There is no evidence the release of stormwater from Abbot Point coal terminal caused widespread contamination of the nearby Caley Valley Wetlands, Queensland's Environment Department has said.
Adani's coal terminal was granted a temporary licence to help it manage water on the site during Tropical Cyclone Debbie in March.
The company was fined by the department after advising it had released water with sediment levels eight times higher than was permitted.
Satellite imagery appeared to show contamination to the wetlands, located near Mackay, prompting the Environment Department to commission an investigation.
It found a coal concentration of 10 per cent in sediment where water was discharged from the facility, reducing to "minor" concentrations of 1 to 2 per cent further away from that point.
The report found no evidence of widespread contamination and little visual evidence of fine coal particles across the wetlands.
"The appearance of water bodies in remotely sensed imagery can be affected by several factors, including the depth and clarity of the water, the angle of the sun and the sensor when the image is captured," the department said in a statement.
The department said it would conduct additional monitoring and had issued a notice to the Abbot Point terminal to prepare an environmental evaluation.
Queensland Conservation Council's Tim Seelig said it was far too early to say there was no evidence of contamination given the substances in question.
"We do know that sediment in sections of the wetlands contains 10 per cent coal pollutant," he said.
"That is vastly more than we would expect to occur naturally … Adani should be held responsible and fined."
