Registration Dossier

Classification & Labelling & PBT assessment

PBT assessment

Administrative data

PBT assessment: overall result

PBT status:
the substance is not PBT / vPvB
Justification:

8.1. Assessment of PBT/vPvB Properties - Comparison with the Criteria of Annex XIII

 

The criteria set out under REACH for determining whether a substance is PBT/vPvB are as follows:

 

Criterion

PBT criteria

vPvB criteria

P

Half-life (T½) > 60 d in marine water or

Half-life (T½) > 40 d in fresh or estuarine water or

Half-life (T½) > 180 d in marine sediment or Half-life (T½) > 120 d in fresh or estuarine water; sediment or

Half-life (T½) in soil > 120 d

Half-life (T½) > 60 d in marine fresh or estuarine water or

Half-life (T½) > 180 d in marine, fresh or estuarine water; sediment

Half-life (T½) > 180 d in soil

B

BCF > 2000 L/kg in fresh or marine aquatic species

BCF > 5000 L/kg

T

Chronic NOEC < 0.01 mg/l for marine or freshwater organisms, or

Substance is classified as carcinogenic (category 1 or 2), mutagenic (category 1 or 2), or toxic for reproduction (category 1, 2 or 3) or

There is other evidence of chronic toxicity, as identified by the classifications: T, R48, or Xn, R48 according to Directive 67/548/EEC.

Not applicable

Note: (a) BCF is bioconcentration factor, NOEC is no-observed effect concentration and CMR is a substance classified as carcinogenic, mutagenic or toxic for reproduction

(b) For marine environmental risk assessment, half-life data in freshwater sediment can be overruled by data obtained under marine conditions

(c) Substances are classified when they fulfil the criteria for all three inherent properties for P, B and T. However, there is certain flexibility, for instance in cases where one criterion is marginally not fulfilled but the others are exceeded considerably.

 

The above criteria are the definitive criteria for PBT assessment and listed in Annex XIII of REACH. However, the first step in the PBT assessment is to conduct a screening assessment using screening criteria. Once this screening step is carried out it is possible to evaluate measured data against the definitive criteria listed above. If a substance is confirmed to be PBT/vPvB a third step is required to estimate the amounts of substance released to the different environmental compartments from all activities and uses.

8.1. Assessment of PBT/vPvB Properties - Comparison with the Criteria of Annex XIII

 

The criteria set out under REACH for determining whether a substance is PBT/vPvB are as follows:

 

The above criteria are the definitive criteria for PBT assessment and listed in Annex XIII of REACH. However, the first step in the PBT assessment is to conduct a screening assessment using screening criteria. Once this screening step is carried out it is possible to evaluate measured data against the definitive criteria listed above. If a substance is confirmed to be PBT/vPvB a third step is required to estimate the amounts of substance released to the different environmental compartments from all activities and uses.

8.1.1  Persistence (P) Assessment

 

One of the screening criteria for persistence is that if a substance is not considered to be readily biodegradable then the substance is screened as being P and vP. Biodegradation screening studies are available for a number of substances in Category E, these being 68037-01-4 (Douglas, 1993; Bianchini-Akbeg, 1991), 68649-11-6 (Douglas, 1993; McGoldrick and Mehta, 1992), 151006-58-5 (Douglas and Sewell, 1989; Handley and Mead, 1995), 68649-12-7 (Mehta and McGoldrick, 1992; Handley and Mead, 2005; Mead, 2005), 151006-60-9 (Handley and Mead, 1995) and 883233-93-0 (Hamwijk, Hanstveit and Verweij, 2002a and 2002b) and all have found the test substance not to be readily biodegradable. Based on read across from this data, the rest of the substances in this category are also considered not to be readily biodegradable. 

 

Therefore, based on the screening criteria for persistence stipulated in the ECHA’s Guidance on Information Requirements and Chemical Safety Assessment - Part C: PBT Assessment (2008) substances in this category are considered persistent (P) and potentially very persistent (vP).

 

8.1.2 Bioaccumulation (B) Assessment

 

The screening criterion for bioaccumulation is that a substance is potentially B or vB if it has a log Kow of >4.5. Experimental data on Kow are available for members of this category. For 68649-11-6 log Kow is measured as >6.5 (Walker and Mullee, 2006) and >4.82 (Hogg and Bartlett, 1995). For 68649-12-7, experimental data measures log Kow as >5 (Howard, 1982), >7.6 (Seary, 2000) and >3.87 (Hogg and Bartlett, 1995). For 68037-01-4 an experimental value of >6.5 (Walker and Mullee, 2006) is given. As the majority of the experimental log Kow for substances in this category are greater than 4.5 this indicates that they meet the screening criteria for bioaccumulation stipulated in the ECHA’s Guidance on Information Requirements and Chemical Safety Assessment - Part C: PBT Assessment (2008) and therefore cannot be ruled out as being B or vB.

 

ECHA’s Guidance on Information Requirements and Chemical Safety Assessment - Part C: PBT Assessment (2008) states that the aquatic BCF of a substance is probably lower than 2000 L/kg if the calculated log Kow is higher than 10. All of the experimental log Kow values for substances in this category are unbounded due to limitations of the experimental method, so do not allow us to conclude if the log Kow is greater than 10. Calculated partition coefficients have been obtained from EPIWEB 4.0 (USEPA, 2008) and SPARC (Karickhoff et al, 2009) for dec-1-ene dimer, hydrogenated (CAS 68649-11-6) and dec-1-ene trimer, hydrogenated (CAS 157707-86-3) as these are the only two members of this category being registered as substances with predominantly a single carbon number. The calculated log Kow for 68649-11-6 is 10.09 and 11.71 and for 157707-86-3 is 14.93 and 17.21 (USEPA, 2008 and Karickhoff et al, 2009 respectively). All of the calculated log Kow values are greater than 10.

