Contaminated Splendor

There's no fishing, swimming or boating on Arizona's second largest lake, which has suddenly appeared in the desert about 80 miles southwest of Phoenix.

It's been 12 years since there was enough winter rainfall to swell the Gila River to the point that it creates the huge lake behind the Painted Rock Dam, about 18 miles northwest of Gila Bend.

But there is little to celebrate about the rare emergence of this massive body of water, second in size in the area only to Roosevelt Lake. Its water will disappear in a few short months under the scorching summer sun, leaving behind a poisonous legacy.

The Painted Rock Reservoir is closed to the public because it is one of the most toxic sinkholes of pesticide contamination in the country.

On a recent March afternoon, I traveled down to the reservoir and found a beautiful sight. The lake's shimmering blue water was surrounded by brilliant yellow, purple and orange desert wildflowers.

I walked down to the water's edge and saw a two-foot-long catfish slithering through the shallow weeds. A turtle popped its head above the surface for a split second and disappeared. A great blue heron lunged from its watery perch and ascended in a timeless arc.

But lurking beneath the surface is an ugly tale of what happens when technological advances are put into practice too soon. The reason the reservoir is so polluted is because the Gila River between Phoenix and Painted Rock Dam is laced with pesticides.

Pesticides have not only made the Gila's fish and aquatic wildlife dangerous to eat, residues from those pesticides are showing up in milk sold to the public.

How did this happen?

Forty-seven years ago, state and federal agriculture officials launched a massive attack on the pink bollworm, spraying the powerful insecticide DDT on 65,000 acres of Maricopa County cotton.

From May 15 to July 19, 1958, about 500,000 pounds of DDT were applied to farmland, mostly in the western county, which is now getting rapidly converted to suburbs.

It was just the first of a series of sweeping DDT applications that would eventually affect more than 100,000 acres in Maricopa County. The Pink Bollworm Eradication Program continued well into the 1960s.

Despite the deluge of DDT, the pest survived. And so has DDT's progeny -- long after the pesticide was banned in Arizona in 1969.

DDT's primary derivative is DDE, which also is considered by federal and international health agencies as a probable human carcinogen. While DDT has essentially disappeared from Arizona's soil, DDE persists in the ground and has spread through our food chain.

DDE routinely shows up in trace amounts in Arizona's milk supply, transferred to cows through hay grown in contaminated soil. The amount of DDE detected in milk is not considered hazardous to humans, according to the state Department of Agriculture.

But no one is monitoring the long-term effects of DDE in milk on Arizonans, particularly on nursing women and their babies. DDE has been found to sharply reduce the lactation period for nursing mothers and is known to accumulate in mother's milk that is higher in fat than cow's milk.

"We have not shared the data with state Department of Health Services, and it has not requested this because monitoring reports show DDE is well below the action level," says Kathy Decker, a Department of Agriculture spokeswoman.

While the state hasn't shown much concern over the presence of DDE in milk supplies, it advises against eating fish and aquatic wildlife taken from the Gila River.

Scientists estimate that approximately 5,000 tons of DDT have been transported from farmland to the Gila west of Phoenix. This winter's heavy rains are expected to transfer more pesticide residue from farms into the river.

"It's in the sediment and surface soil, and that drainage goes right down to the Gila River basin," says Will Humble, chief of environmental health for the state Department of Health Services. "It's probably the most contaminated waterway in Arizona."

DDT's impact on the wildlife in the river has been profound.

By the 1970s, the Gila was the most DDT-contaminated stream in the western United States. In the 1980s, federal wildlife officials found that DDE residues in birds collected in the Goodyear-Avondale area were among the highest in the nation.

By the early 1990s, state environmental and health officials posted warning signs not to eat aquatic wildlife taken from the Gila River between 59th Avenue in west Phoenix and Painted Rock Dam.

DDT and DDE are not the only dangerous pesticides found in the Gila downstream from Phoenix. After DDT was banned in 1969, farmers began using another type of organochlorine pesticide called toxaphene.

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John Dougherty
Contact: John Dougherty