Distillation residue, butyl alcohols production, rectification

Endpoint summary

Additional information

Terrestrial toxicity data for the substance was not available in literature. Normally, a set of indicators representing three soil organism groups of major ecological importance and covering all relevant soil exposure pathways is required for a comprehensive effect assessment of substances in soils for REACH chemical safety assessment. Testing is proposed for invertebrate and plant in order to generate data for the hazard assessment. Testing with micro-organism what not considered necessary.

The physico-chemical properties of the substance indicate that terrestrial toxicity on soil organisms is necessary to be conducted.The substance is water soluble (1.8-9 g/l) but most probably also contains constituents having low solubility in water. According to the test results the substances has constituents having log K_owvalues of 1.8 to 5.8, but also constituents corresponding the log K_owvalues of 6.4 up to 7.5. Based on the experimental data, the substance is non volatile at room temperature and partly volatile at 35 °C (7.9 kPa) and 50 °C (19.4 kPa). Substance is hydrolytically stable and the estimated half-life is over one year. The biodegradation screening test indicated that the substance is inherently biodegradable. Some biodegradation occurred (biodeg-% 49.6) but the criteria for ready biodegradability was not fulfilled.

The EPM screening method is recommended if substance shows potential for terrestrial adverse effects based on physical-chemical properties and results from aquatic toxicity testing. However, for this UVCB substance EPM was not considered feasible. In addition, soil testing reflects better the real bioavailability of the substance for soil organisms compared to EPM screening. Because the composition of the substance is not easily identifiable, the grouping methods and read-across to evaluate the overall fate and pathways were also regarded unsuitable approach for this substance.

Therefore, the terrestrial plant and invertebrate testing was conducted for the substance based on the accepted testing proposal (TPE-D-0000002369-68-03/F). The seedling emergence and seedling growth test in accordance with GLP and OECD 208 and the earthworm reproduction test according to OECD 222 in acordance with GLP were performed.

In the seedling emergence and seedling growth study some stunting or effects on emergence were observed. Based on the study results sugar beet and wheat were the most sensitive plants in the test. The lowest EC50 and NOEC-values for the most sensitive plant (sugar beet) and for the most sensitive endpoint (shoot height) were selected as a key values for CSA. The EC50 value for shoot height was determined as 238 mg/kg dry soil for sugar beet. The corresponding NOEC value for emergence was determined as 125 mg/kg dry soil for sugar beet and NOEC value for shoot height was determined as 125 mg/kg for sugar beet. NOEC value for dry shoot weight was determined as 125 mg/kg dry soil for sugar beet.

The acute toxicity study to earthworms (Eisenia fetida) in artificial soil was conducted for the substance according to the OECD 207 in accordance with GLP. The LC50 323.20 mg/kg soil dry weight with condidence limits: 290.81 – 359.20. The NOEC related to mortality and related to biomass change was 250 mg/kg soil dry weight. This study was conducted as a range finding study for earthworm reproduction toxicity study (OECD 222).

The key values for CSA were selected based on the lowest endpoint results of OECD 222. In this study the mortality, behavioural effects, weight change after 28 days, and the number of juveniles (reproduction) after 56 days were assessed on earthworm (Eisenia fetida).Test species were adult worms (with clitellum and weight 266-598 mg), less than one year old from in-house culture, and the test concentrations were control, 18.75; 37.5; 75; 150 and 300 mgTest Item/kg soil dry weight prepared in OECD 222 artificial soil.

Based on the key study results, the 56-d EC50, based on the reproduction rate (juvenile numbers) of Eisenia fetida was determined as 270.92 mg/kg soil dry weight (95 % confidence limits: 203.86 - 360.03 mg/kg soil dry weight). The 28-d LC50 was determined as 287.43 mg/kg soil dry weight (95 % confidence limits: 257.03 – 329.11 mg/kg soil dry weight).

Based on the adult mortality and biomass development, the NOEC (28 day) was 150 mg Test Item/kg soil dry weight and the NOAEC (56 day) was 150 mg Test Item/kg soil dry weight based on reproduction.

Based on these studies there is enough information to derive the PNEC soil and further investigations for chemical safety assesment are not necessary. The exposure assessment and risk characterisation is also concluding that the risks to terrestrial compartment are adequately controlled (ES&RC in section 9 and 10).