PemMex is Mexico's only oil and gas company. Large farm owners in south Texas, who are losing out to cheaper production south of the border, are listening to sales overtures. And Blankenship is interested in that land to extend a wildlife corridor along the Rio Grande. The south Texas native is supervisory biologist at the refuge. But the pristine refuge stands in stark contrast to much of the valley.
Raw sewage flows into the river from streams in Mexico.
Pesticide-laced ground water seeps into it, and high levels of manufacturing plant discharges are growing concerns. With the proliferation of factories outpacing the development of infrastructure that can handle toxic byproducts, millions of dollars will need to be spent to protect water, air, wildlife and people on both sides of the border. Three of the fastest-growing metropolitan areas in the United States are along the border with Mexico, home to more than 10 million people. Leading the list is wastewater treatment. Juarez, Mexico, for example, with a population of more than 1.2 million, has never had a public sewer treatment plant and produces 75 million gallons of raw sewage each day.