Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Adsorption / Desorption:

In accordance with column 2 of REACH Annex VIII, the study does not need to be conducted if based on the physicochemical properties the substance can be expected to have a low potential for adsorption (e.g. the substance has a low octanol water partition coefficient), or the substance and its relevant degradation products decompose rapidly.1,4-Dimethyl-1H-pyrazole(CAS 1072 -68 -0) has a log Kow of 0.95(@25°C, pH 6.1, Kurume, Report No. 80546, 1994), howeverthe substance is not readily biodegradable (see IUCLID-Chapter 5.2.1).


Estimates for 1,4 -Dimethyl-1H-pyrazole by the MCI method and the log-Kow method of KOCWIN v2.00 (EPISuite v4.11; BASF SE 2016) calculated

log Koc values of 1.72 (MCI) and 1.85 (log Kow). Due to the results an adsorption to solid phase is not expected. Furthermore, regarding the experimental estimated log Kow, high water solubility and poor biodegradation the product might trickles away and can be transported to deeper soil areas with larger water loads.


Henry’s Law Constant (HLC):

The Henry’s Law Constant was calculated by using the bond estimation method of HENRYWIN v3.20 (EPISuite v 4.11) to be 8.81 Pa*m³/mol. The estimation refers to the uncharged molecule. The substance is within the applicability domain of the model.

Based on the calculated data the substance is expected to slowly evaporate into the atmosphere from the water surface


Distribution Modelling:

Based on the results of the Mackay LEVEL I v3.00 calculation, over time, the substance will preferentially distribute into the compartment water (97.8%); the data refer to the uncharged molecule (pKa value: 2.77).

At environmentally relevant conditions, the substance is predominantly present in its uncharged form (pH 4: 91.5%; pH 7 & pH 9: 100% uncharged).