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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Ecotoxicological information

Toxicity to microorganisms

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Administrative data

Link to relevant study record(s)

Description of key information

The NOEC of 20 mg carbon/L (i.e., 26.25 mg 3-methylpyridine/L, or 0.282 mmol/L) from the guideline ready biodegradability assay by Weytjens and Wils (1991) was the key value for the short-term toxicity to micro-organisms in sewage treatment plants for the chemical category (pyridine, 2-methylpyridine, 3-methylpyridine and 4-methylpyridine).  

Key value for chemical safety assessment

EC50 for microorganisms:
20 mg/L

Additional information

The point of departure for the derivation of the PNECSTPwas the NOEC from the ready biodegradability CO2 evolution assay (OECD Guideline 301B) of 20 mg C/L (i.e., 26.25 mg 3 -methylpyridine/L, or 0.282 mmol/L), for the chemical category including pyridine, 2-methylpyridine, 3-methylpyridine and 4-methylpyridine. 

2-Methylpyridine (alpha-picoline, CAS 109-06-8) is a member of a category with is utilized for “read-across” to fill data gaps and for risk assessment for hazard identification. The category of pyridine and alkyl pyridine derivatives is comprised of pyridine (CAS 110 -86 -1), 2-methylpyridine (CAS 109-06-8), 3-methylpyridine (CAS 108-99-6) and 4-methylpyridine (CAS 108-89-4). The foundation of the category is a common functional group (the pyridine unsaturated ring structure) and similar physico-chemical properties, environmental fate and toxicity, and mammalian toxicity. Similar ecotoxicological and environmental fate properties derive from physico-chemical parameters and common pathways of metabolism and elimination among all members of the category. Three of four members of this category have harmonized classification and labelling. Read-across for non-harmonized endpoints is adequate for risk assessment purposes.