scientist on boat filtering water sample


Herbicides, insecticides and fungicides can enter our marine ecosystems from run-off

More than 50 land pesticides (herbicides, insecticides and fungicides) have been detected in waters of the Great Barrier Reef and its catchments.

Our research

AIMS’ work helps determine the risk pesticides pose to tropical organisms and marine ecosystems. Our ecotoxicologists use laboratory studies to establish the concentration levels that can cause ‘ecologically relevant’ effects. This information contributes to water quality guideline values and informs ecological risk assessments.

Our ecotoxicologists also investigate how external factors such as increasing sea surface temperatures may affect pesticide toxicity, stability and persistence in tropical marine waters.

Condition / status

Farm run-off continues to reach the reef, with evidence of widespread contemporary agricultural pesticides in coastal waters. Like sediment and nutrients, higher concentrations of pesticides are detected close to shore, with lower concentrations further from the coast.


Concentrations of individual pesticides detected in coastal waters of the Great Barrier Reef are generally below water quality guideline values.

Current evidence suggests that:

  • pesticide levels detected in coastal waters of the Great Barrier Reef have a low (between 1 and 5% affected of species affected) to negligible risk to the ecosystem, with possible low-level exposure in wet seasons only
  • in the mid-shelf and outer-shelf regions, the risk is considered very low (less than 1% of species affected) to negligible, with possible low-level exposure during large wet season events only


Pesticide impacts are managed by reducing end-of-catchment pesticide loads and assessing concentrations against relevant water quality guidelines.