title: Assessing the additive risks of PSII herbicide exposure to the Great Barrier Reef.
abstract: Herbicide residues have been measured in the Great Barrier Reef lagoon at concentrations which have the potential to harm marine plant communities. Monitoring on the Great Barrier Reef lagoon following wet season discharge show that 80% of the time when herbicides are detected, more than one are present. These herbicides have been shown to act in an additive manner with regards to photosystem-II inhibition. In this study, the area of the Great Barrier Reef considered to be at risk from herbicides is compared when exposures are considered for each herbicide individually and also for herbicide mixtures. Two normalisation indices for herbicide mixtures were calculated based on current guidelines and PSII inhibition thresholds. The results show that the area of risk for most regions is greatly increased under the proposed additive PSII inhibition threshold and that the resilience of this important ecosystem could be reduced by exposure to these herbicides.
authors.affiliation: Catchment to Reef Research Group, Australian Centre for Tropical Freshwater Research, James Cook University, Townsville, Qld 4811, Australia. stephen.lewis@jcu.edu.au
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Lewis
authors.forename: Britta
authors.initials: B
authors.lastname: Schaffelke
authors.forename: Melanie
authors.initials: M
authors.lastname: Shaw
authors.forename: Zoë T
authors.initials: ZT
authors.lastname: Bainbridge
authors.forename: Ken W
authors.initials: KW
authors.lastname: Rohde
authors.forename: Karen
authors.initials: K
authors.lastname: Kennedy
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Davis
authors.forename: Bronwyn L
authors.initials: BL
authors.lastname: Masters
authors.forename: Michelle J
authors.initials: MJ
authors.lastname: Devlin
authors.forename: Jochen F
authors.initials: JF
authors.lastname: Mueller
authors.forename: Jon E
authors.initials: JE
authors.lastname: Brodie
mesh_terms: D001315:Australia; D057894:Coral Reefs; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D006540:Herbicides / Q000032:analysis* / Q000633:toxicity; D045332:Photosystem II Protein Complex / Q000187:drug effects; D018570:Risk Assessment; D012621:Seasons; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data
chemical_list: D006540:Herbicides; D045332:Photosystem II Protein Complex; D014874:Water Pollutants, Chemical