 

There is a clear trend of increasing log Kow with increasing carbon number in the alkanes and olefins. 68649-11-6 is the category member with the lowest carbon number, and therefore will be the category member with the lowest partition coefficient. This therefore indicates that the calculated log Kow of all category members would be >10. As QSAR models do not have experimental data in this Kow range the reliability of modelled Kow values >10 is not known. However, as the model indicates a log Kow >10 for the category member with the lowest carbon number we can conclude that members of this category are unlikely to meet the definitive criteria for B/vB.

 

A measured BCF is not currently available for members of this category so data cannot be compared to the definitive criteria given in REACH Annex XIII. However, on the basis of the calculated log Kow for two category members this category is not considered as bioaccumulative (B) or very bioaccumulative (vB).

 

8.1.3 Toxicity (T) Assessment

 

8.1.3.1 Environmental Toxicity

 

The screening criteria for toxicity are that an acute EC50 or LC50 <0.1mg/l is considered to be T, and that an EC50 or LC50 <0.01mg/l indicates that the substance is definitely T.

There is acute aquatic toxicity data available for a number of substances in this category. The EL50 and LL50 values measured for these substances are considered to be suitable for read across to the rest of this category. Acute ecotoxicity studies are available for invertebrates, algae and fish. Due to the very low solubility of the category members all of the results are expressed as Water Accommodated Fractions (WAF). All report the EL or LL50 were greater than the highest concentration tested. As these studies report results as WAF they cannot be compared directly with the screening criteria for toxicity. However, they do indicate that the poly alpha olefins in this category are not acutely toxic at their limits of solubility.

 

The toxicity of the poly alpha olefins in this category has been predicted using the PETROTOX 3.01 model. PETROTOX indicates that branched and linear alkanes and alkenes with a carbon number equal to or greater than C14 will not exert any toxicity at concentrations up to their limit of solubility. The components of the substances in this category have carbon numbers equal to or greater than C20. PETROTOX therefore predicts that toxicity will not be observed at concentrations up to the limit of solubility.

Therefore, based on the weight of evidence category members are considered not T for the purposes of the PBT assessment.

 

8.1.3.2 Human Health Hazards Assessment (T)

 

Poly alpha olefins do not fulfill the toxicity criterion for human health based on the evidence described below:

  • Carcinogenicity. Poly alpha olefins are not classifiable as to human carcinogenicity based on a lack of available carcinogenicity data on experimental animals and humans. However, based on available mutagenicity, genotoxicity and repeated dose studies, Poly alpha olefins are not considered likely to be human carcinogens. In vivo and in vitro mutagenicity and genotoxicity tests for all identified studies within poly alpha olefins or from structural analogues were negative. Additionally, there was no evidence of cumulative toxicity or hyperplasia in repeated dose toxicity studies (subacute and subchronic oral repeated dose studies within poly alpha olefins or from structural analogues). There were no relevant human studies identified. In summary, there are no data to suggest that poly alpha olefins are potentially carcinogenic to humans.

 

  • Mutagenicity. Poly alpha olefins are not considered likely to be mutagenic based on in vitro and in vivo studies conducted with Poly alpha olefins or with structural analogues. For example, results from reliable and robust in vitro bacterial and chromosome aberration assays on poly alpha olefins and structural analogues were negative. In addition, a read-across in vitro gene mutation assay indicated that Alkane 4, a structural analogue, was not mutagenic in a mouse lymphoma assay. In well conducted and reported in vivo inhalation mammalian bone marrow micronucleus assays, exposure to poly alpha olefins and structural analogues did not produce a significant dose-related increase in the formation of micronuclei in bone marrow cells. Overall evaluation of the available mutagenicity data on poly alpha olefins or structural analogues indicates that poly alpha olefins are not likely to be mutagenic.

 

·        Reproductive Toxicity. No developmental or 2-generation reproductive toxicity data are available for poly alpha olefins. However two one-generation reproduction toxicity studies from 1 -decene, homopolymer, hydrogenated and another from a structural analogue, Alkane 4, showed no effect on reproductive or developmental parameters. There were no relevant human studies identified. Data on all other toxicological endpoints for PAOs show low toxicological activity, including an absence of effects on reproductive endpoints. Repeat dose studies up to 90 days did not identify any adverse effects on reproductive organs. Collectively, these data suggest that poly alpha olefins are unlikely to be reproductive toxins; therefore further testing is not warranted.

  • Other Concern. Poly alpha olefins are not classified as T, R48, or Xn, R48 according to Directive 67/548/EEC.

 

8.1.4  Summary and overall Conclusions onPBTand vPvB properties

 

The screening assessment of the available data for this category indicates that conclusion (ii) is appropriate for this substance as stipulated below.

 

ii) The data show that the properties of the substance do not meet the specific criteria detailed in Annex XIII or do not allow a direct comparison with all the criteria in Annex XIII but nevertheless indicate that the substance would not have these properties and the substance is not considered a PBT/vPvB.

 

Therefore the PBT/vPvB assessment stops at this point.

 

8.2   Emission Characterisation

 

This section of the report is not required for non PBT/vPvB substances.