State Rivers and Water Supply Commission
4th of July 1960
Chief Irrigation Officer … issued Circular L.D.46 on the 29/12/59 setting out the precautions to be taken when using sprays, the types of sprays, quantity for the various species of weeds, and concluding with the statement that before using a channel after it had been sprayed, the channel was to be flushed out and the flushing water disposed of on pasture paddocks or wastelands, and not so as to reach the river systems or horticultural plantings.
The District Engineers considered this statement, put a complete stoppage to their winter spraying program because it would be almost impossible to prevent flushing water reaching a river system.
The reason for the insertion of the statement concerned has now been ascertained with certainty, but before *** left for overseas he informed me that last Summer there were some citrus growers in the Mildura region who claimed the loss of leaf from the trees was due to the Commission’s use of chemicals spray on irrigation channels in the Goulburn-Murray District.
*** stated it was most unlikely the loss of leaf was due to the chemicals, but it more likely to have been caused by the heat wave experienced last summer. *** said that the amount of chemicals in the River Murray at Mildura was so infinitesimal as to be unmeasureable, but that the only way to convince the Mildura growers that chemicals were not the cause of their trouble was to keep all chemicals out of the river until the matter had been cleared up.
The amount of 2,4-D at Mildura, under the worst possible conditions, is estimated at 1 in 500,000,000 but the actual quantity would be considerably less…
Attached herewith is a statement produced by *** giving information on the estimated amount of pollution by 2,4-D. *** estimates the dilution of 1 in 200,000,000 assuming all the 2,4-D used appeared in the River Murray.
The quantities are so small and the dilution so great, that there is no risk of any damage being caused to citrus vines, or any other sort of production irrigated from the River Murray.
*** states that crops would not be harmed by an irrigation using water containing 20 p.p.m.