It is hoping a State Government investigation will uncover the source of the chemicals, with timber giant Gunns Ltd, Forestry Tasmania and neighbouring properties all denying any part in the contamination.
Western Creek resident and Upper Meander Catchment Landcare Group leader Kevin Knowles said as part of Gunns’ good neighbour charter it had agreed not to use either simazine or atrazine on the plantation.
He said terbacil, which was also found at low levels in the creek, was used by Gunns when the plantation was being established.
Resident Debbie Lynch said she was not concerned with who was using the chemicals, only that it was stopped.
Mr Knowles said most of the properties along Western Creek drew water directly from the creek, with one house having an inlet just 10m from where the contaminated Tusons Creek entered Western Creek.
He said the State Government needed to investigate the source of the contamination and ban such chemicals outright.
Testing showed the water contained 0.61 micrograms a litre of simazine — above the specified guidelines of 0.5 micrograms, triggering an investigation.
The Primary Industries, Water and Environment Department yesterday confirmed it would investigate the matter and would conduct more testing.
Gunns brand manager Sarah Dent said Gunns had not used atrazine or simazine at the plantation.
Last week the small township clashed with Gunns over 1080 baiting at another plantation, with a 28-signature petition eventually convincing the $1 billion company to cease its baiting plans.