Glyphosate persistence in seawater.
Glyphosate is one of the most widely applied herbicides globally but its persistence in seawater has not been reported. Here we quantify the biodegradation of glyphosate using standard "simulation" flask tests with native bacterial populations and coastal seawater from the Great Barrier Reef. The half-life for glyphosate at 25 °C in low-light was 47 days, extending to 267 days in the dark at 25 °C and 315 days in the dark at 31 °C, which is the longest persistence reported for this herbicide. AMPA, the microbial transformation product of glyphosate, was detected under all conditions, confirming that degradation was mediated by the native microbial community. This study demonstrates glyphosate is moderately persistent in the marine water under low light conditions and is highly persistent in the dark. Little degradation would be expected during flood plumes in the tropics, which could potentially deliver dissolved and sediment-bound glyphosate far from shore.
The University of Queensland, National Research Centre for Environmental Toxicology, 39 Kessels Road, Coopers Plains, Brisbane, QLD 4108, Australia; Australian Institute of Marine Science, PMB No. 3, Townsville, QLD 4810, Australia. Electronic address: p.mercurio@aims.gov.au.
Philip
P
Mercurio
Australian Institute of Marine Science, PMB No. 3, Townsville, QLD 4810, Australia.
Florita
F
Flores
The University of Queensland, National Research Centre for Environmental Toxicology, 39 Kessels Road, Coopers Plains, Brisbane, QLD 4108, Australia.
Jochen F
JF
Mueller
Forensic and Scientific Services, Health Services Support Agency, QLD Department of Health, PO Box 594, Archerfield, QLD 4108, Australia.
Steve
S
Carter
Australian Institute of Marine Science, PMB No. 3, Townsville, QLD 4810, Australia.
Andrew P
AP
Negri
D001673:Biodegradation, Environmental; D004784:Environmental Monitoring; D005998:Glycine / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry; D006207:Half-Life; D006540:Herbicides / Q000032:analysis* / Q000737:chemistry; D012623:Seawater / Q000737:chemistry* / Q000382:microbiology; D000097797:Glyphosate
D005998:Glycine; D006540:Herbicides; D000097797:Glyphosate
Degradation; Glyphosate; Microbial; Persistence; Seawater; Tropical