilled:

yes

Conclusions:

The bioconcentration factor of naphthenic acids in rainbow trout has been estimated based on an experimental uptake/ depuration test. The estimated BCF value is approximately 2L/kg fish flesh (wet weight) at pH=8.2.
The depuration occured quickly when the rainbow trout were placed in naphthenic acids-free water

Executive summary:

Rainbow trout were exposed to solutions containing Merichem naphthenic acids. Ten fish were in each of seven aquaria. The exposure to NAs was done using a 96-h static renewal procedure (Young et al., 2007). All fish remained healthy during their time in the aquaria. Based on the analyses of 19 fish, the mean concentration of NAs in the fish kept in the NAs solution from days 2 to 9 inclusive, was 5.6 ±1.9 mg k g - 1 . The fish were exposed to solutions containing 3mg/L Merichem naphthenic acids, the bioconcentration factor for NAs is approximately 2 at pH 8.2.

Reference 2

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1991

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

A reliability score of 2 has been given because the data comes from the japan METI-NITE database as described in the ECHA endpoint specific guidance (R.7c). This database This database collects bioconcentration values obtained according to the OECD305C method. According to the guidance all tests included in this database are conductare conducted in accordance with GLP standards, however this could not be verified.

Qualifier:

according to guideline

Guideline:

OECD Guideline 305 C (Bioaccumulation: Test for the Degree of Bioconcentration in Fish)

Deviations:

not specified

GLP compliance:

not specified

Radiolabelling:

not specified

Vehicle:

not specified

Test organisms (species):

Cyprinus carpio

Route of exposure:

aqueous

Test type:

flow-through

Total exposure / uptake duration:

6 wk

Lipid content:

3.9 %

Conc. / dose:

0.5 mg/L

Type:

BCF

Value:

>= 1.6 - <= 4.4 dimensionless

Basis:

whole body w.w.

Remarks on result:

other: monocyclic compound

Conc. / dose:

0.05 mg/L

Type:

BCF

Value:

<= 13 dimensionless

Basis:

whole body w.w.

Remarks on result:

other: monocyclic compound

Conc. / dose:

0.5 mg/L

Type:

BCF

Value:

>= 7.8 - ca. 14 dimensionless

Basis:

whole body w.w.

Remarks on result:

other: dicyclic compound

Conc. / dose:

0.05 mg/L

Type:

BCF

Value:

>= 14 - <= 27 dimensionless

Basis:

whole body w.w.

Remarks on result:

other: dicyclic compound

Conc. / dose:

0.5 mg/L

Type:

BCF

Value:

< 9.2 dimensionless

Basis:

whole body w.w.

Remarks on result:

other: tricyclic compound

monocylic compound

	test concentration set	BCF
1st concentration area	0.5 mg/L	1.6 - 4.4
2nd concentration area	0.05 mg/L	<10 - 13

dicyclic compound

	test concentration set	BCF
1st concentration area	0.5 mg/L	7.8 - 14
2nd concentration area	0.05 mg/L	14 - 27

tricyclic compound

	test concentration set	BCF
1st concentration area	0.5 mg/L	<9.2

for the tricyclic compound only the first concentration area was analysed because the tricyclic content was too low to be detected in the GC analysis

Validity criteria fulfilled:

yes

Conclusions:

Sodium naphthenate is non or not highly bioaccumulative. The structure of sodium naphthenate is used as a surrogate for naphthenic acids and hence the same conclusion is applicable to naphthenic acids.

Description of key information

Young et al (2008)reported a value of BCF=2 L/kg wet-wt based on one C-13 component of a naphthenic acid mixture.  The Japanese METI-NITI database reports a range of BCF between 1.6 and 27 L/kg wet-wt for sodium naphthenate.

Key value for chemical safety assessment

BCF (aquatic species):

27 L/kg ww

Additional information

The BCF of a commercial naphthenic acids was measured in rainbow trout by Young et al. (2008). The BCF of 2 L/kg wet-wt based, was measured for one C-13 component of the naphthenic acids. The Japanese METI-NITI database reports a measured range of BCF values between 1.6 and 27 (wet-wt based) for sodium naphthenate, with one, two and three cycles. The available data suggest low or no bioaccumulation potential. For further details

Value to be used for CSA:low or no bioaccumulation potential, BCF ≤ 27 (wet-wt based)