Floodwaters continue to engulf the Mississippi River Delta region as the bloated river continues to overflow its banks.
In Memphis, Tenn., parts of downtown are underwater and residents fear for their health from the contaminated water.
"Filthy. I mean it is scary filthy!," resident Karen Soro said.
New tests have revealed the flood waters are full of dangerous toxins. Deadly E-coli bacteria, coliform, and fecal matter are at 2,000 times higher than acceptable levels.
Scientists say the water also contains high levels of nitrogen and phosphorous after the river and its tributaries overflowed on to farmlands.
Government officials fear the contaminated water could eventually get into the drinking water.
The flood crest is expected to push past the Delta by late next week.
Mississippi Gov. Haley Barbour urged people to get out if they think there is even a chance their homes will flood.
He said there is no reason to believe a levee on the Yazoo River would fail, but if it did, 107 feet of water would flow over small towns.
"More than anything else, save your life and don't put at risk other people who might have to come in and save your lives," he said.
Even after the flood waters crest, the water will remain high for weeks. It could take months for flooded homes to dry out.
"About 600,000 acres of cultivated row crops could flood, mainly winter wheat, corn, soybeans, cotton and rice," said Andy Prosser, spokesman with the Mississippi Department of Agriculture.
"Even if the levees hold, the state expects to lose $150 million to $200 million worth of crops," the governor said.
Mississippi's catfish farmers could also be wiped out if the Yazoo floods their ponds and washes away their fish.
Late Wednesday, President Barack Obama signed a disaster declaration for 14 counties in Mississippi because of the flooding. Low-interest loans will be available to residents cover uninsured damage.