Mackay, Whitsunday rivers top list for herbicide pollution

The chemicals are entering the Great Barrier Reef but experts say findings are only the ‘tip of the iceberg’

The results come from samples taken from 11 sites covering the Wet Tropics at Cairns down to the Fitzroy region near Yeppoon, which tested for 26 herbicides and pesticides commonly used in agriculture.

New data shows Mackay Whitsunday region rivers have the worst herbicide pollution throughout northern and central Queensland.

The results come from samples taken from 11 sites covering the Wet Tropics at Cairns down to the Fitzroy region near Yeppoon, which tested for 26 herbicides and pesticides commonly used in agriculture.

Repulse Bay, between Conway Beach and Midge Point, ranked in the highest percentiles for nine types of herbicides while Flat Top Island, not far off East Mackay, was in the highest percentiles for seven varieties - both topping the list for diuron.

"In line with previous monitoring years, diuron, atrazine and hexazinone were the most frequently detected and abundant of the pesticides at most sites, reflecting their high usage in sugar cane cultivation, which is located along much of the Great Barrier Reef coastline," the report by the Great Barrier Reef Marine Park Authority stated.

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But a Griffith University and WWF study said the water quality check, which tracked about 30 pollutants across 11 out of the 35 catchments flowing into the Great Barrier Reef, fell short on detecting the full spectrum of chemicals.

"Criteria are too narrow and do not include many commonly used chemicals, such as antifouling paint, plasticisers, flame retardants, hydrocarbons (from fuels), UV filters in sunscreens, pharmaceuticals and personal care products," the study said.

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"The more chemicals we look for in GBR habitats, the more we find - indicating that routine water quality monitoring programs are only detecting "the tip of the iceberg" in terms of chemical pollution on the reef.

"With more than 150,000 chemicals in production and use in Australia and over 40,000 chemicals globally identified as contaminants of emerging concern, much more research is needed."

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