Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Diquat

Diquat (C12H12N2) is a bipyridyl herbicide generally marketed as a dibromide salt or a dichloride monohydrate. It is used as a pre-harvest desiccant for various seed crops, for potato haulm destruction and for the control of aquatic weeds. Less than 100 000 kg are used annually in Canada; 96% of this amount is applied as a harvest aid. The maximum acceptable concentration (MAC) for diquat (measured as the cation) in drinking water is 0.07 mg/L (70 µg/L).