2-(2H-Benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol

Monitoring data

Administrative data

Endpoint:

monitoring data

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

Data source

Reference

Reference Type:

publication

Title:

Benzotriazole UV stabilizers in sediments, suspended particulate matter and fish of German rivers: New insights into occurrence, time trends and persistency

Author:

Arne Wick, Björn Jacobs, Uwe Kunkel, Peter Heininger, Thomas A. Ternes

Year:

2016

Bibliographic source:

Environmental Pollution 212, 401-412

Materials and methods

Principles of method if other than guideline:

Freeze-dried samples were extracted by pressurized liquid extraction (PLE) using a Dionex ASE 200 instrument. Bream liver, sediment and SPM samples were weighed into 22 mL stainless steel extraction cells pre-filled with baked-out sea sand. The bream liver and SPM samples were extracted with a 50:50 or 90:10 mixture of n-hexane and acetone, respectively. The following PLE conditions were set: prefill method, 5 min equilibration, 10 min static time, 120% flush volume, 300 s purge time, 300 s, 3 static cycles, 100°C temperature, and 100 bar pressure. All extracts were dried using an evaporation unit and reconstituted in approximately 1 mL n-hexane/acetone (90/10; v/v).

First, a silica clean-up of the PLE extracts was üerformed using a prepacked Chromabond SiOH glass columns (6 mL, 1 g). Befor usage the columns were heated to approx. 90°C for at least 3 h and conditioned with 3 x 2 mL n-hexane/acetone (90/10; v/v). Columns were loaded with 1 mL extracts and the BUVSs were eluted with 5 x 2 mL n-hexane/acetone (90/10; v/v). The eluate was then evaporated to dryness under a gentle flow of N2 gas. Sediment and SPM samples were reconstituted in 2 mL methanol for LC-MS/MS analysis. In contrast, bream liver samples were reconstituted in 5 mL of cyclohexane/ethyl acetate (50/50; v/v) for a further clean-up by gel permeation chromatography (GPC) to remove the lipid fraction from the bream liver extracts. GPC was performed using a Knauer HPLC system consisting of a Smartline Autosampler 3950, Smartline Manager 5050 (degasser) and a Smartline Pump 1000.
A GPC column filled with Bio Beads S X3 material from LCTech was used for the separation of BUVSs from lipids and other matrix constituents. For the mobile phase a mixture of cyclohexane and ethyl acetate (50/50; v/v) was used and the flow rate was set to 4.8 mL/min. The injection volume was 2 mL of each sample and the total run time was 60 min. The fraction contained the target compounds eluted between 16 and 32 min and was separated using a sample collector. The eluates were dried using an evaporation unit and reconstituted in 2 mL methanol for LC-MS/MS analysis.

GLP compliance:

no

Type of measurement:

other: occurrence, time trends and persistency

Media:

other: sediment, suspended particulate matter and fish liver

Test material

Specific details on test material used for the study:

The following BUVSs were investigated:

- 2-tert-butyl-6-(5-chlorobenzotriazol-2-yl)-4-methylphenol (UV-326)
- 2-(benzotriazol-2-yl)-4,6-ditert-butylphenol (UV-320)
- 2-(benzotriazol-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol (UV-329)
- 2-(benzotriazol-2-yl)-6-butan-2-yl-4-tert-butylphenol (UV-350)
- 2,4-ditert-butyl-6-(5-chlorobenzotriazol-2-yl)phenol (UV-327)
- 2-(benzotriazol-2-yl)-4,6-bis(2-methylbutan-2-yl)phenol (UV-328)
- 2-(benzotriazol-2-yl)-6-(2-phenylpropan-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol (UV-928)
- 2-(benzotriazol-2-yl)-4,6-bis(2-phenylpropan-2-yl)phenol (UV-234)
- 2-(benzotriazol-2-yl)-6-[[3-(benzotriazol-2-yl)-2-hydroxy-5-(2,4,4-trimethylpentan-2-yl)phenyl]methyl]-4-(2,4,4-trimethylpentan-2-yl)phenol (UV-360)

Study design

Details on sampling:

Sediment and suspended partical matter (SPM):
Sediment and SPM samples were taken from eleven sampling sites at five different German rivers. Bulk samples were collected from the sediment surface using a Van Veen grab sampler covering an area of 0.1 m2 and a depth of 10 to 20 cm. SPM samples were collected by continuous-flow centrifugation within 6 to 8 h, except for the sample from Rehlingen which was provided by the German Environmental Specimen Bank (ESB). The samples were frozen (-20°C), freeze-dried, sieved (< 2 mm) and homogenized in planetary ball mill. Annual composite SPM samples from two sites (Rhine and Saar) were provided by the German ESB for the analysis of time trends annual composite. SPM sampling and preparation were conducted in accordance to the corresponding standard operation procedure of the German ESB (Ricking et al., 2012).

Bream liver
All bream liver samples were provided by the German ESB, and thus were sampled and prepared according to a standard operation procedure of the German ESB (Klein et al., 2012).

Water-sediment batch systems
Water-sediment batch systems were conducted following the OECD guideline 308.

