Septic systems, but not sanitary sewer lines, are associated with elevated estradiol in male frog metamorphs from suburban ponds

Highlights • We measured estradiol in metamorphosing froglets from forested and suburban ponds. • Suburban ponds were serviced either by septic systems or sanitary sewers. • Estradiol was elevated in male froglets from ponds in septic, but not sewered, neighborhoods. • This is evidence that endocrine disruption differs among septic and sewer neighborhoods.