Mosaic plant sinkhole dumps 215 million gallons of reprocessed water into Floridan Aquifer

A massive sinkhole that opened underneath a gypsum stack at a Mosaic phosphate fertilizer plant in Mulberry may have dumped at least 215 million gallons of contaminated water into the Floridan Aquifer over the past three weeks, company officials say.

And it could be months before the hole is plugged, the officials acknowledge.

The 45-foot-wide sinkhole opened at the New Wales plant, where phosphate rock mined elsewhere is converted into fertilizer.

It drained millions of gallons of acidic water laced with sulfate and sodium from a pool atop a 120-foot gypsum stack. An unknown amount of gypsum, a fertilizer byproduct with low levels of radiation, also fell into the sinkhole, which is believed be at least 300 feet deep.

The pond is now drained, but aerial video taken Friday shows polluted water is still seeping from the gypsum stack and plunging like a waterfall into the sinkhole. More contaminated water will leak with every new rainfall until the sinkhole is filled. The acidic level of the water is roughly equivalent to vinegar or lemon juice.

Mosaic workers became aware of the leak when water levels in the pond dropped 2 feet between readings on Aug. 27. They began diverting water from the pond, which can hold up to about 250 million gallons.

Wells were used to monitor groundwater around the sinkhole. No off-site contamination has been detected, Mosaic officials said.