The following site have been sampled:
Rhine: R1 = Iffezheim, R2 = Koblenz
Elbe: E1 = Meissen/Zehren, E2 = Wittenberg, E3 = Barby, E4 = Cumlosen
Saale: SL1 = Wettin, SL2 = Rosenburg
Saar: SR = Rehlingen/Dillingen
Moselle: M = Koblenz

Results and discussion

Any other information on results incl. tables

All BUVSs were detected above the LOQ (0.05 to 0.2 ng/g dw) in all sediments samples except for UV-350 that was only found at concentrations above the LOQ (0.4 ng/gdw) in the two samples from the river Rhine.

For sediment samples the highest median concentrations were determined for UV 360 (21 ng/g dw) followed by UV-326 (12 ng/g dw), UV-234 (6.1 ng/g dw), UV-328 (4.6 ng/g dw), UV-327 (3.4 ng/g dw), UV-329 (2.2 ng/g dw), UV-320 (0.55 ng/g dw) and UV-928 (0.23 ng/g dw).

UV-326 and UV-360 were found with maximum concentrations of 44 ng/g dw and 62 ng/g dw,respectively.

BUVS concentrations in SPM were comparable to those found in sediments, except for UV-329. The concenntration of UV-329 in SPM samples from two sampling sites was 4 times higer compared to the corresponding sediment samples.

Five of the nine BUVSs (UV-327, UV-328, UV-320, UV-350 and UV-234) were found above their LOQ in at least one of the bream liver samples. UV-327 and UV-328 were even detected in all analyzed bream liver samples. UV-327 was determined to be the dominant BUVS in bream liver samples with a maximum concentration of 65 ng/g dw corresponding to a lipid weight (lw) normalized concentration of 155 ng/g lw. UV-360, UV-326 and UV-329 were not found above their LOQ in any of the bream liver samples.

Concentrations in SPM for UV-320 and UV-328 showed a signifigant decrease of 46-48% and 25 -30% in samples from two sites, respectively. At one of the sites UV-326, UV-350 and UV-327 were also found to decrease significantly by 61, 67 and 35% in SPM samples, respectively. Whereas, at the second sampling site concentrations of UV-326 and UV-327 were not significantly changing and concentrations of UV-350 were always below LOQ.

A significant linear increase in the concentrations of UV-329 (from 60 ng/g TOC to 140 ng/g TOC) was found at both sampling sites. The concentrations increased by almost 200% and 100% in the SPM samples.

The highest increase of almost 5000% was observed for UV-928 in SPM samples from one of the sampling sites. At the second sampling site no significant trend of UV-928 was found in the SPM samples. For UV-234 opposing findings regarding the sampling sites were observed with an increase of 67%.

In bream liver samples a significant decrease (96%) of UV-350 was detected. The other BUVSs (UV-327, UV-320, UV-328 and UV-234) showed either no significant trend or were below LOQ (UV-326, UV-329, UV-928 and UV-360) in bream liver samples.

In the sediment-water system more than 99.5% of the applied amount (2 µg) of UV-326, UV-350, UV-329, UV-328 and UV-327 and even more than 99.9% of UV-928 and UV-234 was sorbed to the sediment after 16 d.

Until the end of incubation no significant decrease of all BUVS concentrations was observed and thus, abiotic and/or biotic degradation were negligible. Therfore, the predicted dissipation half-lives (DT50) in sediment were considerably higher than 100 d.

Applicant's summary and conclusion

Conclusions:

The results of the study show that UV-360 was one of the most dominant BUVSs. Five (UV-327, UV-328, UV-320, UV-350 and UV-234) of the nine BVSs were also found in bream liver. This finding confirmed their high bioaccumulation potential. Furthermore, the study indicates that BUVSs are ubiquitous and rather persistent in sediments and SPM in German rivers. The sample analysis in aerated sediment-water systems showed a complete sorption to the sediment and no significant degradation over a period of 100 d. A significant change of concentration levels in SPM over the last 10 years was observed for most of the BUVSs and the it can be suggested that time trends were both, compound-and region-specific. Currently, the contamination levels of UV-329, UV-234 and UV-928 seems to be rather increasing, while those of the others are remaining fairly constant (UV-360) or are decreasing (UV-326, UV-320, UV-350, UV-328 and UV-327).

Executive summary:

The occurrence of nine different lipophilic BUVSs (UV-326, UV-320, UV-329, UV-350, UV-328, UV-327, UV-928, UV-234 and UV-360) in sediment, suspended particulate matter (SPM) and bream liver samples of German rivers were investigated. All BUVSs were detected in sediments and SPM at concentrations in the low ng/g dry weight (dw) range. UV-360 and UV-326 were the predominant BUVSs in sediments and SPM from the river Rhine reaching maximum concentrations of 62 and 44 ng/g dw, respectively. Five BUVSs (UV-327, UV-328, UV-320, UV-350 and UV-234) were confirmed to bioaccumulate in bream liver, but neither UV-360 nor UV-326 was detected above LOQ. Whereas, highest concentrations for UV-327 (65 ng/g dw) and UV-328 (40 ng/g dw) were found in bream liver. A retrospective time trend analysis of BUVSs in SPM from two sites (river Rhine, 2005 to 2013; river Saar, 2006 to 2013) showed increasing contamination levels of UV-329 and decreasing levels of UV-320 and UV-350. At one site (river Rhine) time trends of BUVS concentrations were also investigated in bream liver (1995 - 2013) and supported a considerably reduced exposure to UV-350. A rapid partitioning into the sediment and no considerable degradation within 100 d was determined through an assessment of the environmental fate of BUVSs by sediment-water batch systems.