Reaction mass of 2,2'-oxybisbutane and 2-methylpropan-2-ol and butan-2-ol and diisopropyl ether

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.046 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.46 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.005 mg/L

Assessment factor:

10 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

24 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

0.277 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.028 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

0.029 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

The reaction mass of 2,2'-oxybisbutane (DSBE), DIPE, SBA and 2-methylpropan-2-ol (TBA) was tested for acute toxicity to daphnia, algae, fish and micro-organisms.

The EC50 value from the 3h-respiration inhibition test with sewage sludge was 2400 mg/L. The results were used in risk assessment, but are not required for classification.

The EC50 value from the 48h-daphnia test (46 mg/L) represented the lowest value in comparison with the 72h-ErC50 from the algae test (58 mg/L, value based on growth rate). Therefore, a 96h limit test with 46 mg/L with fish was performed to evaluate if fish were more sensitive than daphnia. As no effects were observed in the limit test, the EC50 (48h, daphnia) is the lowest value among the three species and used for risk assessment and classification. Based on this value and the lack of biodegradability, the reaction mass is considered harmful for aquatic life with long lasting effects and has to be classified with H412 (CLP Regulation).

Comparing the test results on daphnia, algae and fish with measured or estimated data on aquatic toxicity for the known components of the reaction mass, it appears likely that mainly DSBE accounts for the observed toxicity: Around 30% DSBE with a aquatic toxicity of 11 - 17 mg/L may be the cause observed aquatic toxicity of 46 - 58 mg/L in daphnia and algae.

Measured and calculated literature values for the reaction mass ingredients can be found in the following table:

	acute toxicity			chronic toxicity
	daphnia (48 -h EC50)	algae (96 -h LC50)	fish (96 -h LC50)	daphnia	algae	fish
DSBE	16.7 mg/l (calculated, (1))	11.0 mg/l (calculated, (1))	14.7 mg/l (calculated, (1)); 30.7 mg/l (measured for n-butyl-ether (nBE) CAS No. 142-96-1, as analogue (2))	1 -2 mg/l (calculated, (1))	1 -2 mg/l (calculated, (1))	1 -2 mg/l (calculated, (1))
DIPE	190 mg/L (measured, (5)); 221.9 mg/l (calculated, (1))	135 mg/L (calculated, (1))	92 mg/L (measured, (3)); 214.1 mg/L (calculated, (1)); 786 mg/L (measured, (4))		10 mg/L (calculated, (1)
SBA	1084 mg/l (calculated (1)); 4227 mg/l (measured, (6))	95 mg/l (toxicity threshold, 7 -d) (6); 625 mg/l (calculated, (1))	1113 mg/l (calculated, (1); 3670 - 4300 mg/l (measured (6))	30 mg/l (16 -day) (calculated, (1))	28 mg/l (96 -h chronic toxicity value, calculated, (1))	115 mg/l (30 -d ChV (chronic toxicity value; calculated, (1))
TBA	5504 mg/l (measured, (7))	>976 mg/l (measured, (7))	6401 mg/l (measured, (7))		6.1 mg/l (LC3, 7 -d)	180 mg/l (measured, (7))

As risk assessment indicated that risk is controlled for water, sediment, sewage treatment plant and soil no further tests on ecotoxicity are required.

References:

(1) EPI SuiteTM (2000). Estimation Program Interface Suite, version 3.12. Syracuse Research Corporation, Syracuse, NY, USA.

(2) Chemicals Inspection and Testing Institute (CITI) (1992). Biodegradation and bioaccumulation data of existing chemicals based on the CSCL Japan. CITI (ed.). Chemical Products Safety Division, Basic Industries Bureau, Ministry of International Trade and Industry, Japan. Japan Chemical Industry Ecology-Toxicology and Information Center.

(3) Veith G, Call D and Brooke L (1983). Structure-Toxicity Relationships for the Fathead Minnow, Pimephales promelas: Narcotic Industrial Chemicals.Can.J. Fish. Aquat. Sci. 40, 743-748.

(4) Geiger D, Poirier S, Brooke L and Call D (eds.) (1986). Acute Toxicities of Organic Chemicals to Fathead Minnows (Pimephales promelas), Vol. 3. Center forLake SuperiorEnvironmental Studies,Univ.ofWisconsin- Superior,Superior,WI,USA.

(5) HIGH PRODUCTION VOLUME (HPV) CHEMICAL CHALLENGE PROGRAM TEST PLAN For: Diisopropyl Ether (DIPE) CAS NO. 108-20-3 Prepared by: ExxonMobil Chemical Company Shell Chemical LP, December 12, 2005

(6) OECD SIDS Dossier for Butan-2 -ol, CAS No.78 -92 -2,ExxonMobil Biomedical Sciences Inc.,09.01.2002

(7) Robust Summaries for t-Butanol, CAS Number 75 -65 -O USEPA HPV Challenge Program SubmissionApril 10, 2002

Conclusion on classification

Based on the lowest EC50 value among the species daphnia, algae and fish (lowest value 46 mg/L for daphnia) in combination with the fact that the substance is not readily biodegradable, a classification into aquatic chronic category 3 (H412) according to the CLP regulation (corresponding to R52/53 under DPD) is necessary (EC50 10-100 mg/l).