sentences:  Mercury and PCB releases were also observed in a surface water and sediment sample taken from a portion of the landfill located within the Great Swamp Wildlife Refuge, according to the EPA.Testing also showed "actual contamination of a terrestrial sensitive environment," and indicated potential exposure of nearby residents, the EPA says.RPublic Health Assessment for Rolling Knolls Landfill July 5, 2006lling Knolls Landfill