At least five towns in Suffolk County have received subpoenas as prosecutors dig deeper into allegations of illegal sand-mining operations, News 12 has learned.

Brookhaven, Islip, Riverhead, Huntington and Babylon have received subpoenas as the Suffolk County District Attorney's Office seeks records on sand mining. Environmentalists say there is concern that contaminated construction waste may have been buried close to the aquifers that supply Long Island's drinking water.

"Anything dumped in that sand mine that's toxic or hazardous leeches right into the water that we drink," says Adrienne Esposito, of Citizens Campaign for the Environment.

Among the sites under investigation is a property on Furrows Road in Holtsville, as well as BlueGreen Farms of Yaphank, a hydroponic farm operation that has been excavating sand, according to Newsday.

The subpoenas are the latest development in an expanding controversy over alleged illegal dumping in Suffolk. Six men and four companies were indicted in December over alleged dumping at a Brentwood park and several other locations.

Environmental advocates like Esposito are calling for a crackdown. "We need the towns and the state regulators to work together for rigorous enforcement of existing laws, and also update those existing laws so that these activities can no longer continue," she says.

News 12 reached out to the Brookhaven town officials for comment on the issue. Town Supervisor Ed Romaine says the town supports the investigation and hopes that it helps the environment.