Bis(isopropyl)naphthalene

Monitoring data

Administrative data

Endpoint:

monitoring data

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Remarks:

official Japanese monitoring programme

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

publication

Title:

Investigation of environmental contamination of mono-isopropylnaphthalene, di-isopropylnaphthalene and tri-isopropylnaphthalene in Hyogo in Japan

Author:

Suzuki M, Matsumura C, Nakano T, Imaishi H

Year:

2012

Bibliographic source:

Environ Sci Pollut Res 19, 3959-3968

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Development and application of simultaneous analytical methods for MIPN, DIPN, TIPN for air, environmental waste, sediment, water, and biological samples, documentation partly limited.

GLP compliance:

not specified

Type of measurement:

concentration at contaminated site

Media:

other: river water, sea water, sediment, fish tissue

Test material

Test material information

Constituent 1

Reference substance name:

Bis(isopropyl)naphthalene

EC Number:

254-052-6

EC Name:

Bis(isopropyl)naphthalene

Cas Number:

38640-62-9

Molecular formula:

C16H20

IUPAC Name:

bis(isopropyl)naphthalene

Details on test material:

- Name of test material: Di-Isopropylnaphthalene, DIPN, analysed in environmental samples

Study design

Details on sampling:

- Geographic coordinates: Osaka Bay, southern Hyogo Prefecture, Japan and Seto Inland Sea, southern Hyogo Prefecture, Japan
- Known emission sources near sampling site: Paper recycling plant close to a waterway which eventually joins the Ibo river.
- Period of sampling: 2009-2010
- Sampling: River and sea water samples: 1 L; sediment samples: 10 g dw; biological samples: 10 g ww
- Sampling points and procedure: Sea sediments were sampled by means of an Ekman-Birch bottom sampler at 41 sampling points in the Seto Inland Sea and Osaka Bay (see publication. fig. 7).
The river sediments were obtained with a dredge at 8 eight rivers that empty into the sea.
Fish samples (Japanese Sea Perch, Lateolabrax japonicas) were sampled in the vicinity of sampling point S27 (see publication, fig. 7). 5 samples were made from fillet of 2 or 3 perches each.

Results and discussion

Concentration

Concentration 1

Country:

Japan

Location:

Sea sediment near the mouth of the Ibo River (Osaka Bay, southern Hyogo Prefecture)

Substance or metabolite:

metabolite

Conc.:

0.1 mg/kg dw

Remarks on result:

other: Obvious source of pollution: Recycling Paper Plant

Concentration 2

Country:

Japan

Location:

Sediment of a river mouth (western Osaka Bay)

Substance or metabolite:

substance

Conc.:

ca. 4.4 mg/kg dw

Remarks on result:

other: Highest measured contamination with DIPN in Japan (2010): solitary case

Details on results:

- Water samples: DIPN concentration in water samples ranged between <1.9 and 9.8 ng/L (MIPN and TIPN was not detected at all sampling points).
In comparison: Water contamination by DIPN, which was examined by the Ministry of Environment (MOE) of Japan at 20 points in Japan (including the points S27 and R7 of this study) in 2006 and 2007 were between <0.83 and 3.2 ng/L (see publication p. 3963 and table 3 below).
- Fish samples: DIPN concentration ranged between 1.2 and 3.4 ng/g ww (no difference between males and females).
[MIPN was detected in all samples under the quantification limit; TIPN was detected only in female samples between 0.65 and 1.4 ng/g ww
(see publication p. 3963 and table 4 below)].
- Sediment samples (see publication, p. 3963 and figures 7 and 8): DIPN was positive at all 41 sampling points. A high concentration of DIPN of 100 ng/g dw in the sea area was measured at sampling point S21 where the Ibo river empties into the Osaka Bay (in addition see Suzuki et al., 2007). The highest concentration was found in river sediment: 4400 ng/g dw DIPN at sampling point R1, a river mouth in the West in the area.
In a different Japanese programme in 2009, 230 ng/g sediment was reported as highest concentration (see p.3964).
- Isomer pattern: The isomer fingerprints in water, sediment, and air samples had almost the same pattern as the reference technical stock solution (data not shown). The isomer fingerprint in male fish samples was the same as the reference standard stock solution, whereas the pattern in female samples was different. Higher proportions of 1,3-DIPN and 1,4-DIPN were detected in female samples (compare also Suzuki et al., 2007).

Any other information on results incl. tables

Table 3 (from Suzuki et al., 2012): Water concentrations of MIPN, DIPN, and TIPN at river sampling points (sampling 2009 - 2010)

Sampling point	Concentration in water (ng/L)
	MIPN	DIPN	TIPN
R1	< 1.8	9.8	< 5.6
R2	< 1.8	2.5	< 5.6
R3	< 1.8	5.1	< 5.6
R4	< 1.8	7.6	< 5.6
R5	< 1.8	3.6	< 5.6
R6	< 1.8	3.5	< 5.6
R7	< 1.8	2.6	< 5.6
R8	< 1.8	1.9	< 5.6
R9	< 1.8	< 1.9	< 5.6
R10	< 1.8	< 1.9	< 5.6
S27	< 1.8	< 1.9	< 5.6

Table 4 (from Suzuki et al., 2012): MIPN, DIPN, and TIPN concentrations of filleted perches (Lateolabrax japonicas) sampled at point S27.

Sample 1 and 2 were prepared from female perches, samples 3,4, and 5 from male perches.

	Concentration (ng/g ww)
	MIPN	DIPN	TIPN
Sample 1	0.23	1.7	< 0.52
Sample 2	0.37	1.8	< 0.52
Sample 3	0.19	1.3	0.67
Sample 4	0.19	3.4	1.4
Sample 5	< 0.15	1.2	0.65