Hi all…Health Canada has been busy. In addition to the new aluminum MAC and request for comments on “Guidance on Waterborne Pathogens” which were due on Feb. 5, they have released another Guideline Technical Document for Public Consultation, this time it is 4-Chloro-2-methylphenoxyacetic Acid (MCPA). Comments are due by May 12, 2021. The proposed MAC has been increased from 0.1 mg/L established in 2010 to 0.4 mg/L (see below and link for rationale). MCPA is a phenoxyacetic acid herbicide, registered in Canada for use on agricultural sites, fine turf and lawns, in forestry, and at industrial sites.
4-Chloro-2-methylphenoxyacetic Acid (MCPA) in Drinking Water: Guideline Technical Document for Public Consultation
“This guideline technical document outlines the evaluation of the available information on 4-chloro-2-methylphenoxyacetic acid (MCPA) with the intent of updating the guidelines for MCPA in drinking water. The purpose of this consultation is to solicit comments on the proposed guidelines, on the approach used for its development, and on the potential impacts of implementing it. The existing guideline technical document on MCPA, developed in 2010, established a maximum acceptable concentration (MAC) of 0.1 mg/L (100 µg/L) based on kidney effects observed in the rat. The present document proposes a MAC of 0.4 mg/L (400 µg/L) for MCPA in drinking water, based on the same key study used to develop the current MAC, which reports kidney effects observed in rats. The Pest Management Regulatory Agency removed the uncertainty factor for database deficiencies in its most recent evaluation of MCPA, and this contributed to a higher proposed MAC.”