Glyphosate in marine water
Toxicant default guideline values for protecting aquatic ecosystems
October 2000
Information on the uses and environmental fate of glyphosate, and its toxicity and mechanisms of toxicity to freshwater species, has recently been updated in the glyphosate in freshwater default guideline values (previously known as ‘trigger values’). The default guideline values for glyphosate in marine water have not been updated since the ANZECC & ARMCANZ (2000) guidelines and, as such, the information presented below is extracted from Section 8.3.7 ‘Detailed descriptions of chemicals’ of the ANZECC & ARMCANZ (2000) guidelines, and relates to glyphosate in marine water only.
The default guideline values and associated information in this technical brief should be used in accordance with the detailed guidance provided in the Australian and New Zealand Guidelines for Fresh and Marine Water Quality.Description of chemical
Glyphosate (CAS 1071-836), first introduced by Monsanto, is a commonly-used, non-selective glycine herbicide which is absorbed by foliage, rapidly translocated in the plant and acts on plant enzyme systems (Tomlin 1994). Its IUPAC name is N-(phosphonomethyl) glycine, and it has a zwitterion structure. Its molecular weight is 228.2 and formula is C6H14N2NaO10P2. It is soluble in water at 12 g/L at 25°C, and it has a very low log Kow (Tomlin 1994). The current analytical practical quantitation limit (PQL) for glyphosate in water is 5 µg/L (NSW EPA 2000).
Aquatic toxicology
No marine data were available for glyphosate.
Guidelines
In the absence of marine data, the 99% freshwater figure from ANZECC & ARMCANZ (2000) (370 µg/L) could be adopted as a low reliability marine trigger value to be used only as an indicative interim working level.
References
ANZECC & ARMCANZ 2000. Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand, Canberra.
NSW EPA 2000. Analytical Chemistry Section, Table of Trigger Values 20 March 2000, LD33/11, Lidcombe, NSW.
Tomlin C 1994. The pesticide manual: A world compendium. 10th edn, British Crop Protection Council & Royal Society of Chemistry, Bath, UK.
