John H. Paul^a, , Joan B. Rose^*a, Sunny C. Jiang^a, Xingting Zhou^a, Pamela Cochran^a, Christina Kellogg^a, Jordan B. Kang^a, Dale Griffin^a, Samual Farrah^*b and Jerzy Lukasik^b

^a University of South Florida, St Petersburg, FL 33701, U.S.A.

^b University of Florida, Gainesville, FL, U.S.A.

 Water Research Volume 31, Issue 6, June 1997, Pages 1448-1454 

ABSTRACT

Injection wells (Class V disposal wells) are a major method for domestic wastewater disposal in coastal environments around Florida, and particularly the Florida keys, where there are nearly 700 in operation.

A recent report published in the June issue of Water Research by researchers at the University of South Florida indicates that wastewater disposed by these practices can rapidly contaminate groundwater and surface marine waters.

These investigators, led by Drs. John H. Paul and Joan B. Rose, used harmless bacterial viruses as a tracer for the movement of wastewater from a recently permitted class V disposal well in the Middle Keys.

This well meets current DEP requirements, which means that the well was drilled to 90 feet and cased with PCV pipe to 60 feet. Within 8 hours of addition of the tracer, it was detected in the groundwater, and within 36 hours it was detected in Florida Bay.

By 53 hours, the tracer appeared in a canal on the other side of US1, on its way to Hawk Channel and the Atlantic Ocean.

A second experiment performed last fall indicated that the tracer could move from the waste disposal well to the same canal in less than 8 hours, if strong North winds associated with a cold front occurred at the same time.

The meaning of these results is that wastewater from injection wells can rapidly make its way to the subsurface. This could cause potentially serious health problems for bathers in canals and coastal waters around the Florida Keys.

Disease causing microorganisms could be transmitted from wastewater to these waters where they could potentially infect bathers, windsurfers, jetski operators and other participants in recreational water-contact activities.

A second reason for concern is the transport of nutrients (inorganic and organic) into marine waters. These act like fertilizers which cause algal growth and water quality deterioration.