KETTLEMAN CITY -- Maria Saucedo cried as she spoke of the two babies she has lost in Kettleman City -- one to birth defects and the other in a miscarriage.

There's no proof, but she blames the toxic landscape surrounding her town. She and others who have suffered in Kettleman City say they live in a nasty soup of pollution. They make a compelling case.

Just west is the largest hazardous waste landfill this side of the Mississippi River. Electricity buzzes overhead along tall towers supplying power up and down the state. Pesticide is sprayed in nearby orchards. Diesel smoke wafts from Interstate 5 and Highway 41.

"It's a nightmare," Saucedo told state health authorities last year.

RELATED: Read other stories in Mark Grossi's Toxic Land series

The latest: Treated human sewage from more than 5 million people in Los Angeles County is supposed to be composted on farmland east of town. The first deliveries could start as soon as late summer.

"When somebody flushes a toilet in Los Angeles County, it will end up in Kings County," says Jonathan London of the University of California at Davis, which published a study in late 2011 about health risks in the San Joaquin Valley.

Indeed, the Valley may lead the world in farming, but tiny Kettleman City reaps a harvest of California castoffs. The town is the most obvious example of the Valley's habit of hosting businesses that nobody wants for a neighbor, but there are others.

You also will find America's biggest ammonia-choked dairies in Tulare County, nearly 1 million animals.

Fleets of diesel trucks at distribution centers have moved in along Highway 99, up and down the Valley. Kern County has become a prime destination for tons of treated human sewage from Los Angeles County.

Tainted groundwater supplies the homes in many rural towns. And the Valley's notorious air quality triggers more asthma and other lung problems for small town residents than folks in larger cities.

Scientists can't prove what Maria Saucedo says, but they have enough evidence now to suggest people living closest to these industries and pollution die younger because of it.

Researchers say polluting businesses often locate near communities of color where public outcry is muted, if there is any outcry at all.

Nearly one-third of the Valley's 4 million residents live with increased risk because of surrounding environmental threats, says London and several other researchers. Their analysis of the Valley is called "Land of Risk, Land of Opportunity."

The people living in Kettleman City are surrounded by the pollution described in the study. Now some townfolk worry about L.A.'s sewage, which is treated to kill off bacteria and dried out so that only a chunky sludge remains.

Such sludge already is trucked over the Grapevine, mostly into Kern from Long Beach, Beverly Hills and other cities. Kern has fought it for the last decade.

A Kings County farm not far from Kettleman City is in line as the next biggest destination for sludge, especially if Kern successfully fights off Southern California legal challenges to its ban. The ban was passed years ago by voters, but it has been held up in court.

If Kern's ban is upheld, 17 cities in Los Angeles County would still have the option of annually sending up to 500,000 tons of sludge to be composted at a farm not far from Kettleman City.

Residents call it "agua negra" or black water.

The yuck factor

Forget the hazardous waste landfills near Kettleman City and Shafter in Kern County and the manure mountains from 1.5 million dairy cows in the Valley. You might not want to live near those businesses, but treated human sewage might have a bigger yuck factor.