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Classification & Labelling & PBT assessment

PBT assessment

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PBT assessment: overall result

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

Persistence Assessment:

P criteria:

– the half-life in marine water is higher than 60 days, or

– the half-life in fresh- or estuarine water is higher than 40 days, or

– the half-life in marine sediment is higher than 180 days, or

– the half-life in fresh- or estuarine water sediment is higher than 120 days, or

– the half-life in soil is higher than 120 days

No relevant half-life data was available from simulation studies. Therefore the assessment of the P/vP criteria was based on the screening criteria of ready biodegradation.

The substance is considered to be readily biodegradable, based on the results of a OECD Guideline 306 "Biodegradability in Seawater - Closed Bottle Test" study in which the substance was degraded 100% after 28 days.

The substance is readily biodegradable. Therefore, based on the screening criteria for persistence, the substance is neither a P or vP substance.

Bioaccumulation Assessment:

B criteria: BCF > 2000

vB criteria: BCF > 5000

An assessment of bioaccumulation has been made using both the screening criteria (log Kow) and bioaccumulation study data.

The octanol/water partition coefficient of the substance has been experimentally determined to be log Pow -2.94 and therefore does not meet the screening criteria for B or vB (log Kow >4.5).

In a bioaccumulation study, carp exposed to 0.1 µg/ml and 0.01 µg/ml carbohydrazide showed the bioconcentration factors (BCF) of less than 3 and less than 6 respectively, over the period from week 2 to week 8 of the test. The results indicate that carbohydrazide is not a bioaccumulative compound and does not meet the criteria for being a B or vB substance.

The substance is not a B or vB substance based on both screening criteria (log Kow substantially below 4.5) or based on the results of a bioaccumulation study, where the maximum BCF value was 6.

Toxicity Assessment:

T criteria:

– the long-term no-observed effect concentration (NOEC) for marine or freshwater organisms is less than 0.01 mg/l, or

– the substance is classified as carcinogenic (category 1 or 2), mutagenic (category 1 or 2) or toxic for reproduction (category 1, 2, or 3) according to Directive 67/548/EEC or as carcinogenic (category 1A, 1B or 2), germ cell mutagenic (category 1A or 1B) or toxic for reproduction (category 1A, 1B or 2) according to Regulation EC No 1272/2008, or

– there is other evidence of chronic toxicity, as identified by the classifications: T, R48, or Xn, R48 according to Directive 67/548/EEC or specific target organ toxicity after repeated exposure (STOT-RE category 1 or 2) according to Regulation EC No 1272/2008.

A 7-day static-renewal Ceriodaphnia dubia chronic test gave a worst case result of NOEC (for reproduction) of 0.98 mg ai/l, so the substance does not meet the T criteria for a marine or freshwater organism long-term NOEC being less than 0.01 mg/l.

The 72 hr algal toxicity test, although a short-term study, can also be reviewed as providing chronic data. The NOEC was 0.074 mg/l and therefore if assessed as a chronic NOEC, the T criteria is not met.

All acute toxicity testing resulted in EC/LC50 values >0.1 mg/l, which based on the screening criteria, further indicates that T is not met for marine/freshwater organisms.

Based on available results from an in-vivo Single Cell Gel Electrophoresis (Comet Assay) conducted in the rat, the test item was considered unable to induce DNA strand breakage in liver and stomach in vivo and did not meet the criteria for classification as a germ cell mutagen. Therefore the T criteria is not met.

Based on the results of a pre-natal developmental study, the substance is not classified for toxicity for reproduction and can be considered not to meet the T criteria.

Based on the results on the OECD 422 study the substance is not classified as STOT-RE Category 1 or 2 (or R48) and therefore the substance can be considered not to meet the T criteria.

Summary

The substance does not meet the criteria for persistence (P or vP), bioaccumulation (B or vB) or Toxicity (T).