Distillation residue, butyl alcohols production, rectification

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

Substance is containing unidentified portion of potential PBTs / vPvBs.

Straightforward assessment of PBT and vPvB properties was not possible for the substance. In order to take into account the uncertainty related to the assessment, appropriate RMM and OC are proposed for the substance.

Rationale:

Assessment of PBT and vPvB properties of the substance was difficult because of the substance properties. The substance is a UVCB substance containing constituents with different kinds of physical-chemical properties. Identification and quantification of the individual components was not possible. Therefore, there were many difficulties related to the assessment:

-         application of PBT and vPvB criteria was not straightforward

-         use of QSAR or read-across methods was not feasible

-         testing of BCF was not technically feasible for the substance

-         there were uncertainties related to the testing of K_owproperties and biodegradation

-         acute toxicity was tested with WAF and effective exposure determined as loading rates

Due to these difficulties, there are uncertainties related to the assessment. All available data on the substance was taken into consideration in the assessment (instead of applying only specific criteria defined in REACH Annex XIII).

Based on the available data, the substance might be determined as persistent (P) or very persistent (vP). According to ready biodegradability screening test, the substance was inherently biodegradable. It should be noted that interpretation of test results is not straightforward due to the substance properties.The half-live estimated based on hydrolysis test results was over one year. Based on the half-live, the substance would be very persistent (vP). 

As determination of BCF experimentally was not feasible, the bioaccumulation assessment was based on the octanol-water partition coefficient test results, which indicated a range log Kow values from 1.8 to 7.5 for the substance. These log Kow values indicate that at least some of the components have potential for bioaccumulation. However, as the test method is developed is for pure substances, the results are uncertain for the target substances containing several different components. 

Due to differences in physical-chemical properties between the components, it is difficult to achieve a homogeneous solution by direct addition of the test substance into the test medium. Therefore, water accommodated fractions (WAFs) were prepared for aquatic toxicity testing. According to the acute aquatic toxicity studies on the substance, the effective loading rates (EL50) are in the range of 10-100 mg/L. This screening information indicates that the substance is not toxic (T).

The substance is not classified as carcinogenic (category 1 or 2), mutagenic (category 1 or 2) or toxic for reproduction (category 1, 2 or 3) due to lack of data. Additionally, there is no other evidence of chronic toxicity, based on surrogate material toxic properties.

Straightforward assessment of PBT and vPvB properties was not possible for the substance. However, it is probable that some of the constituents have P and B properties. However, as there was no evidence on toxicity properties for this substance, this substance is not considered as PBT or vPvB substance. In order to take into account the uncertainty in the assessment, appropriate RMM and OC are presented in the CSR Section 9.

Likely routes of exposure:

Straightforward assessment of PBT and vPvB properties was not possible for the substance. However, it is probable that some of the constituents have P and B properties. However, as there was no evidence on toxicity properties for this substance, this substance is not considered as PBT or vPvB substance. In order to take into account the uncertainty in the assessment, appropriate RMM and OC are presented in the CSR Section 9.