Blackhearts: Ecology in Outback Australia by Richard Symanski
P 91/92 Snooping about in the farming lands around Kununurra, I learn that in the 1960s this frontier land of once infinite promise was an insecticide hell (Drewe 1990; Pratchett 1990). Farmers were spraying up to fifty times a season. They were drowning rather than poisoning the Heliothis armigera, a ravenous little creature that loved the cotton they were growing. To rid themselves of Heliothis, which proved easy in theory and virtually impossible in practice, the farmers killed everything – snakes, goannas, birds, insects. In their hell-bent eagerness to find economic success in yet another tropical insect heaven, they were, it would seem, even willing to risk killing themselves and their families.
Because of spray drift, the frequent aerial application of DDT led to contamination of nearby irrigated pastures. The residues then showed up in renal fat of cattle grazing this land. There was so much spraying that cattle were found to contain up to two hundred parts per million of DDT. The permissible level for cattle coming into the United States was then seven parts per million. The DDT was still detectable in the fat of cattle grazed on these pastures fifteen years after spraying ceased. The levels of DDT in cattle around Kununurra didn’t get down to acceptable levels until 1979.